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Message-ID: <alpine.DEB.2.21.1802041609440.1035@nanos.tec.linutronix.de>
Date: Sun, 4 Feb 2018 16:31:12 +0100 (CET)
From: Thomas Gleixner <tglx@...utronix.de>
To: Linus Torvalds <torvalds@...ux-foundation.org>
cc: LKML <linux-kernel@...r.kernel.org>,
Ingo Molnar <mingo@...nel.org>,
David Woodhouse <dwmw@...zon.co.uk>,
Greg KH <gregkh@...uxfoundation.org>
Subject: [GIT pull] More melted spectrum mitigations for 4.16
Linus,
please pull the latest x86-pti-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-pti-for-linus
The next round of updates related to melted spectrum:
- The initial set of spectre V1 mitigations:
- Array index speculation blocker and its usage for syscall, fdtable
and the n180211 driver.
- Speculation barrier and its usage in user access functions
- Make indirect calls in KVM speculation safe
- Blacklisting of known to be broken microcodes so IPBP/IBSR are not
touched.
- The initial IBPB support and its usage in context switch
- The exposure of the new speculation MSRs to KVM guests.
- A fix for a regression in x86/32 related to the cpu entry area
- Proper whitelisting for known to be safe CPUs from the mitigations.
- objtool fixes to deal proper with retpolines and alternatives
- Exclude __init functions from retpolines which speeds up the boot
process.
- Removal of the syscall64 fast path and related cleanups and
simplifications
- Removal of the unpatched paravirt mode which is yet another source of
indirect unproteced calls.
- A new and undisputed version of the module mismatch warning
- A couple of cleanup and correctness fixes all over the place
Yet another step towards full mitigation. There are a few things still
missing like the RBS underflow mitigation for Skylake and other small
details, but that's being worked on.
That said, I'm taking a belated christmas vacation for a week and hope that
everything is magically solved when I'm back on Feb. 12th.
Thanks,
tglx
------------------>
Andi Kleen (1):
module/retpoline: Warn about missing retpoline in module
Andy Lutomirski (3):
x86/entry/64: Remove the SYSCALL64 fast path
x86/entry/64: Push extra regs right away
x86/asm: Move 'status' from thread_struct to thread_info
Arnd Bergmann (1):
x86/pti: Mark constant arrays as __initconst
Ashok Raj (1):
KVM/x86: Add IBPB support
Borislav Petkov (5):
x86/alternative: Print unadorned pointers
x86/nospec: Fix header guards names
x86/bugs: Drop one "mitigation" from dmesg
x86/retpoline: Simplify vmexit_fill_RSB()
x86/speculation: Simplify indirect_branch_prediction_barrier()
Colin Ian King (1):
x86/spectre: Fix spelling mistake: "vunerable"-> "vulnerable"
Dan Williams (12):
array_index_nospec: Sanitize speculative array de-references
x86: Implement array_index_mask_nospec
x86: Introduce barrier_nospec
x86: Introduce __uaccess_begin_nospec() and uaccess_try_nospec
x86/usercopy: Replace open coded stac/clac with __uaccess_{begin, end}
x86/uaccess: Use __uaccess_begin_nospec() and uaccess_try_nospec
x86/get_user: Use pointer masking to limit speculation
x86/syscall: Sanitize syscall table de-references under speculation
vfs, fdtable: Prevent bounds-check bypass via speculative execution
nl80211: Sanitize array index in parse_txq_params
x86/spectre: Report get_user mitigation for spectre_v1
x86/kvm: Update spectre-v1 mitigation
Darren Kenny (1):
x86/speculation: Fix typo IBRS_ATT, which should be IBRS_ALL
David Woodhouse (10):
x86/cpufeatures: Add CPUID_7_EDX CPUID leaf
x86/cpufeatures: Add Intel feature bits for Speculation Control
x86/cpufeatures: Add AMD feature bits for Speculation Control
x86/msr: Add definitions for new speculation control MSRs
x86/pti: Do not enable PTI on CPUs which are not vulnerable to Meltdown
x86/cpufeature: Blacklist SPEC_CTRL/PRED_CMD on early Spectre v2 microcodes
x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support
x86/cpufeatures: Clean up Spectre v2 related CPUID flags
x86/cpuid: Fix up "virtual" IBRS/IBPB/STIBP feature bits on Intel
x86/retpoline: Avoid retpolines for built-in __init functions
Dou Liyang (1):
x86/spectre: Check CONFIG_RETPOLINE in command line parser
Jim Mattson (1):
KVM: nVMX: Eliminate vmcs02 pool
Josh Poimboeuf (4):
objtool: Improve retpoline alternative handling
objtool: Add support for alternatives at the end of a section
objtool: Warn on stripped section symbol
x86/paravirt: Remove 'noreplace-paravirt' cmdline option
KarimAllah Ahmed (5):
x86/spectre: Simplify spectre_v2 command line parsing
KVM/x86: Update the reverse_cpuid list to include CPUID_7_EDX
KVM/VMX: Emulate MSR_IA32_ARCH_CAPABILITIES
KVM/VMX: Allow direct access to MSR_IA32_SPEC_CTRL
KVM/SVM: Allow direct access to MSR_IA32_SPEC_CTRL
Mark Rutland (1):
Documentation: Document array_index_nospec
Paolo Bonzini (2):
KVM: VMX: introduce alloc_loaded_vmcs
KVM: VMX: make MSR bitmaps per-VCPU
Peter Zijlstra (2):
KVM: x86: Make indirect calls in emulator speculation safe
KVM: VMX: Make indirect call speculation safe
Thomas Gleixner (1):
x86/cpu/bugs: Make retpoline module warning conditional
Tim Chen (1):
x86/speculation: Use Indirect Branch Prediction Barrier in context switch
William Grant (1):
x86/mm: Fix overlap of i386 CPU_ENTRY_AREA with FIX_BTMAP
Documentation/admin-guide/kernel-parameters.txt | 2 -
Documentation/speculation.txt | 90 ++++
arch/x86/entry/common.c | 9 +-
arch/x86/entry/entry_32.S | 3 +-
arch/x86/entry/entry_64.S | 130 +----
arch/x86/entry/syscall_64.c | 7 +-
arch/x86/include/asm/asm-prototypes.h | 3 +
arch/x86/include/asm/barrier.h | 28 +
arch/x86/include/asm/cpufeature.h | 7 +-
arch/x86/include/asm/cpufeatures.h | 22 +-
arch/x86/include/asm/disabled-features.h | 3 +-
arch/x86/include/asm/fixmap.h | 6 +-
arch/x86/include/asm/msr-index.h | 12 +
arch/x86/include/asm/msr.h | 3 +-
arch/x86/include/asm/nospec-branch.h | 86 +--
arch/x86/include/asm/pgtable_32_types.h | 5 +-
arch/x86/include/asm/processor.h | 5 +-
arch/x86/include/asm/required-features.h | 3 +-
arch/x86/include/asm/syscall.h | 6 +-
arch/x86/include/asm/thread_info.h | 3 +-
arch/x86/include/asm/tlbflush.h | 2 +
arch/x86/include/asm/uaccess.h | 15 +-
arch/x86/include/asm/uaccess_32.h | 6 +-
arch/x86/include/asm/uaccess_64.h | 12 +-
arch/x86/kernel/alternative.c | 28 +-
arch/x86/kernel/cpu/bugs.c | 134 +++--
arch/x86/kernel/cpu/common.c | 70 ++-
arch/x86/kernel/cpu/intel.c | 66 +++
arch/x86/kernel/cpu/scattered.c | 2 -
arch/x86/kernel/process_64.c | 4 +-
arch/x86/kernel/ptrace.c | 2 +-
arch/x86/kernel/signal.c | 2 +-
arch/x86/kvm/cpuid.c | 22 +-
arch/x86/kvm/cpuid.h | 1 +
arch/x86/kvm/emulate.c | 9 +-
arch/x86/kvm/svm.c | 116 +++++
arch/x86/kvm/vmx.c | 660 ++++++++++++++----------
arch/x86/kvm/x86.c | 1 +
arch/x86/lib/Makefile | 1 +
arch/x86/lib/getuser.S | 10 +
arch/x86/lib/retpoline.S | 56 ++
arch/x86/lib/usercopy_32.c | 8 +-
arch/x86/mm/tlb.c | 33 +-
include/linux/fdtable.h | 5 +-
include/linux/init.h | 9 +-
include/linux/module.h | 9 +
include/linux/nospec.h | 72 +++
kernel/module.c | 11 +
net/wireless/nl80211.c | 9 +-
scripts/mod/modpost.c | 9 +
tools/objtool/check.c | 89 ++--
tools/objtool/orc_gen.c | 5 +
52 files changed, 1279 insertions(+), 632 deletions(-)
create mode 100644 Documentation/speculation.txt
create mode 100644 include/linux/nospec.h
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 46b26bfee27b..1e762c210f1b 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2742,8 +2742,6 @@
norandmaps Don't use address space randomization. Equivalent to
echo 0 > /proc/sys/kernel/randomize_va_space
- noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops
-
noreplace-smp [X86-32,SMP] Don't replace SMP instructions
with UP alternatives
diff --git a/Documentation/speculation.txt b/Documentation/speculation.txt
new file mode 100644
index 000000000000..e9e6cbae2841
--- /dev/null
+++ b/Documentation/speculation.txt
@@ -0,0 +1,90 @@
+This document explains potential effects of speculation, and how undesirable
+effects can be mitigated portably using common APIs.
+
+===========
+Speculation
+===========
+
+To improve performance and minimize average latencies, many contemporary CPUs
+employ speculative execution techniques such as branch prediction, performing
+work which may be discarded at a later stage.
+
+Typically speculative execution cannot be observed from architectural state,
+such as the contents of registers. However, in some cases it is possible to
+observe its impact on microarchitectural state, such as the presence or
+absence of data in caches. Such state may form side-channels which can be
+observed to extract secret information.
+
+For example, in the presence of branch prediction, it is possible for bounds
+checks to be ignored by code which is speculatively executed. Consider the
+following code:
+
+ int load_array(int *array, unsigned int index)
+ {
+ if (index >= MAX_ARRAY_ELEMS)
+ return 0;
+ else
+ return array[index];
+ }
+
+Which, on arm64, may be compiled to an assembly sequence such as:
+
+ CMP <index>, #MAX_ARRAY_ELEMS
+ B.LT less
+ MOV <returnval>, #0
+ RET
+ less:
+ LDR <returnval>, [<array>, <index>]
+ RET
+
+It is possible that a CPU mis-predicts the conditional branch, and
+speculatively loads array[index], even if index >= MAX_ARRAY_ELEMS. This
+value will subsequently be discarded, but the speculated load may affect
+microarchitectural state which can be subsequently measured.
+
+More complex sequences involving multiple dependent memory accesses may
+result in sensitive information being leaked. Consider the following
+code, building on the prior example:
+
+ int load_dependent_arrays(int *arr1, int *arr2, int index)
+ {
+ int val1, val2,
+
+ val1 = load_array(arr1, index);
+ val2 = load_array(arr2, val1);
+
+ return val2;
+ }
+
+Under speculation, the first call to load_array() may return the value
+of an out-of-bounds address, while the second call will influence
+microarchitectural state dependent on this value. This may provide an
+arbitrary read primitive.
+
+====================================
+Mitigating speculation side-channels
+====================================
+
+The kernel provides a generic API to ensure that bounds checks are
+respected even under speculation. Architectures which are affected by
+speculation-based side-channels are expected to implement these
+primitives.
+
+The array_index_nospec() helper in <linux/nospec.h> can be used to
+prevent information from being leaked via side-channels.
+
+A call to array_index_nospec(index, size) returns a sanitized index
+value that is bounded to [0, size) even under cpu speculation
+conditions.
+
+This can be used to protect the earlier load_array() example:
+
+ int load_array(int *array, unsigned int index)
+ {
+ if (index >= MAX_ARRAY_ELEMS)
+ return 0;
+ else {
+ index = array_index_nospec(index, MAX_ARRAY_ELEMS);
+ return array[index];
+ }
+ }
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index d7d3cc24baf4..21dbdf0e476b 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -21,6 +21,7 @@
#include <linux/export.h>
#include <linux/context_tracking.h>
#include <linux/user-return-notifier.h>
+#include <linux/nospec.h>
#include <linux/uprobes.h>
#include <linux/livepatch.h>
#include <linux/syscalls.h>
@@ -206,7 +207,7 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
* special case only applies after poking regs and before the
* very next return to user mode.
*/
- current->thread.status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
+ ti->status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
#endif
user_enter_irqoff();
@@ -282,7 +283,8 @@ __visible void do_syscall_64(struct pt_regs *regs)
* regs->orig_ax, which changes the behavior of some syscalls.
*/
if (likely((nr & __SYSCALL_MASK) < NR_syscalls)) {
- regs->ax = sys_call_table[nr & __SYSCALL_MASK](
+ nr = array_index_nospec(nr & __SYSCALL_MASK, NR_syscalls);
+ regs->ax = sys_call_table[nr](
regs->di, regs->si, regs->dx,
regs->r10, regs->r8, regs->r9);
}
@@ -304,7 +306,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
unsigned int nr = (unsigned int)regs->orig_ax;
#ifdef CONFIG_IA32_EMULATION
- current->thread.status |= TS_COMPAT;
+ ti->status |= TS_COMPAT;
#endif
if (READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY) {
@@ -318,6 +320,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
}
if (likely(nr < IA32_NR_syscalls)) {
+ nr = array_index_nospec(nr, IA32_NR_syscalls);
/*
* It's possible that a 32-bit syscall implementation
* takes a 64-bit parameter but nonetheless assumes that
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 60c4c342316c..2a35b1e0fb90 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -252,7 +252,8 @@ ENTRY(__switch_to_asm)
* exist, overwrite the RSB with entries which capture
* speculative execution to prevent attack.
*/
- FILL_RETURN_BUFFER %ebx, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
+ /* Clobbers %ebx */
+ FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
#endif
/* restore callee-saved registers */
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index ff6f8022612c..c752abe89d80 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -236,91 +236,20 @@ GLOBAL(entry_SYSCALL_64_after_hwframe)
pushq %r9 /* pt_regs->r9 */
pushq %r10 /* pt_regs->r10 */
pushq %r11 /* pt_regs->r11 */
- sub $(6*8), %rsp /* pt_regs->bp, bx, r12-15 not saved */
- UNWIND_HINT_REGS extra=0
-
- TRACE_IRQS_OFF
-
- /*
- * If we need to do entry work or if we guess we'll need to do
- * exit work, go straight to the slow path.
- */
- movq PER_CPU_VAR(current_task), %r11
- testl $_TIF_WORK_SYSCALL_ENTRY|_TIF_ALLWORK_MASK, TASK_TI_flags(%r11)
- jnz entry_SYSCALL64_slow_path
-
-entry_SYSCALL_64_fastpath:
- /*
- * Easy case: enable interrupts and issue the syscall. If the syscall
- * needs pt_regs, we'll call a stub that disables interrupts again
- * and jumps to the slow path.
- */
- TRACE_IRQS_ON
- ENABLE_INTERRUPTS(CLBR_NONE)
-#if __SYSCALL_MASK == ~0
- cmpq $__NR_syscall_max, %rax
-#else
- andl $__SYSCALL_MASK, %eax
- cmpl $__NR_syscall_max, %eax
-#endif
- ja 1f /* return -ENOSYS (already in pt_regs->ax) */
- movq %r10, %rcx
-
- /*
- * This call instruction is handled specially in stub_ptregs_64.
- * It might end up jumping to the slow path. If it jumps, RAX
- * and all argument registers are clobbered.
- */
-#ifdef CONFIG_RETPOLINE
- movq sys_call_table(, %rax, 8), %rax
- call __x86_indirect_thunk_rax
-#else
- call *sys_call_table(, %rax, 8)
-#endif
-.Lentry_SYSCALL_64_after_fastpath_call:
-
- movq %rax, RAX(%rsp)
-1:
+ pushq %rbx /* pt_regs->rbx */
+ pushq %rbp /* pt_regs->rbp */
+ pushq %r12 /* pt_regs->r12 */
+ pushq %r13 /* pt_regs->r13 */
+ pushq %r14 /* pt_regs->r14 */
+ pushq %r15 /* pt_regs->r15 */
+ UNWIND_HINT_REGS
- /*
- * If we get here, then we know that pt_regs is clean for SYSRET64.
- * If we see that no exit work is required (which we are required
- * to check with IRQs off), then we can go straight to SYSRET64.
- */
- DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF
- movq PER_CPU_VAR(current_task), %r11
- testl $_TIF_ALLWORK_MASK, TASK_TI_flags(%r11)
- jnz 1f
-
- LOCKDEP_SYS_EXIT
- TRACE_IRQS_ON /* user mode is traced as IRQs on */
- movq RIP(%rsp), %rcx
- movq EFLAGS(%rsp), %r11
- addq $6*8, %rsp /* skip extra regs -- they were preserved */
- UNWIND_HINT_EMPTY
- jmp .Lpop_c_regs_except_rcx_r11_and_sysret
-1:
- /*
- * The fast path looked good when we started, but something changed
- * along the way and we need to switch to the slow path. Calling
- * raise(3) will trigger this, for example. IRQs are off.
