From: Sean Christopherson via Linux-kernel-mentees <linux-kernel-mentees@lists.linuxfoundation.org>
To: David Woodhouse <dwmw2@infradead.org>
Cc: x86@kernel.org, kvm@vger.kernel.org,
Pavel Skripkin <paskripkin@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
syzbot+e54f930ed78eb0f85281@syzkaller.appspotmail.com,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H . Peter Anvin" <hpa@zytor.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: Re: [PATCH v3 2/2] KVM: x86/xen: Stop Xen timer before changing IRQ
Date: Tue, 9 Aug 2022 14:07:30 +0000 [thread overview]
Message-ID: <YvJqIsQsg+ThMg/C@google.com> (raw)
In-Reply-To: <4fc1371b83001b4eed1617c37bec6b9d007e45c2.camel@infradead.org>
On Tue, Aug 09, 2022, David Woodhouse wrote:
> On Tue, 2022-08-09 at 14:59 +0200, Paolo Bonzini wrote:
> > On 8/9/22 11:22, David Woodhouse wrote:
> > > On Mon, 2022-08-08 at 14:06 -0500, Coleman Dietsch wrote:
> > > > Stop Xen timer (if it's running) prior to changing the IRQ vector and
> > > > potentially (re)starting the timer. Changing the IRQ vector while the
> > > > timer is still running can result in KVM injecting a garbage event, e.g.
> > > > vm_xen_inject_timer_irqs() could see a non-zero xen.timer_pending from
> > > > a previous timer but inject the new xen.timer_virq.
> > >
> > > Hm, wasn't that already addressed in the first patch I saw, which just
> > > called kvm_xen_stop_timer() unconditionally before (possibly) setting
> > > it up again?
> >
> > Which patch is that?
>
> The one I acked in
> https://lore.kernel.org/all/9bad724858b6a06c25ead865b2b3d9dfc216d01c.camel@infradead.org/
It's effectively the same patch. I had asked Coleman to split it into two separate
patches: (1) fix the re-initialization of an active timer bug and (2) stop the active
timer before changing the vector (this patch).
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WARNING: multiple messages have this Message-ID (diff)
From: Sean Christopherson <seanjc@google.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Coleman Dietsch <dietschc@csp.edu>,
kvm@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, skhan@linuxfoundation.org,
Pavel Skripkin <paskripkin@gmail.com>,
linux-kernel-mentees@lists.linuxfoundation.org,
stable@vger.kernel.org,
syzbot+e54f930ed78eb0f85281@syzkaller.appspotmail.com
Subject: Re: [PATCH v3 2/2] KVM: x86/xen: Stop Xen timer before changing IRQ
Date: Tue, 9 Aug 2022 14:07:30 +0000 [thread overview]
Message-ID: <YvJqIsQsg+ThMg/C@google.com> (raw)
In-Reply-To: <4fc1371b83001b4eed1617c37bec6b9d007e45c2.camel@infradead.org>
On Tue, Aug 09, 2022, David Woodhouse wrote:
> On Tue, 2022-08-09 at 14:59 +0200, Paolo Bonzini wrote:
> > On 8/9/22 11:22, David Woodhouse wrote:
> > > On Mon, 2022-08-08 at 14:06 -0500, Coleman Dietsch wrote:
> > > > Stop Xen timer (if it's running) prior to changing the IRQ vector and
> > > > potentially (re)starting the timer. Changing the IRQ vector while the
> > > > timer is still running can result in KVM injecting a garbage event, e.g.
> > > > vm_xen_inject_timer_irqs() could see a non-zero xen.timer_pending from
> > > > a previous timer but inject the new xen.timer_virq.
> > >
> > > Hm, wasn't that already addressed in the first patch I saw, which just
> > > called kvm_xen_stop_timer() unconditionally before (possibly) setting
> > > it up again?
> >
> > Which patch is that?
>
> The one I acked in
> https://lore.kernel.org/all/9bad724858b6a06c25ead865b2b3d9dfc216d01c.camel@infradead.org/
It's effectively the same patch. I had asked Coleman to split it into two separate
patches: (1) fix the re-initialization of an active timer bug and (2) stop the active
timer before changing the vector (this patch).
next prev parent reply other threads:[~2022-08-09 14:07 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-08 19:06 [PATCH v3 1/2] KVM: x86/xen: Initialize Xen timer only once Coleman Dietsch
2022-08-08 19:06 ` Coleman Dietsch
2022-08-08 19:06 ` [PATCH v3 2/2] KVM: x86/xen: Stop Xen timer before changing IRQ Coleman Dietsch
2022-08-08 19:06 ` Coleman Dietsch
2022-08-09 0:34 ` Sean Christopherson via Linux-kernel-mentees
2022-08-09 0:34 ` Sean Christopherson
2022-08-09 9:22 ` David Woodhouse
2022-08-09 9:22 ` David Woodhouse
2022-08-09 12:59 ` Paolo Bonzini
2022-08-09 12:59 ` Paolo Bonzini
2022-08-09 13:51 ` David Woodhouse
2022-08-09 13:51 ` David Woodhouse
2022-08-09 14:07 ` Sean Christopherson via Linux-kernel-mentees [this message]
2022-08-09 14:07 ` Sean Christopherson
2022-08-09 14:16 ` David Woodhouse
2022-08-09 14:16 ` David Woodhouse
2022-08-09 14:31 ` Paolo Bonzini
2022-08-09 14:31 ` Paolo Bonzini
2022-08-09 14:36 ` David Woodhouse
2022-08-09 14:36 ` David Woodhouse
2022-08-09 14:40 ` Sean Christopherson via Linux-kernel-mentees
2022-08-09 14:40 ` Sean Christopherson
2022-08-09 14:52 ` David Woodhouse
2022-08-09 14:52 ` David Woodhouse
2022-08-09 0:32 ` [PATCH v3 1/2] KVM: x86/xen: Initialize Xen timer only once Sean Christopherson via Linux-kernel-mentees
2022-08-09 0:32 ` Sean Christopherson
2022-08-09 12:59 ` Paolo Bonzini
2022-08-09 12:59 ` Paolo Bonzini
-- strict thread matches above, loose matches on Subject: below --
2022-08-08 19:02 [PATCH v3 0/2] KVM: x86/xen: Prevent Xen timer init when running Coleman Dietsch
2022-08-08 19:02 ` [PATCH v3 2/2] KVM: x86/xen: Stop Xen timer before changing IRQ Coleman Dietsch
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