From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 1/2] vmx,svm: Add module parameter to ignore the 'in use' check Date: Tue, 05 Jul 2011 13:37:05 +0300 Message-ID: <4E12E951.3040304@redhat.com> References: <1309820954-8629-1-git-send-email-levinsasha928@gmail.com> <4E12C6A1.70105@redhat.com> <1309853683.4117.33.camel@sasha> <20110705091106.GK29299@8bytes.org> <1309858322.4117.36.camel@sasha> <4E12DB73.9040601@redhat.com> <1309859802.4117.44.camel@sasha> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Joerg Roedel , kvm@vger.kernel.org, Marcelo Tosatti To: Sasha Levin Return-path: Received: from mx1.redhat.com ([209.132.183.28]:36010 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755344Ab1GEKhM (ORCPT ); Tue, 5 Jul 2011 06:37:12 -0400 In-Reply-To: <1309859802.4117.44.camel@sasha> Sender: kvm-owner@vger.kernel.org List-ID: On 07/05/2011 12:56 PM, Sasha Levin wrote: > Please note that I don't have access to the hardware in question, this > was done over IRC. > I understand that. Can you get in contact with the reporter again? > Here are the steps taken in debugging this issue: > > 1. Looking at the dmesg ( http://pastebin.com/eM7bDY8r ) we saw that > when trying to load the kvm module, the following error shows up: 'kvm: > enabling virtualization on CPU0 failed'. > > 2. We went through the lsmod output (unfortunately I don't have the link > as it's gone from my IRC buffer) and didn't see any modules belonging to > other hypervisors. > > 3. At that point, looking at the code - we figured that a set SVM flag > is the possible culprit since it's the only code path which fails > loading the module with that error message without printing anything > else. > > 4. Installed msr-tools and injected the msr module so that we could read > msr values from userspace. > > 5. Ran 'rdmsr 0xc0000080' to read the extended feature register. The > output had bit 12 set - which means that SVM bit was enabled. > > 6. Ran 'wrmsr 0xc0000080 0xd01' which disabled the SVM bit. > > 7. kvm module loaded ok. My questions are: - was a BIOS update attempted? at least VMware uses the same check as kvm, and probably virtualbox as well, so this problem should have been seen before. - was the vendor contacted? Not that I think we'll see a lot of good from that. - was this after a reset or cold boot? - maybe a stealth rootkit is involved? -- error compiling committee.c: too many arguments to function