- */
- TRACE_IRQS_ON
- ENABLE_INTERRUPTS(CLBR_ANY)
- SAVE_EXTRA_REGS
- movq %rsp, %rdi
- call syscall_return_slowpath /* returns with IRQs disabled */
- jmp return_from_SYSCALL_64
-
-entry_SYSCALL64_slow_path:
/* IRQs are off. */
- SAVE_EXTRA_REGS
movq %rsp, %rdi
call do_syscall_64 /* returns with IRQs disabled */
-return_from_SYSCALL_64:
TRACE_IRQS_IRETQ /* we're about to change IF */
/*
@@ -393,7 +322,6 @@ syscall_return_via_sysret:
/* rcx and r11 are already restored (see code above) */
UNWIND_HINT_EMPTY
POP_EXTRA_REGS
-.Lpop_c_regs_except_rcx_r11_and_sysret:
popq %rsi /* skip r11 */
popq %r10
popq %r9
@@ -424,47 +352,6 @@ syscall_return_via_sysret:
USERGS_SYSRET64
END(entry_SYSCALL_64)
-ENTRY(stub_ptregs_64)
- /*
- * Syscalls marked as needing ptregs land here.
- * If we are on the fast path, we need to save the extra regs,
- * which we achieve by trying again on the slow path. If we are on
- * the slow path, the extra regs are already saved.
- *
- * RAX stores a pointer to the C function implementing the syscall.
- * IRQs are on.
- */
- cmpq $.Lentry_SYSCALL_64_after_fastpath_call, (%rsp)
- jne 1f
-
- /*
- * Called from fast path -- disable IRQs again, pop return address
- * and jump to slow path
- */
- DISABLE_INTERRUPTS(CLBR_ANY)
- TRACE_IRQS_OFF
- popq %rax
- UNWIND_HINT_REGS extra=0
- jmp entry_SYSCALL64_slow_path
-
-1:
- JMP_NOSPEC %rax /* Called from C */
-END(stub_ptregs_64)
-
-.macro ptregs_stub func
-ENTRY(ptregs_\func)
- UNWIND_HINT_FUNC
- leaq \func(%rip), %rax
- jmp stub_ptregs_64
-END(ptregs_\func)
-.endm
-
-/* Instantiate ptregs_stub for each ptregs-using syscall */
-#define __SYSCALL_64_QUAL_(sym)
-#define __SYSCALL_64_QUAL_ptregs(sym) ptregs_stub sym
-#define __SYSCALL_64(nr, sym, qual) __SYSCALL_64_QUAL_##qual(sym)
-#include <asm/syscalls_64.h>
-
/*
* %rdi: prev task
* %rsi: next task
@@ -499,7 +386,8 @@ ENTRY(__switch_to_asm)
* exist, overwrite the RSB with entries which capture
* speculative execution to prevent attack.
*/
- FILL_RETURN_BUFFER %r12, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
+ /* Clobbers %rbx */
+ FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
#endif
/* restore callee-saved registers */
diff --git a/arch/x86/entry/syscall_64.c b/arch/x86/entry/syscall_64.c
index 9c09775e589d..c176d2fab1da 100644
--- a/arch/x86/entry/syscall_64.c
+++ b/arch/x86/entry/syscall_64.c
@@ -7,14 +7,11 @@
#include <asm/asm-offsets.h>
#include <asm/syscall.h>
-#define __SYSCALL_64_QUAL_(sym) sym
-#define __SYSCALL_64_QUAL_ptregs(sym) ptregs_##sym
-
-#define __SYSCALL_64(nr, sym, qual) extern asmlinkage long __SYSCALL_64_QUAL_##qual(sym)(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
+#define __SYSCALL_64(nr, sym, qual) extern asmlinkage long sym(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
#include <asm/syscalls_64.h>
#undef __SYSCALL_64
-#define __SYSCALL_64(nr, sym, qual) [nr] = __SYSCALL_64_QUAL_##qual(sym),
+#define __SYSCALL_64(nr, sym, qual) [nr] = sym,
extern long sys_ni_syscall(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
diff --git a/arch/x86/include/asm/asm-prototypes.h b/arch/x86/include/asm/asm-prototypes.h
index 1908214b9125..4d111616524b 100644
--- a/arch/x86/include/asm/asm-prototypes.h
+++ b/arch/x86/include/asm/asm-prototypes.h
@@ -38,4 +38,7 @@ INDIRECT_THUNK(dx)
INDIRECT_THUNK(si)
INDIRECT_THUNK(di)
INDIRECT_THUNK(bp)
+asmlinkage void __fill_rsb(void);
+asmlinkage void __clear_rsb(void);
+
#endif /* CONFIG_RETPOLINE */
diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index 7fb336210e1b..30d406146016 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -24,6 +24,34 @@
#define wmb() asm volatile("sfence" ::: "memory")
#endif
+/**
+ * array_index_mask_nospec() - generate a mask that is ~0UL when the
+ * bounds check succeeds and 0 otherwise
+ * @index: array element index
+ * @size: number of elements in array
+ *
+ * Returns:
+ * 0 - (index < size)
+ */
+static inline unsigned long array_index_mask_nospec(unsigned long index,
+ unsigned long size)
+{
+ unsigned long mask;
+
+ asm ("cmp %1,%2; sbb %0,%0;"
+ :"=r" (mask)
+ :"r"(size),"r" (index)
+ :"cc");
+ return mask;
+}
+
+/* Override the default implementation from linux/nospec.h. */
+#define array_index_mask_nospec array_index_mask_nospec
+
+/* Prevent speculative execution past this barrier. */
+#define barrier_nospec() alternative_2("", "mfence", X86_FEATURE_MFENCE_RDTSC, \
+ "lfence", X86_FEATURE_LFENCE_RDTSC)
+
#ifdef CONFIG_X86_PPRO_FENCE
#define dma_rmb() rmb()
#else
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index ea9a7dde62e5..70eddb3922ff 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -29,6 +29,7 @@ enum cpuid_leafs
CPUID_8000_000A_EDX,
CPUID_7_ECX,
CPUID_8000_0007_EBX,
+ CPUID_7_EDX,
};
#ifdef CONFIG_X86_FEATURE_NAMES
@@ -79,8 +80,9 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) || \
CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) || \
CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) || \
+ CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) || \
REQUIRED_MASK_CHECK || \
- BUILD_BUG_ON_ZERO(NCAPINTS != 18))
+ BUILD_BUG_ON_ZERO(NCAPINTS != 19))
#define DISABLED_MASK_BIT_SET(feature_bit) \
( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 0, feature_bit) || \
@@ -101,8 +103,9 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) || \
CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) || \
CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) || \
+ CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) || \
DISABLED_MASK_CHECK || \
- BUILD_BUG_ON_ZERO(NCAPINTS != 18))
+ BUILD_BUG_ON_ZERO(NCAPINTS != 19))
#define cpu_has(c, bit) \
(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 25b9375c1484..73b5fff159a4 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -13,7 +13,7 @@
/*
* Defines x86 CPU feature bits
*/
-#define NCAPINTS 18 /* N 32-bit words worth of info */
+#define NCAPINTS 19 /* N 32-bit words worth of info */
#define NBUGINTS 1 /* N 32-bit bug flags */
/*
@@ -203,14 +203,14 @@
#define X86_FEATURE_PROC_FEEDBACK ( 7*32+ 9) /* AMD ProcFeedbackInterface */
#define X86_FEATURE_SME ( 7*32+10) /* AMD Secure Memory Encryption */
#define X86_FEATURE_PTI ( 7*32+11) /* Kernel Page Table Isolation enabled */
-#define X86_FEATURE_RETPOLINE ( 7*32+12) /* Generic Retpoline mitigation for Spectre variant 2 */
-#define X86_FEATURE_RETPOLINE_AMD ( 7*32+13) /* AMD Retpoline mitigation for Spectre variant 2 */
+#define X86_FEATURE_RETPOLINE ( 7*32+12) /* "" Generic Retpoline mitigation for Spectre variant 2 */
+#define X86_FEATURE_RETPOLINE_AMD ( 7*32+13) /* "" AMD Retpoline mitigation for Spectre variant 2 */
#define X86_FEATURE_INTEL_PPIN ( 7*32+14) /* Intel Processor Inventory Number */
-#define X86_FEATURE_AVX512_4VNNIW ( 7*32+16) /* AVX-512 Neural Network Instructions */
-#define X86_FEATURE_AVX512_4FMAPS ( 7*32+17) /* AVX-512 Multiply Accumulation Single precision */
#define X86_FEATURE_MBA ( 7*32+18) /* Memory Bandwidth Allocation */
-#define X86_FEATURE_RSB_CTXSW ( 7*32+19) /* Fill RSB on context switches */
+#define X86_FEATURE_RSB_CTXSW ( 7*32+19) /* "" Fill RSB on context switches */
+
+#define X86_FEATURE_USE_IBPB ( 7*32+21) /* "" Indirect Branch Prediction Barrier enabled */
/* Virtualization flags: Linux defined, word 8 */
#define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */
@@ -271,6 +271,9 @@
#define X86_FEATURE_CLZERO (13*32+ 0) /* CLZERO instruction */
#define X86_FEATURE_IRPERF (13*32+ 1) /* Instructions Retired Count */
#define X86_FEATURE_XSAVEERPTR (13*32+ 2) /* Always save/restore FP error pointers */
+#define X86_FEATURE_IBPB (13*32+12) /* Indirect Branch Prediction Barrier */
+#define X86_FEATURE_IBRS (13*32+14) /* Indirect Branch Restricted Speculation */
+#define X86_FEATURE_STIBP (13*32+15) /* Single Thread Indirect Branch Predictors */
/* Thermal and Power Management Leaf, CPUID level 0x00000006 (EAX), word 14 */
#define X86_FEATURE_DTHERM (14*32+ 0) /* Digital Thermal Sensor */
@@ -319,6 +322,13 @@
#define X86_FEATURE_SUCCOR (17*32+ 1) /* Uncorrectable error containment and recovery */
#define X86_FEATURE_SMCA (17*32+ 3) /* Scalable MCA */
+/* Intel-defined CPU features, CPUID level 0x00000007:0 (EDX), word 18 */
+#define X86_FEATURE_AVX512_4VNNIW (18*32+ 2) /* AVX-512 Neural Network Instructions */
+#define X86_FEATURE_AVX512_4FMAPS (18*32+ 3) /* AVX-512 Multiply Accumulation Single precision */
+#define X86_FEATURE_SPEC_CTRL (18*32+26) /* "" Speculation Control (IBRS + IBPB) */
+#define X86_FEATURE_INTEL_STIBP (18*32+27) /* "" Single Thread Indirect Branch Predictors */
+#define X86_FEATURE_ARCH_CAPABILITIES (18*32+29) /* IA32_ARCH_CAPABILITIES MSR (Intel) */
+
/*
* BUG word(s)
*/
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index b027633e7300..33833d1909af 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -77,6 +77,7 @@
#define DISABLED_MASK15 0
#define DISABLED_MASK16 (DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP)
#define DISABLED_MASK17 0
-#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 18)
+#define DISABLED_MASK18 0
+#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 19)
#endif /* _ASM_X86_DISABLED_FEATURES_H */
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 64c4a30e0d39..e203169931c7 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -137,8 +137,10 @@ enum fixed_addresses {
extern void reserve_top_address(unsigned long reserve);
-#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
-#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
+#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
+#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
+#define FIXADDR_TOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
+#define FIXADDR_TOT_START (FIXADDR_TOP - FIXADDR_TOT_SIZE)
extern int fixmaps_set;
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index e7b983a35506..e520a1e6fc11 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -39,6 +39,13 @@
/* Intel MSRs. Some also available on other CPUs */
+#define MSR_IA32_SPEC_CTRL 0x00000048 /* Speculation Control */
+#define SPEC_CTRL_IBRS (1 << 0) /* Indirect Branch Restricted Speculation */
+#define SPEC_CTRL_STIBP (1 << 1) /* Single Thread Indirect Branch Predictors */
+
+#define MSR_IA32_PRED_CMD 0x00000049 /* Prediction Command */
+#define PRED_CMD_IBPB (1 << 0) /* Indirect Branch Prediction Barrier */
+
#define MSR_PPIN_CTL 0x0000004e
#define MSR_PPIN 0x0000004f
@@ -57,6 +64,11 @@
#define SNB_C3_AUTO_UNDEMOTE (1UL << 28)
#define MSR_MTRRcap 0x000000fe
+
+#define MSR_IA32_ARCH_CAPABILITIES 0x0000010a
+#define ARCH_CAP_RDCL_NO (1 << 0) /* Not susceptible to Meltdown */
+#define ARCH_CAP_IBRS_ALL (1 << 1) /* Enhanced IBRS support */
+
#define MSR_IA32_BBL_CR_CTL 0x00000119
#define MSR_IA32_BBL_CR_CTL3 0x0000011e
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 07962f5f6fba..30df295f6d94 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -214,8 +214,7 @@ static __always_inline unsigned long long rdtsc_ordered(void)
* that some other imaginary CPU is updating continuously with a
* time stamp.
*/
- alternative_2("", "mfence", X86_FEATURE_MFENCE_RDTSC,
- "lfence", X86_FEATURE_LFENCE_RDTSC);
+ barrier_nospec();
return rdtsc();
}
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 4ad41087ce0e..4d57894635f2 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -1,56 +1,12 @@
/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __NOSPEC_BRANCH_H__
-#define __NOSPEC_BRANCH_H__
+#ifndef _ASM_X86_NOSPEC_BRANCH_H_
+#define _ASM_X86_NOSPEC_BRANCH_H_
#include <asm/alternative.h>
#include <asm/alternative-asm.h>
#include <asm/cpufeatures.h>
-/*
- * Fill the CPU return stack buffer.
- *
- * Each entry in the RSB, if used for a speculative 'ret', contains an
- * infinite 'pause; lfence; jmp' loop to capture speculative execution.
- *
- * This is required in various cases for retpoline and IBRS-based
- * mitigations for the Spectre variant 2 vulnerability. Sometimes to
- * eliminate potentially bogus entries from the RSB, and sometimes
- * purely to ensure that it doesn't get empty, which on some CPUs would
- * allow predictions from other (unwanted!) sources to be used.
- *
- * We define a CPP macro such that it can be used from both .S files and
- * inline assembly. It's possible to do a .macro and then include that
- * from C via asm(".include <asm/nospec-branch.h>") but let's not go there.
- */
-
-#define RSB_CLEAR_LOOPS 32 /* To forcibly overwrite all entries */
-#define RSB_FILL_LOOPS 16 /* To avoid underflow */
-
-/*
- * Google experimented with loop-unrolling and this turned out to be
- * the optimal version — two calls, each with their own speculation
- * trap should their return address end up getting used, in a loop.
- */
-#define __FILL_RETURN_BUFFER(reg, nr, sp) \
- mov $(nr/2), reg; \
-771: \
- call 772f; \
-773: /* speculation trap */ \
- pause; \
- lfence; \
- jmp 773b; \
-772: \
- call 774f; \
-775: /* speculation trap */ \
- pause; \
- lfence; \
- jmp 775b; \
-774: \
- dec reg; \
- jnz 771b; \
- add $(BITS_PER_LONG/8) * nr, sp;
-
#ifdef __ASSEMBLY__
/*
@@ -121,17 +77,10 @@
#endif
.endm
- /*
- * A simpler FILL_RETURN_BUFFER macro. Don't make people use the CPP
- * monstrosity above, manually.
- */
-.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
+/* This clobbers the BX register */
+.macro FILL_RETURN_BUFFER nr:req ftr:req
#ifdef CONFIG_RETPOLINE
- ANNOTATE_NOSPEC_ALTERNATIVE
- ALTERNATIVE "jmp .Lskip_rsb_\@", \
- __stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)) \
- \ftr
-.Lskip_rsb_\@:
+ ALTERNATIVE "", "call __clear_rsb", \ftr
#endif
.endm
@@ -201,22 +150,25 @@ extern char __indirect_thunk_end[];
* On VMEXIT we must ensure that no RSB predictions learned in the guest
* can be followed in the host, by overwriting the RSB completely. Both
* retpoline and IBRS mitigations for Spectre v2 need this; only on future
- * CPUs with IBRS_ATT *might* it be avoided.
+ * CPUs with IBRS_ALL *might* it be avoided.
*/
static inline void vmexit_fill_RSB(void)
{
#ifdef CONFIG_RETPOLINE
- unsigned long loops;
-
- asm volatile (ANNOTATE_NOSPEC_ALTERNATIVE
- ALTERNATIVE("jmp 910f",
- __stringify(__FILL_RETURN_BUFFER(%0, RSB_CLEAR_LOOPS, %1)),
- X86_FEATURE_RETPOLINE)
- "910:"
- : "=r" (loops), ASM_CALL_CONSTRAINT
- : : "memory" );
+ alternative_input("",
+ "call __fill_rsb",
+ X86_FEATURE_RETPOLINE,
+ ASM_NO_INPUT_CLOBBER(_ASM_BX, "memory"));
#endif
}
+static inline void indirect_branch_prediction_barrier(void)
+{
+ alternative_input("",
+ "call __ibp_barrier",
+ X86_FEATURE_USE_IBPB,
+ ASM_NO_INPUT_CLOBBER("eax", "ecx", "edx", "memory"));
+}
+
#endif /* __ASSEMBLY__ */
-#endif /* __NOSPEC_BRANCH_H__ */
+#endif /* _ASM_X86_NOSPEC_BRANCH_H_ */
diff --git a/arch/x86/include/asm/pgtable_32_types.h b/arch/x86/include/asm/pgtable_32_types.h
index ce245b0cdfca..0777e18a1d23 100644
--- a/arch/x86/include/asm/pgtable_32_types.h
+++ b/arch/x86/include/asm/pgtable_32_types.h
@@ -44,8 +44,9 @@ extern bool __vmalloc_start_set; /* set once high_memory is set */
*/
#define CPU_ENTRY_AREA_PAGES (NR_CPUS * 40)
-#define CPU_ENTRY_AREA_BASE \
- ((FIXADDR_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) & PMD_MASK)
+#define CPU_ENTRY_AREA_BASE \
+ ((FIXADDR_TOT_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) \
+ & PMD_MASK)
#define PKMAP_BASE \
((CPU_ENTRY_AREA_BASE - PAGE_SIZE) & PMD_MASK)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index d3a67fba200a..513f9604c192 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -460,8 +460,6 @@ struct thread_struct {
unsigned short gsindex;
#endif
- u32 status; /* thread synchronous flags */
-
#ifdef CONFIG_X86_64
unsigned long fsbase;
unsigned long gsbase;
@@ -971,4 +969,7 @@ bool xen_set_default_idle(void);
void stop_this_cpu(void *dummy);
void df_debug(struct pt_regs *regs, long error_code);
+
+void __ibp_barrier(void);
+
#endif /* _ASM_X86_PROCESSOR_H */
diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
index d91ba04dd007..fb3a6de7440b 100644
--- a/arch/x86/include/asm/required-features.h
+++ b/arch/x86/include/asm/required-features.h
@@ -106,6 +106,7 @@
#define REQUIRED_MASK15 0
#define REQUIRED_MASK16 (NEED_LA57)
#define REQUIRED_MASK17 0
-#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 18)
+#define REQUIRED_MASK18 0
+#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 19)
#endif /* _ASM_X86_REQUIRED_FEATURES_H */
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index e3c95e8e61c5..03eedc21246d 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -60,7 +60,7 @@ static inline long syscall_get_error(struct task_struct *task,
* TS_COMPAT is set for 32-bit syscall entries and then
* remains set until we return to user mode.
*/
- if (task->thread.status & (TS_COMPAT|TS_I386_REGS_POKED))
+ if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
/*
* Sign-extend the value so (int)-EFOO becomes (long)-EFOO
* and will match correctly in comparisons.
@@ -116,7 +116,7 @@ static inline void syscall_get_arguments(struct task_struct *task,
unsigned long *args)
{
# ifdef CONFIG_IA32_EMULATION
- if (task->thread.status & TS_COMPAT)
+ if (task->thread_info.status & TS_COMPAT)
switch (i) {
case 0:
if (!n--) break;
@@ -177,7 +177,7 @@ static inline void syscall_set_arguments(struct task_struct *task,
const unsigned long *args)
{
# ifdef CONFIG_IA32_EMULATION
- if (task->thread.status & TS_COMPAT)
+ if (task->thread_info.status & TS_COMPAT)
switch (i) {
case 0:
if (!n--) break;
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 00223333821a..eda3b6823ca4 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -55,6 +55,7 @@ struct task_struct;
struct thread_info {
unsigned long flags; /* low level flags */
+ u32 status; /* thread synchronous flags */
};
#define INIT_THREAD_INFO(tsk) \
@@ -221,7 +222,7 @@ static inline int arch_within_stack_frames(const void * const stack,
#define in_ia32_syscall() true
#else
#define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \
- current->thread.status & TS_COMPAT)
+ current_thread_info()->status & TS_COMPAT)
#endif
/*
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index d33e4a26dc7e..2b8f18ca5874 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -174,6 +174,8 @@ struct tlb_state {
struct mm_struct *loaded_mm;
u16 loaded_mm_asid;
u16 next_asid;
+ /* last user mm's ctx id */
+ u64 last_ctx_id;
/*
* We can be in one of several states:
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 574dff4d2913..aae77eb8491c 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -124,6 +124,11 @@ extern int __get_user_bad(void);
#define __uaccess_begin() stac()
#define __uaccess_end() clac()
+#define __uaccess_begin_nospec() \
+({ \
+ stac(); \
+ barrier_nospec(); \
+})
/*
* This is a type: either unsigned long, if the argument fits into
@@ -445,7 +450,7 @@ do { \
({ \
int __gu_err; \
__inttype(*(ptr)) __gu_val; \
- __uaccess_begin(); \
+ __uaccess_begin_nospec(); \
__get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
__uaccess_end(); \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
@@ -487,6 +492,10 @@ struct __large_struct { unsigned long buf[100]; };
__uaccess_begin(); \
barrier();
+#define uaccess_try_nospec do { \
+ current->thread.uaccess_err = 0; \
+ __uaccess_begin_nospec(); \
+
#define uaccess_catch(err) \
__uaccess_end(); \
(err) |= (current->thread.uaccess_err ? -EFAULT : 0); \
@@ -548,7 +557,7 @@ struct __large_struct { unsigned long buf[100]; };
* get_user_ex(...);
* } get_user_catch(err)
*/
-#define get_user_try uaccess_try
+#define get_user_try uaccess_try_nospec
#define get_user_catch(err) uaccess_catch(err)
#define get_user_ex(x, ptr) do { \
@@ -582,7 +591,7 @@ extern void __cmpxchg_wrong_size(void)
__typeof__(ptr) __uval = (uval); \
__typeof__(*(ptr)) __old = (old); \
__typeof__(*(ptr)) __new = (new); \
- __uaccess_begin(); \
+ __uaccess_begin_nospec(); \
switch (size) { \
case 1: \
{ \
diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h
index 72950401b223..ba2dc1930630 100644
--- a/arch/x86/include/asm/uaccess_32.h
+++ b/arch/x86/include/asm/uaccess_32.h
@@ -29,21 +29,21 @@ raw_copy_from_user(void *to, const void __user *from, unsigned long n)
switch (n) {
case 1:
ret = 0;
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm_nozero(*(u8 *)to, from, ret,
"b", "b", "=q", 1);
__uaccess_end();
return ret;
case 2:
ret = 0;
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm_nozero(*(u16 *)to, from, ret,
"w", "w", "=r", 2);
__uaccess_end();
return ret;
case 4:
ret = 0;
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm_nozero(*(u32 *)to, from, ret,
"l", "k", "=r", 4);
__uaccess_end();
diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h
index f07ef3c575db..62546b3a398e 100644
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -55,31 +55,31 @@ raw_copy_from_user(void *dst, const void __user *src, unsigned long size)
return copy_user_generic(dst, (__force void *)src, size);
switch (size) {
case 1:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm_nozero(*(u8 *)dst, (u8 __user *)src,
ret, "b", "b", "=q", 1);
__uaccess_end();
return ret;
case 2:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm_nozero(*(u16 *)dst, (u16 __user *)src,
ret, "w", "w", "=r", 2);
__uaccess_end();
return ret;
case 4:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm_nozero(*(u32 *)dst, (u32 __user *)src,
ret, "l", "k", "=r", 4);
__uaccess_end();
return ret;
case 8:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,
ret, "q", "", "=r", 8);
__uaccess_end();
return ret;
case 10:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,
ret, "q", "", "=r", 10);
if (likely(!ret))
@@ -89,7 +89,7 @@ raw_copy_from_user(void *dst, const void __user *src, unsigned long size)
__uaccess_end();
return ret;
case 16:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm_nozero(*(u64 *)dst, (u64 __user *)src,
ret, "q", "", "=r", 16);
if (likely(!ret))
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 4817d743c263..a481763a3776 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -46,17 +46,6 @@ static int __init setup_noreplace_smp(char *str)
}
__setup("noreplace-smp", setup_noreplace_smp);
-#ifdef CONFIG_PARAVIRT
-static int __initdata_or_module noreplace_paravirt = 0;
-
-static int __init setup_noreplace_paravirt(char *str)
-{
- noreplace_paravirt = 1;
- return 1;
-}
-__setup("noreplace-paravirt", setup_noreplace_paravirt);
-#endif
-
#define DPRINTK(fmt, args...) \
do { \
if (debug_alternative) \
@@ -298,7 +287,7 @@ recompute_jump(struct alt_instr *a, u8 *orig_insn, u8 *repl_insn, u8 *insnbuf)
tgt_rip = next_rip + o_dspl;
n_dspl = tgt_rip - orig_insn;
- DPRINTK("target RIP: %p, new_displ: 0x%x", tgt_rip, n_dspl);
+ DPRINTK("target RIP: %px, new_displ: 0x%x", tgt_rip, n_dspl);
if (tgt_rip - orig_insn >= 0) {
if (n_dspl - 2 <= 127)
@@ -355,7 +344,7 @@ static void __init_or_module noinline optimize_nops(struct alt_instr *a, u8 *ins
add_nops(instr + (a->instrlen - a->padlen), a->padlen);
local_irq_restore(flags);
- DUMP_BYTES(instr, a->instrlen, "%p: [%d:%d) optimized NOPs: ",
+ DUMP_BYTES(instr, a->instrlen, "%px: [%d:%d) optimized NOPs: ",
instr, a->instrlen - a->padlen, a->padlen);
}
@@ -376,7 +365,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
u8 *instr, *replacement;
u8 insnbuf[MAX_PATCH_LEN];
- DPRINTK("alt table %p -> %p", start, end);
+ DPRINTK("alt table %px, -> %px", start, end);
/*
* The scan order should be from start to end. A later scanned
* alternative code can overwrite previously scanned alternative code.
@@ -400,14 +389,14 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
continue;
}
- DPRINTK("feat: %d*32+%d, old: (%p, len: %d), repl: (%p, len: %d), pad: %d",
+ DPRINTK("feat: %d*32+%d, old: (%px len: %d), repl: (%px, len: %d), pad: %d",
a->cpuid >> 5,
a->cpuid & 0x1f,
instr, a->instrlen,
replacement, a->replacementlen, a->padlen);
- DUMP_BYTES(instr, a->instrlen, "%p: old_insn: ", instr);
- DUMP_BYTES(replacement, a->replacementlen, "%p: rpl_insn: ", replacement);
+ DUMP_BYTES(instr, a->instrlen, "%px: old_insn: ", instr);
+ DUMP_BYTES(replacement, a->replacementlen, "%px: rpl_insn: ", replacement);
memcpy(insnbuf, replacement, a->replacementlen);
insnbuf_sz = a->replacementlen;
@@ -433,7 +422,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
a->instrlen - a->replacementlen);
insnbuf_sz += a->instrlen - a->replacementlen;
}
- DUMP_BYTES(insnbuf, insnbuf_sz, "%p: final_insn: ", instr);
+ DUMP_BYTES(insnbuf, insnbuf_sz, "%px: final_insn: ", instr);
text_poke_early(instr, insnbuf, insnbuf_sz);
}
@@ -599,9 +588,6 @@ void __init_or_module apply_paravirt(struct paravirt_patch_site *start,
struct paravirt_patch_site *p;
char insnbuf[MAX_PATCH_LEN];
- if (noreplace_paravirt)
- return;
-
for (p = start; p < end; p++) {
unsigned int used;
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 390b3dc3d438..71949bf2de5a 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -11,6 +11,7 @@
#include <linux/init.h>
#include <linux/utsname.h>
#include <linux/cpu.h>
+#include <linux/module.h>
#include <asm/nospec-branch.h>
#include <asm/cmdline.h>
@@ -90,20 +91,41 @@ static const char *spectre_v2_strings[] = {
};
#undef pr_fmt
-#define pr_fmt(fmt) "Spectre V2 mitigation: " fmt
+#define pr_fmt(fmt) "Spectre V2 : " fmt
static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE;
+#ifdef RETPOLINE
+static bool spectre_v2_bad_module;
+
+bool retpoline_module_ok(bool has_retpoline)
+{
+ if (spectre_v2_enabled == SPECTRE_V2_NONE || has_retpoline)
+ return true;
+
+ pr_err("System may be vulnerable to spectre v2\n");
+ spectre_v2_bad_module = true;
+ return false;
+}
+
+static inline const char *spectre_v2_module_string(void)
+{
+ return spectre_v2_bad_module ? " - vulnerable module loaded" : "";
+}
+#else
+static inline const char *spectre_v2_module_string(void) { return ""; }
+#endif
+
static void __init spec2_print_if_insecure(const char *reason)
{
if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
- pr_info("%s\n", reason);
+ pr_info("%s selected on command line.\n", reason);
}
static void __init spec2_print_if_secure(const char *reason)
{
if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
- pr_info("%s\n", reason);
+ pr_info("%s selected on command line.\n", reason);
}
static inline bool retp_compiler(void)
@@ -118,42 +140,68 @@ static inline bool match_option(const char *arg, int arglen, const char *opt)
return len == arglen && !strncmp(arg, opt, len);
}
+static const struct {
+ const char *option;
+ enum spectre_v2_mitigation_cmd cmd;
+ bool secure;
+} mitigation_options[] = {
+ { "off", SPECTRE_V2_CMD_NONE, false },
+ { "on", SPECTRE_V2_CMD_FORCE, true },
+ { "retpoline", SPECTRE_V2_CMD_RETPOLINE, false },
+ { "retpoline,amd", SPECTRE_V2_CMD_RETPOLINE_AMD, false },
+ { "retpoline,generic", SPECTRE_V2_CMD_RETPOLINE_GENERIC, false },
+ { "auto", SPECTRE_V2_CMD_AUTO, false },
+};
+
static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
{
char arg[20];
- int ret;
-
- ret = cmdline_find_option(boot_command_line, "spectre_v2", arg,
- sizeof(arg));
- if (ret > 0) {
- if (match_option(arg, ret, "off")) {
- goto disable;
- } else if (match_option(arg, ret, "on")) {
- spec2_print_if_secure("force enabled on command line.");
- return SPECTRE_V2_CMD_FORCE;
- } else if (match_option(arg, ret, "retpoline")) {
- spec2_print_if_insecure("retpoline selected on command line.");
- return SPECTRE_V2_CMD_RETPOLINE;
- } else if (match_option(arg, ret, "retpoline,amd")) {
- if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
- pr_err("retpoline,amd selected but CPU is not AMD. Switching to AUTO select\n");
- return SPECTRE_V2_CMD_AUTO;
- }
- spec2_print_if_insecure("AMD retpoline selected on command line.");
- return SPECTRE_V2_CMD_RETPOLINE_AMD;
- } else if (match_option(arg, ret, "retpoline,generic")) {
- spec2_print_if_insecure("generic retpoline selected on command line.");
- return SPECTRE_V2_CMD_RETPOLINE_GENERIC;
- } else if (match_option(arg, ret, "auto")) {
+ int ret, i;
+ enum spectre_v2_mitigation_cmd cmd = SPECTRE_V2_CMD_AUTO;
+
+ if (cmdline_find_option_bool(boot_command_line, "nospectre_v2"))
+ return SPECTRE_V2_CMD_NONE;
+ else {
+ ret = cmdline_find_option(boot_command_line, "spectre_v2", arg,
+ sizeof(arg));
+ if (ret < 0)
+ return SPECTRE_V2_CMD_AUTO;
+
+ for (i = 0; i < ARRAY_SIZE(mitigation_options); i++) {
+ if (!match_option(arg, ret, mitigation_options[i].option))
+ continue;
+ cmd = mitigation_options[i].cmd;
+ break;
+ }
+
+ if (i >= ARRAY_SIZE(mitigation_options)) {
+ pr_err("unknown option (%s). Switching to AUTO select\n",
+ mitigation_options[i].option);
return SPECTRE_V2_CMD_AUTO;
}
}
- if (!cmdline_find_option_bool(boot_command_line, "nospectre_v2"))
+ if ((cmd == SPECTRE_V2_CMD_RETPOLINE ||
+ cmd == SPECTRE_V2_CMD_RETPOLINE_AMD ||
+ cmd == SPECTRE_V2_CMD_RETPOLINE_GENERIC) &&
+ !IS_ENABLED(CONFIG_RETPOLINE)) {
+ pr_err("%s selected but not compiled in. Switching to AUTO select\n",
+ mitigation_options[i].option);
return SPECTRE_V2_CMD_AUTO;
-disable:
- spec2_print_if_insecure("disabled on command line.");
- return SPECTRE_V2_CMD_NONE;
+ }
+
+ if (cmd == SPECTRE_V2_CMD_RETPOLINE_AMD &&
+ boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
+ pr_err("retpoline,amd selected but CPU is not AMD. Switching to AUTO select\n");
+ return SPECTRE_V2_CMD_AUTO;
+ }
+
+ if (mitigation_options[i].secure)
+ spec2_print_if_secure(mitigation_options[i].option);
+ else
+ spec2_print_if_insecure(mitigation_options[i].option);
+
+ return cmd;
}
/* Check for Skylake-like CPUs (for RSB handling) */
@@ -191,10 +239,10 @@ static void __init spectre_v2_select_mitigation(void)
return;
case SPECTRE_V2_CMD_FORCE:
- /* FALLTRHU */
case SPECTRE_V2_CMD_AUTO:
- goto retpoline_auto;
-
+ if (IS_ENABLED(CONFIG_RETPOLINE))
+ goto retpoline_auto;
+ break;
case SPECTRE_V2_CMD_RETPOLINE_AMD:
if (IS_ENABLED(CONFIG_RETPOLINE))
goto retpoline_amd;
@@ -249,6 +297,12 @@ static void __init spectre_v2_select_mitigation(void)
setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW);
pr_info("Filling RSB on context switch\n");
}
+
+ /* Initialize Indirect Branch Prediction Barrier if supported */
+ if (boot_cpu_has(X86_FEATURE_IBPB)) {
+ setup_force_cpu_cap(X86_FEATURE_USE_IBPB);
+ pr_info("Enabling Indirect Branch Prediction Barrier\n");
+ }
}
#undef pr_fmt
@@ -269,7 +323,7 @@ ssize_t cpu_show_spectre_v1(struct device *dev,
{
if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V1))
return sprintf(buf, "Not affected\n");
- return sprintf(buf, "Vulnerable\n");
+ return sprintf(buf, "Mitigation: __user pointer sanitization\n");
}
ssize_t cpu_show_spectre_v2(struct device *dev,
@@ -278,6 +332,14 @@ ssize_t cpu_show_spectre_v2(struct device *dev,
if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
return sprintf(buf, "Not affected\n");
- return sprintf(buf, "%s\n", spectre_v2_strings[spectre_v2_enabled]);
+ return sprintf(buf, "%s%s%s\n", spectre_v2_strings[spectre_v2_enabled],
+ boot_cpu_has(X86_FEATURE_USE_IBPB) ? ", IBPB" : "",
+ spectre_v2_module_string());
}
#endif
+
+void __ibp_barrier(void)
+{
+ __wrmsr(MSR_IA32_PRED_CMD, PRED_CMD_IBPB, 0);
+}
+EXPORT_SYMBOL_GPL(__ibp_barrier);
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index ef29ad001991..d63f4b5706e4 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -47,6 +47,8 @@
#include <asm/pat.h>
#include <asm/microcode.h>
#include <asm/microcode_intel.h>
+#include <asm/intel-family.h>
+#include <asm/cpu_device_id.h>
#ifdef CONFIG_X86_LOCAL_APIC
#include <asm/uv/uv.h>
@@ -748,6 +750,26 @@ static void apply_forced_caps(struct cpuinfo_x86 *c)
}
}
+static void init_speculation_control(struct cpuinfo_x86 *c)
+{
+ /*
+ * The Intel SPEC_CTRL CPUID bit implies IBRS and IBPB support,
+ * and they also have a different bit for STIBP support. Also,
+ * a hypervisor might have set the individual AMD bits even on
+ * Intel CPUs, for finer-grained selection of what's available.
+ *
+ * We use the AMD bits in 0x8000_0008 EBX as the generic hardware
+ * features, which are visible in /proc/cpuinfo and used by the
+ * kernel. So set those accordingly from the Intel bits.
+ */
+ if (cpu_has(c, X86_FEATURE_SPEC_CTRL)) {
+ set_cpu_cap(c, X86_FEATURE_IBRS);
+ set_cpu_cap(c, X86_FEATURE_IBPB);
+ }
+ if (cpu_has(c, X86_FEATURE_INTEL_STIBP))
+ set_cpu_cap(c, X86_FEATURE_STIBP);
+}
+
void get_cpu_cap(struct cpuinfo_x86 *c)
{
u32 eax, ebx, ecx, edx;
@@ -769,6 +791,7 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx);
c->x86_capability[CPUID_7_0_EBX] = ebx;
c->x86_capability[CPUID_7_ECX] = ecx;
+ c->x86_capability[CPUID_7_EDX] = edx;
}
/* Extended state features: level 0x0000000d */
@@ -841,6 +864,7 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a);
init_scattered_cpuid_features(c);
+ init_speculation_control(c);
/*
* Clear/Set all flags overridden by options, after probe.
@@ -876,6 +900,41 @@ static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
#endif
}
+static const __initconst struct x86_cpu_id cpu_no_speculation[] = {
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CEDARVIEW, X86_FEATURE_ANY },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CLOVERVIEW, X86_FEATURE_ANY },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_LINCROFT, X86_FEATURE_ANY },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PENWELL, X86_FEATURE_ANY },
+ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PINEVIEW, X86_FEATURE_ANY },
+ { X86_VENDOR_CENTAUR, 5 },
+ { X86_VENDOR_INTEL, 5 },
+ { X86_VENDOR_NSC, 5 },
+ { X86_VENDOR_ANY, 4 },
+ {}
+};
+
+static const __initconst struct x86_cpu_id cpu_no_meltdown[] = {
+ { X86_VENDOR_AMD },
+ {}
+};
+
+static bool __init cpu_vulnerable_to_meltdown(struct cpuinfo_x86 *c)
+{
+ u64 ia32_cap = 0;
+
+ if (x86_match_cpu(cpu_no_meltdown))
+ return false;
+
+ if (cpu_has(c, X86_FEATURE_ARCH_CAPABILITIES))
+ rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap);
+
+ /* Rogue Data Cache Load? No! */
+ if (ia32_cap & ARCH_CAP_RDCL_NO)
+ return false;
+
+ return true;
+}
+
/*
* Do minimum CPU detection early.
* Fields really needed: vendor, cpuid_level, family, model, mask,
@@ -923,11 +982,12 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
setup_force_cpu_cap(X86_FEATURE_ALWAYS);
- if (c->x86_vendor != X86_VENDOR_AMD)
- setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN);
-
- setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
- setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
+ if (!x86_match_cpu(cpu_no_speculation)) {
+ if (cpu_vulnerable_to_meltdown(c))
+ setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN);
+ setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
+ setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
+ }
fpu__init_system(c);
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index b1af22073e28..319bf989fad1 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -102,6 +102,59 @@ static void probe_xeon_phi_r3mwait(struct cpuinfo_x86 *c)
ELF_HWCAP2 |= HWCAP2_RING3MWAIT;
}
+/*
+ * Early microcode releases for the Spectre v2 mitigation were broken.
+ * Information taken from;
+ * - https://newsroom.intel.com/wp-content/uploads/sites/11/2018/01/microcode-update-guidance.pdf
+ * - https://kb.vmware.com/s/article/52345
+ * - Microcode revisions observed in the wild
+ * - Release note from 20180108 microcode release
+ */
+struct sku_microcode {
+ u8 model;
+ u8 stepping;
+ u32 microcode;
+};
+static const struct sku_microcode spectre_bad_microcodes[] = {
+ { INTEL_FAM6_KABYLAKE_DESKTOP, 0x0B, 0x84 },
+ { INTEL_FAM6_KABYLAKE_DESKTOP, 0x0A, 0x84 },
+ { INTEL_FAM6_KABYLAKE_DESKTOP, 0x09, 0x84 },
+ { INTEL_FAM6_KABYLAKE_MOBILE, 0x0A, 0x84 },
+ { INTEL_FAM6_KABYLAKE_MOBILE, 0x09, 0x84 },
+ { INTEL_FAM6_SKYLAKE_X, 0x03, 0x0100013e },
+ { INTEL_FAM6_SKYLAKE_X, 0x04, 0x0200003c },
+ { INTEL_FAM6_SKYLAKE_MOBILE, 0x03, 0xc2 },
+ { INTEL_FAM6_SKYLAKE_DESKTOP, 0x03, 0xc2 },
+ { INTEL_FAM6_BROADWELL_CORE, 0x04, 0x28 },
+ { INTEL_FAM6_BROADWELL_GT3E, 0x01, 0x1b },
+ { INTEL_FAM6_BROADWELL_XEON_D, 0x02, 0x14 },
+ { INTEL_FAM6_BROADWELL_XEON_D, 0x03, 0x07000011 },
+ { INTEL_FAM6_BROADWELL_X, 0x01, 0x0b000025 },
+ { INTEL_FAM6_HASWELL_ULT, 0x01, 0x21 },
+ { INTEL_FAM6_HASWELL_GT3E, 0x01, 0x18 },
+ { INTEL_FAM6_HASWELL_CORE, 0x03, 0x23 },
+ { INTEL_FAM6_HASWELL_X, 0x02, 0x3b },
+ { INTEL_FAM6_HASWELL_X, 0x04, 0x10 },
+ { INTEL_FAM6_IVYBRIDGE_X, 0x04, 0x42a },
+ /* Updated in the 20180108 release; blacklist until we know otherwise */
+ { INTEL_FAM6_ATOM_GEMINI_LAKE, 0x01, 0x22 },
+ /* Observed in the wild */
+ { INTEL_FAM6_SANDYBRIDGE_X, 0x06, 0x61b },
+ { INTEL_FAM6_SANDYBRIDGE_X, 0x07, 0x712 },
+};
+
+static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(spectre_bad_microcodes); i++) {
+ if (c->x86_model == spectre_bad_microcodes[i].model &&
+ c->x86_mask == spectre_bad_microcodes[i].stepping)
+ return (c->microcode <= spectre_bad_microcodes[i].microcode);
+ }
+ return false;
+}
+
static void early_init_intel(struct cpuinfo_x86 *c)
{
u64 misc_enable;
@@ -122,6 +175,19 @@ static void early_init_intel(struct cpuinfo_x86 *c)
if (c->x86 >= 6 && !cpu_has(c, X86_FEATURE_IA64))
c->microcode = intel_get_microcode_revision();
+ /* Now if any of them are set, check the blacklist and clear the lot */
+ if ((cpu_has(c, X86_FEATURE_SPEC_CTRL) ||
+ cpu_has(c, X86_FEATURE_INTEL_STIBP) ||
+ cpu_has(c, X86_FEATURE_IBRS) || cpu_has(c, X86_FEATURE_IBPB) ||
+ cpu_has(c, X86_FEATURE_STIBP)) && bad_spectre_microcode(c)) {
+ pr_warn("Intel Spectre v2 broken microcode detected; disabling Speculation Control\n");
+ setup_clear_cpu_cap(X86_FEATURE_IBRS);
+ setup_clear_cpu_cap(X86_FEATURE_IBPB);
+ setup_clear_cpu_cap(X86_FEATURE_STIBP);
+ setup_clear_cpu_cap(X86_FEATURE_SPEC_CTRL);
+ setup_clear_cpu_cap(X86_FEATURE_INTEL_STIBP);
+ }
+
/*
* Atom erratum AAE44/AAF40/AAG38/AAH41:
*
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index d0e69769abfd..df11f5d604be 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -21,8 +21,6 @@ struct cpuid_bit {
static const struct cpuid_bit cpuid_bits[] = {
{ X86_FEATURE_APERFMPERF, CPUID_ECX, 0, 0x00000006, 0 },
{ X86_FEATURE_EPB, CPUID_ECX, 3, 0x00000006, 0 },
- { X86_FEATURE_AVX512_4VNNIW, CPUID_EDX, 2, 0x00000007, 0 },
- { X86_FEATURE_AVX512_4FMAPS, CPUID_EDX, 3, 0x00000007, 0 },
{ X86_FEATURE_CAT_L3, CPUID_EBX, 1, 0x00000010, 0 },
{ X86_FEATURE_CAT_L2, CPUID_EBX, 2, 0x00000010, 0 },
{ X86_FEATURE_CDP_L3, CPUID_ECX, 2, 0x00000010, 1 },
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index c75466232016..9eb448c7859d 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -557,7 +557,7 @@ static void __set_personality_x32(void)
* Pretend to come from a x32 execve.
*/
task_pt_regs(current)->orig_ax = __NR_x32_execve | __X32_SYSCALL_BIT;
- current->thread.status &= ~TS_COMPAT;
+ current_thread_info()->status &= ~TS_COMPAT;
#endif
}
@@ -571,7 +571,7 @@ static void __set_personality_ia32(void)
current->personality |= force_personality32;
/* Prepare the first "return" to user space */
task_pt_regs(current)->orig_ax = __NR_ia32_execve;
- current->thread.status |= TS_COMPAT;
+ current_thread_info()->status |= TS_COMPAT;
#endif
}
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index f37d18124648..ed5c4cdf0a34 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -935,7 +935,7 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 value)
*/
regs->orig_ax = value;
if (syscall_get_nr(child, regs) >= 0)
- child->thread.status |= TS_I386_REGS_POKED;
+ child->thread_info.status |= TS_I386_REGS_POKED;
break;
case offsetof(struct user32, regs.eflags):
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index b9e00e8f1c9b..4cdc0b27ec82 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -787,7 +787,7 @@ static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
* than the tracee.
*/
#ifdef CONFIG_IA32_EMULATION
- if (current->thread.status & (TS_COMPAT|TS_I386_REGS_POKED))
+ if (current_thread_info()->status & (TS_COMPAT|TS_I386_REGS_POKED))
return __NR_ia32_restart_syscall;
#endif
#ifdef CONFIG_X86_X32_ABI
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 0099e10eb045..13f5d4217e4f 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -67,9 +67,7 @@ u64 kvm_supported_xcr0(void)
#define F(x) bit(X86_FEATURE_##x)
-/* These are scattered features in cpufeatures.h. */
-#define KVM_CPUID_BIT_AVX512_4VNNIW 2
-#define KVM_CPUID_BIT_AVX512_4FMAPS 3
+/* For scattered features from cpufeatures.h; we currently expose none */
#define KF(x) bit(KVM_CPUID_BIT_##x)
int kvm_update_cpuid(struct kvm_vcpu *vcpu)
@@ -367,6 +365,10 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM);
+ /* cpuid 0x80000008.ebx */
+ const u32 kvm_cpuid_8000_0008_ebx_x86_features =
+ F(IBPB) | F(IBRS);
+
/* cpuid 0xC0000001.edx */
const u32 kvm_cpuid_C000_0001_edx_x86_features =
F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
@@ -392,7 +394,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
/* cpuid 7.0.edx*/
const u32 kvm_cpuid_7_0_edx_x86_features =
- KF(AVX512_4VNNIW) | KF(AVX512_4FMAPS);
+ F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
+ F(ARCH_CAPABILITIES);
/* all calls to cpuid_count() should be made on the same cpu */
get_cpu();
@@ -477,7 +480,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE))
entry->ecx &= ~F(PKU);
entry->edx &= kvm_cpuid_7_0_edx_x86_features;
- entry->edx &= get_scattered_cpuid_leaf(7, 0, CPUID_EDX);
+ cpuid_mask(&entry->edx, CPUID_7_EDX);
} else {
entry->ebx = 0;
entry->ecx = 0;
@@ -627,7 +630,14 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
if (!g_phys_as)
g_phys_as = phys_as;
entry->eax = g_phys_as | (virt_as << 8);
- entry->ebx = entry->edx = 0;
+ entry->edx = 0;
+ /* IBRS and IBPB aren't necessarily present in hardware cpuid */
+ if (boot_cpu_has(X86_FEATURE_IBPB))
+ entry->ebx |= F(IBPB);
+ if (boot_cpu_has(X86_FEATURE_IBRS))
+ entry->ebx |= F(IBRS);
+ entry->ebx &= kvm_cpuid_8000_0008_ebx_x86_features;
+ cpuid_mask(&entry->ebx, CPUID_8000_0008_EBX);
break;
}
case 0x80000019:
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index c2cea6651279..9a327d5b6d1f 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -54,6 +54,7 @@ static const struct cpuid_reg reverse_cpuid[] = {
[CPUID_8000_000A_EDX] = {0x8000000a, 0, CPUID_EDX},
[CPUID_7_ECX] = { 7, 0, CPUID_ECX},
[CPUID_8000_0007_EBX] = {0x80000007, 0, CPUID_EBX},
+ [CPUID_7_EDX] = { 7, 0, CPUID_EDX},
};
static __always_inline struct cpuid_reg x86_feature_cpuid(unsigned x86_feature)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b514b2b2845a..290ecf711aec 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -25,6 +25,7 @@
#include <asm/kvm_emulate.h>
#include <linux/stringify.h>
#include <asm/debugreg.h>
+#include <asm/nospec-branch.h>
#include "x86.h"
#include "tss.h"
@@ -1021,8 +1022,8 @@ static __always_inline u8 test_cc(unsigned int condition, unsigned long flags)
void (*fop)(void) = (void *)em_setcc + 4 * (condition & 0xf);
flags = (flags & EFLAGS_MASK) | X86_EFLAGS_IF;
- asm("push %[flags]; popf; call *%[fastop]"
- : "=a"(rc) : [fastop]"r"(fop), [flags]"r"(flags));
+ asm("push %[flags]; popf; " CALL_NOSPEC
+ : "=a"(rc) : [thunk_target]"r"(fop), [flags]"r"(flags));
return rc;
}
@@ -5335,9 +5336,9 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *))
if (!(ctxt->d & ByteOp))
fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE;
- asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n"
+ asm("push %[flags]; popf; " CALL_NOSPEC " ; pushf; pop %[flags]\n"
: "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags),
- [fastop]"+S"(fop), ASM_CALL_CONSTRAINT
+ [thunk_target]"+S"(fop), ASM_CALL_CONSTRAINT
: "c"(ctxt->src2.val));
ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f40d0da1f1d3..4e3c79530526 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -184,6 +184,8 @@ struct vcpu_svm {
u64 gs_base;
} host;
+ u64 spec_ctrl;
+
u32 *msrpm;
ulong nmi_iret_rip;
@@ -249,6 +251,8 @@ static const struct svm_direct_access_msrs {
{ .index = MSR_CSTAR, .always = true },
{ .index = MSR_SYSCALL_MASK, .always = true },
#endif
+ { .index = MSR_IA32_SPEC_CTRL, .always = false },
+ { .index = MSR_IA32_PRED_CMD, .always = false },
{ .index = MSR_IA32_LASTBRANCHFROMIP, .always = false },
{ .index = MSR_IA32_LASTBRANCHTOIP, .always = false },
{ .index = MSR_IA32_LASTINTFROMIP, .always = false },
@@ -529,6 +533,7 @@ struct svm_cpu_data {
struct kvm_ldttss_desc *tss_desc;
struct page *save_area;
+ struct vmcb *current_vmcb;
};
static DEFINE_PER_CPU(struct svm_cpu_data *, svm_data);
@@ -880,6 +885,25 @@ static bool valid_msr_intercept(u32 index)
return false;
}
+static bool msr_write_intercepted(struct kvm_vcpu *vcpu, unsigned msr)
+{
+ u8 bit_write;
+ unsigned long tmp;
+ u32 offset;
+ u32 *msrpm;
+
+ msrpm = is_guest_mode(vcpu) ? to_svm(vcpu)->nested.msrpm:
+ to_svm(vcpu)->msrpm;
+
+ offset = svm_msrpm_offset(msr);
+ bit_write = 2 * (msr & 0x0f) + 1;
+ tmp = msrpm[offset];
+
+ BUG_ON(offset == MSR_INVALID);
+
+ return !!test_bit(bit_write, &tmp);
+}
+
static void set_msr_interception(u32 *msrpm, unsigned msr,
int read, int write)
{
@@ -1582,6 +1606,8 @@ static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
u32 dummy;
u32 eax = 1;
+ svm->spec_ctrl = 0;
+
if (!init_event) {
svm->vcpu.arch.apic_base = APIC_DEFAULT_PHYS_BASE |
MSR_IA32_APICBASE_ENABLE;
@@ -1703,11 +1729,17 @@ static void svm_free_vcpu(struct kvm_vcpu *vcpu)
__free_pages(virt_to_page(svm->nested.msrpm), MSRPM_ALLOC_ORDER);
kvm_vcpu_uninit(vcpu);
kmem_cache_free(kvm_vcpu_cache, svm);
+ /*
+ * The vmcb page can be recycled, causing a false negative in
+ * svm_vcpu_load(). So do a full IBPB now.
