[PATCHv2 4/7] KVM: SVM: Report NMI not allowed when Guest busy handling VNMI

From: Santosh Shukla
Date: Sat Jul 09 2022 - 09:44:16 EST


In the VNMI case, Report NMI is not allowed when the processor set the
V_NMI_MASK to 1 which means the Guest is busy handling VNMI.

Signed-off-by: Santosh Shukla <santosh.shukla@xxxxxxx>
---
v2:
- Moved vnmi check after is_guest_mode() in func _nmi_blocked().
- Removed is_vnmi_mask_set check from _enable_nmi_window().
as it was a redundent check.

arch/x86/kvm/svm/svm.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 3574e804d757..44c1f2317b45 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3480,6 +3480,9 @@ bool svm_nmi_blocked(struct kvm_vcpu *vcpu)
if (is_guest_mode(vcpu) && nested_exit_on_nmi(svm))
return false;

+ if (is_vnmi_enabled(svm) && is_vnmi_mask_set(svm))
+ return true;
+
ret = (vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) ||
(vcpu->arch.hflags & HF_NMI_MASK);

@@ -3609,6 +3612,9 @@ static void svm_enable_nmi_window(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);

+ if (is_vnmi_enabled(svm))
+ return;
+
if ((vcpu->arch.hflags & (HF_NMI_MASK | HF_IRET_MASK)) == HF_NMI_MASK)
return; /* IRET will cause a vm exit */

--
2.25.1