linux-kernel - [PATCH v2 1/8] KVM: SVM: svm_set_vintr don't warn if AVIC is active but is about to be deactivated

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Date:   Tue, 13 Jul 2021 17:20:16 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND
        64-BIT)), Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, Borislav Petkov <bp@...en8.de>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
        x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
        Sean Christopherson <seanjc@...gle.com>,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH v2 1/8] KVM: SVM: svm_set_vintr don't warn if AVIC is active but is about to be deactivated

It is possible for AVIC inhibit and AVIC active state to be mismatched.
Currently we disable AVIC right away on vCPU which started the AVIC inhibit
request thus this warning doesn't trigger but at least in theory,
if svm_set_vintr is called at the same time on multiple vCPUs,
the warning can happen.

Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
 arch/x86/kvm/svm/svm.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 12c06ea28f5c..d4d14e318ab5 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1560,8 +1560,11 @@ static void svm_set_vintr(struct vcpu_svm *svm)
 {
 	struct vmcb_control_area *control;
 
-	/* The following fields are ignored when AVIC is enabled */
-	WARN_ON(kvm_vcpu_apicv_active(&svm->vcpu));
+	/*
+	 * The following fields are ignored when AVIC is enabled
+	 */
+	WARN_ON(kvm_apicv_activated(svm->vcpu.kvm));
+
 	svm_set_intercept(svm, INTERCEPT_VINTR);
 
 	/*
-- 
2.26.3