On Thu, Apr 18, 2013 at 02:47:21PM +0000, Ren, Yongjie wrote: > > -----Original Message----- > > From: Gleb Natapov [mailto:gleb@xxxxxxxxxx] > > Sent: Thursday, April 18, 2013 7:08 PM > > To: Ren, Yongjie > > Cc: Marcelo Tosatti; kvm@xxxxxxxxxxxxxxx; qemu-devel@xxxxxxxxxx; > > ehabkost@xxxxxxxxxx > > Subject: Re: [PATCH] target-i386: upgrade family number of qemu64 CPU > > model to 15 > > > > On Thu, Apr 18, 2013 at 10:45:38AM +0000, Ren, Yongjie wrote: > > > qemu64 is the default CPU model for QEMU/KVM on x86-64, but its > > family number > > > definition is not accurate. The vendor of 'qemu64' is defined as 'AMD'. > > For AMD > > > processors, AMD K8 (i.e. Family 15) firstly introduced SSE3 instruction > > set. > > > 'qemu64' already has 'CPUID_EXT_SSE3' in its ext_features, but its family > > > number is only 6 which is not equal to or greater than 15. > > > So, upgrade the CPU family number of qemu64 model to 15. > > > After this upgrade, 32bit Windows 8 can boot up with qemu64 CPU > > model. > > > This upgrade can be also a fix to the below bug about 32bit Windows 8 > > booting. > > > https://bugs.launchpad.net/qemu/+bug/1007269 > > > > Changing cpuid info is not that simple since this is guest visible > > information and can impact migration. Old machine models should still > > expose the old family. > > > Sorry, I didn't consider migration issue. I just think the cupid info for qemu64 > is not compatible with real-world CPU. Family 6 AMD CPU should not have > SSE3 but it has SSE3 in qemu64 model. > If it's not so simple to modify cupid info, just ignore my patch. :-) We have other fixes for CPUID information sent by other people that will require special handling to allow migration compatibility as well. The ongoing static-properties and X86CPU subclasses work would help us on this, but they probably won't be in 1.5. So I am planning to gather those CPUID fixes and make them use a simple (and temporary) compatibility mechanism and submit them next week. -- Eduardo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
