From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: David Matlack <dmatlack@google.com>
Cc: Sean Christopherson <seanjc@google.com>,
stable@vger.kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Pattara Teerapong <pteerapong@google.com>,
David Stevens <stevensd@google.com>,
Yiwei Zhang <zzyiwei@google.com>, Paul Hsia <paulhsia@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH] KVM: x86/mmu: Stop zapping invalidated TDP MMU roots asynchronously
Date: Sat, 21 Oct 2023 11:10:51 +0200 [thread overview]
Message-ID: <2023102145-unstylish-vertigo-ab7c@gregkh> (raw)
In-Reply-To: <ZTLMcmj-ycWhZuTX@google.com>
On Fri, Oct 20, 2023 at 11:52:34AM -0700, David Matlack wrote:
> On 2023-10-19 01:11 PM, Sean Christopherson wrote:
> > [ Upstream commit 0df9dab891ff0d9b646d82e4fe038229e4c02451 ]
> >
> > Stop zapping invalidate TDP MMU roots via work queue now that KVM
> > preserves TDP MMU roots until they are explicitly invalidated. Zapping
> > roots asynchronously was effectively a workaround to avoid stalling a vCPU
> > for an extended during if a vCPU unloaded a root, which at the time
> > happened whenever the guest toggled CR0.WP (a frequent operation for some
> > guest kernels).
> >
> [...]
> >
> > Reported-by: Pattara Teerapong <pteerapong@google.com>
> > Cc: David Stevens <stevensd@google.com>
> > Cc: Yiwei Zhang<zzyiwei@google.com>
> > Cc: Paul Hsia <paulhsia@google.com>
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Sean Christopherson <seanjc@google.com>
> > Message-Id: <20230916003916.2545000-4-seanjc@google.com>
> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> > Cc: David Matlack <dmatlack@google.com>
> > Signed-off-by: Sean Christopherson <seanjc@google.com>
> > ---
>
> Reviewed-by: David Matlack <dmatlack@google.com>
> Tested-by: David Matlack <dmatlack@google.com>
>
> (Ran all KVM selftests and kvm-unit-tests with lockdep enabled.)
Thanks, now queued up.
greg k-h
prev parent reply other threads:[~2023-10-21 9:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-19 20:11 [PATCH] KVM: x86/mmu: Stop zapping invalidated TDP MMU roots asynchronously Sean Christopherson
2023-10-19 21:55 ` Sean Christopherson
2023-10-20 18:52 ` David Matlack
2023-10-21 9:10 ` Greg Kroah-Hartman [this message]
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