Re: [Xen-devel] Bug in x86 instruction emulator?

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 06.04.16 at 01:38, <wogiz@xxxxxxxxxxxxxxx> wrote:
> I'm running Xen 4.6.1 with Alpine Linux 3.3.3 in dom0. In a HVM domU 
> with vga="qxl", Xorg will segfault instantly if tried started. Multiple 
> Linux distros have been tested and Xorg segfaults in all.
> 
> Attached are a full backtrace from domU generated by Xorg, and a 
> assembler dump of function 'sse2_blt'.

Just FYI: Looks like I can repro this finally, and it also looks like at
least for me it isn't an SSE2 instruction that the issue is with.
Instead I'm getting an #UD in the middle of an instruction a few
lines down from the last SSE2 one, which suggests we're having
an issue with sizing instructions (however odd that may seem).
Now that I can repro it, at least I have something to actually
debug ...

Jan


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