From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Daniel P. Berrange" Subject: Re: expose host CPU features to guests Date: Wed, 5 Sep 2007 20:44:48 +0100 Message-ID: <20070905194448.GN5503@redhat.com> References: <20070905174530.GA3945@karma.qumranet.com> <1189020371.7206.3.camel@squirrel> <46DF04D5.5000807@qumranet.com> Reply-To: "Daniel P. Berrange" Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel , qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org To: Avi Kivity Return-path: Content-Disposition: inline In-Reply-To: <46DF04D5.5000807-atKUWr5tajBWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.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-atKUWr5tajBWk0Htik3J/w@public.gmane.org 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 -=| ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/