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From: Chris Lalancette <clalance@redhat.com>
To: kvm-devel <kvm-devel@lists.sourceforge.net>
Subject: Re: [PATCH]: Fake MSR_K7 performance counters
Date: Thu, 01 May 2008 10:23:29 -0400	[thread overview]
Message-ID: <4819D261.5050305@redhat.com> (raw)
In-Reply-To: <4815FF35.70809@redhat.com>

Chris Lalancette wrote:
> Attached is a patch that fixes a guest crash when booting older Linux kernels.
> The problem stems from the fact that we are currently emulating
> MSR_K7_EVNTSEL[0-3], but not emulating MSR_K7_PERFCTR[0-3].  Because of this,
> setup_k7_watchdog() in the Linux kernel receives a GPF when it attempts to write
> into MSR_K7_PERFCTR, which causes an OOPs.
> 
> The patch fixes it by just "fake" emulating the appropriate MSRs, throwing away
> the data in the process.  This causes the NMI watchdog to not actually work, but
> it's not such a big deal in a virtualized environment.
> 
> Tested by myself on a RHEL-4 guest, and Joerg Roedel on a Windows XP 64-bit guest.

Avi,
     Do you mind applying this patch for me (unless you see something wrong with
it, of course)?

Thanks,
Chris Lalancette

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  reply	other threads:[~2008-05-01 14:23 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-28 16:45 [PATCH]: Fake MSR_K7 performance counters Chris Lalancette
2008-05-01 14:23 ` Chris Lalancette [this message]
2008-05-02 10:00   ` Avi Kivity
  -- strict thread matches above, loose matches on Subject: below --
2008-05-05 17:05 Chris Lalancette
2008-05-06 11:28 ` Avi Kivity

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