+ */
+ indirect_branch_prediction_barrier();
}
static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
+ struct svm_cpu_data *sd = per_cpu(svm_data, cpu);
int i;
if (unlikely(cpu != vcpu->cpu)) {
@@ -1736,6 +1768,10 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
if (static_cpu_has(X86_FEATURE_RDTSCP))
wrmsrl(MSR_TSC_AUX, svm->tsc_aux);
+ if (sd->current_vmcb != svm->vmcb) {
+ sd->current_vmcb = svm->vmcb;
+ indirect_branch_prediction_barrier();
+ }
avic_vcpu_load(vcpu, cpu);
}
@@ -3593,6 +3629,13 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_VM_CR:
msr_info->data = svm->nested.vm_cr_msr;
break;
+ case MSR_IA32_SPEC_CTRL:
+ if (!msr_info->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_IBRS))
+ return 1;
+
+ msr_info->data = svm->spec_ctrl;
+ break;
case MSR_IA32_UCODE_REV:
msr_info->data = 0x01000065;
break;
@@ -3684,6 +3727,49 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
case MSR_IA32_TSC:
kvm_write_tsc(vcpu, msr);
break;
+ case MSR_IA32_SPEC_CTRL:
+ if (!msr->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_IBRS))
+ return 1;
+
+ /* The STIBP bit doesn't fault even if it's not advertised */
+ if (data & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP))
+ return 1;
+
+ svm->spec_ctrl = data;
+
+ if (!data)
+ break;
+
+ /*
+ * For non-nested:
+ * When it's written (to non-zero) for the first time, pass
+ * it through.
+ *
+ * For nested:
+ * The handling of the MSR bitmap for L2 guests is done in
+ * nested_svm_vmrun_msrpm.
+ * We update the L1 MSR bit as well since it will end up
+ * touching the MSR anyway now.
+ */
+ set_msr_interception(svm->msrpm, MSR_IA32_SPEC_CTRL, 1, 1);
+ break;
+ case MSR_IA32_PRED_CMD:
+ if (!msr->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_IBPB))
+ return 1;
+
+ if (data & ~PRED_CMD_IBPB)
+ return 1;
+
+ if (!data)
+ break;
+
+ wrmsrl(MSR_IA32_PRED_CMD, PRED_CMD_IBPB);
+ if (is_guest_mode(vcpu))
+ break;
+ set_msr_interception(svm->msrpm, MSR_IA32_PRED_CMD, 0, 1);
+ break;
case MSR_STAR:
svm->vmcb->save.star = data;
break;
@@ -4936,6 +5022,15 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
local_irq_enable();
+ /*
+ * If this vCPU has touched SPEC_CTRL, restore the guest's value if
+ * it's non-zero. Since vmentry is serialising on affected CPUs, there
+ * is no need to worry about the conditional branch over the wrmsr
+ * being speculatively taken.
+ */
+ if (svm->spec_ctrl)
+ wrmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl);
+
asm volatile (
"push %%" _ASM_BP "; \n\t"
"mov %c[rbx](%[svm]), %%" _ASM_BX " \n\t"
@@ -5028,6 +5123,27 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
#endif
);
+ /*
+ * We do not use IBRS in the kernel. If this vCPU has used the
+ * SPEC_CTRL MSR it may have left it on; save the value and
+ * turn it off. This is much more efficient than blindly adding
+ * it to the atomic save/restore list. Especially as the former
+ * (Saving guest MSRs on vmexit) doesn't even exist in KVM.
+ *
+ * For non-nested case:
+ * If the L01 MSR bitmap does not intercept the MSR, then we need to
+ * save it.
+ *
+ * For nested case:
+ * If the L02 MSR bitmap does not intercept the MSR, then we need to
+ * save it.
+ */
+ if (!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL))
+ rdmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl);
+
+ if (svm->spec_ctrl)
+ wrmsrl(MSR_IA32_SPEC_CTRL, 0);
+
/* Eliminate branch target predictions from guest mode */
vmexit_fill_RSB();
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c829d89e2e63..bee4c49f6dd0 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -34,6 +34,7 @@
#include <linux/tboot.h>
#include <linux/hrtimer.h>
#include <linux/frame.h>
+#include <linux/nospec.h>
#include "kvm_cache_regs.h"
#include "x86.h"
@@ -111,6 +112,14 @@ static u64 __read_mostly host_xss;
static bool __read_mostly enable_pml = 1;
module_param_named(pml, enable_pml, bool, S_IRUGO);
+#define MSR_TYPE_R 1
+#define MSR_TYPE_W 2
+#define MSR_TYPE_RW 3
+
+#define MSR_BITMAP_MODE_X2APIC 1
+#define MSR_BITMAP_MODE_X2APIC_APICV 2
+#define MSR_BITMAP_MODE_LM 4
+
#define KVM_VMX_TSC_MULTIPLIER_MAX 0xffffffffffffffffULL
/* Guest_tsc -> host_tsc conversion requires 64-bit division. */
@@ -185,7 +194,6 @@ module_param(ple_window_max, int, S_IRUGO);
extern const ulong vmx_return;
#define NR_AUTOLOAD_MSRS 8
-#define VMCS02_POOL_SIZE 1
struct vmcs {
u32 revision_id;
@@ -210,6 +218,7 @@ struct loaded_vmcs {
int soft_vnmi_blocked;
ktime_t entry_time;
s64 vnmi_blocked_time;
+ unsigned long *msr_bitmap;
struct list_head loaded_vmcss_on_cpu_link;
};
@@ -226,7 +235,7 @@ struct shared_msr_entry {
* stored in guest memory specified by VMPTRLD, but is opaque to the guest,
* which must access it using VMREAD/VMWRITE/VMCLEAR instructions.
* More than one of these structures may exist, if L1 runs multiple L2 guests.
- * nested_vmx_run() will use the data here to build a vmcs02: a VMCS for the
+ * nested_vmx_run() will use the data here to build the vmcs02: a VMCS for the
* underlying hardware which will be used to run L2.
* This structure is packed to ensure that its layout is identical across
* machines (necessary for live migration).
@@ -409,13 +418,6 @@ struct __packed vmcs12 {
*/
#define VMCS12_SIZE 0x1000
-/* Used to remember the last vmcs02 used for some recently used vmcs12s */
-struct vmcs02_list {
- struct list_head list;
- gpa_t vmptr;
- struct loaded_vmcs vmcs02;
-};
-
/*
* The nested_vmx structure is part of vcpu_vmx, and holds information we need
* for correct emulation of VMX (i.e., nested VMX) on this vcpu.
@@ -440,15 +442,15 @@ struct nested_vmx {
*/
bool sync_shadow_vmcs;
- /* vmcs02_list cache of VMCSs recently used to run L2 guests */
- struct list_head vmcs02_pool;
- int vmcs02_num;
bool change_vmcs01_virtual_x2apic_mode;
/* L2 must run next, and mustn't decide to exit to L1. */
bool nested_run_pending;
+
+ struct loaded_vmcs vmcs02;
+
/*
- * Guest pages referred to in vmcs02 with host-physical pointers, so
- * we must keep them pinned while L2 runs.
+ * Guest pages referred to in the vmcs02 with host-physical
+ * pointers, so we must keep them pinned while L2 runs.
*/
struct page *apic_access_page;
struct page *virtual_apic_page;
@@ -457,8 +459,6 @@ struct nested_vmx {
bool pi_pending;
u16 posted_intr_nv;
- unsigned long *msr_bitmap;
-
struct hrtimer preemption_timer;
bool preemption_timer_expired;
@@ -581,6 +581,7 @@ struct vcpu_vmx {
struct kvm_vcpu vcpu;
unsigned long host_rsp;
u8 fail;
+ u8 msr_bitmap_mode;
u32 exit_intr_info;
u32 idt_vectoring_info;
ulong rflags;
@@ -592,6 +593,10 @@ struct vcpu_vmx {
u64 msr_host_kernel_gs_base;
u64 msr_guest_kernel_gs_base;
#endif
+
+ u64 arch_capabilities;
+ u64 spec_ctrl;
+
u32 vm_entry_controls_shadow;
u32 vm_exit_controls_shadow;
u32 secondary_exec_control;
@@ -898,21 +903,18 @@ static const unsigned short vmcs_field_to_offset_table[] = {
static inline short vmcs_field_to_offset(unsigned long field)
{
- BUILD_BUG_ON(ARRAY_SIZE(vmcs_field_to_offset_table) > SHRT_MAX);
+ const size_t size = ARRAY_SIZE(vmcs_field_to_offset_table);
+ unsigned short offset;
- if (field >= ARRAY_SIZE(vmcs_field_to_offset_table))
+ BUILD_BUG_ON(size > SHRT_MAX);
+ if (field >= size)
return -ENOENT;
- /*
- * FIXME: Mitigation for CVE-2017-5753. To be replaced with a
- * generic mechanism.
- */
- asm("lfence");
-
- if (vmcs_field_to_offset_table[field] == 0)
+ field = array_index_nospec(field, size);
+ offset = vmcs_field_to_offset_table[field];
+ if (offset == 0)
return -ENOENT;
-
- return vmcs_field_to_offset_table[field];
+ return offset;
}
static inline struct vmcs12 *get_vmcs12(struct kvm_vcpu *vcpu)
@@ -935,6 +937,9 @@ static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu);
static void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked);
static bool nested_vmx_is_page_fault_vmexit(struct vmcs12 *vmcs12,
u16 error_code);
+static void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu);
+static void __always_inline vmx_disable_intercept_for_msr(unsigned long *msr_bitmap,
+ u32 msr, int type);
static DEFINE_PER_CPU(struct vmcs *, vmxarea);
static DEFINE_PER_CPU(struct vmcs *, current_vmcs);
@@ -954,12 +959,6 @@ static DEFINE_PER_CPU(spinlock_t, blocked_vcpu_on_cpu_lock);
enum {
VMX_IO_BITMAP_A,
VMX_IO_BITMAP_B,
- VMX_MSR_BITMAP_LEGACY,
- VMX_MSR_BITMAP_LONGMODE,
- VMX_MSR_BITMAP_LEGACY_X2APIC_APICV,
- VMX_MSR_BITMAP_LONGMODE_X2APIC_APICV,
- VMX_MSR_BITMAP_LEGACY_X2APIC,
- VMX_MSR_BITMAP_LONGMODE_X2APIC,
VMX_VMREAD_BITMAP,
VMX_VMWRITE_BITMAP,
VMX_BITMAP_NR
@@ -969,12 +968,6 @@ static unsigned long *vmx_bitmap[VMX_BITMAP_NR];
#define vmx_io_bitmap_a (vmx_bitmap[VMX_IO_BITMAP_A])
#define vmx_io_bitmap_b (vmx_bitmap[VMX_IO_BITMAP_B])
-#define vmx_msr_bitmap_legacy (vmx_bitmap[VMX_MSR_BITMAP_LEGACY])
-#define vmx_msr_bitmap_longmode (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE])
-#define vmx_msr_bitmap_legacy_x2apic_apicv (vmx_bitmap[VMX_MSR_BITMAP_LEGACY_X2APIC_APICV])
-#define vmx_msr_bitmap_longmode_x2apic_apicv (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE_X2APIC_APICV])
-#define vmx_msr_bitmap_legacy_x2apic (vmx_bitmap[VMX_MSR_BITMAP_LEGACY_X2APIC])
-#define vmx_msr_bitmap_longmode_x2apic (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE_X2APIC])
#define vmx_vmread_bitmap (vmx_bitmap[VMX_VMREAD_BITMAP])
#define vmx_vmwrite_bitmap (vmx_bitmap[VMX_VMWRITE_BITMAP])
@@ -1918,6 +1911,52 @@ static void update_exception_bitmap(struct kvm_vcpu *vcpu)
vmcs_write32(EXCEPTION_BITMAP, eb);
}
+/*
+ * Check if MSR is intercepted for currently loaded MSR bitmap.
+ */
+static bool msr_write_intercepted(struct kvm_vcpu *vcpu, u32 msr)
+{
+ unsigned long *msr_bitmap;
+ int f = sizeof(unsigned long);
+
+ if (!cpu_has_vmx_msr_bitmap())
+ return true;
+
+ msr_bitmap = to_vmx(vcpu)->loaded_vmcs->msr_bitmap;
+
+ if (msr <= 0x1fff) {
+ return !!test_bit(msr, msr_bitmap + 0x800 / f);
+ } else if ((msr >= 0xc0000000) && (msr <= 0xc0001fff)) {
+ msr &= 0x1fff;
+ return !!test_bit(msr, msr_bitmap + 0xc00 / f);
+ }
+
+ return true;
+}
+
+/*
+ * Check if MSR is intercepted for L01 MSR bitmap.
+ */
+static bool msr_write_intercepted_l01(struct kvm_vcpu *vcpu, u32 msr)
+{
+ unsigned long *msr_bitmap;
+ int f = sizeof(unsigned long);
+
+ if (!cpu_has_vmx_msr_bitmap())
+ return true;
+
+ msr_bitmap = to_vmx(vcpu)->vmcs01.msr_bitmap;
+
+ if (msr <= 0x1fff) {
+ return !!test_bit(msr, msr_bitmap + 0x800 / f);
+ } else if ((msr >= 0xc0000000) && (msr <= 0xc0001fff)) {
+ msr &= 0x1fff;
+ return !!test_bit(msr, msr_bitmap + 0xc00 / f);
+ }
+
+ return true;
+}
+
static void clear_atomic_switch_msr_special(struct vcpu_vmx *vmx,
unsigned long entry, unsigned long exit)
{
@@ -2296,6 +2335,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
if (per_cpu(current_vmcs, cpu) != vmx->loaded_vmcs->vmcs) {
per_cpu(current_vmcs, cpu) = vmx->loaded_vmcs->vmcs;
vmcs_load(vmx->loaded_vmcs->vmcs);
+ indirect_branch_prediction_barrier();
}
if (!already_loaded) {
@@ -2572,36 +2612,6 @@ static void move_msr_up(struct vcpu_vmx *vmx, int from, int to)
vmx->guest_msrs[from] = tmp;
}
-static void vmx_set_msr_bitmap(struct kvm_vcpu *vcpu)
-{
- unsigned long *msr_bitmap;
-
- if (is_guest_mode(vcpu))
- msr_bitmap = to_vmx(vcpu)->nested.msr_bitmap;
- else if (cpu_has_secondary_exec_ctrls() &&
- (vmcs_read32(SECONDARY_VM_EXEC_CONTROL) &
- SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE)) {
- if (enable_apicv && kvm_vcpu_apicv_active(vcpu)) {
- if (is_long_mode(vcpu))
- msr_bitmap = vmx_msr_bitmap_longmode_x2apic_apicv;
- else
- msr_bitmap = vmx_msr_bitmap_legacy_x2apic_apicv;
- } else {
- if (is_long_mode(vcpu))
- msr_bitmap = vmx_msr_bitmap_longmode_x2apic;
- else
- msr_bitmap = vmx_msr_bitmap_legacy_x2apic;
- }
- } else {
- if (is_long_mode(vcpu))
- msr_bitmap = vmx_msr_bitmap_longmode;
- else
- msr_bitmap = vmx_msr_bitmap_legacy;
- }
-
- vmcs_write64(MSR_BITMAP, __pa(msr_bitmap));
-}
-
/*
* Set up the vmcs to automatically save and restore system
* msrs. Don't touch the 64-bit msrs if the guest is in legacy
@@ -2642,7 +2652,7 @@ static void setup_msrs(struct vcpu_vmx *vmx)
vmx->save_nmsrs = save_nmsrs;
if (cpu_has_vmx_msr_bitmap())
- vmx_set_msr_bitmap(&vmx->vcpu);
+ vmx_update_msr_bitmap(&vmx->vcpu);
}
/*
@@ -3276,6 +3286,20 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_TSC:
msr_info->data = guest_read_tsc(vcpu);
break;
+ case MSR_IA32_SPEC_CTRL:
+ if (!msr_info->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_IBRS) &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))
+ return 1;
+
+ msr_info->data = to_vmx(vcpu)->spec_ctrl;
+ break;
+ case MSR_IA32_ARCH_CAPABILITIES:
+ if (!msr_info->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_ARCH_CAPABILITIES))
+ return 1;
+ msr_info->data = to_vmx(vcpu)->arch_capabilities;
+ break;
case MSR_IA32_SYSENTER_CS:
msr_info->data = vmcs_read32(GUEST_SYSENTER_CS);
break;
@@ -3383,6 +3407,70 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_TSC:
kvm_write_tsc(vcpu, msr_info);
break;
+ case MSR_IA32_SPEC_CTRL:
+ if (!msr_info->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_IBRS) &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))
+ return 1;
+
+ /* The STIBP bit doesn't fault even if it's not advertised */
+ if (data & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP))
+ return 1;
+
+ vmx->spec_ctrl = data;
+
+ if (!data)
+ break;
+
+ /*
+ * For non-nested:
+ * When it's written (to non-zero) for the first time, pass
+ * it through.
