From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: linux 3.13 guest crash with -cpu host Date: Mon, 03 Feb 2014 15:19:18 +0100 Message-ID: <52EFA566.4010402@redhat.com> References: <20140202205930.GA2157@redhat.com> <20140203125828.GH2221@otherpad.lan.raisama.net> <20140203140601.GA24944@redhat.com> <20140203141235.GJ8874@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Eduardo Habkost , kvm@vger.kernel.org To: Peter Zijlstra , "Michael S. Tsirkin" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:34309 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751751AbaBCOTr (ORCPT ); Mon, 3 Feb 2014 09:19:47 -0500 In-Reply-To: <20140203141235.GJ8874@twins.programming.kicks-ass.net> Sender: kvm-owner@vger.kernel.org List-ID: Il 03/02/2014 15:12, Peter Zijlstra ha scritto: >> > But why doesn't it crash on baremetal? >> > Probably baremetal simply returns 0 or something. >> > Let me try .. > The claim "v2 and above have FEATURE_PDCM" is in fact true for real > hardware. > > If it didn't the rdmsr() would have generated an exception and we'd have > crashed just like your virtual thingy did. Right, and the virt thingy has no PEBS, so there is no correct value that we could return from the MSR. That's why the CPUID bit is zero. A strange game. The only winning move is not to play. How about a nice game of chess? Paolo