From 1a5e1852941d0d8ae98a4b5c769ec998e3708158 Mon Sep 17 00:00:00 2001 From: Ladi Prosek Date: Wed, 21 Jun 2017 09:07:01 +0200 Subject: [PATCH] KVM: SVM: suppress unnecessary NMI singlestep on GIF=0 and nested exit enable_nmi_window is supposed to be a no-op if we know that we'll see a VM exit by the time the NMI window opens. This commit adds two more cases: * We intercept stgi so we don't need to singlestep on GIF=0. * We emulate nested vmexit so we don't need to singlestep when nested VM exit is required. Signed-off-by: Ladi Prosek Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 597337987a16..03df7c1da581 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -4678,6 +4678,12 @@ static void enable_nmi_window(struct kvm_vcpu *vcpu) == HF_NMI_MASK) return; /* IRET will cause a vm exit */ + if ((svm->vcpu.arch.hflags & HF_GIF_MASK) == 0) + return; /* STGI will cause a vm exit */ + + if (svm->nested.exit_required) + return; /* we're not going to run the guest yet */ + /* * Something prevents NMI from been injected. Single step over possible * problem (IRET or exception injection or interrupt shadow)