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From:   Maxim Levitsky <mlevitsk@redhat.com>
To:     kvm@vger.kernel.org
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Sean Christopherson <seanjc@google.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Joerg Roedel <joro@8bytes.org>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND
        64-BIT)),
        x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
        Jim Mattson <jmattson@google.com>,
        Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH 04/10] KVM: SVM: add warning for mistmatch between AVIC state and AVIC access page state
Date:   Wed, 23 Jun 2021 14:29:56 +0300
Message-Id: <20210623113002.111448-5-mlevitsk@redhat.com>
In-Reply-To: <20210623113002.111448-1-mlevitsk@redhat.com>
References: <20210623113002.111448-1-mlevitsk@redhat.com>
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It is never a good idea to enter a guest when the AVIC state doesn't match
the state of the AVIC MMIO memory slot.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/svm/svm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 12c06ea28f5c..50405c561394 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3780,6 +3780,9 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
 
 	pre_svm_run(vcpu);
 
+	WARN_ON_ONCE(vcpu->kvm->arch.apic_access_memslot_enabled !=
+		     kvm_vcpu_apicv_active(vcpu));
+
 	sync_lapic_to_cr8(vcpu);
 
 	if (unlikely(svm->asid != svm->vmcb->control.asid)) {
-- 
2.26.3