+ *
+ * For nested:
+ * The handling of the MSR bitmap for L2 guests is done in
+ * nested_vmx_merge_msr_bitmap. We should not touch the
+ * vmcs02.msr_bitmap here since it gets completely overwritten
+ * in the merging. We update the vmcs01 here for L1 as well
+ * since it will end up touching the MSR anyway now.
+ */
+ vmx_disable_intercept_for_msr(vmx->vmcs01.msr_bitmap,
+ MSR_IA32_SPEC_CTRL,
+ MSR_TYPE_RW);
+ break;
+ case MSR_IA32_PRED_CMD:
+ if (!msr_info->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_IBPB) &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))
+ return 1;
+
+ if (data & ~PRED_CMD_IBPB)
+ return 1;
+
+ if (!data)
+ break;
+
+ wrmsrl(MSR_IA32_PRED_CMD, PRED_CMD_IBPB);
+
+ /*
+ * For non-nested:
+ * When it's written (to non-zero) for the first time, pass
+ * it through.
+ *
+ * For nested:
+ * The handling of the MSR bitmap for L2 guests is done in
+ * nested_vmx_merge_msr_bitmap. We should not touch the
+ * vmcs02.msr_bitmap here since it gets completely overwritten
+ * in the merging.
+ */
+ vmx_disable_intercept_for_msr(vmx->vmcs01.msr_bitmap, MSR_IA32_PRED_CMD,
+ MSR_TYPE_W);
+ break;
+ case MSR_IA32_ARCH_CAPABILITIES:
+ if (!msr_info->host_initiated)
+ return 1;
+ vmx->arch_capabilities = data;
+ break;
case MSR_IA32_CR_PAT:
if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) {
if (!kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, data))
@@ -3837,11 +3925,6 @@ static struct vmcs *alloc_vmcs_cpu(int cpu)
return vmcs;
}
-static struct vmcs *alloc_vmcs(void)
-{
- return alloc_vmcs_cpu(raw_smp_processor_id());
-}
-
static void free_vmcs(struct vmcs *vmcs)
{
free_pages((unsigned long)vmcs, vmcs_config.order);
@@ -3857,9 +3940,38 @@ static void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs)
loaded_vmcs_clear(loaded_vmcs);
free_vmcs(loaded_vmcs->vmcs);
loaded_vmcs->vmcs = NULL;
+ if (loaded_vmcs->msr_bitmap)
+ free_page((unsigned long)loaded_vmcs->msr_bitmap);
WARN_ON(loaded_vmcs->shadow_vmcs != NULL);
}
+static struct vmcs *alloc_vmcs(void)
+{
+ return alloc_vmcs_cpu(raw_smp_processor_id());
+}
+
+static int alloc_loaded_vmcs(struct loaded_vmcs *loaded_vmcs)
+{
+ loaded_vmcs->vmcs = alloc_vmcs();
+ if (!loaded_vmcs->vmcs)
+ return -ENOMEM;
+
+ loaded_vmcs->shadow_vmcs = NULL;
+ loaded_vmcs_init(loaded_vmcs);
+
+ if (cpu_has_vmx_msr_bitmap()) {
+ loaded_vmcs->msr_bitmap = (unsigned long *)__get_free_page(GFP_KERNEL);
+ if (!loaded_vmcs->msr_bitmap)
+ goto out_vmcs;
+ memset(loaded_vmcs->msr_bitmap, 0xff, PAGE_SIZE);
+ }
+ return 0;
+
+out_vmcs:
+ free_loaded_vmcs(loaded_vmcs);
+ return -ENOMEM;
+}
+
static void free_kvm_area(void)
{
int cpu;
@@ -4918,10 +5030,8 @@ static void free_vpid(int vpid)
spin_unlock(&vmx_vpid_lock);
}
-#define MSR_TYPE_R 1
-#define MSR_TYPE_W 2
-static void __vmx_disable_intercept_for_msr(unsigned long *msr_bitmap,
- u32 msr, int type)
+static void __always_inline vmx_disable_intercept_for_msr(unsigned long *msr_bitmap,
+ u32 msr, int type)
{
int f = sizeof(unsigned long);
@@ -4955,6 +5065,50 @@ static void __vmx_disable_intercept_for_msr(unsigned long *msr_bitmap,
}
}
+static void __always_inline vmx_enable_intercept_for_msr(unsigned long *msr_bitmap,
+ u32 msr, int type)
+{
+ int f = sizeof(unsigned long);
+
+ if (!cpu_has_vmx_msr_bitmap())
+ return;
+
+ /*
+ * See Intel PRM Vol. 3, 20.6.9 (MSR-Bitmap Address). Early manuals
+ * have the write-low and read-high bitmap offsets the wrong way round.
+ * We can control MSRs 0x00000000-0x00001fff and 0xc0000000-0xc0001fff.
+ */
+ if (msr <= 0x1fff) {
+ if (type & MSR_TYPE_R)
+ /* read-low */
+ __set_bit(msr, msr_bitmap + 0x000 / f);
+
+ if (type & MSR_TYPE_W)
+ /* write-low */
+ __set_bit(msr, msr_bitmap + 0x800 / f);
+
+ } else if ((msr >= 0xc0000000) && (msr <= 0xc0001fff)) {
+ msr &= 0x1fff;
+ if (type & MSR_TYPE_R)
+ /* read-high */
+ __set_bit(msr, msr_bitmap + 0x400 / f);
+
+ if (type & MSR_TYPE_W)
+ /* write-high */
+ __set_bit(msr, msr_bitmap + 0xc00 / f);
+
+ }
+}
+
+static void __always_inline vmx_set_intercept_for_msr(unsigned long *msr_bitmap,
+ u32 msr, int type, bool value)
+{
+ if (value)
+ vmx_enable_intercept_for_msr(msr_bitmap, msr, type);
+ else
+ vmx_disable_intercept_for_msr(msr_bitmap, msr, type);
+}
+
/*
* If a msr is allowed by L0, we should check whether it is allowed by L1.
* The corresponding bit will be cleared unless both of L0 and L1 allow it.
@@ -5001,30 +5155,70 @@ static void nested_vmx_disable_intercept_for_msr(unsigned long *msr_bitmap_l1,
}
}
-static void vmx_disable_intercept_for_msr(u32 msr, bool longmode_only)
+static u8 vmx_msr_bitmap_mode(struct kvm_vcpu *vcpu)
{
- if (!longmode_only)
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy,
- msr, MSR_TYPE_R | MSR_TYPE_W);
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode,
- msr, MSR_TYPE_R | MSR_TYPE_W);
+ u8 mode = 0;
+
+ if (cpu_has_secondary_exec_ctrls() &&
+ (vmcs_read32(SECONDARY_VM_EXEC_CONTROL) &
+ SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE)) {
+ mode |= MSR_BITMAP_MODE_X2APIC;
+ if (enable_apicv && kvm_vcpu_apicv_active(vcpu))
+ mode |= MSR_BITMAP_MODE_X2APIC_APICV;
+ }
+
+ if (is_long_mode(vcpu))
+ mode |= MSR_BITMAP_MODE_LM;
+
+ return mode;
}
-static void vmx_disable_intercept_msr_x2apic(u32 msr, int type, bool apicv_active)
+#define X2APIC_MSR(r) (APIC_BASE_MSR + ((r) >> 4))
+
+static void vmx_update_msr_bitmap_x2apic(unsigned long *msr_bitmap,
+ u8 mode)
{
- if (apicv_active) {
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy_x2apic_apicv,
- msr, type);
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode_x2apic_apicv,
- msr, type);
- } else {
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy_x2apic,
- msr, type);
- __vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode_x2apic,
- msr, type);
+ int msr;
+
+ for (msr = 0x800; msr <= 0x8ff; msr += BITS_PER_LONG) {
+ unsigned word = msr / BITS_PER_LONG;
+ msr_bitmap[word] = (mode & MSR_BITMAP_MODE_X2APIC_APICV) ? 0 : ~0;
+ msr_bitmap[word + (0x800 / sizeof(long))] = ~0;
+ }
+
+ if (mode & MSR_BITMAP_MODE_X2APIC) {
+ /*
+ * TPR reads and writes can be virtualized even if virtual interrupt
+ * delivery is not in use.
+ */
+ vmx_disable_intercept_for_msr(msr_bitmap, X2APIC_MSR(APIC_TASKPRI), MSR_TYPE_RW);
+ if (mode & MSR_BITMAP_MODE_X2APIC_APICV) {
+ vmx_enable_intercept_for_msr(msr_bitmap, X2APIC_MSR(APIC_TMCCT), MSR_TYPE_R);
+ vmx_disable_intercept_for_msr(msr_bitmap, X2APIC_MSR(APIC_EOI), MSR_TYPE_W);
+ vmx_disable_intercept_for_msr(msr_bitmap, X2APIC_MSR(APIC_SELF_IPI), MSR_TYPE_W);
+ }
}
}
+static void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ unsigned long *msr_bitmap = vmx->vmcs01.msr_bitmap;
+ u8 mode = vmx_msr_bitmap_mode(vcpu);
+ u8 changed = mode ^ vmx->msr_bitmap_mode;
+
+ if (!changed)
+ return;
+
+ vmx_set_intercept_for_msr(msr_bitmap, MSR_KERNEL_GS_BASE, MSR_TYPE_RW,
+ !(mode & MSR_BITMAP_MODE_LM));
+
+ if (changed & (MSR_BITMAP_MODE_X2APIC | MSR_BITMAP_MODE_X2APIC_APICV))
+ vmx_update_msr_bitmap_x2apic(msr_bitmap, mode);
+
+ vmx->msr_bitmap_mode = mode;
+}
+
static bool vmx_get_enable_apicv(struct kvm_vcpu *vcpu)
{
return enable_apicv;
@@ -5274,7 +5468,7 @@ static void vmx_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
}
if (cpu_has_vmx_msr_bitmap())
- vmx_set_msr_bitmap(vcpu);
+ vmx_update_msr_bitmap(vcpu);
}
static u32 vmx_exec_control(struct vcpu_vmx *vmx)
@@ -5461,7 +5655,7 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx)
vmcs_write64(VMWRITE_BITMAP, __pa(vmx_vmwrite_bitmap));
}
if (cpu_has_vmx_msr_bitmap())
- vmcs_write64(MSR_BITMAP, __pa(vmx_msr_bitmap_legacy));
+ vmcs_write64(MSR_BITMAP, __pa(vmx->vmcs01.msr_bitmap));
vmcs_write64(VMCS_LINK_POINTER, -1ull); /* 22.3.1.5 */
@@ -5539,6 +5733,8 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx)
++vmx->nmsrs;
}
+ if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES))
+ rdmsrl(MSR_IA32_ARCH_CAPABILITIES, vmx->arch_capabilities);
vm_exit_controls_init(vmx, vmcs_config.vmexit_ctrl);
@@ -5567,6 +5763,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
u64 cr0;
vmx->rmode.vm86_active = 0;
+ vmx->spec_ctrl = 0;
vmx->vcpu.arch.regs[VCPU_REGS_RDX] = get_rdx_init_val();
kvm_set_cr8(vcpu, 0);
@@ -6744,7 +6941,7 @@ void vmx_enable_tdp(void)
static __init int hardware_setup(void)
{
- int r = -ENOMEM, i, msr;
+ int r = -ENOMEM, i;
rdmsrl_safe(MSR_EFER, &host_efer);
@@ -6764,9 +6961,6 @@ static __init int hardware_setup(void)
memset(vmx_io_bitmap_b, 0xff, PAGE_SIZE);
- memset(vmx_msr_bitmap_legacy, 0xff, PAGE_SIZE);
- memset(vmx_msr_bitmap_longmode, 0xff, PAGE_SIZE);
-
if (setup_vmcs_config(&vmcs_config) < 0) {
r = -EIO;
goto out;
@@ -6835,42 +7029,8 @@ static __init int hardware_setup(void)
kvm_tsc_scaling_ratio_frac_bits = 48;
}
- vmx_disable_intercept_for_msr(MSR_FS_BASE, false);
- vmx_disable_intercept_for_msr(MSR_GS_BASE, false);
- vmx_disable_intercept_for_msr(MSR_KERNEL_GS_BASE, true);
- vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_CS, false);
- vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_ESP, false);
- vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
-
- memcpy(vmx_msr_bitmap_legacy_x2apic_apicv,
- vmx_msr_bitmap_legacy, PAGE_SIZE);
- memcpy(vmx_msr_bitmap_longmode_x2apic_apicv,
- vmx_msr_bitmap_longmode, PAGE_SIZE);
- memcpy(vmx_msr_bitmap_legacy_x2apic,
- vmx_msr_bitmap_legacy, PAGE_SIZE);
- memcpy(vmx_msr_bitmap_longmode_x2apic,
- vmx_msr_bitmap_longmode, PAGE_SIZE);
-
set_bit(0, vmx_vpid_bitmap); /* 0 is reserved for host */
- for (msr = 0x800; msr <= 0x8ff; msr++) {
- if (msr == 0x839 /* TMCCT */)
- continue;
- vmx_disable_intercept_msr_x2apic(msr, MSR_TYPE_R, true);
- }
-
- /*
- * TPR reads and writes can be virtualized even if virtual interrupt
- * delivery is not in use.
- */
- vmx_disable_intercept_msr_x2apic(0x808, MSR_TYPE_W, true);
- vmx_disable_intercept_msr_x2apic(0x808, MSR_TYPE_R | MSR_TYPE_W, false);
-
- /* EOI */
- vmx_disable_intercept_msr_x2apic(0x80b, MSR_TYPE_W, true);
- /* SELF-IPI */
- vmx_disable_intercept_msr_x2apic(0x83f, MSR_TYPE_W, true);
-
if (enable_ept)
vmx_enable_tdp();
else
@@ -6973,94 +7133,6 @@ static int handle_monitor(struct kvm_vcpu *vcpu)
return handle_nop(vcpu);
}
-/*
- * To run an L2 guest, we need a vmcs02 based on the L1-specified vmcs12.
- * We could reuse a single VMCS for all the L2 guests, but we also want the
- * option to allocate a separate vmcs02 for each separate loaded vmcs12 - this
- * allows keeping them loaded on the processor, and in the future will allow
- * optimizations where prepare_vmcs02 doesn't need to set all the fields on
- * every entry if they never change.
- * So we keep, in vmx->nested.vmcs02_pool, a cache of size VMCS02_POOL_SIZE
- * (>=0) with a vmcs02 for each recently loaded vmcs12s, most recent first.
- *
- * The following functions allocate and free a vmcs02 in this pool.
- */
-
-/* Get a VMCS from the pool to use as vmcs02 for the current vmcs12. */
-static struct loaded_vmcs *nested_get_current_vmcs02(struct vcpu_vmx *vmx)
-{
- struct vmcs02_list *item;
- list_for_each_entry(item, &vmx->nested.vmcs02_pool, list)
- if (item->vmptr == vmx->nested.current_vmptr) {
- list_move(&item->list, &vmx->nested.vmcs02_pool);
- return &item->vmcs02;
- }
-
- if (vmx->nested.vmcs02_num >= max(VMCS02_POOL_SIZE, 1)) {
- /* Recycle the least recently used VMCS. */
- item = list_last_entry(&vmx->nested.vmcs02_pool,
- struct vmcs02_list, list);
- item->vmptr = vmx->nested.current_vmptr;
- list_move(&item->list, &vmx->nested.vmcs02_pool);
- return &item->vmcs02;
- }
-
- /* Create a new VMCS */
- item = kzalloc(sizeof(struct vmcs02_list), GFP_KERNEL);
- if (!item)
- return NULL;
- item->vmcs02.vmcs = alloc_vmcs();
- item->vmcs02.shadow_vmcs = NULL;
- if (!item->vmcs02.vmcs) {
- kfree(item);
- return NULL;
- }
- loaded_vmcs_init(&item->vmcs02);
- item->vmptr = vmx->nested.current_vmptr;
- list_add(&(item->list), &(vmx->nested.vmcs02_pool));
- vmx->nested.vmcs02_num++;
- return &item->vmcs02;
-}
-
-/* Free and remove from pool a vmcs02 saved for a vmcs12 (if there is one) */
-static void nested_free_vmcs02(struct vcpu_vmx *vmx, gpa_t vmptr)
-{
- struct vmcs02_list *item;
- list_for_each_entry(item, &vmx->nested.vmcs02_pool, list)
- if (item->vmptr == vmptr) {
- free_loaded_vmcs(&item->vmcs02);
- list_del(&item->list);
- kfree(item);
- vmx->nested.vmcs02_num--;
- return;
- }
-}
-
-/*
- * Free all VMCSs saved for this vcpu, except the one pointed by
- * vmx->loaded_vmcs. We must be running L1, so vmx->loaded_vmcs
- * must be &vmx->vmcs01.
- */
-static void nested_free_all_saved_vmcss(struct vcpu_vmx *vmx)
-{
- struct vmcs02_list *item, *n;
-
- WARN_ON(vmx->loaded_vmcs != &vmx->vmcs01);
- list_for_each_entry_safe(item, n, &vmx->nested.vmcs02_pool, list) {
- /*
- * Something will leak if the above WARN triggers. Better than
- * a use-after-free.
