From: Jan Kiszka Date: Tue, 11 May 2010 13:16:46 +0000 (+0200) Subject: KVM: VMX: blocked-by-sti must not defer NMI injections X-Git-Tag: firefly_0821_release~9833^2~2167^2~1 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f8c5fae16649445e15656667f72bd51d777f7766;p=firefly-linux-kernel-4.4.55.git KVM: VMX: blocked-by-sti must not defer NMI injections As the processor may not consider GUEST_INTR_STATE_STI as a reason for blocking NMI, it could return immediately with EXIT_REASON_NMI_WINDOW when we asked for it. But as we consider this state as NMI-blocking, we can run into an endless loop. Resolve this by allowing NMI injection if just GUEST_INTR_STATE_STI is active (originally suggested by Gleb). Intel confirmed that this is safe, the processor will never complain about NMI injection in this state. Signed-off-by: Jan Kiszka KVM-Stable-Tag Acked-by: Gleb Natapov Signed-off-by: Marcelo Tosatti --- diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index bc933cfb4e66..2f8db0ec8ae4 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2703,8 +2703,7 @@ static int vmx_nmi_allowed(struct kvm_vcpu *vcpu) return 0; return !(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & - (GUEST_INTR_STATE_STI | GUEST_INTR_STATE_MOV_SS | - GUEST_INTR_STATE_NMI)); + (GUEST_INTR_STATE_MOV_SS | GUEST_INTR_STATE_NMI)); } static bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu)