From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Graphics pass-through Date: Wed, 11 May 2011 16:54:40 +0300 Message-ID: <4DCA9520.2080207@redhat.com> References: <4D415D70.8070105@web.de> <1296175554.2891.29.camel@x201> <4DC264CD.9080700@siemens.com> <1304608642.3081.35.camel@x201> <4DC7CCB3.8030607@siemens.com> <4DC807E3.4080706@siemens.com> <1304956091.26106.39.camel@x201> <4DCA7217.5020806@redhat.com> <4DCA8A66.4080304@siemens.com> <4DCA8E9E.8000705@redhat.com> <4DCA9421.6060703@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Alex Williamson , Prasad Joshi , =?UTF-8?B?QW5kcsOpIFdlaWRlbWFubg==?= , "kvm@vger.kernel.org" , Oswaldo Cadenas , "Nikolaev, Maxim" To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:35488 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757334Ab1EKQRG (ORCPT ); Wed, 11 May 2011 12:17:06 -0400 In-Reply-To: <4DCA9421.6060703@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 05/11/2011 04:50 PM, Jan Kiszka wrote: > On 2011-05-11 15:26, Avi Kivity wrote: > > On 05/11/2011 04:08 PM, Jan Kiszka wrote: > >> On 2011-05-11 13:25, Avi Kivity wrote: > >>> On 05/09/2011 06:48 PM, Alex Williamson wrote: > >>>>> That's an interesting trace! We'll check this here, but I bet it > >>>>> contributes to the problems. Our FX 3800 has 1G memory... > >>>> > >>>> Yes, qemu leaves far too little MMIO space to think about assigning > >>>> graphics cards. Both of my cards have 512MB and I hacked qemu to leave > >>>> a bigger gap via something like: > >>>> > >>> > >>> What about 64-bit BARs? > >> > >> Aren't they backward compatible? Or do you think some guest drivers may > >> assume to find their 64-bit capable bars also registered as such and get > >> upset when seeing them as 32-bit ones? > >> > > > > I mean, if you have a 1GB framebuffer, put it above 4GB and hope the > > OS/driver can handle it. > > The question is if the drivers actually depend on this. At least the > binary nvidia thing here on my notebook, it is obviously happy with > below-4G-bars (and likely change the mapped window on demand): > > 01:00.0 VGA compatible controller: nVidia Corporation GT216 [Quadro FX 880M] (rev a2) (prog-if 00 [VGA controller]) > Subsystem: Fujitsu Limited. Device 1584 > Flags: bus master, fast devsel, latency 0, IRQ 16 > Memory at cc000000 (32-bit, non-prefetchable) [size=16M] > Memory at d0000000 (64-bit, prefetchable) [size=256M] > Memory at ce000000 (64-bit, prefetchable) [size=32M] > I/O ports at 2000 [size=128] > [virtual] Expansion ROM at cd000000 [disabled] [size=512K] > Capabilities: [60] Power Management version 3 > Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+ > Capabilities: [78] Express Endpoint, MSI 00 > Capabilities: [b4] Vendor Specific Information: Len=14 > Capabilities: [100] Virtual Channel > Capabilities: [128] Power Budgeting > Capabilities: [600] Vendor Specific Information: ID=0001 Rev=1 Len=024 > Kernel driver in use: nvidia > > Maybe the crashing Windows driver of the FX3800 has different > requirements. I doubt it. A 64-bit BAR would be configured as 32-bit on an older BIOS, no? I'd guess 64-bit BARs are only needed for large BARs. -- error compiling committee.c: too many arguments to function