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From: Avi Kivity <avi@redhat.com>
To: Alexander Graf <agraf@suse.de>
Cc: Kevin Wolf <kwolf@suse.de>, kvm@vger.kernel.org
Subject: Re: Linux in VirtualPC in KVM fails
Date: Fri, 09 Jan 2009 21:34:49 +0200	[thread overview]
Message-ID: <4967A6D9.9090309@redhat.com> (raw)
In-Reply-To: <BF37150A-0572-47D3-BDCA-26D0068E0A8C@suse.de>

Alexander Graf wrote:
>> We're in a nice compatibility mess.  We can't just switch paravirt 
>> detection methods since that will break older guests _and_ older 
>> hosts on non-nested virtualization (which is the common case).
>
> Shouldn't it be ok to push patches to linux-stable to use the CPUID 
> and MSR information and simply not expose the CPUID identification in 
> newer KVM versions? That way older guests on newer KVM don't use KVM 
> paravirt (which should still be ok), but everything else runs as 
> smoothly as possible.

No.  It's a regression (esp. kvmclock).

It's perfectly legitimate to say we support Virtual PC beginning some 
kvm version (and to supply the command line workaround for older 
versions).  But we shouldn't knowingly break existing setups.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.


  parent reply	other threads:[~2009-01-09 19:34 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-09 15:43 Linux in VirtualPC in KVM fails Kevin Wolf
2009-01-09 17:50 ` Avi Kivity
2009-01-09 19:00   ` Alexander Graf
2009-01-09 19:04     ` Anthony Liguori
2009-01-09 19:32       ` Avi Kivity
2009-01-09 20:10         ` Anthony Liguori
2009-01-11  7:16           ` Avi Kivity
2009-01-09 19:34     ` Avi Kivity [this message]
2009-01-09 19:05   ` Anthony Liguori
2009-01-09 19:24     ` Alexander Graf
2009-01-09 20:09       ` Anthony Liguori
2009-01-11  7:17         ` Avi Kivity

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