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

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Message-ID: <20220709134230.2397-5-santosh.shukla@amd.com>
Date:   Sat, 9 Jul 2022 19:12:27 +0530
From:   Santosh Shukla <santosh.shukla@....com>
To:     Paolo Bonzini <pbonzini@...hat.com>
CC:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        Tom Lendacky <thomas.lendacky@....com>, <kvm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <Santosh.Shukla@....com>
Subject: [PATCHv2 4/7] KVM: SVM: Report NMI not allowed when Guest busy handling VNMI

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@....com>
---
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