From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43564) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aOFH0-0004LM-VO for qemu-devel@nongnu.org; Tue, 26 Jan 2016 20:51:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aOFGx-0001nZ-PY for qemu-devel@nongnu.org; Tue, 26 Jan 2016 20:51:54 -0500 Received: from mga01.intel.com ([192.55.52.88]:30437) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aOFGx-0001nU-JH for qemu-devel@nongnu.org; Tue, 26 Jan 2016 20:51:51 -0500 Message-ID: <56A822AC.50300@intel.com> Date: Wed, 27 Jan 2016 09:51:40 +0800 From: Jike Song MIME-Version: 1.0 References: <569C5071.6080004@intel.com> <1453092476.32741.67.camel@redhat.com> <569CA8AD.6070200@intel.com> <1453143919.32741.169.camel@redhat.com> <569F4C86.2070501@intel.com> <56A6083E.10703@intel.com> <1453757426.32741.614.camel@redhat.com> <56A72313.9030009@intel.com> <56A77D2D.40109@gmail.com> <56A809F5.6010001@intel.com> <56A81EB6.9070106@gmail.com> In-Reply-To: <56A81EB6.9070106@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] VFIO based vGPU(was Re: [Announcement] 2015-Q3 release of XenGT - a Mediated ...) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Yang Zhang Cc: "Ruan, Shuai" , "Tian, Kevin" , Neo Jia , "kvm@vger.kernel.org" , "igvt-g@lists.01.org" , qemu-devel , Alex Williamson , "Lv, Zhiyuan" , Paolo Bonzini , Gerd Hoffmann On 01/27/2016 09:34 AM, Yang Zhang wrote: > On 2016/1/27 8:06, Jike Song wrote: >> On 01/26/2016 10:05 PM, Yang Zhang wrote: >>> On 2016/1/26 15:41, Jike Song wrote: >>> >>>> We will need to extend: >>>> >>>> - VFIO_DEVICE_GET_REGION_INFO >>>> >>>> >>>> a) adding a flag: DONT_MAP. For example, the MMIO of vgpu >>>> should be trapped instead of being mmap-ed. >>> >>> I may not in the context, but i am curious how to handle the DONT_MAP in >>> vfio driver? Since there are no real MMIO maps into the region and i >>> suppose the access to the region should be handled by vgpu in i915 >>> driver, but currently most of the mmio accesses are handled by Qemu. >>> >> >> Hi Yang, >> >> MMIO accesses are supposed to be handled in kernel, without vm-exiting >> to QEMU, similar to in-kernel irqchip :) > > The question is current vfio doesn't support it. The long discussion > between Alex and Kevin is what i am to understand how KVMGT works under > vfio framework. > Yes, good to expose it earlier. Previously Kevin and I thought KVMGT is free to register an iodev, responsible for a MMIO range r/w, to KVM hypervisor directly. If this is not acceptable then we will have to figure out an alternative. -- Thanks, Jike