linux-kernel - [PATCH v2 15/22] KVM: nVMX: Preserve IRQ/NMI priority irrespective of exiting behavior

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Date:   Sat, 25 Apr 2020 03:01:47 -0400
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     wei.huang2@....com, cavery@...hat.com, vkuznets@...hat.com,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Oliver Upton <oupton@...gle.com>,
        Jim Mattson <jmattson@...gle.com>
Subject: [PATCH v2 15/22] KVM: nVMX: Preserve IRQ/NMI priority irrespective of exiting behavior

From: Sean Christopherson <sean.j.christopherson@...el.com>

Short circuit vmx_check_nested_events() if an unblocked IRQ/NMI is
pending and needs to be injected into L2, priority between coincident
events is not dependent on exiting behavior.

Fixes: b6b8a1451fc4 ("KVM: nVMX: Rework interception of IRQs and NMIs")
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Message-Id: <20200423022550.15113-9-sean.j.christopherson@...el.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/vmx/nested.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 9edd9464fedf..188ff4cfdbaf 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3750,9 +3750,12 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu)
 		return 0;
 	}
 
-	if (vcpu->arch.nmi_pending && nested_exit_on_nmi(vcpu)) {
+	if (vcpu->arch.nmi_pending && !vmx_nmi_blocked(vcpu)) {
 		if (block_nested_events)
 			return -EBUSY;
+		if (!nested_exit_on_nmi(vcpu))
+			goto no_vmexit;
+
 		nested_vmx_vmexit(vcpu, EXIT_REASON_EXCEPTION_NMI,
 				  NMI_VECTOR | INTR_TYPE_NMI_INTR |
 				  INTR_INFO_VALID_MASK, 0);
@@ -3765,9 +3768,11 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu)
 		return 0;
 	}
 
-	if (kvm_cpu_has_interrupt(vcpu) && nested_exit_on_intr(vcpu)) {
+	if (kvm_cpu_has_interrupt(vcpu) && !vmx_interrupt_blocked(vcpu)) {
 		if (block_nested_events)
 			return -EBUSY;
+		if (!nested_exit_on_intr(vcpu))
+			goto no_vmexit;
 		nested_vmx_vmexit(vcpu, EXIT_REASON_EXTERNAL_INTERRUPT, 0, 0);
 		return 0;
 	}
-- 
2.18.2