From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: KVM PMU virtualization Date: Sun, 28 Feb 2010 17:34:33 +0100 Message-ID: <20100228163433.GC19879@8bytes.org> References: <4B87AF44.9090702@redhat.com> <20100226114217.GI7463@elte.hu> <4B87C354.9020209@redhat.com> <20100226130656.GA2518@elte.hu> <4B87CCF5.6000209@redhat.com> <20100226134400.GB23422@elte.hu> <4B87D26F.7080703@redhat.com> <20100226141229.GD23422@elte.hu> <4B87E060.8060506@redhat.com> <1267197248.22519.651.camel@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Avi Kivity , Ingo Molnar , Jes Sorensen , KVM General , Zachary Amsden , Gleb Natapov , ming.m.lin@intel.com, "Zhang, Yanmin" , Thomas Gleixner , "H. Peter Anvin" , Arjan van de Ven , Fr??d??ric Weisbecker , Arnaldo Carvalho de Melo To: Peter Zijlstra Return-path: Received: from 8bytes.org ([88.198.83.132]:51507 "EHLO 8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030247Ab0B1Qee (ORCPT ); Sun, 28 Feb 2010 11:34:34 -0500 Content-Disposition: inline In-Reply-To: <1267197248.22519.651.camel@laptop> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, Feb 26, 2010 at 04:14:08PM +0100, Peter Zijlstra wrote: > On Fri, 2010-02-26 at 16:53 +0200, Avi Kivity wrote: > > > If you give a full PMU to a guest it's a whole different dimension and quality > > > of information. Literally hundreds of different events about all sorts of > > > aspects of the CPU and the hardware in general. > > > > > > > Well, we filter out the bad events then. > > Which requires trapping the MSR access, at which point a soft-PMU is > almost there, right? The perfctl msrs need to be trapped anyway. Otherwise the guest could generate NMIs in host context. But access to the perfctr registers could be given to the guest. Joerg