linux-kernel - [PATCH v2] KVM: x86: Pending interrupt may be delivered after INIT

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Date:	Mon, 30 Jun 2014 12:03:02 +0300
From:	Nadav Amit <namit@...technion.ac.il>
To:	pbonzini@...hat.com
Cc:	gleb@...nel.org, tglx@...utronix.de, mingo@...hat.com,
	x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
	Nadav Amit <namit@...technion.ac.il>
Subject: [PATCH v2] KVM: x86: Pending interrupt may be delivered after INIT

We encountered a scenario in which after an INIT is delivered, a pending
interrupt is delivered, although it was sent before the INIT.  As the SDM
states in section 10.4.7.1, the ISR and the IRR should be cleared after INIT as
KVM does.  This also means that pending interrupts should be cleared.  This
patch clears upon reset (and INIT) the pending interrupts; and at the same
occassion clears the pending exceptions, since they may cause a similar issue.

Signed-off-by: Nadav Amit <namit@...technion.ac.il>
---
 arch/x86/kvm/x86.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f32a025..6425a31 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6835,6 +6835,8 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu)
 	atomic_set(&vcpu->arch.nmi_queued, 0);
 	vcpu->arch.nmi_pending = 0;
 	vcpu->arch.nmi_injected = false;
+	kvm_clear_interrupt_queue(vcpu);
+	kvm_clear_exception_queue(vcpu);
 
 	memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db));
 	vcpu->arch.dr6 = DR6_FIXED_1;
-- 
1.9.1

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