Re: [PATCH v7 00/15] x86/hvm: I/O emulation cleanup and fix | Full Backtrace of domU's X crash caused by SSE2 istruction in attachment

From: Paul Durrant <Paul.Durrant@citrix.com>
To: Fabio Fantoni <fabio.fantoni@m2r.biz>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Cc: Andrew Cooper <Andrew.Cooper3@citrix.com>,
	Jan Beulich <JBeulich@suse.com>
Subject: Re: [PATCH v7 00/15] x86/hvm: I/O emulation cleanup and fix | Full Backtrace of domU's X crash caused by SSE2 istruction in attachment
Date: Fri, 10 Jul 2015 09:31:58 +0000	[thread overview]
Message-ID: <9AAE0902D5BC7E449B7C8E4E778ABCD02F4B7F7B@AMSPEX01CL02.citrite.net> (raw)
In-Reply-To: <559F900E.6070904@m2r.biz>

> -----Original Message-----
> From: Fabio Fantoni [mailto:fabio.fantoni@m2r.biz]
> Sent: 10 July 2015 10:28
> To: Paul Durrant; xen-devel@lists.xen.org
> Cc: Jan Beulich; Andrew Cooper
> Subject: Re: [Xen-devel] [PATCH v7 00/15] x86/hvm: I/O emulation cleanup
> and fix | Full Backtrace of domU's X crash caused by SSE2 istruction in
> attachment
> 
> Il 09/07/2015 15:10, Paul Durrant ha scritto:
> > This patch series re-works much of the code involved in emulation of port
> > and memory mapped I/O for HVM guests.
> >
> > The code has become very convoluted and, at least by inspection, certain
> > emulations will apparently malfunction.
> >
> > The series is broken down into 15 patches (which are also available in
> > my xenbits repo:
> http://xenbits.xen.org/gitweb/?p=people/pauldu/xen.git
> > on the emulation34 branch).
> 
> Yesterday I retried with this version and seems that you fixed something
> that make possible atleast debug in the domU.
> 
> I taken gdb data of X crash inside Sid hvm domU:
> #0  sse2_blt (src_bits=<optimized out>, dst_bits=<optimized out>,
> src_stride=<optimized out>, dst_stride=<optimized out>,
> src_bpp=<optimized out>, src_x=<optimized out>, src_y=0, dest_x=0,
> dest_y=0, width=1024, height=<optimized out>, dst_bpp=<optimized out>,
> imp=<optimized out>) at ../../pixman/pixman-sse2.c:4773
> 
> Latest istruction:
> => 0x7f70360ef8eb <sse2_blt+459>:    movaps %xmm0,-0x10(%rsi)
> 
> Full log in attachment.
> 
> If you need more informations/tests tell me and I'll post them.
> 

I imagine you got a GP fault due to handle_mmio() returning X86EMUL_UNHANDLEABLE, but that's only a guess. I suggest you try to instrument Xen a little to find out why.

  Paul

> Thanks for any reply and sorry for my bad english.
> 
> >
> > Previous changelog
> > ------------------
> >
> > v4:
> >   - Removed previous patch (make sure translated MMIO reads or
> >     writes fall within a page) and rebased rest of series.
> >   - Address Jan's comments on patch #1
> >
> > v3:
> >   - Addressed comments from Jan
> >   - Re-ordered series to bring a couple of more trivial patches to the
> >     front
> >   - Backport to XenServer (4.5) now passing automated tests
> >   - Tested on unstable with QEMU upstream and trad, with and without
> >     HAP (to force shadow emulation)
> >
> > v2:
> >   - Removed bogus assertion from patch #15
> >   - Re-worked patch #17 after basic testing of back-port onto XenServer
> >
> > Subsequent changes are logged in the individual patch files (thanks
> > to David Vrabel for that).
> >
> > Testing
> > -------
> >
> > v6 of the series was been back-ported to staging-4.5 and then dropped
> > onto the XenServer (Dundee) patch queue. All automated branch-safety
> tests
> > pass.
> >
> > v7 has just been compile tested since changes were largely cosmetic. It
> > will be back-ported in the near future.
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xen.org
> > http://lists.xen.org/xen-devel