Commit f6d58266 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

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: a149180f ("x86: Add magic AMD return-thunk")
Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent f7ef2801

arch/x86/kvm/kvm-asm-offsets.c

+2 −0
Original line number Diff line number Diff line
@@ -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)) {

arch/x86/kvm/svm/svm.c

+2 −3
Original line number Diff line number Diff line
@@ -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));

arch/x86/kvm/svm/svm.h

+2 −2
Original line number Diff line number Diff line
@@ -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

arch/x86/kvm/svm/vmenter.S

+10 −10
Original line number Diff line number Diff line
@@ -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