linux-kernel - [PATCH v2 18/22] KVM: nSVM: Preserve IRQ/NMI/SMI priority irrespective of exiting behavior

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Date:   Sat, 25 Apr 2020 03:01:50 -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 18/22] KVM: nSVM: Preserve IRQ/NMI/SMI priority irrespective of exiting behavior

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

Fixes: b518ba9fa691 ("KVM: nSVM: implement check_nested_events for interrupts")
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/svm/nested.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index a7a3d695405e..7c86ccb0e939 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -811,23 +811,29 @@ static int svm_check_nested_events(struct kvm_vcpu *vcpu)
 		kvm_event_needs_reinjection(vcpu) || svm->nested.exit_required ||
 		svm->nested.nested_run_pending;
 
-	if (vcpu->arch.smi_pending && nested_exit_on_smi(svm)) {
+	if (vcpu->arch.smi_pending && !svm_smi_blocked(vcpu)) {
 		if (block_nested_events)
 			return -EBUSY;
+		if (!nested_exit_on_smi(svm))
+			return 0;
 		nested_svm_smi(svm);
 		return 0;
 	}
 
-	if (vcpu->arch.nmi_pending && nested_exit_on_nmi(svm)) {
+	if (vcpu->arch.nmi_pending && !svm_nmi_blocked(vcpu)) {
 		if (block_nested_events)
 			return -EBUSY;
+		if (!nested_exit_on_nmi(svm))
+			return 0;
 		nested_svm_nmi(svm);
 		return 0;
 	}
 
-	if (kvm_cpu_has_interrupt(vcpu) && nested_exit_on_intr(svm)) {
+	if (kvm_cpu_has_interrupt(vcpu) && !svm_interrupt_blocked(vcpu)) {
 		if (block_nested_events)
 			return -EBUSY;
+		if (!nested_exit_on_intr(svm))
+			return 0;
 		nested_svm_intr(svm);
 		return 0;
 	}
-- 
2.18.2