- */
- if (vmx->loaded_vmcs == &item->vmcs02)
- continue;
-
- free_loaded_vmcs(&item->vmcs02);
- list_del(&item->list);
- kfree(item);
- vmx->nested.vmcs02_num--;
- }
-}
-
/*
* The following 3 functions, nested_vmx_succeed()/failValid()/failInvalid(),
* set the success or error code of an emulated VMX instruction, as specified
@@ -7241,13 +7313,11 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
struct vmcs *shadow_vmcs;
+ int r;
- if (cpu_has_vmx_msr_bitmap()) {
- vmx->nested.msr_bitmap =
- (unsigned long *)__get_free_page(GFP_KERNEL);
- if (!vmx->nested.msr_bitmap)
- goto out_msr_bitmap;
- }
+ r = alloc_loaded_vmcs(&vmx->nested.vmcs02);
+ if (r < 0)
+ goto out_vmcs02;
vmx->nested.cached_vmcs12 = kmalloc(VMCS12_SIZE, GFP_KERNEL);
if (!vmx->nested.cached_vmcs12)
@@ -7264,9 +7334,6 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu)
vmx->vmcs01.shadow_vmcs = shadow_vmcs;
}
- INIT_LIST_HEAD(&(vmx->nested.vmcs02_pool));
- vmx->nested.vmcs02_num = 0;
-
hrtimer_init(&vmx->nested.preemption_timer, CLOCK_MONOTONIC,
HRTIMER_MODE_REL_PINNED);
vmx->nested.preemption_timer.function = vmx_preemption_timer_fn;
@@ -7278,9 +7345,9 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu)
kfree(vmx->nested.cached_vmcs12);
out_cached_vmcs12:
- free_page((unsigned long)vmx->nested.msr_bitmap);
+ free_loaded_vmcs(&vmx->nested.vmcs02);
-out_msr_bitmap:
+out_vmcs02:
return -ENOMEM;
}
@@ -7423,10 +7490,6 @@ static void free_nested(struct vcpu_vmx *vmx)
free_vpid(vmx->nested.vpid02);
vmx->nested.posted_intr_nv = -1;
vmx->nested.current_vmptr = -1ull;
- if (vmx->nested.msr_bitmap) {
- free_page((unsigned long)vmx->nested.msr_bitmap);
- vmx->nested.msr_bitmap = NULL;
- }
if (enable_shadow_vmcs) {
vmx_disable_shadow_vmcs(vmx);
vmcs_clear(vmx->vmcs01.shadow_vmcs);
@@ -7434,7 +7497,7 @@ static void free_nested(struct vcpu_vmx *vmx)
vmx->vmcs01.shadow_vmcs = NULL;
}
kfree(vmx->nested.cached_vmcs12);
- /* Unpin physical memory we referred to in current vmcs02 */
+ /* Unpin physical memory we referred to in the vmcs02 */
if (vmx->nested.apic_access_page) {
kvm_release_page_dirty(vmx->nested.apic_access_page);
vmx->nested.apic_access_page = NULL;
@@ -7450,7 +7513,7 @@ static void free_nested(struct vcpu_vmx *vmx)
vmx->nested.pi_desc = NULL;
}
- nested_free_all_saved_vmcss(vmx);
+ free_loaded_vmcs(&vmx->nested.vmcs02);
}
/* Emulate the VMXOFF instruction */
@@ -7493,8 +7556,6 @@ static int handle_vmclear(struct kvm_vcpu *vcpu)
vmptr + offsetof(struct vmcs12, launch_state),
&zero, sizeof(zero));
- nested_free_vmcs02(vmx, vmptr);
-
nested_vmx_succeed(vcpu);
return kvm_skip_emulated_instruction(vcpu);
}
@@ -8406,10 +8467,11 @@ static bool nested_vmx_exit_reflected(struct kvm_vcpu *vcpu, u32 exit_reason)
/*
* The host physical addresses of some pages of guest memory
- * are loaded into VMCS02 (e.g. L1's Virtual APIC Page). The CPU
- * may write to these pages via their host physical address while
- * L2 is running, bypassing any address-translation-based dirty
- * tracking (e.g. EPT write protection).
+ * are loaded into the vmcs02 (e.g. vmcs12's Virtual APIC
+ * Page). The CPU may write to these pages via their host
+ * physical address while L2 is running, bypassing any
+ * address-translation-based dirty tracking (e.g. EPT write
+ * protection).
*
* Mark them dirty on every exit from L2 to prevent them from
* getting out of sync with dirty tracking.
@@ -8943,7 +9005,7 @@ static void vmx_set_virtual_x2apic_mode(struct kvm_vcpu *vcpu, bool set)
}
vmcs_write32(SECONDARY_VM_EXEC_CONTROL, sec_exec_control);
- vmx_set_msr_bitmap(vcpu);
+ vmx_update_msr_bitmap(vcpu);
}
static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu, hpa_t hpa)
@@ -9129,14 +9191,14 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
#endif
"pushf\n\t"
__ASM_SIZE(push) " $%c[cs]\n\t"
- "call *%[entry]\n\t"
+ CALL_NOSPEC
:
#ifdef CONFIG_X86_64
[sp]"=&r"(tmp),
#endif
ASM_CALL_CONSTRAINT
:
- [entry]"r"(entry),
+ THUNK_TARGET(entry),
[ss]"i"(__KERNEL_DS),
[cs]"i"(__KERNEL_CS)
);
@@ -9373,6 +9435,15 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
vmx_arm_hv_timer(vcpu);
+ /*
+ * If this vCPU has touched SPEC_CTRL, restore the guest's value if
+ * it's non-zero. Since vmentry is serialising on affected CPUs, there
+ * is no need to worry about the conditional branch over the wrmsr
+ * being speculatively taken.
+ */
+ if (vmx->spec_ctrl)
+ wrmsrl(MSR_IA32_SPEC_CTRL, vmx->spec_ctrl);
+
vmx->__launched = vmx->loaded_vmcs->launched;
asm(
/* Store host registers */
@@ -9491,6 +9562,27 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
#endif
);
+ /*
+ * We do not use IBRS in the kernel. If this vCPU has used the
+ * SPEC_CTRL MSR it may have left it on; save the value and
+ * turn it off. This is much more efficient than blindly adding
+ * it to the atomic save/restore list. Especially as the former
+ * (Saving guest MSRs on vmexit) doesn't even exist in KVM.
+ *
+ * For non-nested case:
+ * If the L01 MSR bitmap does not intercept the MSR, then we need to
+ * save it.
+ *
+ * For nested case:
+ * If the L02 MSR bitmap does not intercept the MSR, then we need to
+ * save it.
+ */
+ if (!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL))
+ rdmsrl(MSR_IA32_SPEC_CTRL, vmx->spec_ctrl);
+
+ if (vmx->spec_ctrl)
+ wrmsrl(MSR_IA32_SPEC_CTRL, 0);
+
/* Eliminate branch target predictions from guest mode */
vmexit_fill_RSB();
@@ -9604,6 +9696,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
{
int err;
struct vcpu_vmx *vmx = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
+ unsigned long *msr_bitmap;
int cpu;
if (!vmx)
@@ -9636,13 +9729,20 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
if (!vmx->guest_msrs)
goto free_pml;
- vmx->loaded_vmcs = &vmx->vmcs01;
- vmx->loaded_vmcs->vmcs = alloc_vmcs();
- vmx->loaded_vmcs->shadow_vmcs = NULL;
- if (!vmx->loaded_vmcs->vmcs)
+ err = alloc_loaded_vmcs(&vmx->vmcs01);
+ if (err < 0)
goto free_msrs;
- loaded_vmcs_init(vmx->loaded_vmcs);
+ msr_bitmap = vmx->vmcs01.msr_bitmap;
+ vmx_disable_intercept_for_msr(msr_bitmap, MSR_FS_BASE, MSR_TYPE_RW);
+ vmx_disable_intercept_for_msr(msr_bitmap, MSR_GS_BASE, MSR_TYPE_RW);
+ vmx_disable_intercept_for_msr(msr_bitmap, MSR_KERNEL_GS_BASE, MSR_TYPE_RW);
+ vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_SYSENTER_CS, MSR_TYPE_RW);
+ vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_SYSENTER_ESP, MSR_TYPE_RW);
+ vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_SYSENTER_EIP, MSR_TYPE_RW);
+ vmx->msr_bitmap_mode = 0;
+
+ vmx->loaded_vmcs = &vmx->vmcs01;
cpu = get_cpu();
vmx_vcpu_load(&vmx->vcpu, cpu);
vmx->vcpu.cpu = cpu;
@@ -10105,10 +10205,25 @@ static inline bool nested_vmx_merge_msr_bitmap(struct kvm_vcpu *vcpu,
int msr;
struct page *page;
unsigned long *msr_bitmap_l1;
- unsigned long *msr_bitmap_l0 = to_vmx(vcpu)->nested.msr_bitmap;
+ unsigned long *msr_bitmap_l0 = to_vmx(vcpu)->nested.vmcs02.msr_bitmap;
+ /*
+ * pred_cmd & spec_ctrl are trying to verify two things:
+ *
+ * 1. L0 gave a permission to L1 to actually passthrough the MSR. This
+ * ensures that we do not accidentally generate an L02 MSR bitmap
+ * from the L12 MSR bitmap that is too permissive.
+ * 2. That L1 or L2s have actually used the MSR. This avoids
+ * unnecessarily merging of the bitmap if the MSR is unused. This
+ * works properly because we only update the L01 MSR bitmap lazily.
+ * So even if L0 should pass L1 these MSRs, the L01 bitmap is only
+ * updated to reflect this when L1 (or its L2s) actually write to
+ * the MSR.
+ */
+ bool pred_cmd = msr_write_intercepted_l01(vcpu, MSR_IA32_PRED_CMD);
+ bool spec_ctrl = msr_write_intercepted_l01(vcpu, MSR_IA32_SPEC_CTRL);
- /* This shortcut is ok because we support only x2APIC MSRs so far. */
- if (!nested_cpu_has_virt_x2apic_mode(vmcs12))
+ if (!nested_cpu_has_virt_x2apic_mode(vmcs12) &&
+ !pred_cmd && !spec_ctrl)
return false;
page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->msr_bitmap);
@@ -10141,6 +10256,19 @@ static inline bool nested_vmx_merge_msr_bitmap(struct kvm_vcpu *vcpu,
MSR_TYPE_W);
}
}
+
+ if (spec_ctrl)
+ nested_vmx_disable_intercept_for_msr(
+ msr_bitmap_l1, msr_bitmap_l0,
+ MSR_IA32_SPEC_CTRL,
+ MSR_TYPE_R | MSR_TYPE_W);
+
+ if (pred_cmd)
+ nested_vmx_disable_intercept_for_msr(
+ msr_bitmap_l1, msr_bitmap_l0,
+ MSR_IA32_PRED_CMD,
+ MSR_TYPE_W);
+
kunmap(page);
kvm_release_page_clean(page);
@@ -10682,6 +10810,9 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
if (kvm_has_tsc_control)
decache_tsc_multiplier(vmx);
+ if (cpu_has_vmx_msr_bitmap())
+ vmcs_write64(MSR_BITMAP, __pa(vmx->nested.vmcs02.msr_bitmap));
+
if (enable_vpid) {
/*
* There is no direct mapping between vpid02 and vpid12, the
@@ -10903,20 +11034,15 @@ static int enter_vmx_non_root_mode(struct kvm_vcpu *vcpu, bool from_vmentry)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
- struct loaded_vmcs *vmcs02;
u32 msr_entry_idx;
u32 exit_qual;
- vmcs02 = nested_get_current_vmcs02(vmx);
- if (!vmcs02)
- return -ENOMEM;
-
enter_guest_mode(vcpu);
if (!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS))
vmx->nested.vmcs01_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL);
- vmx_switch_vmcs(vcpu, vmcs02);
+ vmx_switch_vmcs(vcpu, &vmx->nested.vmcs02);
vmx_segment_cache_clear(vmx);
if (prepare_vmcs02(vcpu, vmcs12, from_vmentry, &exit_qual)) {
@@ -11485,7 +11611,7 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
if (cpu_has_vmx_msr_bitmap())
- vmx_set_msr_bitmap(vcpu);
+ vmx_update_msr_bitmap(vcpu);
if (nested_vmx_load_msr(vcpu, vmcs12->vm_exit_msr_load_addr,
vmcs12->vm_exit_msr_load_count))
@@ -11534,10 +11660,6 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
vm_exit_controls_reset_shadow(vmx);
vmx_segment_cache_clear(vmx);
- /* if no vmcs02 cache requested, remove the one we used */
- if (VMCS02_POOL_SIZE == 0)
- nested_free_vmcs02(vmx, vmx->nested.current_vmptr);
-
/* Update any VMCS fields that might have changed while L2 ran */
vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.nr);
vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.nr);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c53298dfbf50..ac381437c291 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1009,6 +1009,7 @@ static u32 msrs_to_save[] = {
#endif
MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
MSR_IA32_FEATURE_CONTROL, MSR_IA32_BNDCFGS, MSR_TSC_AUX,
+ MSR_IA32_SPEC_CTRL, MSR_IA32_ARCH_CAPABILITIES
};
static unsigned num_msrs_to_save;
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index f23934bbaf4e..69a473919260 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -27,6 +27,7 @@ lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o
lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
lib-$(CONFIG_RETPOLINE) += retpoline.o
+OBJECT_FILES_NON_STANDARD_retpoline.o :=y
obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o
diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S
index c97d935a29e8..49b167f73215 100644
--- a/arch/x86/lib/getuser.S
+++ b/arch/x86/lib/getuser.S
@@ -40,6 +40,8 @@ ENTRY(__get_user_1)
mov PER_CPU_VAR(current_task), %_ASM_DX
cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
jae bad_get_user
+ sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */
+ and %_ASM_DX, %_ASM_AX
ASM_STAC
1: movzbl (%_ASM_AX),%edx
xor %eax,%eax
@@ -54,6 +56,8 @@ ENTRY(__get_user_2)
mov PER_CPU_VAR(current_task), %_ASM_DX
cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
jae bad_get_user
+ sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */
+ and %_ASM_DX, %_ASM_AX
ASM_STAC
2: movzwl -1(%_ASM_AX),%edx
xor %eax,%eax
@@ -68,6 +72,8 @@ ENTRY(__get_user_4)
mov PER_CPU_VAR(current_task), %_ASM_DX
cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
jae bad_get_user
+ sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */
+ and %_ASM_DX, %_ASM_AX
ASM_STAC
3: movl -3(%_ASM_AX),%edx
xor %eax,%eax
@@ -83,6 +89,8 @@ ENTRY(__get_user_8)
mov PER_CPU_VAR(current_task), %_ASM_DX
cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
jae bad_get_user
+ sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */
+ and %_ASM_DX, %_ASM_AX
ASM_STAC
4: movq -7(%_ASM_AX),%rdx
xor %eax,%eax
@@ -94,6 +102,8 @@ ENTRY(__get_user_8)
mov PER_CPU_VAR(current_task), %_ASM_DX
cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
jae bad_get_user_8
+ sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */
+ and %_ASM_DX, %_ASM_AX
ASM_STAC
4: movl -7(%_ASM_AX),%edx
5: movl -3(%_ASM_AX),%ecx
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index c909961e678a..480edc3a5e03 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -7,6 +7,7 @@
#include <asm/alternative-asm.h>
#include <asm/export.h>
#include <asm/nospec-branch.h>
+#include <asm/bitsperlong.h>
.macro THUNK reg
.section .text.__x86.indirect_thunk
@@ -46,3 +47,58 @@ GENERATE_THUNK(r13)
GENERATE_THUNK(r14)
GENERATE_THUNK(r15)
#endif
+
+/*
+ * Fill the CPU return stack buffer.
+ *
+ * Each entry in the RSB, if used for a speculative 'ret', contains an
+ * infinite 'pause; lfence; jmp' loop to capture speculative execution.
+ *
+ * This is required in various cases for retpoline and IBRS-based
+ * mitigations for the Spectre variant 2 vulnerability. Sometimes to
+ * eliminate potentially bogus entries from the RSB, and sometimes
+ * purely to ensure that it doesn't get empty, which on some CPUs would
+ * allow predictions from other (unwanted!) sources to be used.
+ *
+ * Google experimented with loop-unrolling and this turned out to be
+ * the optimal version - two calls, each with their own speculation
+ * trap should their return address end up getting used, in a loop.
