[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Xen 4.5 Development Update (RC4)
On 16/12/14 20:49, Konrad Rzeszutek Wilk wrote: > On Tue, Dec 16, 2014 at 05:43:08PM +0000, Andrew Cooper wrote: >> On 16/12/14 16:13, konrad.wilk@xxxxxxxxxx wrote: >>> Xen 4.5-rc4 was out on Monday (Dec 15th). This is the last RC and then >>> we have the General Release on Jan 7th! >>> >>> Details for the test-day are at >>> >>> http://wiki.xen.org/wiki/Xen_4.5_RC4_test_instructions >>> >>> In terms of bugs, we have: >> From the XenServer testing. > Thank you for doing this testing! >> * Fail to reliably boot on IBM Flex x222 blades, apparent regression >> from 4.4 >> >> I have declared this a latent BIOS bug, and not a regression from 4.4. >> Across regular reboots, the exact positions of the ACPI tables, and the >> e820 layout is unstable. The first consistent difference between 4.4 >> and 4.5 is that 4.4 reports 1 MBR signature while 4.5 reports 0. This >> is because the int $0x13, ah=2 call is returning differently. I can get >> the call to return differently (and correctly for 4.5) by simply making >> the boot trampoline larger (with my debugging routines but not being >> called). > This sounds very familiar, but I can't place where I saw mention of > a similar issue. >> * VM fail to resume on upgrade from Xen < 4.5 >> >> This is the issue I am currently looking into. Currently, all the >> "upgrade from older XenServer" tests are failing due to VMs crashing on >> resume. I have not yet identified whether this is a XenServer issue or > Ugh. I have got to the bottom of this, and it it turns out to be a legacy -> migration v2 conversion bug which only surfaced now because Xen-4.5 is more strict than Xen-4.4. HVM_PARAM_PAE_ENABLED is sent out-of-band in legacy, but passed to xc_domain_restore(), which does a set_param(), unconnected with any contents of the stream. Migration v2 saves and restores it properly, but the legacy -> v2 conversion neglected to combine the out-of-band information. No VMs blew up because all versions of Xen at that point were not correctly auditing updates to cr4 against the domain cpuid policy. Xen-4.5 now does, causing #GP faults on cr4 writes for guests which had PAE enabled before migrate. I shall be fixing this in the migration v2 series, and also looking for any other obvious out-of-band information which needs injecting into a converted stream. With this fixed(^W hacked around for now), I have identified and solved all discrepancies XenServer testing has noticed between Xen-4.4 and Xen-4.5 so far. There will be another full nightly test happening tonight (based on c/s 7e88c23 "libxl: Tell qemu to use raw format when using a tapdisk"), and some stress and scale tests if time allows. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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