linux-kernel - Re: [PATCH v2 3/4] x86: KVM: SVM: refresh AVIC inhibition in svm_leave

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Message-ID: <ZRYde2P413vWOYDq@google.com>
Date:   Thu, 28 Sep 2023 17:42:35 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Maxim Levitsky <mlevitsk@...hat.com>
Cc:     kvm@...r.kernel.org, iommu@...ts.linux.dev,
        "H. Peter Anvin" <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>, Joerg Roedel <joro@...tes.org>,
        x86@...nel.org,
        Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
        linux-kernel@...r.kernel.org,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Will Deacon <will@...nel.org>, Ingo Molnar <mingo@...hat.com>,
        Robin Murphy <robin.murphy@....com>, stable@...r.kernel.org
Subject: Re: [PATCH v2 3/4] x86: KVM: SVM: refresh AVIC inhibition in svm_leave_nested()

On Thu, Sep 28, 2023, Maxim Levitsky wrote:
> 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.
> 
> Fixes: f44509f849fe ("KVM: x86: SVM: allow AVIC to co-exist with a nested guest running")
> Cc: stable@...r.kernel.org
> Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
> ---

Reviewed-by: Sean Christopherson <seanjc@...gle.com>