Messages in this thread | | | Subject | Re: [PATCH 1/8] KVM: SVM: Fix nested nmi handling | From | Alexander Graf <> | Date | Fri, 23 Apr 2010 15:46:07 +0200 |
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On 22.04.2010, at 12:33, Joerg Roedel wrote:
> The patch introducing nested nmi handling had a bug. The > check does not belong to enable_nmi_window but must be in > nmi_allowed. This patch fixes this. > > Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> > --- > arch/x86/kvm/svm.c | 16 +++++++++------- > 1 files changed, 9 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index ab78eb8..ec20584 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -2771,8 +2771,12 @@ static int svm_nmi_allowed(struct kvm_vcpu *vcpu) > { > struct vcpu_svm *svm = to_svm(vcpu); > struct vmcb *vmcb = svm->vmcb; > - return !(vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) && > - !(svm->vcpu.arch.hflags & HF_NMI_MASK); > + int ret; > + ret = !(vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) && > + !(svm->vcpu.arch.hflags & HF_NMI_MASK); > + ret = ret && gif_set(svm) && nested_svm_nmi(svm); > + > + return ret; > } > > static bool svm_get_nmi_mask(struct kvm_vcpu *vcpu) > @@ -2841,11 +2845,9 @@ static void enable_nmi_window(struct kvm_vcpu *vcpu) > * Something prevents NMI from been injected. Single step over possible > * problem (IRET or exception injection or interrupt shadow) > */ > - if (gif_set(svm) && nested_svm_nmi(svm)) { > - svm->nmi_singlestep = true; > - svm->vmcb->save.rflags |= (X86_EFLAGS_TF | X86_EFLAGS_RF); > - update_db_intercept(vcpu); > - } > + svm->nmi_singlestep = true; > + svm->vmcb->save.rflags |= (X86_EFLAGS_TF | X86_EFLAGS_RF); > + update_db_intercept(vcpu);
So we're always messing with the nested guest state when the host wants to inject an nmi into the l1 guest? Is that safe?
Alex
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