From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jike Song Subject: Re: VFIO based vGPU(was Re: [Announcement] 2015-Q3 release of XenGT - a Mediated ...) Date: Wed, 27 Jan 2016 08:06:13 +0800 Message-ID: <56A809F5.6010001@intel.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Alex Williamson , "Tian, Kevin" , Gerd Hoffmann , Paolo Bonzini , "Lv, Zhiyuan" , "Ruan, Shuai" , "kvm@vger.kernel.org" , qemu-devel , "igvt-g@lists.01.org" , Neo Jia To: Yang Zhang Return-path: Received: from mga02.intel.com ([134.134.136.20]:2060 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751295AbcA0AF4 (ORCPT ); Tue, 26 Jan 2016 19:05:56 -0500 In-Reply-To: <56A77D2D.40109@gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: 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 :) -- Thanks, Jike From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47895) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aODcb-0001U7-4J for qemu-devel@nongnu.org; Tue, 26 Jan 2016 19:06:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aODcX-0003mS-Qx for qemu-devel@nongnu.org; Tue, 26 Jan 2016 19:06:05 -0500 Received: from mga01.intel.com ([192.55.52.88]:37739) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aODcX-0003hv-K6 for qemu-devel@nongnu.org; Tue, 26 Jan 2016 19:06:01 -0500 Message-ID: <56A809F5.6010001@intel.com> Date: Wed, 27 Jan 2016 08:06:13 +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> In-Reply-To: <56A77D2D.40109@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 01/26/2016 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 :) -- Thanks, Jike