From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56424) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zzbuz-0005QY-My for qemu-devel@nongnu.org; Thu, 19 Nov 2015 21:59:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zzbuu-0002Ns-M6 for qemu-devel@nongnu.org; Thu, 19 Nov 2015 21:59:21 -0500 Received: from mga02.intel.com ([134.134.136.20]:20435) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zzbuu-0002Nj-Gf for qemu-devel@nongnu.org; Thu, 19 Nov 2015 21:59:16 -0500 Message-ID: <564E8C51.6070706@intel.com> Date: Fri, 20 Nov 2015 10:58:25 +0800 From: Jike Song MIME-Version: 1.0 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> <1447948366.4697.119.camel@redhat.com> In-Reply-To: <1447948366.4697.119.camel@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Intel-gfx] [Announcement] 2015-Q3 release of XenGT - a Mediated Graphics Passthrough Solution from Intel List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Williamson Cc: "igvt-g@ml01.01.org" , "Tian, Kevin" , "Reddy, Raghuveer" , qemu-devel , Stefano Stabellini , "White, Michael L" , "Cowperthwaite, David J" , "intel-gfx@lists.freedesktop.org" , "Li, Susie" , "Dong, Eddie" , "linux-kernel@vger.kernel.org" , "xen-devel@lists.xen.org" , Gerd Hoffmann , "Zhou, Chao" , Paolo Bonzini , "Zhu, Libo" , "Wang, Hongbo" , "Lv, Zhiyuan" On 11/19/2015 11:52 PM, Alex Williamson wrote: > On Thu, 2015-11-19 at 15:32 +0000, Stefano Stabellini wrote: >> On Thu, 19 Nov 2015, Jike Song wrote: >>> Hi Alex, thanks for the discussion. >>> >>> 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. > > Right, but in this case we're talking about device MMUs, which are owned > by the device driver which I think is running in dom0, right? This > proposal doesn't require support of the system IOMMU, the dom0 driver > maps IOVA translations just as it would for itself. We're largely > proposing use of the VFIO API to provide a common interface to expose a > PCI(e) device to QEMU, but what happens in the vGPU vendor device and > IOMMU backends is specific to the device and perhaps even specific to > the hypervisor. Thanks, Let me conclude this, and please correct me in case of any misread: the vGPU interface between kernel and QEMU will be through VFIO, with a new VFIO backend (instead of the existing type1), for both KVMGT and XenGT? > > Alex > -- Thanks, Jike