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Subject[PATCH 5/8] KVM: SVM: retrieve VMCB from assembly
Date
This is needed in order to keep the number of arguments to 3 or less,
so that they are all passed in registers on either 32-bit or 64-bit
builds.

It is not strictly necessary for __svm_sev_es_vcpu_run, but staying
consistent is a good idea since it makes __svm_sev_es_vcpu_run a
stripped version of _svm_vcpu_run.

No functional change intended.

Cc: stable@vger.kernel.org
Fixes: f14eec0a3203 ("KVM: SVM: move more vmentry code to assembly")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kernel/asm-offsets.c | 1 +
arch/x86/kvm/svm/svm.c | 5 ++---
arch/x86/kvm/svm/svm.h | 4 ++--
arch/x86/kvm/svm/vmenter.S | 20 ++++++++++----------
4 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index f01293a1e594..69d1fed51086 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -114,6 +114,7 @@ static void __used common(void)
BLANK();
OFFSET(SVM_vcpu_arch_regs, vcpu_svm, vcpu.arch.regs);
OFFSET(SVM_vmcb01, vcpu_svm, vmcb01);
+ OFFSET(SVM_current_vmcb, vcpu_svm, current_vmcb);
OFFSET(KVM_VMCB_pa, kvm_vmcb_info, pa);
}

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index ae65cdcab660..550a364be8d3 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3915,16 +3915,15 @@ 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);

- __svm_vcpu_run(vmcb_pa, svm);
+ __svm_vcpu_run(svm);
vmload(__sme_page_pa(sd->save_area));
}

diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 5f8dfc9cd9a7..c5b8ec370108 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -483,7 +483,7 @@ 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 4709bc8868d7..9738ce41fac9 100644
--- a/arch/x86/kvm/svm/vmenter.S
+++ b/arch/x86/kvm/svm/vmenter.S
@@ -34,7 +34,6 @@

/**
* __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)
@@ -51,13 +50,12 @@ 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

/*
* Use a single vmcb (vmcb01 because it's always valid) for
@@ -69,8 +67,9 @@ SYM_FUNC_START(__svm_vcpu_run)
1: vmload %_ASM_AX
2:

- /* "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
@@ -197,7 +196,7 @@ 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
@@ -212,8 +211,9 @@ 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
--
2.31.1

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