According to the AMD manual, the effect of turning off EFER.SVME while a
guest is running is undefined. We make it leave guest mode immediately,
similar to the effect of clearing the VMX bit in MSR_IA32_FEAT_CTL.
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/svm/nested.c | 16 ++++++++++++++++
arch/x86/kvm/svm/svm.c | 8 ++++++--
arch/x86/kvm/svm/svm.h | 1 +
3 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 54a3384a60f8..3e37410d0b94 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -587,6 +587,22 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
return 0;
}
+/*
+ * Forcibly leave nested mode in order to be able to reset the VCPU later on.
+ */
+void svm_leave_nested(struct vcpu_svm *svm)
+{
+ if (is_guest_mode(&svm->vcpu)) {
+ struct vmcb *hsave = svm->nested.hsave;
+ struct vmcb *vmcb = svm->vmcb;
+
+ svm->nested.nested_run_pending = 0;
+ leave_guest_mode(&svm->vcpu);
+ copy_vmcb_control_area(&vmcb->control, &hsave->control);
+ nested_svm_uninit_mmu_context(&svm->vcpu);
+ }
+}
+
static int nested_svm_exit_handled_msr(struct vcpu_svm *svm)
{
u32 offset, msr, value;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 6a19cb3e3b1f..09b345892fc9 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -265,6 +265,7 @@ static int get_npt_level(struct kvm_vcpu *vcpu)
void svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
{
+ struct vcpu_svm *svm = to_svm(vcpu);
vcpu->arch.efer = efer;
if (!npt_enabled) {
@@ -275,8 +276,11 @@ void svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
efer &= ~EFER_LME;
}
- to_svm(vcpu)->vmcb->save.efer = efer | EFER_SVME;
- mark_dirty(to_svm(vcpu)->vmcb, VMCB_CR);
+ if (!(efer & EFER_SVME))
+ svm_leave_nested(svm);
+
+ svm->vmcb->save.efer = efer | EFER_SVME;
+ mark_dirty(svm->vmcb, VMCB_CR);
}
static int is_external_interrupt(u32 info)
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 73986f96ba2a..4d57270cac3f 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -388,6 +388,7 @@ static inline bool nested_exit_on_nmi(struct vcpu_svm *svm)
void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa,
struct vmcb *nested_vmcb);
+void svm_leave_nested(struct vcpu_svm *svm);
int nested_svm_vmrun(struct vcpu_svm *svm);
void nested_svm_vmloadsave(struct vmcb *from_vmcb, struct vmcb *to_vmcb);
int nested_svm_vmexit(struct vcpu_svm *svm);
--
2.18.2
