Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754434AbbKSQMo (ORCPT ); Thu, 19 Nov 2015 11:12:44 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:47953 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752007AbbKSQMn (ORCPT ); Thu, 19 Nov 2015 11:12:43 -0500 X-IronPort-AV: E=Sophos;i="5.20,318,1444694400"; d="scan'208";a="319321113" Date: Thu, 19 Nov 2015 16:12:06 +0000 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Paolo Bonzini CC: Stefano Stabellini , Jike Song , Alex Williamson , "Tian, Kevin" , "xen-devel@lists.xen.org" , "igvt-g@ml01.01.org" , "intel-gfx@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , "White, Michael L" , "Dong, Eddie" , "Li, Susie" , "Cowperthwaite, David J" , "Reddy, Raghuveer" , "Zhu, Libo" , "Zhou, Chao" , "Wang, Hongbo" , "Lv, Zhiyuan" , qemu-devel , Gerd Hoffmann Subject: Re: [Intel-gfx] [Announcement] 2015-Q3 release of XenGT - a Mediated Graphics Passthrough Solution from Intel In-Reply-To: <564DEF9A.3010901@redhat.com> Message-ID: References: <53D215D3.50608@intel.com> <547FCAAD.2060406@intel.com> <54AF967B.3060503@intel.com> <5527CEC4.9080700@intel.com> <559B3E38.1080707@intel.com> <562F4311.9@intel.com> <1447870341.4697.92.camel@redhat.com> <564D78D0.80904@intel.com> <564DEF9A.3010901@redhat.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1269 Lines: 31 On Thu, 19 Nov 2015, Paolo Bonzini wrote: > On 19/11/2015 16:32, Stefano Stabellini wrote: > > > In addition to Kevin's replies, I have a high-level question: can VFIO > > > be used by QEMU for both KVM and Xen? > > > > No. VFIO cannot be used with Xen today. When running on Xen, the IOMMU > > is owned by Xen. > > I don't think QEMU command line compatibility between KVM and Xen should > be a design goal for GVT-g. Right, I agree. In fact I don't want my comment to be taken as "VFIO should not be used at all". I only meant to reply to the question. I think it is unlikely to be the best path for Xen, but it could very well be the right answer for KVM. > Nevertheless, it shouldn't be a problem to use a "virtual" VFIO (which > doesn't need the IOMMU, because it uses the MMU in the physical GPU) > even under Xen. That could be true, but I would expect some extra work to be needed to make use of VFIO on Xen. Also it might cause some duplication of functionalities with the current Xen passthrough code base. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/