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: a149180fbcf3 ("x86: Add magic AMD return-thunk")
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/kvm-asm-offsets.c b/arch/x86/kvm/kvm-asm-offsets.c
index 30db968..f1b694e 100644 (file)
--- a/arch/x86/kvm/kvm-asm-offsets.c
+++ b/arch/x86/kvm/kvm-asm-offsets.c
@@ -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)) {

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index b412bc5..0c86c43 100644 (file)
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -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));

diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 447e25c..7ff1879 100644 (file)
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -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

diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
index 531510a..d07bac1 100644 (file)
--- a/arch/x86/kvm/svm/vmenter.S
+++ b/arch/x86/kvm/svm/vmenter.S
@@ -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