From: Paolo Bonzini <pbonzini@redhat.com>
To: Jack Wang <jack.wang.usish@gmail.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: stable@vger.kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, "Radim Krčmář" <rkrcmar@redhat.com>
Subject: Re: [PATCH stable-4.19 1/2] KVM: nVMX: do not use dangling shadow VMCS after guest reset
Date: Mon, 29 Jul 2019 11:10:26 +0200 [thread overview]
Message-ID: <2ea5d588-8573-6653-b848-0b06d1f98310@redhat.com> (raw)
In-Reply-To: <CA+res+RfqpT=g1QbCqr3OkHVzFFSAt3cfCYNcwqiemWmOifFxg@mail.gmail.com>
On 29/07/19 10:58, Jack Wang wrote:
> Vitaly Kuznetsov <vkuznets@redhat.com> 于2019年7月25日周四 下午3:29写道：
>>
>> From: Paolo Bonzini <pbonzini@redhat.com>
>>
>> [ Upstream commit 88dddc11a8d6b09201b4db9d255b3394d9bc9e57 ]
>>
>> If a KVM guest is reset while running a nested guest, free_nested will
>> disable the shadow VMCS execution control in the vmcs01. However,
>> on the next KVM_RUN vmx_vcpu_run would nevertheless try to sync
>> the VMCS12 to the shadow VMCS which has since been freed.
>>
>> This causes a vmptrld of a NULL pointer on my machime, but Jan reports
>> the host to hang altogether. Let's see how much this trivial patch fixes.
>>
>> Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
>> Cc: Liran Alon <liran.alon@oracle.com>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>
> Hi all,
>
> Do we need to backport the fix also to stable 4.14? It applies
> cleanly and compiles fine.
The reproducer required newer kernels that support KVM_GET_NESTED_STATE
and KVM_SET_NESTED_STATE, so it would be hard to test it. However, the
patch itself should be safe.
Paolo
next prev parent reply other threads:[~2019-07-29 9:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 10:46 [PATCH stable-4.19 0/2] KVM: nVMX: guest reset fixes Vitaly Kuznetsov
2019-07-25 10:46 ` [PATCH stable-4.19 1/2] KVM: nVMX: do not use dangling shadow VMCS after guest reset Vitaly Kuznetsov
2019-07-29 8:58 ` Jack Wang
2019-07-29 9:10 ` Paolo Bonzini [this message]
2019-07-29 9:29 ` Jack Wang
2019-07-29 9:30 ` Paolo Bonzini
2019-07-29 15:31 ` Greg Kroah-Hartman
2019-07-25 10:46 ` [PATCH stable-4.19 2/2] KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12_PAGES when leaving nested Vitaly Kuznetsov
2019-07-25 11:24 ` [PATCH stable-4.19 0/2] KVM: nVMX: guest reset fixes Paolo Bonzini
2019-07-26 13:48 ` Greg KH
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