From: Sean Christopherson <seanjc@google.com>
To: mlevitsk@redhat.com
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, Borislav Petkov <bp@alien8.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] KVM: x86: Fix a semi theoretical bug in kvm_arch_async_page_present_queued
Date: Thu, 30 Oct 2025 13:28:30 -0700 [thread overview]
Message-ID: <aQPKbmJGKFvMX56f@google.com> (raw)
In-Reply-To: <c9b893a643cea2ffd4324c25b9d169f920db1ad4.camel@redhat.com>
On Thu, Oct 30, 2025, mlevitsk@redhat.com wrote:
> On Mon, 2025-10-27 at 08:00 -0700, Sean Christopherson wrote:
> > On Tue, Sep 23, 2025, Sean Christopherson wrote:
> > > On x86, the "page ready" IRQ is only injected from vCPU context, so AFAICT nothing
> > > is guarnateed wake the vCPU in the above sequence.
> >
> > Gah, KVM checks async_pf.done instead of the request. So I don't think there's
> > a bug, just weird code.
>
> Hi!
>
> Note that I posted a v2 of this patch series.
I got 'em, and looked at them in depth (which is how I figured out the above
weirdness with async_pf.done). They're sitting in my "for_next" folder, I just
haven't spent any time on applying+testing upstream patches this week (I expect
to get to your series tomorrow, or early next week).
> Do I need to drop this patch or its better to keep it (the patch should still
> be correct, but maybe an overkill I think).
It's probably overkill, but there's no real downside, so I'm inclined to apply
the v2 version (and am planning on doing so).
next prev parent reply other threads:[~2025-10-30 20:28 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-13 19:23 [PATCH 0/3] Fix a lost async pagefault notification when the guest is using SMM Maxim Levitsky
2025-08-13 19:23 ` [PATCH 1/3] KVM: x86: Warn if KVM tries to deliver an #APF completion when APF is not enabled Maxim Levitsky
2025-08-13 19:23 ` [PATCH 2/3] KVM: x86: Fix a semi theoretical bug in kvm_arch_async_page_present_queued Maxim Levitsky
2025-08-18 18:08 ` Sean Christopherson
2025-09-23 15:58 ` Paolo Bonzini
2025-09-23 16:23 ` Paolo Bonzini
2025-09-23 18:55 ` Sean Christopherson
2025-09-23 19:28 ` Paolo Bonzini
2025-09-23 23:14 ` Sean Christopherson
2025-10-27 15:00 ` Sean Christopherson
2025-10-30 19:57 ` mlevitsk
2025-10-30 20:28 ` Sean Christopherson [this message]
2025-08-13 19:23 ` [PATCH 3/3] KVM: x86: Fix the interaction between SMM and the asynchronous pagefault Maxim Levitsky
2025-08-18 18:20 ` Sean Christopherson
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