From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41024) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WzjqY-0002mB-31 for qemu-devel@nongnu.org; Wed, 25 Jun 2014 05:50:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WzjqQ-0004wj-7W for qemu-devel@nongnu.org; Wed, 25 Jun 2014 05:50:29 -0400 Received: from mga09.intel.com ([134.134.136.24]:55313) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WzjqQ-0004wP-24 for qemu-devel@nongnu.org; Wed, 25 Jun 2014 05:50:22 -0400 Message-ID: <53AA9B58.6050803@intel.com> Date: Wed, 25 Jun 2014 17:50:16 +0800 From: "Chen, Tiejun" MIME-Version: 1.0 References: <1403662641-28526-1-git-send-email-tiejun.chen@intel.com> <53AA69E7.8050406@redhat.com> <53AA7BD7.1080309@intel.com> <53AA7DCE.2030100@redhat.com> <20140625083121.GC32652@redhat.com> <53AA8ACF.3070101@redhat.com> <20140625084835.GF32652@redhat.com> <53AA8E7D.809@intel.com> <20140625090925.GH32652@redhat.com> <53AA9480.1010005@intel.com> <53AA96DF.6070501@redhat.com> In-Reply-To: <53AA96DF.6070501@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [v5][PATCH 0/5] xen: add Intel IGD passthrough support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , "Michael S. Tsirkin" Cc: peter.maydell@linaro.org, xen-devel@lists.xensource.com, stefano.stabellini@eu.citrix.com, allen.m.kay@intel.com, qemu-devel@nongnu.org, Kelly.Zytaruk@amd.com, anthony.perard@citrix.com, anthony@codemonkey.ws, yang.z.zhang@intel.com On 2014/6/25 17:31, Paolo Bonzini wrote: > Il 25/06/2014 11:21, Chen, Tiejun ha scritto: >>> Adding a vendor-specific capability or BAR >>> in an existing device is painful - hard to find >>> free space for it. >> >> Yes, this is a potential risk as well since we can't guarantee current >> free space is always valid for ever. > > For past devices, we know which BARs they use. For future devices, it > would be nice if the PCH/MCH backdoor was specified so that we know they > will leave a free BAR for virtualization. > Now I'm a bit confused about BAR here. You're saying we will reserve a free BAR to address those information to expose to guest, but which device does this free BAR belong to? The video device? Or PCH/MCH? Thanks Tiejun From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chen, Tiejun" Subject: Re: [v5][PATCH 0/5] xen: add Intel IGD passthrough support Date: Wed, 25 Jun 2014 17:50:16 +0800 Message-ID: <53AA9B58.6050803@intel.com> References: <1403662641-28526-1-git-send-email-tiejun.chen@intel.com> <53AA69E7.8050406@redhat.com> <53AA7BD7.1080309@intel.com> <53AA7DCE.2030100@redhat.com> <20140625083121.GC32652@redhat.com> <53AA8ACF.3070101@redhat.com> <20140625084835.GF32652@redhat.com> <53AA8E7D.809@intel.com> <20140625090925.GH32652@redhat.com> <53AA9480.1010005@intel.com> <53AA96DF.6070501@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <53AA96DF.6070501@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org To: Paolo Bonzini , "Michael S. Tsirkin" Cc: peter.maydell@linaro.org, xen-devel@lists.xensource.com, stefano.stabellini@eu.citrix.com, allen.m.kay@intel.com, qemu-devel@nongnu.org, Kelly.Zytaruk@amd.com, anthony.perard@citrix.com, anthony@codemonkey.ws, yang.z.zhang@intel.com List-Id: xen-devel@lists.xenproject.org On 2014/6/25 17:31, Paolo Bonzini wrote: > Il 25/06/2014 11:21, Chen, Tiejun ha scritto: >>> Adding a vendor-specific capability or BAR >>> in an existing device is painful - hard to find >>> free space for it. >> >> Yes, this is a potential risk as well since we can't guarantee current >> free space is always valid for ever. > > For past devices, we know which BARs they use. For future devices, it > would be nice if the PCH/MCH backdoor was specified so that we know they > will leave a free BAR for virtualization. > Now I'm a bit confused about BAR here. You're saying we will reserve a free BAR to address those information to expose to guest, but which device does this free BAR belong to? The video device? Or PCH/MCH? Thanks Tiejun