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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Radim Krčmář" <rkrcmar@redhat.com>, "Gleb Natapov" <gleb@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	stable@vger.kernel.org
Subject: Re: [PATCH] KVM: SVM: fix cr8 intercept window
Date: Fri, 14 Mar 2014 10:57:32 +0100	[thread overview]
Message-ID: <5322D28C.9080009@redhat.com> (raw)
In-Reply-To: <20140313170846.GA23297@potion.brq.redhat.com>

Il 13/03/2014 18:08, Radim Krčmář ha scritto:
> > I agree that old code is wrong and the patch looks correct, but I only
> > see how the bug may cause pending IRR to not be delivered in time,
> > not how interrupt can disrupt a higher priority task.

Right.  Also, on SMP guests the effect would likely be just a deadlock
if a lower-priority ISR interrupted a higher priority task and accessed 
shared data (since you need anyway a spinlock in addition to raising the 
IRQL).

A more likely explanation is that if the remote processor delays an IPI 
too much, it will have a stable TLB entry.  The resulting random 
corruption of paged memory is compatible with the BAD_POOL_HEADER error 
codes that Radim observed.

> Paolo, can you change the last sentence to ", which means we don't
> inject pending IRR immediately."?  (or do we just forget it?)

It's already in Linus's tree.

Paolo

      reply	other threads:[~2014-03-14  9:57 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-11 18:11 [PATCH] KVM: SVM: fix cr8 intercept window Radim Krčmář
2014-03-12  1:05 ` Marcelo Tosatti
2014-03-12 10:40   ` Radim Krčmář
2014-03-12 14:54     ` Marcelo Tosatti
2014-03-12 17:20     ` Paolo Bonzini
2014-03-13 13:52       ` Gleb Natapov
2014-03-13 17:08         ` Radim Krčmář
2014-03-14  9:57           ` Paolo Bonzini [this message]

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