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 16:01:40 +0100 Message-ID: <52EFAF54.1000200@redhat.com> References: <20140202205930.GA2157@redhat.com> <20140203125828.GH2221@otherpad.lan.raisama.net> <20140203140601.GA24944@redhat.com> <20140203141235.GJ8874@twins.programming.kicks-ass.net> <52EFA566.4010402@redhat.com> <20140203142642.GK8874@twins.programming.kicks-ass.net> <20140203142847.GD3229@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "Michael S. Tsirkin" , Eduardo Habkost , kvm@vger.kernel.org To: Peter Zijlstra Return-path: Received: from mx1.redhat.com ([209.132.183.28]:61722 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751294AbaBCPCH (ORCPT ); Mon, 3 Feb 2014 10:02:07 -0500 In-Reply-To: <20140203142847.GD3229@twins.programming.kicks-ass.net> Sender: kvm-owner@vger.kernel.org List-ID: Il 03/02/2014 15:28, Peter Zijlstra ha scritto: >>> > > 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. >> > >> > There's more than PEBS in there, there's also the LBR format (which you >> > obviously also don't have) > On that.. LBR is purely model based, what do you guys do with those > MSRs? On Intel nothing, the MSRs always returns 0. AMD did add LBR virtualization to its virtualization exception, so on AMD you can use LBR from a guest. Paolo