[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] XenServer Xen-4.5 (-rc3ish) testing
On 08/12/2014 20:00, Konrad Rzeszutek Wilk wrote: > 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. This is purely an implementer of the ioreq server infrastructure providing an emulated set of BARs in the guest as qemu would, but without using dom0 map-foreign powers. The gfn ranges in question are regular guest RAM as far as I am aware, and should not require any special io permissions. Either way, the identified changeset has apparently caused a regression, but I am not yet certain whether it is legitimately disabling something which should not have worked in the first place, or whether it is a change which needs reconsidering. > >> 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? XenServer expermental-4.5 is strictly using migration v2, including upgrade from legacy, but as far as I am aware identical migration v2 as our current Xen-4.4 trunk which works fine for all tests. >> 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? They are all IBM blades to the best of my knowledge, which are a similar system to the hardware which gave me 1ed7679 to debug, so I am hoping it is a latent BIOS issue and not a Xen 4.5 issue. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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