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KVM/x86: Use 32bit xor to clear registers in svm.c 

x86_64 zero-extends 32bit xor operation to a full 64bit register.

Also add a comment and remove unnecessary instruction suffix in vmx.c

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Uros Bizjak 2018-10-17 16:46:57 +02:00 committed by Paolo Bonzini
parent c4f55198c7
commit 43ce76ce73
2 changed files with 18 additions and 16 deletions
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28
arch/x86/kvm/svm.c
View File

@ -5637,26 +5637,24 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
"mov %%r13, %c[r13](%[svm]) \n\t"
"mov %%r14, %c[r14](%[svm]) \n\t"
"mov %%r15, %c[r15](%[svm]) \n\t"
#endif
/*
* Clear host registers marked as clobbered to prevent
* speculative use.
*/
"xor %%" _ASM_BX ", %%" _ASM_BX " \n\t"
"xor %%" _ASM_CX ", %%" _ASM_CX " \n\t"
"xor %%" _ASM_DX ", %%" _ASM_DX " \n\t"
"xor %%" _ASM_SI ", %%" _ASM_SI " \n\t"
"xor %%" _ASM_DI ", %%" _ASM_DI " \n\t"
#ifdef CONFIG_X86_64
"xor %%r8, %%r8 \n\t"
"xor %%r9, %%r9 \n\t"
"xor %%r10, %%r10 \n\t"
"xor %%r11, %%r11 \n\t"
"xor %%r12, %%r12 \n\t"
"xor %%r13, %%r13 \n\t"
"xor %%r14, %%r14 \n\t"
"xor %%r15, %%r15 \n\t"
"xor %%r8d, %%r8d \n\t"
"xor %%r9d, %%r9d \n\t"
"xor %%r10d, %%r10d \n\t"
"xor %%r11d, %%r11d \n\t"
"xor %%r12d, %%r12d \n\t"
"xor %%r13d, %%r13d \n\t"
"xor %%r14d, %%r14d \n\t"
"xor %%r15d, %%r15d \n\t"
#endif
"xor %%ebx, %%ebx \n\t"
"xor %%ecx, %%ecx \n\t"
"xor %%edx, %%edx \n\t"
"xor %%esi, %%esi \n\t"
"xor %%edi, %%edi \n\t"
"pop %%" _ASM_BP
:
: [svm]"a"(svm),

6
arch/x86/kvm/vmx.c
View File

@ -62,7 +62,7 @@
#define __ex(x) __kvm_handle_fault_on_reboot(x)
#define __ex_clear(x, reg) \
____kvm_handle_fault_on_reboot(x, "xorl " reg " , " reg)
____kvm_handle_fault_on_reboot(x, "xor " reg ", " reg)
MODULE_AUTHOR("Qumranet");
MODULE_LICENSE("GPL");
@ -11285,6 +11285,10 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
"mov %%r13, %c[r13](%0) \n\t"
"mov %%r14, %c[r14](%0) \n\t"
"mov %%r15, %c[r15](%0) \n\t"
/*
* Clear host registers marked as clobbered to prevent
* speculative use.
*/
"xor %%r8d, %%r8d \n\t"
"xor %%r9d, %%r9d \n\t"
"xor %%r10d, %%r10d \n\t"