| Message ID | 20210517135054.1914802-5-vkuznets@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: nVMX: Fixes for nested state migration when eVMCS is in use | expand |
On Mon, 2021-05-17 at 15:50 +0200, Vitaly Kuznetsov wrote: > 'need_vmcs12_to_shadow_sync' is used for both shadow and enlightened > VMCS sync when we exit to L1. The comment in nested_vmx_failValid() > validly states why shadow vmcs sync can be omitted but this doesn't > apply to enlightened VMCS as it 'shadows' all VMCS12 fields. > > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> > --- > arch/x86/kvm/vmx/nested.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c > index ec476f64df73..eb2d25a93356 100644 > --- a/arch/x86/kvm/vmx/nested.c > +++ b/arch/x86/kvm/vmx/nested.c > @@ -194,9 +194,13 @@ static int nested_vmx_failValid(struct kvm_vcpu *vcpu, > | X86_EFLAGS_ZF); > get_vmcs12(vcpu)->vm_instruction_error = vm_instruction_error; > /* > - * We don't need to force a shadow sync because > - * VM_INSTRUCTION_ERROR is not shadowed > + * We don't need to force sync to shadow VMCS because > + * VM_INSTRUCTION_ERROR is not shadowed. Enlightened VMCS 'shadows' all > + * fields and thus must be synced. > */ > + if (nested_evmcs_is_used(to_vmx(vcpu))) > + to_vmx(vcpu)->nested.need_vmcs12_to_shadow_sync = true; Cool, this is a bug that I noticed too while reviewing previous patches in this series. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Best regards, Maxim Levitsky > + > return kvm_skip_emulated_instruction(vcpu); > } >
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index ec476f64df73..eb2d25a93356 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -194,9 +194,13 @@ static int nested_vmx_failValid(struct kvm_vcpu *vcpu, | X86_EFLAGS_ZF); get_vmcs12(vcpu)->vm_instruction_error = vm_instruction_error; /* - * We don't need to force a shadow sync because - * VM_INSTRUCTION_ERROR is not shadowed + * We don't need to force sync to shadow VMCS because + * VM_INSTRUCTION_ERROR is not shadowed. Enlightened VMCS 'shadows' all + * fields and thus must be synced. */ + if (nested_evmcs_is_used(to_vmx(vcpu))) + to_vmx(vcpu)->nested.need_vmcs12_to_shadow_sync = true; + return kvm_skip_emulated_instruction(vcpu); }
'need_vmcs12_to_shadow_sync' is used for both shadow and enlightened VMCS sync when we exit to L1. The comment in nested_vmx_failValid() validly states why shadow vmcs sync can be omitted but this doesn't apply to enlightened VMCS as it 'shadows' all VMCS12 fields. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> --- arch/x86/kvm/vmx/nested.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)