From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fabio Fantoni Subject: Re: Xen 4.3 development update Date: Tue, 14 May 2013 11:58:27 +0200 Message-ID: <51920AC3.6040800@m2r.biz> References: <518CD8D8.3090307@citrix.com> <518D046A.2090002@m2r.biz> <1368440802.537.45.camel@zakaz.uk.xensource.com> <5190FE81.3060106@m2r.biz> <519101E5.2060309@eu.citrix.com> <1368458106.537.118.camel@zakaz.uk.xensource.com> <51910937.8090803@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <51910937.8090803@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Anthony PERARD Cc: George Dunlap , "xen-devel@lists.xen.org" , Ian Campbell , Stefano Stabellini List-Id: xen-devel@lists.xenproject.org Il 13/05/2013 17:39, Anthony PERARD ha scritto: > On 13/05/13 16:15, Ian Campbell wrote: >> On Mon, 2013-05-13 at 16:08 +0100, George Dunlap wrote: >>> OK -- so you're saying that qxl actually *does* work, but just in a >>> limited fashion: as long as the guest only access the standard vga >>> interface, then you can connect over spice; but if the guest uses the >>> special qxl interface, then it crashes. > Of what I can understand of the few tests I've run, and what it said in > this thread, qxl *does not* work. The standard vga is, IMHO, for > compatibility with a guest that does not have qxl driver or early at > boot when a qxl driver can not be started. > > QXL is not require in order to use SPICE. So there is no benefit for now > of having "vga = qxl" in the guest config file. > >>> We don't really use qxl, so that wasn't clear at first; we thought that >>> you were saying it didn't work at all. >> yes, it's all much clearer to me now, thanks Fabio. >> >>> If it didn't work at all, then there's no point exposing functionality >>> that can't actually work. But since there is new functionality (albeit >>> limited) exposed by the "qxl" option, we should keep it in. >>> >>> But we do need to make sure to set people's expectations properly -- our >>> release notes will have to advertize "partial qxl support". >> Fabio, Is there some mechanism by which we can disable the magic qxl >> interface and only leave qxl vga enabled, i.e. to workaround the >> unfortunate crash? > I believe we would have to remove "vga = qxl" somehow, like adding an > error "QXL not supported for now", unless we are able to find the issue > between Xen and QXL. > Anthony we did some considerations as follow based on our tests: - According to this link: http://xenbits.xen.org/docs/unstable/misc/libxl_memory.txt we noticed that on hvm domU the videomemory is actually passed separately by guest ram and after the build start. - In presence of the xen hypervisor seabios gets some parameters/tables from hvmloader, which is not the case in absence of xen hypervisor. - On qemu log when qxl is enabled and qemu crashes there are error about memory address, which may be related to some mismatch between hvmloader's tables and/or actual libxl memory settings.