From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Graphics pass-through Date: Wed, 11 May 2011 17:14:31 +0300 Message-ID: <4DCA99C7.60408@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> <4DCA9520.2080207@redhat.com> <4DCA97F5.20106@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 S1757323Ab1EKQRG (ORCPT ); Wed, 11 May 2011 12:17:06 -0400 In-Reply-To: <4DCA97F5.20106@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 05/11/2011 05:06 PM, Jan Kiszka wrote: > > > > 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. > > > > The BIOS can't configure the bars to 64 bit as it does not know which > type of OS (32 or 64 bits) is going to pick them up. If it's a really large BAR, it has no choice. BTW, a 32-bit OS can handle 64-bit BARs, all it needs is PAE or PSE-36. > But maybe 64-bit > Windows reconfigures the bars before it starts the driver. Would we > support this? Yes. qemu doesn't know if it's the BIOS reprogramming the BARs or the OS. Of course unmap+remap is not a heavily tested code path. -- error compiling committee.c: too many arguments to function