From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753970Ab2GIOYR (ORCPT ); Mon, 9 Jul 2012 10:24:17 -0400 Received: from merlin.infradead.org ([205.233.59.134]:60571 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750767Ab2GIOYQ convert rfc822-to-8bit (ORCPT ); Mon, 9 Jul 2012 10:24:16 -0400 Message-ID: <1341843844.3462.75.camel@twins> Subject: Re: perf with precise attribute kills all KVM based VMs From: Peter Zijlstra To: Gleb Natapov Cc: David Ahern , Avi Kivity , LKML Date: Mon, 09 Jul 2012 16:24:04 +0200 In-Reply-To: <20120709141904.GC7298@redhat.com> References: <4FFAE6D8.5050609@gmail.com> <20120709141904.GC7298@redhat.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2012-07-09 at 17:19 +0300, Gleb Natapov wrote: > Yes, this is knows problem that I can't find time to fix. The crash is > cause by CPU using host PEBS virtual address while guest is running > which causes guest memory corruption. We should disable evens that use > PEBS at the guest entry. Whoops.. so the hardware is reading the DS address as programmed by the host (host linear address) and using it as a guest linear address? Quality stuff.. Disabling PEBS events for guests isn't pretty though.. but I guess the only alternative is mapping the DS into the guest and reprogramming MSR_IA32_DS_AREA which is all a little involved I suppose?