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Date: Mon, 15 Jul 2019 16:16:41 +0100
From: Andrew Cooper <andrew.cooper3@...rix.com>
To: LKML <linux-kernel@...r.kernel.org>
CC: Andrew Cooper <andrew.cooper3@...rix.com>, <x86@...nel.org>,
<virtualization@...ts.linux-foundation.org>,
Borislav Petkov <bp@...en8.de>,
Peter Zijlstra <peterz@...radead.org>,
Andy Lutomirski <luto@...nel.org>,
Nadav Amit <namit@...are.com>,
Stephane Eranian <eranian@...gle.com>,
"Feng Tang" <feng.tang@...el.com>, Juergen Gross <jgross@...e.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
"Pavel Machek" <pavel@....cz>
Subject: [PATCH v2] x86/paravirt: Drop {read,write}_cr8() hooks
There is a lot of infrastructure for functionality which is used
exclusively in __{save,restore}_processor_state() on the suspend/resume
path.
cr8 is an alias of APIC_TASKPRI, and APIC_TASKPRI is saved/restored by
lapic_{suspend,resume}(). Saving and restoring cr8 independently of the
rest of the Local APIC state isn't a clever thing to be doing.
Delete the suspend/resume cr8 handling, which shrinks the size of struct
saved_context, and allows for the removal of both PVOPS.
Signed-off-by: Andrew Cooper <andrew.cooper3@...rix.com>
---
CC: x86@...nel.org
CC: virtualization@...ts.linux-foundation.org
CC: Borislav Petkov <bp@...en8.de>
CC: Peter Zijlstra <peterz@...radead.org>
CC: Andy Lutomirski <luto@...nel.org>
CC: Nadav Amit <namit@...are.com>
CC: Stephane Eranian <eranian@...gle.com>
CC: Feng Tang <feng.tang@...el.com>
CC: Juergen Gross <jgross@...e.com>
CC: Boris Ostrovsky <boris.ostrovsky@...cle.com>
CC: "Rafael J. Wysocki" <rjw@...ysocki.net>
CC: Pavel Machek <pavel@....cz>
Spotted while reviewing "x86/apic: Initialize TPR to block interrupts 16-31"
https://lore.kernel.org/lkml/dc04a9f8b234d7b0956a8d2560b8945bcd9c4bf7.1563117760.git.luto@kernel.org/
v2:
* Drop saved_context.cr8 as well (Juergen)
* Remove akataria@...are.com from the CC list due to bounces
---
arch/x86/include/asm/paravirt.h | 12 ------------
arch/x86/include/asm/paravirt_types.h | 5 -----
arch/x86/include/asm/special_insns.h | 24 ------------------------
arch/x86/include/asm/suspend_64.h | 2 +-
arch/x86/kernel/asm-offsets_64.c | 1 -
arch/x86/kernel/paravirt.c | 4 ----
arch/x86/power/cpu.c | 4 ----
arch/x86/xen/enlighten_pv.c | 15 ---------------
8 files changed, 1 insertion(+), 66 deletions(-)
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index c25c38a05c1c..0e4a0539c353 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -139,18 +139,6 @@ static inline void __write_cr4(unsigned long x)
PVOP_VCALL1(cpu.write_cr4, x);
}
-#ifdef CONFIG_X86_64
-static inline unsigned long read_cr8(void)
-{
- return PVOP_CALL0(unsigned long, cpu.read_cr8);
-}
-
-static inline void write_cr8(unsigned long x)
-{
- PVOP_VCALL1(cpu.write_cr8, x);
-}
-#endif
-
static inline void arch_safe_halt(void)
{
PVOP_VCALL0(irq.safe_halt);
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 946f8f1f1efc..3c775fb5524b 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -119,11 +119,6 @@ struct pv_cpu_ops {
void (*write_cr4)(unsigned long);
-#ifdef CONFIG_X86_64
- unsigned long (*read_cr8)(void);
- void (*write_cr8)(unsigned long);
-#endif
-
/* Segment descriptor handling */
void (*load_tr_desc)(void);
void (*load_gdt)(const struct desc_ptr *);
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