+ */
+.macro STUFF_RSB nr:req sp:req
+ mov $(\nr / 2), %_ASM_BX
+ .align 16
+771:
+ call 772f
+773: /* speculation trap */
+ pause
+ lfence
+ jmp 773b
+ .align 16
+772:
+ call 774f
+775: /* speculation trap */
+ pause
+ lfence
+ jmp 775b
+ .align 16
+774:
+ dec %_ASM_BX
+ jnz 771b
+ add $((BITS_PER_LONG/8) * \nr), \sp
+.endm
+
+#define RSB_FILL_LOOPS 16 /* To avoid underflow */
+
+ENTRY(__fill_rsb)
+ STUFF_RSB RSB_FILL_LOOPS, %_ASM_SP
+ ret
+END(__fill_rsb)
+EXPORT_SYMBOL_GPL(__fill_rsb)
+
+#define RSB_CLEAR_LOOPS 32 /* To forcibly overwrite all entries */
+
+ENTRY(__clear_rsb)
+ STUFF_RSB RSB_CLEAR_LOOPS, %_ASM_SP
+ ret
+END(__clear_rsb)
+EXPORT_SYMBOL_GPL(__clear_rsb)
diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c
index 1b377f734e64..7add8ba06887 100644
--- a/arch/x86/lib/usercopy_32.c
+++ b/arch/x86/lib/usercopy_32.c
@@ -331,12 +331,12 @@ do { \
unsigned long __copy_user_ll(void *to, const void *from, unsigned long n)
{
- stac();
+ __uaccess_begin_nospec();
if (movsl_is_ok(to, from, n))
__copy_user(to, from, n);
else
n = __copy_user_intel(to, from, n);
- clac();
+ __uaccess_end();
return n;
}
EXPORT_SYMBOL(__copy_user_ll);
@@ -344,7 +344,7 @@ EXPORT_SYMBOL(__copy_user_ll);
unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *from,
unsigned long n)
{
- stac();
+ __uaccess_begin_nospec();
#ifdef CONFIG_X86_INTEL_USERCOPY
if (n > 64 && static_cpu_has(X86_FEATURE_XMM2))
n = __copy_user_intel_nocache(to, from, n);
@@ -353,7 +353,7 @@ unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *fr
#else
__copy_user(to, from, n);
#endif
- clac();
+ __uaccess_end();
return n;
}
EXPORT_SYMBOL(__copy_from_user_ll_nocache_nozero);
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 5bfe61a5e8e3..012d02624848 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -6,13 +6,14 @@
#include <linux/interrupt.h>
#include <linux/export.h>
#include <linux/cpu.h>
+#include <linux/debugfs.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
+#include <asm/nospec-branch.h>
#include <asm/cache.h>
#include <asm/apic.h>
#include <asm/uv/uv.h>
-#include <linux/debugfs.h>
/*
* TLB flushing, formerly SMP-only
@@ -247,6 +248,27 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
} else {
u16 new_asid;
bool need_flush;
+ u64 last_ctx_id = this_cpu_read(cpu_tlbstate.last_ctx_id);
+
+ /*
+ * Avoid user/user BTB poisoning by flushing the branch
+ * predictor when switching between processes. This stops
+ * one process from doing Spectre-v2 attacks on another.
+ *
+ * As an optimization, flush indirect branches only when
+ * switching into processes that disable dumping. This
+ * protects high value processes like gpg, without having
+ * too high performance overhead. IBPB is *expensive*!
+ *
+ * This will not flush branches when switching into kernel
+ * threads. It will also not flush if we switch to idle
+ * thread and back to the same process. It will flush if we
+ * switch to a different non-dumpable process.
+ */
+ if (tsk && tsk->mm &&
+ tsk->mm->context.ctx_id != last_ctx_id &&
+ get_dumpable(tsk->mm) != SUID_DUMP_USER)
+ indirect_branch_prediction_barrier();
if (IS_ENABLED(CONFIG_VMAP_STACK)) {
/*
@@ -292,6 +314,14 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, 0);
}
+ /*
+ * Record last user mm's context id, so we can avoid
+ * flushing branch buffer with IBPB if we switch back
+ * to the same user.
+ */
+ if (next != &init_mm)
+ this_cpu_write(cpu_tlbstate.last_ctx_id, next->context.ctx_id);
+
this_cpu_write(cpu_tlbstate.loaded_mm, next);
this_cpu_write(cpu_tlbstate.loaded_mm_asid, new_asid);
}
@@ -369,6 +399,7 @@ void initialize_tlbstate_and_flush(void)
write_cr3(build_cr3(mm->pgd, 0));
/* Reinitialize tlbstate. */
+ this_cpu_write(cpu_tlbstate.last_ctx_id, mm->context.ctx_id);
this_cpu_write(cpu_tlbstate.loaded_mm_asid, 0);
this_cpu_write(cpu_tlbstate.next_asid, 1);
this_cpu_write(cpu_tlbstate.ctxs[0].ctx_id, mm->context.ctx_id);
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index 1c65817673db..41615f38bcff 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -10,6 +10,7 @@
#include <linux/compiler.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
+#include <linux/nospec.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/fs.h>
@@ -82,8 +83,10 @@ static inline struct file *__fcheck_files(struct files_struct *files, unsigned i
{
struct fdtable *fdt = rcu_dereference_raw(files->fdt);
- if (fd < fdt->max_fds)
+ if (fd < fdt->max_fds) {
+ fd = array_index_nospec(fd, fdt->max_fds);
return rcu_dereference_raw(fdt->fd[fd]);
+ }
return NULL;
}
diff --git a/include/linux/init.h b/include/linux/init.h
index ea1b31101d9e..506a98151131 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -5,6 +5,13 @@
#include <linux/compiler.h>
#include <linux/types.h>
+/* Built-in __init functions needn't be compiled with retpoline */
+#if defined(RETPOLINE) && !defined(MODULE)
+#define __noretpoline __attribute__((indirect_branch("keep")))
+#else
+#define __noretpoline
+#endif
+
/* These macros are used to mark some functions or
* initialized data (doesn't apply to uninitialized data)
* as `initialization' functions. The kernel can take this
@@ -40,7 +47,7 @@
/* These are for everybody (although not all archs will actually
discard it in modules) */
-#define __init __section(.init.text) __cold __latent_entropy
+#define __init __section(.init.text) __cold __latent_entropy __noretpoline
#define __initdata __section(.init.data)
#define __initconst __section(.init.rodata)
#define __exitdata __section(.exit.data)
diff --git a/include/linux/module.h b/include/linux/module.h
index c69b49abe877..1d8f245967be 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -801,6 +801,15 @@ static inline void module_bug_finalize(const Elf_Ehdr *hdr,
static inline void module_bug_cleanup(struct module *mod) {}
#endif /* CONFIG_GENERIC_BUG */
+#ifdef RETPOLINE
+extern bool retpoline_module_ok(bool has_retpoline);
+#else
+static inline bool retpoline_module_ok(bool has_retpoline)
+{
+ return true;
+}
+#endif
+
#ifdef CONFIG_MODULE_SIG
static inline bool module_sig_ok(struct module *module)
{
diff --git a/include/linux/nospec.h b/include/linux/nospec.h
new file mode 100644
index 000000000000..b99bced39ac2
--- /dev/null
+++ b/include/linux/nospec.h
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright(c) 2018 Linus Torvalds. All rights reserved.
+// Copyright(c) 2018 Alexei Starovoitov. All rights reserved.
+// Copyright(c) 2018 Intel Corporation. All rights reserved.
+
+#ifndef _LINUX_NOSPEC_H
+#define _LINUX_NOSPEC_H
+
+/**
+ * array_index_mask_nospec() - generate a ~0 mask when index < size, 0 otherwise
+ * @index: array element index
+ * @size: number of elements in array
+ *
+ * When @index is out of bounds (@index >= @size), the sign bit will be
+ * set. Extend the sign bit to all bits and invert, giving a result of
+ * zero for an out of bounds index, or ~0 if within bounds [0, @size).
+ */
+#ifndef array_index_mask_nospec
+static inline unsigned long array_index_mask_nospec(unsigned long index,
+ unsigned long size)
+{
+ /*
+ * Warn developers about inappropriate array_index_nospec() usage.
+ *
+ * Even if the CPU speculates past the WARN_ONCE branch, the
+ * sign bit of @index is taken into account when generating the
+ * mask.
+ *
+ * This warning is compiled out when the compiler can infer that
+ * @index and @size are less than LONG_MAX.
+ */
+ if (WARN_ONCE(index > LONG_MAX || size > LONG_MAX,
+ "array_index_nospec() limited to range of [0, LONG_MAX]\n"))
+ return 0;
+
+ /*
+ * Always calculate and emit the mask even if the compiler
+ * thinks the mask is not needed. The compiler does not take
+ * into account the value of @index under speculation.
+ */
+ OPTIMIZER_HIDE_VAR(index);
+ return ~(long)(index | (size - 1UL - index)) >> (BITS_PER_LONG - 1);
+}
+#endif
+
+/*
+ * array_index_nospec - sanitize an array index after a bounds check
+ *
+ * For a code sequence like:
+ *
+ * if (index < size) {
+ * index = array_index_nospec(index, size);
+ * val = array[index];
+ * }
+ *
+ * ...if the CPU speculates past the bounds check then
+ * array_index_nospec() will clamp the index within the range of [0,
+ * size).
+ */
+#define array_index_nospec(index, size) \
+({ \
+ typeof(index) _i = (index); \
+ typeof(size) _s = (size); \
+ unsigned long _mask = array_index_mask_nospec(_i, _s); \
+ \
+ BUILD_BUG_ON(sizeof(_i) > sizeof(long)); \
+ BUILD_BUG_ON(sizeof(_s) > sizeof(long)); \
+ \
+ _i &= _mask; \
+ _i; \
+})
+#endif /* _LINUX_NOSPEC_H */
diff --git a/kernel/module.c b/kernel/module.c
index dea01ac9cb74..09e48eee4d55 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2863,6 +2863,15 @@ static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
}
#endif /* CONFIG_LIVEPATCH */
+static void check_modinfo_retpoline(struct module *mod, struct load_info *info)
+{
+ if (retpoline_module_ok(get_modinfo(info, "retpoline")))
+ return;
+
+ pr_warn("%s: loading module not compiled with retpoline compiler.\n",
+ mod->name);
+}
+
/* Sets info->hdr and info->len. */
static int copy_module_from_user(const void __user *umod, unsigned long len,
struct load_info *info)
@@ -3029,6 +3038,8 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK);
}
+ check_modinfo_retpoline(mod, info);
+
if (get_modinfo(info, "staging")) {
add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK);
pr_warn("%s: module is from the staging directory, the quality "
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 542a4fc0a8d7..4bbcfc1e2d43 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -16,6 +16,7 @@
#include <linux/nl80211.h>
#include <linux/rtnetlink.h>
#include <linux/netlink.h>
+#include <linux/nospec.h>
#include <linux/etherdevice.h>
#include <net/net_namespace.h>
#include <net/genetlink.h>
@@ -2056,20 +2057,22 @@ static const struct nla_policy txq_params_policy[NL80211_TXQ_ATTR_MAX + 1] = {
static int parse_txq_params(struct nlattr *tb[],
struct ieee80211_txq_params *txq_params)
{
+ u8 ac;
+
if (!tb[NL80211_TXQ_ATTR_AC] || !tb[NL80211_TXQ_ATTR_TXOP] ||
!tb[NL80211_TXQ_ATTR_CWMIN] || !tb[NL80211_TXQ_ATTR_CWMAX] ||
!tb[NL80211_TXQ_ATTR_AIFS])
return -EINVAL;
- txq_params->ac = nla_get_u8(tb[NL80211_TXQ_ATTR_AC]);
+ ac = nla_get_u8(tb[NL80211_TXQ_ATTR_AC]);
txq_params->txop = nla_get_u16(tb[NL80211_TXQ_ATTR_TXOP]);
txq_params->cwmin = nla_get_u16(tb[NL80211_TXQ_ATTR_CWMIN]);
txq_params->cwmax = nla_get_u16(tb[NL80211_TXQ_ATTR_CWMAX]);
txq_params->aifs = nla_get_u8(tb[NL80211_TXQ_ATTR_AIFS]);
- if (txq_params->ac >= NL80211_NUM_ACS)
+ if (ac >= NL80211_NUM_ACS)
return -EINVAL;
-
+ txq_params->ac = array_index_nospec(ac, NL80211_NUM_ACS);
return 0;
}
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index f51cf977c65b..6510536c06df 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -2165,6 +2165,14 @@ static void add_intree_flag(struct buffer *b, int is_intree)
buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
}
+/* Cannot check for assembler */
+static void add_retpoline(struct buffer *b)
+{
+ buf_printf(b, "\n#ifdef RETPOLINE\n");
+ buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
+ buf_printf(b, "#endif\n");
+}
+
static void add_staging_flag(struct buffer *b, const char *name)
{
static const char *staging_dir = "drivers/staging";
@@ -2506,6 +2514,7 @@ int main(int argc, char **argv)
err |= check_modname_len(mod);
add_header(&buf, mod);
add_intree_flag(&buf, !external_module);
+ add_retpoline(&buf);
add_staging_flag(&buf, mod->name);
err |= add_versions(&buf, mod);
add_depends(&buf, mod, modules);
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f40d46e24bcc..9cd028aa1509 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -543,18 +543,14 @@ static int add_call_destinations(struct objtool_file *file)
dest_off = insn->offset + insn->len + insn->immediate;
insn->call_dest = find_symbol_by_offset(insn->sec,
dest_off);
- /*
- * FIXME: Thanks to retpolines, it's now considered
- * normal for a function to call within itself. So
- * disable this warning for now.
- */
-#if 0
- if (!insn->call_dest) {
- WARN_FUNC("can't find call dest symbol at offset 0x%lx",
- insn->sec, insn->offset, dest_off);
+
+ if (!insn->call_dest && !insn->ignore) {
+ WARN_FUNC("unsupported intra-function call",
+ insn->sec, insn->offset);
+ WARN("If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE.");
return -1;
}
-#endif
+
} else if (rela->sym->type == STT_SECTION) {
insn->call_dest = find_symbol_by_offset(rela->sym->sec,
rela->addend+4);
@@ -598,7 +594,7 @@ static int handle_group_alt(struct objtool_file *file,
struct instruction *orig_insn,
struct instruction **new_insn)
{
- struct instruction *last_orig_insn, *last_new_insn, *insn, *fake_jump;
+ struct instruction *last_orig_insn, *last_new_insn, *insn, *fake_jump = NULL;
unsigned long dest_off;
last_orig_insn = NULL;
@@ -614,28 +610,30 @@ static int handle_group_alt(struct objtool_file *file,
last_orig_insn = insn;
}
- if (!next_insn_same_sec(file, last_orig_insn)) {
- WARN("%s: don't know how to handle alternatives at end of section",
- special_alt->orig_sec->name);
- return -1;
- }
-
- fake_jump = malloc(sizeof(*fake_jump));
- if (!fake_jump) {
- WARN("malloc failed");
- return -1;
+ if (next_insn_same_sec(file, last_orig_insn)) {
+ fake_jump = malloc(sizeof(*fake_jump));
+ if (!fake_jump) {
+ WARN("malloc failed");
+ return -1;
+ }
+ memset(fake_jump, 0, sizeof(*fake_jump));
+ INIT_LIST_HEAD(&fake_jump->alts);
+ clear_insn_state(&fake_jump->state);
+
+ fake_jump->sec = special_alt->new_sec;
+ fake_jump->offset = -1;
+ fake_jump->type = INSN_JUMP_UNCONDITIONAL;
+ fake_jump->jump_dest = list_next_entry(last_orig_insn, list);
+ fake_jump->ignore = true;
}
- memset(fake_jump, 0, sizeof(*fake_jump));
- INIT_LIST_HEAD(&fake_jump->alts);
- clear_insn_state(&fake_jump->state);
-
- fake_jump->sec = special_alt->new_sec;
- fake_jump->offset = -1;
- fake_jump->type = INSN_JUMP_UNCONDITIONAL;
- fake_jump->jump_dest = list_next_entry(last_orig_insn, list);
- fake_jump->ignore = true;
if (!special_alt->new_len) {
+ if (!fake_jump) {
+ WARN("%s: empty alternative at end of section",
+ special_alt->orig_sec->name);
+ return -1;
+ }
+
*new_insn = fake_jump;
return 0;
}
@@ -648,6 +646,8 @@ static int handle_group_alt(struct objtool_file *file,
last_new_insn = insn;
+ insn->ignore = orig_insn->ignore_alts;
+
if (insn->type != INSN_JUMP_CONDITIONAL &&
insn->type != INSN_JUMP_UNCONDITIONAL)
continue;
@@ -656,8 +656,14 @@ static int handle_group_alt(struct objtool_file *file,
continue;
dest_off = insn->offset + insn->len + insn->immediate;
- if (dest_off == special_alt->new_off + special_alt->new_len)
+ if (dest_off == special_alt->new_off + special_alt->new_len) {
+ if (!fake_jump) {
+ WARN("%s: alternative jump to end of section",
+ special_alt->orig_sec->name);
+ return -1;
+ }
insn->jump_dest = fake_jump;
+ }
if (!insn->jump_dest) {
WARN_FUNC("can't find alternative jump destination",
@@ -672,7 +678,8 @@ static int handle_group_alt(struct objtool_file *file,
return -1;
}
- list_add(&fake_jump->list, &last_new_insn->list);
+ if (fake_jump)
+ list_add(&fake_jump->list, &last_new_insn->list);
return 0;
}
@@ -729,10 +736,6 @@ static int add_special_section_alts(struct objtool_file *file)
goto out;
}
- /* Ignore retpoline alternatives. */
- if (orig_insn->ignore_alts)
- continue;
-
new_insn = NULL;
if (!special_alt->group || special_alt->new_len) {
new_insn = find_insn(file, special_alt->new_sec,
@@ -1089,11 +1092,11 @@ static int decode_sections(struct objtool_file *file)
if (ret)
return ret;
- ret = add_call_destinations(file);
+ ret = add_special_section_alts(file);
if (ret)
return ret;
- ret = add_special_section_alts(file);
+ ret = add_call_destinations(file);
if (ret)
return ret;
@@ -1720,10 +1723,12 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
insn->visited = true;
- list_for_each_entry(alt, &insn->alts, list) {
- ret = validate_branch(file, alt->insn, state);
- if (ret)
- return 1;
+ if (!insn->ignore_alts) {
+ list_for_each_entry(alt, &insn->alts, list) {
+ ret = validate_branch(file, alt->insn, state);
+ if (ret)
+ return 1;
+ }
}
switch (insn->type) {
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index e61fe703197b..18384d9be4e1 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -98,6 +98,11 @@ static int create_orc_entry(struct section *u_sec, struct section *ip_relasec,
struct orc_entry *orc;
struct rela *rela;
+ if (!insn_sec->sym) {
+ WARN("missing symbol for section %s", insn_sec->name);
+ return -1;
+ }
+
/* populate ORC data */
orc = (struct orc_entry *)u_sec->data->d_buf + idx;
memcpy(orc, o, sizeof(*orc));
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