From mboxrd@z Thu Jan 1 00:00:00 1970 From: Razvan Cojocaru Subject: Re: [PATCH 0/2] Xen/mem_event: Do not rely on the toolstack being bug-free Date: Thu, 17 Jul 2014 23:26:36 +0300 Message-ID: <53C8317C.6020807@bitdefender.com> References: <1405602637-8321-1-git-send-email-andrew.cooper3@citrix.com> <97A500D504438F4ABC02EBA81613CC6331885B2C@xmb-aln-x02.cisco.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <97A500D504438F4ABC02EBA81613CC6331885B2C@xmb-aln-x02.cisco.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Aravindh Puthiyaparambil (aravindp)" , Andrew Cooper Cc: Xen-devel List-Id: xen-devel@lists.xenproject.org On 07/17/2014 10:01 PM, Aravindh Puthiyaparambil (aravindp) wrote: >> Xen performs insufficient validation of the contents of mem_event responses >>from the toolstack. As a result, a buggy toolstack could cause Xen to walk off >> the end of a domain's vcpu list, and get out of sync with vcpu pause reference >> counts. >> >> These two fixes are compile tested only, as I have no way to plausibly test the >> mem-event functionality itself. > > One easy way of testing is to use the tools/tests/xen-access test program which exercises mem_access and thereby mem_event. It is fairly easy to run. Bring up a domain and execute " xen-access write|exec". But I understand if you are under time constraints and cannot do it. If you Cc me on these patches, I will gladly test them for you. Indeed, our application is very xen-access-like (except quite a bit more involved), and I've tested the original patches with 5 different domains 3 times over - but it's a well-behaved citizen of the Xen ecosystem and there were no gimmicks involved. No mem_events piled up, and there was always just one mem_event handler per domain. Everything went without a hitch, but I did not try to pause the domain while it was running or try to trick the hypervisor in any way. Thanks, Razvan Cojocaru