From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] KVM: SVM: fix random segfaults with NPT enabled Date: Wed, 27 Aug 2008 16:53:26 +0300 Message-ID: <48B55C56.2060503@qumranet.com> References: <1219839523-25677-1-git-send-email-joerg.roedel@amd.com> <48B55266.4000300@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, stable@kernel.org, Alexander Graf To: Joerg Rodel Return-path: Received: from il.qumranet.com ([212.179.150.194]:25057 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757043AbYH0Nx2 (ORCPT ); Wed, 27 Aug 2008 09:53:28 -0400 In-Reply-To: <48B55266.4000300@qumranet.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > Joerg Rodel wrote: >> From: Joerg Roedel >> >> This patch introduces a guest TLB flush on every NPF exit in KVM. >> This fixes >> random segfaults and #UD exceptions in the guest seen under some >> workloads >> (e.g. long running compile workloads or tbench). A kernbench run with >> and >> without that fix showed that it has a slowdown lower than 0.5% >> >> > > hm. tbench doesn't allocate memory, so there shouldn't be any npt > faults. I don't see how this can make a difference. > > It can only change something if X is started and we're tracking writes > to the framebuffer. Is this the case? > I fixed a missing flush in this area. Does it help? (I doubt it). Can you post instructions on how to reproduce? -- error compiling committee.c: too many arguments to function