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KVM: SVM: retrieve VMCB from assembly 

Continue moving accesses to struct vcpu_svm to vmenter.S.  Reducing the
number of arguments limits the chance of mistakes due to different
registers used for argument passing in 32- and 64-bit ABIs; pushing the
VMCB argument and almost immediately popping it into a different
register looks pretty weird.

32-bit ABI is not a concern for __svm_sev_es_vcpu_run() which is 64-bit
only; however, it will soon need @svm to save/restore SPEC_CTRL so stay
consistent with __svm_vcpu_run() and let them share the same prototype.

No functional change intended.

Cc: stable@vger.kernel.org
Fixes: a149180fbc ("x86: Add magic AMD return-thunk")
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2022-11-07 04:17:29 -05:00
parent f7ef280132
commit f6d58266d7
4 changed files with 16 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/kvm/kvm-asm-offsets.c
View File

@ -15,6 +15,8 @@ static void __used common(void)
if (IS_ENABLED(CONFIG_KVM_AMD)) {
BLANK();
OFFSET(SVM_vcpu_arch_regs, vcpu_svm, vcpu.arch.regs);
OFFSET(SVM_current_vmcb, vcpu_svm, current_vmcb);
OFFSET(KVM_VMCB_pa, kvm_vmcb_info, pa);
}
if (IS_ENABLED(CONFIG_KVM_INTEL)) {

5
arch/x86/kvm/svm/svm.c
View File

@ -3914,12 +3914,11 @@ static fastpath_t svm_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
unsigned long vmcb_pa = svm->current_vmcb->pa;
guest_state_enter_irqoff();
if (sev_es_guest(vcpu->kvm)) {
__svm_sev_es_vcpu_run(vmcb_pa);
__svm_sev_es_vcpu_run(svm);
} else {
struct svm_cpu_data *sd = per_cpu(svm_data, vcpu->cpu);
@ -3930,7 +3929,7 @@ static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu)
* vmcb02 when switching vmcbs for nested virtualization.
*/
vmload(svm->vmcb01.pa);
__svm_vcpu_run(vmcb_pa, svm);
__svm_vcpu_run(svm);
vmsave(svm->vmcb01.pa);
vmload(__sme_page_pa(sd->save_area));

4
arch/x86/kvm/svm/svm.h
View File

@ -683,7 +683,7 @@ void sev_es_unmap_ghcb(struct vcpu_svm *svm);
/* vmenter.S */
void __svm_sev_es_vcpu_run(unsigned long vmcb_pa);
void __svm_vcpu_run(unsigned long vmcb_pa, struct vcpu_svm *svm);
void __svm_sev_es_vcpu_run(struct vcpu_svm *svm);
void __svm_vcpu_run(struct vcpu_svm *svm);
#endif

20
arch/x86/kvm/svm/vmenter.S
View File

@ -32,7 +32,6 @@
/**
* __svm_vcpu_run - Run a vCPU via a transition to SVM guest mode
* @vmcb_pa: unsigned long
* @svm: struct vcpu_svm *
*/
SYM_FUNC_START(__svm_vcpu_run)
@ -49,16 +48,16 @@ SYM_FUNC_START(__svm_vcpu_run)
push %_ASM_BX
/* Save @svm. */
push %_ASM_ARG2
/* Save @vmcb. */
push %_ASM_ARG1
.ifnc _ASM_ARG1, _ASM_DI
/* Move @svm to RDI. */
mov %_ASM_ARG2, %_ASM_DI
mov %_ASM_ARG1, %_ASM_DI
.endif
/* "POP" @vmcb to RAX. */
pop %_ASM_AX
/* Get svm->current_vmcb->pa into RAX. */
mov SVM_current_vmcb(%_ASM_DI), %_ASM_AX
mov KVM_VMCB_pa(%_ASM_AX), %_ASM_AX
/* Load guest registers. */
mov VCPU_RCX(%_ASM_DI), %_ASM_CX
@ -170,7 +169,7 @@ SYM_FUNC_END(__svm_vcpu_run)
/**
* __svm_sev_es_vcpu_run - Run a SEV-ES vCPU via a transition to SVM guest mode
* @vmcb_pa: unsigned long
* @svm: struct vcpu_svm *
*/
SYM_FUNC_START(__svm_sev_es_vcpu_run)
push %_ASM_BP
@ -185,8 +184,9 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
#endif
push %_ASM_BX
/* Move @vmcb to RAX. */
mov %_ASM_ARG1, %_ASM_AX
/* Get svm->current_vmcb->pa into RAX. */
mov SVM_current_vmcb(%_ASM_ARG1), %_ASM_AX
mov KVM_VMCB_pa(%_ASM_AX), %_ASM_AX
/* Enter guest mode */
sti