From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <Ian.Campbell@citrix.com>
Subject: Re: xenstored crashes with SIGSEGV
Date: Thu, 18 Dec 2014 10:17:47 +0000
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To: Frediano Ziglio <freddy77@gmail.com>
Cc: George Dunlap <george.dunlap@eu.citrix.com>, Philipp Hahn <hahn@univention.de>, Ian Jackson <Ian.Jackson@eu.citrix.com>, Xen-devel@lists.xen.org, David Vrabel <david.vrabel@citrix.com>, Jan Beulich <JBeulich@suse.com>
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On Tue, 2014-12-16 at 16:13 +0000, Frediano Ziglio wrote:
> Do we have a bug in Xen that affect SSE instructions (possibly already
> fixed after Philipp version) ?

I've had a niggling feeling of Deja Vu over this which I'd been putting
down to an old Xen on ARM bug in the area of FPU register switching.

But it seems at some point (possibly even still) there was a similar
issue with pvops kernels on x86, see:
        http://bugs.xenproject.org/xen/bug/40

Philipp, what kernel are you guys using?

CCing Jan and the x86 kernel guys (and George since he registered the
bug). I'm not seeing anything in the kernel logs which looks like a fix
(there's some PVH related cr0 frobbing, but I don't think that's it).

I also can't quite shake the feeling that there was another much older
issue relating to FPU context switch on x86, but I think that was truly
ancient history (2.6.18 era stuff)

Ian.