From: Andrea Arcangeli <andrea-Vyt77T80VFVWk0Htik3J/w@public.gmane.org>
To: Marcelo Tosatti <marcelo-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org>
Cc: kvm-devel
<kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>,
Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
Subject: Re: [PATCH] Use cmpxchg for pte updates on walk_addr()
Date: Fri, 7 Dec 2007 18:54:01 +0100 [thread overview]
Message-ID: <20071207175401.GQ9506@v2.random> (raw)
In-Reply-To: <20071207125658.GB2841@dmt>
On Fri, Dec 07, 2007 at 07:56:58AM -0500, Marcelo Tosatti wrote:
> I see that possibility, but why on earth would the guest be continuously
> updating a pagetable entry ?
If I understood correctly this would be just to be more robust against
malicious guests that could try to create unkillable tight loops in
host kernel mode with -smp > 1. Not sure if timings would allow it
though. With numa archs if the guest cpu is lucky and has the pte in
its direct connected ram, and the walker cpu instead need to access it
remotely, such starvation could probably materialize.
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next prev parent reply other threads:[~2007-12-07 17:54 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-06 15:04 [PATCH] Use cmpxchg for pte updates on walk_addr() Marcelo Tosatti
2007-12-06 15:24 ` Avi Kivity
[not found] ` <47581418.8000506-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-12-07 2:32 ` Marcelo Tosatti
2007-12-07 5:06 ` Avi Kivity
[not found] ` <4758D4D2.8090208-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-12-07 12:56 ` Marcelo Tosatti
2007-12-07 17:54 ` Andrea Arcangeli [this message]
2007-12-09 8:38 ` Avi Kivity
2007-12-07 22:47 ` Marcelo Tosatti
2007-12-09 8:47 ` Avi Kivity
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