From: Sean Christopherson <seanjc@google.com>
To: Maxim Levitsky <mlevitsk@redhat.com>
Cc: kvm@vger.kernel.org, Will Deacon <will@kernel.org>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Paolo Bonzini <pbonzini@redhat.com>,
x86@kernel.org, Robin Murphy <robin.murphy@arm.com>,
iommu@lists.linux.dev, Ingo Molnar <mingo@redhat.com>,
Joerg Roedel <joro@8bytes.org>, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 3/5] x86: KVM: SVM: refresh AVIC inhibition in svm_leave_nested()
Date: Thu, 28 Sep 2023 09:03:31 -0700 [thread overview]
Message-ID: <ZRWj0_VGvrg148He@google.com> (raw)
In-Reply-To: <20230928150428.199929-4-mlevitsk@redhat.com>
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.
>
> Cc: stable@vger.kernel.org
Unnecessary newline.
Fixes: f44509f849fe ("KVM: x86: SVM: allow AVIC to co-exist with a nested guest running")
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.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
>
prev parent reply other threads:[~2023-09-28 16:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230928150428.199929-1-mlevitsk@redhat.com>
2023-09-28 15:04 ` [PATCH 1/5] x86: KVM: SVM: fix for x2avic CVE-2023-5090 Maxim Levitsky
2023-09-28 15:53 ` Sean Christopherson
2023-09-28 15:04 ` [PATCH 2/5] x86: KVM: SVM: add support for Invalid IPI Vector interception Maxim Levitsky
2023-09-28 15:46 ` Sean Christopherson
2023-09-28 15:04 ` [PATCH 3/5] x86: KVM: SVM: refresh AVIC inhibition in svm_leave_nested() Maxim Levitsky
2023-09-28 16:03 ` Sean Christopherson [this message]
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