linux-kernel - [PATCH 3/5] x86: KVM: SVM: refresh AVIC inhibition in svm_leave

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Date:   Thu, 28 Sep 2023 18:04:26 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Will Deacon <will@...nel.org>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Paolo Bonzini <pbonzini@...hat.com>, x86@...nel.org,
        Robin Murphy <robin.murphy@....com>, iommu@...ts.linux.dev,
        Ingo Molnar <mingo@...hat.com>, Joerg Roedel <joro@...tes.org>,
        Sean Christopherson <seanjc@...gle.com>,
        "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
        Maxim Levitsky <mlevitsk@...hat.com>, stable@...r.kernel.org
Subject: [PATCH 3/5] x86: KVM: SVM: refresh AVIC inhibition in svm_leave_nested()

svm_leave_nested() similar to a nested VM exit, get the vCPU out of nested
mode and thus should end the local inhibition of AVIC on this vCPU.

Failure to do so, can lead to hangs on guest reboot.

Raise the KVM_REQ_APICV_UPDATE request to refresh the AVIC state of the
current vCPU in this case.

Cc: stable@...r.kernel.org

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

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index dd496c9e5f91f28..3fea8c47679e689 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1253,6 +1253,9 @@ void svm_leave_nested(struct kvm_vcpu *vcpu)
 
 		nested_svm_uninit_mmu_context(vcpu);
 		vmcb_mark_all_dirty(svm->vmcb);
+
+		if (kvm_apicv_activated(vcpu->kvm))
+			kvm_make_request(KVM_REQ_APICV_UPDATE, vcpu);
 	}
 
 	kvm_clear_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu);
-- 
2.26.3