From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: New CPUID/MSR driver; virtualization hooks Date: Thu, 05 Apr 2007 14:59:34 -0700 Message-ID: <46157146.1090406@zytor.com> References: <461447F2.9010807@zytor.com> <20070405011640.GL19575@sequoia.sous-sol.org> <46144FA6.1000802@zytor.com> <4614867C.4060506@vmware.com> <461539DF.6010502@zytor.com> <46156591.8080802@vmware.com> <46156783.9030501@zytor.com> <461569B7.7060008@vmware.com> <46156CC2.7080600@zytor.com> <46156D95.4070001@vmware.com> <46156EDC.8080403@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <46156EDC.8080403@goop.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jeremy Fitzhardinge Cc: Chris Wright , Virtualization Mailing List List-Id: virtualization@lists.linuxfoundation.org Jeremy Fitzhardinge wrote: > Zachary Amsden wrote: >> Or implement anything useful at all ... perhaps it might be useful to >> simply wrap them with an -ENOSYS in some cases. >> >> Rusty, Jeremy. Chris - any feedback on MSR support? > = > I've looked at hpa's patch a bit, but I don't quite get what the point > is yet. Is it that rdmsr/wrmsr can use multiple random registers, so > its necessary to haul them all around? And that cpuid might use more > beyond the current eax-edx? > Yes, pretty much. There are enough evidence that you can't trust CPU = architecture to stay sane. Inside Transmeta it was a constant battle, = and we were a small company. > Xen will trap and emulate any rd/wrmsr instructions, so I don't think it > needs anything beyond native support. If that's true for all hypervisors, then that's obviously the easiest = all around. -hpa