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Message-Id: <20230206192419.24525-5-decui@microsoft.com>
Date: Mon, 6 Feb 2023 11:24:17 -0800
From: Dexuan Cui <decui@...rosoft.com>
To: ak@...ux.intel.com, arnd@...db.de, bp@...en8.de,
brijesh.singh@....com, dan.j.williams@...el.com,
dave.hansen@...ux.intel.com, haiyangz@...rosoft.com, hpa@...or.com,
jane.chu@...cle.com, kirill.shutemov@...ux.intel.com,
kys@...rosoft.com, linux-arch@...r.kernel.org,
linux-hyperv@...r.kernel.org, luto@...nel.org, mingo@...hat.com,
peterz@...radead.org, rostedt@...dmis.org,
sathyanarayanan.kuppuswamy@...ux.intel.com, seanjc@...gle.com,
tglx@...utronix.de, tony.luck@...el.com, wei.liu@...nel.org,
x86@...nel.org, mikelley@...rosoft.com
Cc: linux-kernel@...r.kernel.org, Tianyu.Lan@...rosoft.com,
Dexuan Cui <decui@...rosoft.com>
Subject: [PATCH v3 4/6] x86/hyperv: Support hypercalls for TDX guests
A TDX guest uses the GHCI call rather than hv_hypercall_pg.
In hv_do_hypercall(), Hyper-V requires that the input/output addresses
must have the cc_mask.
Signed-off-by: Dexuan Cui <decui@...rosoft.com>
---
Changes in v2:
Implemented hv_tdx_hypercall() in C rather than in assembly code.
Renamed the parameter names of hv_tdx_hypercall().
Used cc_mkdec() directly in hv_do_hypercall().
Changes in v3:
Decrypted/encrypted hyperv_pcpu_input_arg in
hv_common_cpu_init() and hv_common_cpu_die().
arch/x86/hyperv/hv_init.c | 8 ++++++++
arch/x86/hyperv/ivm.c | 14 ++++++++++++++
arch/x86/include/asm/mshyperv.h | 17 +++++++++++++++++
drivers/hv/hv_common.c | 21 +++++++++++++++++++++
4 files changed, 60 insertions(+)
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 41ef036ebb7b..6a0bcbd18306 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -430,6 +430,10 @@ void __init hyperv_init(void)
/* Hyper-V requires to write guest os id via ghcb in SNP IVM. */
hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id);
+ /* A TDX guest uses the GHCI call rather than hv_hypercall_pg. */
+ if (hv_isolation_type_tdx())
+ goto skip_hypercall_pg_init;
+
hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START,
VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
@@ -469,6 +473,7 @@ void __init hyperv_init(void)
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
}
+skip_hypercall_pg_init:
/*
* hyperv_init() is called before LAPIC is initialized: see
* apic_intr_mode_init() -> x86_platform.apic_post_init() and
@@ -602,6 +607,9 @@ bool hv_is_hyperv_initialized(void)
if (x86_hyper_type != X86_HYPER_MS_HYPERV)
return false;
+ /* A TDX guest uses the GHCI call rather than hv_hypercall_pg. */
+ if (hv_isolation_type_tdx())
+ return true;
/*
* Verify that earlier initialization succeeded by checking
* that the hypercall page is setup
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 13ccb52eecd7..07e4253b5809 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -276,6 +276,20 @@ bool hv_isolation_type_tdx(void)
{
return static_branch_unlikely(&isolation_type_tdx);
}
+
+u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2)
+{
+ struct tdx_hypercall_args args = { };
+
+ args.r10 = control;
+ args.rdx = param1;
+ args.r8 = param2;
+
+ (void)__tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
+
+ return args.r11;
+}
+EXPORT_SYMBOL_GPL(hv_tdx_hypercall);
#endif
/*
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 49bca07bbd2c..159ab74d80e6 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -10,6 +10,7 @@
#include <asm/nospec-branch.h>
#include <asm/paravirt.h>
#include <asm/mshyperv.h>
+#include <asm/coco.h>
union hv_ghcb;
@@ -37,6 +38,12 @@ int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
+u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2);
+
+/*
+ * If the hypercall involves no input or output parameters, the hypervisor
+ * ignores the corresponding GPA pointer.
+ */
static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
{
u64 input_address = input ? virt_to_phys(input) : 0;
@@ -44,6 +51,10 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
u64 hv_status;
#ifdef CONFIG_X86_64
+ if (hv_isolation_type_tdx())
+ return hv_tdx_hypercall(control,
+ cc_mkdec(input_address),
+ cc_mkdec(output_address));
if (!hv_hypercall_pg)
return U64_MAX;
@@ -81,6 +92,9 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
#ifdef CONFIG_X86_64
+ if (hv_isolation_type_tdx())
+ return hv_tdx_hypercall(control, input1, 0);
+
{
__asm__ __volatile__(CALL_NOSPEC
: "=a" (hv_status), ASM_CALL_CONSTRAINT,
@@ -112,6 +126,9 @@ static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
#ifdef CONFIG_X86_64
+ if (hv_isolation_type_tdx())
+ return hv_tdx_hypercall(control, input1, input2);
+
{
__asm__ __volatile__("mov %4, %%r8\n"
CALL_NOSPEC
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index a9a03ab04b97..219c3f235c50 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -21,6 +21,7 @@
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/dma-map-ops.h>
+#include <linux/set_memory.h>
#include <asm/hyperv-tlfs.h>
#include <asm/mshyperv.h>
@@ -125,6 +126,7 @@ int hv_common_cpu_init(unsigned int cpu)
u64 msr_vp_index;
gfp_t flags;
int pgcount = hv_root_partition ? 2 : 1;
+ int ret;
/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
@@ -134,6 +136,17 @@ int hv_common_cpu_init(unsigned int cpu)
if (!(*inputarg))
return -ENOMEM;
+ if (hv_isolation_type_tdx()) {
+ ret = set_memory_decrypted((unsigned long)*inputarg, pgcount);
+ if (ret) {
+ /* It may be unsafe to free *inputarg */
+ *inputarg = NULL;
+ return ret;
+ }
+
+ memset(*inputarg, 0x00, pgcount * HV_HYP_PAGE_SIZE);
+ }
+
if (hv_root_partition) {
outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
*outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;
@@ -154,6 +167,8 @@ int hv_common_cpu_die(unsigned int cpu)
unsigned long flags;
void **inputarg, **outputarg;
void *mem;
+ int pgcount = hv_root_partition ? 2 : 1;
+ int ret;
local_irq_save(flags);
@@ -168,6 +183,12 @@ int hv_common_cpu_die(unsigned int cpu)
local_irq_restore(flags);
+ if (hv_isolation_type_tdx()) {
+ ret = set_memory_encrypted((unsigned long)mem, pgcount);
+ if (ret)
+ return ret;
+ }
+
kfree(mem);
return 0;
--
2.25.1
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