From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: Xen 4.3 development update RC2 imminent Date: Wed, 22 May 2013 13:58:02 +0100 Message-ID: <519CC0DA.7050706@citrix.com> References: <519B7F67.2050602@citrix.com> <519B8541.8090505@citrix.com> <519BA6F302000078000D7CF2@nat28.tlf.novell.com> <519B9D15.7060004@eu.citrix.com> <519B9DF9.7090303@eu.citrix.com> <519CBEF3.4020701@m2r.biz> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <519CBEF3.4020701@m2r.biz> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Fabio Fantoni Cc: George Dunlap , Anthony Perard , Jan Beulich , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On 22/05/13 13:49, Fabio Fantoni wrote: > Il 21/05/2013 18:16, George Dunlap ha scritto: >> On 05/21/2013 05:13 PM, George Dunlap wrote: >>> On 05/21/2013 03:55 PM, Jan Beulich wrote: >>>>>>> On 21.05.13 at 16:31, Andrew Cooper >>>>>>> wrote: >>>>> On 21/05/13 15:06, Anthony PERARD wrote: >>>>>> But then, once this applied, qxl is still not able to start. Xorg >>>>>> crash >>>>>> (in the guest), and here is why: >>>>>> >>>>>> (XEN) emulate.c:88:d18 bad mmio size 16 >>>>>> (XEN) io.c:201:d18 MMIO emulation failed @ 0033:7fd2de390430: f3 >>>>>> 0f 6f >>>>>> 19 41 83 e8 403 >>>>>> (XEN) emulate.c:88:d18 bad mmio size 16 >>>>>> (XEN) io.c:201:d18 MMIO emulation failed @ 0033:7fd2de390430: f3 >>>>>> 0f 6f >>>>>> 19 41 83 e8 403 >>>>> Disassembly of section .data: >>>>> >>>>> 0000000000000000 <.data>: >>>>> 0: f3 0f 6f 19 movdqu (%rcx),%xmm3 >>>>> >>>>> Xen does not support emulating SSE instructions. We have sporadically >>>>> seen similar errors from Windows guests. The best guess I have >>>>> managed >>>>> to get so far is that %rcx is a pointer to something which Xen >>>>> thinks is >>>>> an MMIO page. >>>>> >>>>> In this case, it looks like X is copying from MMIO into an xmm >>>>> register, >>>>> scraping the framebuffer perhaps? In the windows failure, it was the >>>>> pagescrub trying to zero ram, which clearly indicated something >>>>> wonky in >>>>> the combined idea of the memory map. >>>>> >>>>> If Spice is doing something valid and sensible, then Xen will likely >>>>> need extending to be able to emulate SSE instructions. >>>> The emulator in the hypervisor can handle simple SSE instructions >>>> like the above quite well. It's not immediately clear to me why >>>> hvmemul_do_io() would need to limit the size to no more than a >>>> long's width. Perhaps the data passing to the device model may >>>> need adjustment to accommodate wider entities... >>> Hmm, but the code seems to indicate that the DM can handle wider >>> entities, by "reading all ones": >>> >>> if ( dir == IOREQ_READ ) >>> memset(p_data, ~0, size); >>> >>> Anthony, do you want to try making that size check one size bigger >>> (e.g., allow it to be 16 or 32)? >> No, that obviously won't work, because of the line just following: >> >> if ( (p_data != NULL) && (dir == IOREQ_WRITE) ) >> { >> memcpy(&value, p_data, size); >> p_data = NULL; >> } >> >> >> value is of size "long", so this won't work. >> >> -George > Thanks for help to solve this problem. > Are there news about? > > Probably this is a stupid question: is this patch related to that problem? > http://lists.xen.org/archives/html/xen-devel/2013-05/msg02142.html > No - that patch is unrelated to this problem. ~Andrew