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From: John Baldwin <jhb@freebsd.org>
To: freebsd-hackers@freebsd.org
Subject: Re: Kernel Panic
Date: Tue, 17 Feb 2015 13:36:27 -0500
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Cc: Robert Simmons <rsimmons0@gmail.com>
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On Tuesday, February 17, 2015 12:42:00 pm Robert Simmons wrote:
> On Tue, Feb 17, 2015 at 3:58 AM, Konstantin Belousov
> <kostikbel@gmail.com> wrote:
> > On Tue, Feb 17, 2015 at 01:27:46AM -0500, Robert Simmons wrote:
> >> I'm experiencing a kernel panic on a VM:
> >> panic: CPU0 does not support X87 or SSE: 0
> >> This is on OpenStack (using KVM).
> >>
> >> Is there a kernel option that I can set that will allow this VM to
> >> boot without panic?
> > The panic indicates that machine you trying to boot on is not compliant
> > with the Intel specification.  You may try the luck with setting
> > hw.use_xsave=0 at the loader prompt, but I expect that you get other
> > problems.
> 
> Thanks!
> 
> This works and allows the VM to boot. The problem appears to be a bug
> in KVM virtualization, and it has been fixed upstream. I'm trying to
> get my cloud provider to patch their stack.
> 
> You mentioned that this may introduce other problems. How bad and what
> kind of problems do you think may happen?

If SSE did not actually work, then userland probably would not work.  If it is 
just that this version of KVM doesn't handle the cpuid reporting for XSAVE 
correctly, tehn Konstantin's workaround should be fine.

-- 
John Baldwin