From xen-devel-bounces@lists.xen.org Wed May 29 23:26:39 2013 Received: (at maildrop) by bugs.xenproject.org; 29 May 2013 22:26:39 +0000 Received: from lists.xen.org ([50.57.142.19]) by bugs.xenproject.org with esmtp (Exim 4.80) (envelope-from ) id 1UhopL-0006Bv-OG for xen-devel-maildrop-Eithu9ie@bugs.xenproject.org; Wed, 29 May 2013 23:26:39 +0100 Received: from localhost ([127.0.0.1] helo=lists.xen.org) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1Uhoo9-0001ws-V8; Wed, 29 May 2013 22:25:25 +0000 Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1Uhoo8-0001wn-7o for xen-devel@lists.xen.org; Wed, 29 May 2013 22:25:24 +0000 Received: from [85.158.137.99:54670] by server-7.bemta-3.messagelabs.com id A4/3F-10169-35086A15; Wed, 29 May 2013 22:25:23 +0000 X-Env-Sender: Andrew.Cooper3@citrix.com X-Msg-Ref: server-5.tower-217.messagelabs.com!1369866322!12871441!1 X-Originating-IP: [46.33.159.39] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogNDYuMzMuMTU5LjM5ID0+IDI2MzI1\n X-StarScan-Received: X-StarScan-Version: 6.9.6; banners=-,-,- X-VirusChecked: Checked Received: (qmail 21752 invoked from network); 29 May 2013 22:25:22 -0000 Received: from smtp.eu.citrix.com (HELO SMTP.EU.CITRIX.COM) (46.33.159.39) by server-5.tower-217.messagelabs.com with RC4-SHA encrypted SMTP; 29 May 2013 22:25:22 -0000 X-IronPort-AV: E=Sophos;i="4.87,766,1363132800"; d="scan'208";a="5111635" Received: from lonpmailmx01.citrite.net ([10.30.203.162]) by LONPIPO01.EU.CITRIX.COM with ESMTP/TLS/RC4-MD5; 29 May 2013 22:25:22 +0000 Received: from [10.30.249.100] (10.30.249.100) by LONPMAILMX01.citrite.net (10.30.203.162) with Microsoft SMTP Server id 8.3.298.1; Wed, 29 May 2013 23:25:21 +0100 Message-ID: <51A68060.7010500@citrix.com> Date: Wed, 29 May 2013 23:25:36 +0100 From: Andrew Cooper User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 MIME-Version: 1.0 To: Ian Campbell References: <1369813427.22605.38.camel@dagon.hellion.org.uk> In-Reply-To: <1369813427.22605.38.camel@dagon.hellion.org.uk> Cc: George Dunlap , Keir Fraser , Ian Jackson , Fabio Fantoni , "xen-devel@lists.xen.org" Subject: Re: [Xen-devel] [PATCH] libxl: Remove qxl support for the 4.3 release X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org On 29/05/2013 08:43, Ian Campbell wrote: > On Tue, 2013-05-28 at 19:09 +0100, Keir Fraser wrote: >> On 28/05/2013 17:51, "Ian Jackson" wrote: >> >>> George Dunlap writes ("[PATCH] libxl: Remove qxl support for the 4.3 >>> release"): >>>> The qxl drivers for Windows and Linux end up calling instructions >>>> that cannot be used for MMIO at the moment. Just for the 4.3 release, >>>> remove qxl support. >>>> >>>> This patch should be reverted as soon as the 4.4 development window opens. >>>> >>>> The issue in question: >>>> >>>> (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 >>>> >>>> The instruction in question is "movdqu (%rcx),%xmm3". Xen knows how >>>> to emulate it, but unfortunately %xmm3 is 16 bytes long, and the interface >>>> between Xen and qemu at the moment would appear to only allow MMIO accesses >>>> of 8 bytes. >>>> >>>> It's too late in the release cycle to find a fix or a workaround. >>> Acked-by: Ian Jackson >> It could be plumbed through hvmemul_do_io's multi-cycle read/write logic, >> and done as two 8-byte cycles to qemu. This would avoid bloating the ioreq >> structure that communicates to qemu. > Are you proposing we do this for 4.3? I'm not sure how big that change > would be in terms of impact (just that one instruction, any 16 byte > operand?). > > Of course even if we did this for 4.3 we don't know what the next issue > will be with QXL. > > Ian. Furthermore, AVX instruction emulation would require support for 32byte operands. I don't see the multi-cycle logic scaling sensibly. ~Andrew > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel