From: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
stable@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
Andrea Righi <andrea.righi@canonical.com>
Subject: Re: [PATCH stable v5.4+ 1/3] x86/kvm: Teardown PV features on boot CPU as well
Date: Thu, 20 May 2021 13:17:54 -0400 [thread overview]
Message-ID: <42392f1d-4547-9c66-f429-f81f55e86574@canonical.com> (raw)
In-Reply-To: <2aff367f-74b5-ba03-229e-6d7b5b79815e@redhat.com>
On 20/05/2021 12:47, Paolo Bonzini wrote:
> On 20/05/21 14:56, Krzysztof Kozlowski wrote:
>> From: Vitaly Kuznetsov <vkuznets@redhat.com>
>>
>> commit 8b79feffeca28c5459458fe78676b081e87c93a4 upstream.
>>
>> Various PV features (Async PF, PV EOI, steal time) work through memory
>> shared with hypervisor and when we restore from hibernation we must
>> properly teardown all these features to make sure hypervisor doesn't
>> write to stale locations after we jump to the previously hibernated kernel
>> (which can try to place anything there). For secondary CPUs the job is
>> already done by kvm_cpu_down_prepare(), register syscore ops to do
>> the same for boot CPU.
>>
>> Krzysztof:
>> This fixes memory corruption visible after second resume from
>> hibernation:
>
> Hi, you should include a cover letter detailing the differences between
> the original patches and the backport.
>
> (I'll review it anyway, but it would have helped).
My bad, I actually was not aware that backport differs that much. I can
describe in v2.
The patch context looks quite a different and now I see
kvm_guest_cpu_offline() ends up within CONFIG_SMP for unclear reasons.
Let me try to fix it in v2.
Best regards,
Krzysztof
prev parent reply other threads:[~2021-05-20 17:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-20 12:56 [PATCH stable v5.4+ 1/3] x86/kvm: Teardown PV features on boot CPU as well Krzysztof Kozlowski
2021-05-20 12:56 ` [PATCH stable v5.4+ 2/3] x86/kvm: Disable kvmclock on all CPUs on shutdown Krzysztof Kozlowski
2021-05-20 12:56 ` [PATCH stable v5.4+ 3/3] x86/kvm: Disable all PV features on crash Krzysztof Kozlowski
2021-05-20 16:47 ` [PATCH stable v5.4+ 1/3] x86/kvm: Teardown PV features on boot CPU as well Paolo Bonzini
2021-05-20 17:17 ` Krzysztof Kozlowski [this message]
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