index 219be88a59d2..6d37b8fcfc77 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -73,20 +73,6 @@ static inline unsigned long native_read_cr4(void)
void native_write_cr4(unsigned long val);
-#ifdef CONFIG_X86_64
-static inline unsigned long native_read_cr8(void)
-{
- unsigned long cr8;
- asm volatile("movq %%cr8,%0" : "=r" (cr8));
- return cr8;
-}
-
-static inline void native_write_cr8(unsigned long val)
-{
- asm volatile("movq %0,%%cr8" :: "r" (val) : "memory");
-}
-#endif
-
#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
static inline u32 rdpkru(void)
{
@@ -200,16 +186,6 @@ static inline void wbinvd(void)
#ifdef CONFIG_X86_64
-static inline unsigned long read_cr8(void)
-{
- return native_read_cr8();
-}
-
-static inline void write_cr8(unsigned long x)
-{
- native_write_cr8(x);
-}
-
static inline void load_gs_index(unsigned selector)
{
native_load_gs_index(selector);
diff --git a/arch/x86/include/asm/suspend_64.h b/arch/x86/include/asm/suspend_64.h
index a7af9f53c0cb..35bb35d28733 100644
--- a/arch/x86/include/asm/suspend_64.h
+++ b/arch/x86/include/asm/suspend_64.h
@@ -34,7 +34,7 @@ struct saved_context {
*/
unsigned long kernelmode_gs_base, usermode_gs_base, fs_base;
- unsigned long cr0, cr2, cr3, cr4, cr8;
+ unsigned long cr0, cr2, cr3, cr4;
u64 misc_enable;
bool misc_enable_saved;
struct saved_msrs saved_msrs;
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index d3d075226c0a..8b54d8e3a561 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -62,7 +62,6 @@ int main(void)
ENTRY(cr2);
ENTRY(cr3);
ENTRY(cr4);
- ENTRY(cr8);
ENTRY(gdt_desc);
BLANK();
#undef ENTRY
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 98039d7fb998..de4d4e8a54c1 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -311,10 +311,6 @@ struct paravirt_patch_template pv_ops = {
.cpu.read_cr0 = native_read_cr0,
.cpu.write_cr0 = native_write_cr0,
.cpu.write_cr4 = native_write_cr4,
-#ifdef CONFIG_X86_64
- .cpu.read_cr8 = native_read_cr8,
- .cpu.write_cr8 = native_write_cr8,
-#endif
.cpu.wbinvd = native_wbinvd,
.cpu.read_msr = native_read_msr,
.cpu.write_msr = native_write_msr,
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 24b079e94bc2..1c58d8982728 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -122,9 +122,6 @@ static void __save_processor_state(struct saved_context *ctxt)
ctxt->cr2 = read_cr2();
ctxt->cr3 = __read_cr3();
ctxt->cr4 = __read_cr4();
-#ifdef CONFIG_X86_64
- ctxt->cr8 = read_cr8();
-#endif
ctxt->misc_enable_saved = !rdmsrl_safe(MSR_IA32_MISC_ENABLE,
&ctxt->misc_enable);
msr_save_context(ctxt);
@@ -207,7 +204,6 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
#else
/* CONFIG X86_64 */
wrmsrl(MSR_EFER, ctxt->efer);
- write_cr8(ctxt->cr8);
__write_cr4(ctxt->cr4);
#endif
write_cr3(ctxt->cr3);
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 4722ba2966ac..27aba18f30e8 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -877,16 +877,6 @@ static void xen_write_cr4(unsigned long cr4)
native_write_cr4(cr4);
}
-#ifdef CONFIG_X86_64
-static inline unsigned long xen_read_cr8(void)
-{
- return 0;
-}
-static inline void xen_write_cr8(unsigned long val)
-{
- BUG_ON(val);
-}
-#endif
static u64 xen_read_msr_safe(unsigned int msr, int *err)
{
@@ -1022,11 +1012,6 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
.write_cr4 = xen_write_cr4,
-#ifdef CONFIG_X86_64
- .read_cr8 = xen_read_cr8,
- .write_cr8 = xen_write_cr8,
-#endif
-
.wbinvd = native_wbinvd,
.read_msr = xen_read_msr,
--
2.11.0
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