From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chen, Tiejun" Subject: Re: [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD Date: Thu, 26 Jun 2014 10:00:15 +0800 Message-ID: <53AB7EAF.3060300@intel.com> References: <1400237624-8505-1-git-send-email-tiejun.chen@intel.com> <1400237624-8505-5-git-send-email-tiejun.chen@intel.com> <1400481887.32155.34.camel@nilsson.home.kraxel.org> <1400498570.32155.59.camel@nilsson.home.kraxel.org> <53AA389D.3010709@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: 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: "Slutz, Donald Christopher" Cc: "peter.maydell@linaro.org" , "xen-devel@lists.xensource.com" , "mst@redhat.com" , "Kelly.Zytaruk@amd.com" , "stefano.stabellini@eu.citrix.com" , "Kay, Allen M" , "qemu-devel@nongnu.org" , "jean.guyader@eu.citrix.com" , "Zhang, Yang Z" , Gerd Hoffmann , "anthony@codemonkey.ws" , "anthony.perard@citrix.com" List-Id: xen-devel@lists.xenproject.org On 2014/6/26 7:04, Slutz, Donald Christopher wrote: > On 06/24/14 22:49, Chen, Tiejun wrote: >> On 2014/5/19 19:22, Gerd Hoffmann wrote: >>> Hi, >>> >>>> I think '-vga none' just guarantees the qemu vga cards doesn't occupy >>>> 00:02.0, but this doesn't mean others use this specific slot since in >>>> qemu internal, we always pass -1 to assign a slot automatically to >>>> register a PCI device. So in some cases, we can't get this slot as we >>>> expect since that is already assigned previously before we need this. >>> >>> Yes, -vga, -net nic, -drive if=scsi (maybe more) can internally create >>> pci devices with auto slot assignment, which will occupy slot 2 indeed. >>> Use -device instead to create the devices. >>> >>>> PCI: slot 2 function 0 not available for xen-pci-passthrough, in use >>>> by xen-platform >>> >>> Ah, the xen platform device. /me looks. Ah, pc_xen_hvm_init creates >>> this automatically. Two options here IMHO: >>> >>> (1) Just move it somewhere else explicitly. For example slot 3, or >>> make it a southbridge function (say 00:01.7). >>> (2) Don't create it automatically, instead expect management add it >>> if needed, using -device xen-plaform,addr=... >>> >> >> Gerd, >> >> Sorry I return this discussion again. >> >> As we discussed here, we should never use -vga xxx to avoid occupying >> slot 2. Instead, we will just use -device to create that emulated vga >> device as you said like this: >> >> -device VGA,vgamem_mb=8,addr=0x4 >> >> But looks this may issue another problem. That is we can't see >> anything until the vga driver is initialized. I means if we pass >> `-device VGA,vgamem_mb=8,addr=0x4', qemu doesn't expose any vga >> interface to BIOS. Right? Or I'm still missing something. >> > > I know for Xen that > > tools/firmware/hvmloader/acpi/dsdt.asl > > also needs to change: > > > /* Make cirrues VGA S3 suspend/resume work in Windows > XP/2003 */ > Device (VGA) > { > - Name (_ADR, 0x00020000) > + // Address of the VGA (device F function 0) > + Name (_ADR, 0x000F0000) > > > is what I have for: > > -device VGA,vgamem_mb=8,addr=0xF.0x0 > Do you mean we need to sync devfn with the passed address to work the emulated VGA before the real graphic device driver is called? Thanks Tiejun > I am not sure, but think that QEMU without Xen does this acpi > adjustment at run time. > > > I also change seabios's config to include more VGA support but > not sure it is needed. > > -Don Slutz > >> Thanks >> Tiejun >>