From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: XenServer Xen-4.5 (-rc3ish) testing Date: Mon, 8 Dec 2014 15:00:34 -0500 Message-ID: <20141208200034.GA3891@laptop.dumpdata.com> References: <5485F5F7.6040206@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <5485F5F7.6040206@citrix.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: Andrew Cooper Cc: Xen-devel List List-Id: xen-devel@lists.xenproject.org On Mon, Dec 08, 2014 at 07:03:19PM +0000, Andrew Cooper wrote: > Hi, Hey Andrew! > > Over the weekend, XenServer testing managed to run a side-by-side test > of XenServer trunk and XenServer experimental xen-4.5. These are > identical other than the version of Xen (and associated libraries) in > use, i.e. identical dom0 kernel, Xapi toolstack and dom0 userspace, > other than as linked against newer Xen libraries. > > The Xen-4.5 tests were on top of c/s e6c3d371d4 "systemd: use pkg-config > to determine systemd library availability" > > There are a few notable issues exposed: > > XEN_DOMCTL_memory_mapping hypercall fails with EPERM where it didn't in > xen-4.4, given identical parameters. The hypercall gained an extra > permission check as part of 0561e1f01e. Our usecase here is a daemon in > dom0 mapping guest RAM to emulate a graphics card, but I currently don't > see how that is incompatible with the new permissions check. I presume the daemon also does 'XEN_DOMCTL_iomem_permission' to grant the other domain access to its RAM? And before it makes the XEN_DOMCTL_memory_mapping hypercall. > > Migrations from older Xens to Xen-4.5 fairly reliably crash domains (90% > of the time, both PV and HVM guests). This includes migrates from older > XenServers using the legacy->v2 migration code which is confirmed-good > in "upgrade to Xen-4.4" case. The migration v2 code in use is identical. The XenServer is not using the in-the-tree migration system except in the older version of XenServer right? > > We have certain machines which are showing reliable failure to boot > under Xen-4.5, where they worked with 4.4. Symptoms range from the dom0 > kernel crashing before printing anything, to complaining that the initrd > is corrupt when attempting to decompress. This appears to be hardware > specific. Hardware specific is good. Could you give some ideas of what make/model this is? > > > I will be looking into all of these issues, to identify whether they are > indeed regressions in xen-4.5, or whether I have make some mistakes > forward porting our patch queue. OK > > Unfortunately, our PCI Passthrough testing has been blocked behind other > regressions which have crept in recently, meaning that both sets of > tests were equally affected, and no 4.4 vs 4.5 comparison has been > possible at this time. I hope this will be fixed by the next time I run > a similar pair of tests. Thank you! > > ~Andrew >