From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1IT0oE-0004NJ-Ug for qemu-devel@nongnu.org; Wed, 05 Sep 2007 15:45:07 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1IT0oD-0004Ly-VD for qemu-devel@nongnu.org; Wed, 05 Sep 2007 15:45:06 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1IT0oD-0004Ll-OP for qemu-devel@nongnu.org; Wed, 05 Sep 2007 15:45:05 -0400 Received: from mx1.redhat.com ([66.187.233.31]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1IT0oD-0004C2-Cb for qemu-devel@nongnu.org; Wed, 05 Sep 2007 15:45:05 -0400 Date: Wed, 5 Sep 2007 20:44:48 +0100 From: "Daniel P. Berrange" Message-ID: <20070905194448.GN5503@redhat.com> References: <20070905174530.GA3945@karma.qumranet.com> <1189020371.7206.3.camel@squirrel> <46DF04D5.5000807@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <46DF04D5.5000807@qumranet.com> Subject: [Qemu-devel] Re: [kvm-devel] expose host CPU features to guests Reply-To: "Daniel P. Berrange" , qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: kvm-devel , qemu-devel@nongnu.org On Wed, Sep 05, 2007 at 10:34:45PM +0300, Avi Kivity wrote: > Anthony Liguori wrote: > > On Wed, 2007-09-05 at 20:45 +0300, danken@qumranet.com wrote: > > > >> Hi, > >> > >> It's a pity not to use a host CPU feature if it is available. This patch > >> exposes host CPU features to guests. It allows fine-tuning the presented > >> features from the command-line. > >> > >> The code could use some serious clean ups, but I think it is interesting > >> enough right now. I'd be happy to hear your opinion and suggestions. > >> The diff are done against qemu cvs. I tried it with kvm, but I thinkg it > >> should be useful also for kqemu. > >> > > > > I like this idea but I have some suggestions about the general approach. > > I think instead of defining another machine type, it would be better to > > just have a command line option like -cpuid that took a comma separate > > string of features with "all" meaning all features that the host has. > > > > > > I think qemu-cvs has a -cpu option for non-x86 which could be used for > this. Agree machine types are the wrong approach. Yep, machine types are already used to switch between a different concept so using the new -cpu option would make sense. Could perhaps extend the syntax so that instead of '-cpu TYPE' it used '-cpu TYPE,FEATURES' where FEATURES was an optional list of CPU features to allow - though perhaps with some shortcut for specifying 'match the host cpu type & features'. Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|