From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: Re: [PATCH] fixup 3dnow! support Date: Tue, 06 May 2008 20:08:39 -0300 Message-ID: <4820E4F7.9000606@redhat.com> References: <12100912622893-git-send-email-gcosta@redhat.com> <6CF4ABCF-B131-41E0-AAFE-2928E01DDAAF@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel , Avi Kivity , virtualization@lists.linux-foundation.org To: Alexander Graf Return-path: In-Reply-To: <6CF4ABCF-B131-41E0-AAFE-2928E01DDAAF@suse.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Alexander Graf wrote: > > On May 6, 2008, at 6:27 PM, Glauber Costa wrote: > >> qemu recently added support for 3dnow instructions. Because of >> that, 3dnow will be featured among cpuid bits. But this will >> break kvm in cpus that don't have those instructions (which includes >> my laptop). So we fixup our cpuid before exposing it to the guest. > > I actually don't see where the problem is here. As far as I read the > code, the CPUID feature function gets received from the host CPU and > bitwise ANDed with a bunch of features that are known to work. What's > wrong with that approach? Probably is that besides that known to work features, there are also features that qemu puts in unconditionally. Among them, 3DNOW. > But I'm pretty sure Dao can tell us a lot more about this. Sure, it would be welcome. ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone