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Date: Fri, 1 Oct 2010 09:00:18 +0100
From: Chris Webb <chris.webb@elastichosts.com>
To: Luke Marsden <luke@hybrid-logic.co.uk>
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Cc: support@elastichosts.com, team@hybrid-logic.co.uk,
	freebsd-stable@FreeBSD.org, Jung-uk Kim <jkim@FreeBSD.org>
Subject: Re: Problem running 8.1R on KVM with AMD hosts
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Luke Marsden <luke@hybrid-logic.co.uk> writes:

> On Thu, 2010-09-30 at 18:55 -0400, Jung-uk Kim wrote:
> > It seems MCA capability is advertised by the CPUID translator but 
> > writing to the MSRs causes GPF.  In other words, it seems like a CPU 
> > emulator bug.  A simple workaround is 'set hw.mca.enabled=0' from the 
> > loader prompt.  If it works, add hw.mca.enabled="0" 
> > in /boot/loader.conf to make it permanent.  MCA does not make any 
> > sense in emulation any way.

Many thanks for tracking this one down for us!

> Awesome, this allows us to boot 8.1R on Linux KVM with AMD hardware!

I'll patch the system on lon-b not to advertise mca this morning Luke. It'll
be interesting to try again once I've done this to check if it fixes normal
booting without the extra hw.mca_enabled="0" flag.

Best wishes,

Chris.