From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59934) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X07oa-0006WI-OP for qemu-devel@nongnu.org; Thu, 26 Jun 2014 07:26:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X07oT-0001hx-0t for qemu-devel@nongnu.org; Thu, 26 Jun 2014 07:26:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:10145) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X07oS-0001hl-Hl for qemu-devel@nongnu.org; Thu, 26 Jun 2014 07:25:56 -0400 Date: Thu, 26 Jun 2014 14:26:03 +0300 From: "Michael S. Tsirkin" Message-ID: <20140626112603.GC21685@redhat.com> References: <53AA8ACF.3070101@redhat.com> <20140625084835.GF32652@redhat.com> <53AA8E7D.809@intel.com> <20140625090925.GH32652@redhat.com> <53AA9480.1010005@intel.com> <53AA96DF.6070501@redhat.com> <53AA9B58.6050803@intel.com> <53AA9C4E.9070506@redhat.com> <53ABE551.3080407@intel.com> <53ABF00E.6000309@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53ABF00E.6000309@redhat.com> 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 Cc: peter.maydell@linaro.org, xen-devel@lists.xensource.com, stefano.stabellini@eu.citrix.com, allen.m.kay@intel.com, Kelly.Zytaruk@amd.com, qemu-devel@nongnu.org, anthony.perard@citrix.com, anthony@codemonkey.ws, yang.z.zhang@intel.com, "Chen, Tiejun" On Thu, Jun 26, 2014 at 12:03:58PM +0200, Paolo Bonzini wrote: > Il 26/06/2014 11:18, Chen, Tiejun ha scritto: > > > >> > >>- offsets 0x0000..0x0fff map to configuration space of the host MCH > >> > > > >Are you saying the config space in the video device? > > No, I am saying in a new BAR, or at some magic offset of an existing MMIO > BAR. > > Paolo I think v5 goes a bit overboard and overrides too many registers, driver likely needs much less. But IMHO retro-fitting this into PIIX is where the problem is. We could invent 1000 ways to do this, all of varying levels of ugliness. But why don't we start by more or less cleanly emulating what the driver needs? If we start with Q35 - it shouldn't be hard to tweak it's MCH to add the necessary config space, right? I know xen doesn't support q35 now but it's opensource :) I think that's a good step 1. We can do PV hacks on top if we decide they aren't too painful. -- MST From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [v5][PATCH 0/5] xen: add Intel IGD passthrough support Date: Thu, 26 Jun 2014 14:26:03 +0300 Message-ID: <20140626112603.GC21685@redhat.com> References: <53AA8ACF.3070101@redhat.com> <20140625084835.GF32652@redhat.com> <53AA8E7D.809@intel.com> <20140625090925.GH32652@redhat.com> <53AA9480.1010005@intel.com> <53AA96DF.6070501@redhat.com> <53AA9B58.6050803@intel.com> <53AA9C4E.9070506@redhat.com> <53ABE551.3080407@intel.com> <53ABF00E.6000309@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <53ABF00E.6000309@redhat.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Paolo Bonzini Cc: peter.maydell@linaro.org, xen-devel@lists.xensource.com, stefano.stabellini@eu.citrix.com, allen.m.kay@intel.com, Kelly.Zytaruk@amd.com, qemu-devel@nongnu.org, anthony.perard@citrix.com, anthony@codemonkey.ws, yang.z.zhang@intel.com, "Chen, Tiejun" List-Id: xen-devel@lists.xenproject.org On Thu, Jun 26, 2014 at 12:03:58PM +0200, Paolo Bonzini wrote: > Il 26/06/2014 11:18, Chen, Tiejun ha scritto: > > > >> > >>- offsets 0x0000..0x0fff map to configuration space of the host MCH > >> > > > >Are you saying the config space in the video device? > > No, I am saying in a new BAR, or at some magic offset of an existing MMIO > BAR. > > Paolo I think v5 goes a bit overboard and overrides too many registers, driver likely needs much less. But IMHO retro-fitting this into PIIX is where the problem is. We could invent 1000 ways to do this, all of varying levels of ugliness. But why don't we start by more or less cleanly emulating what the driver needs? If we start with Q35 - it shouldn't be hard to tweak it's MCH to add the necessary config space, right? I know xen doesn't support q35 now but it's opensource :) I think that's a good step 1. We can do PV hacks on top if we decide they aren't too painful. -- MST