Re: [xen-unstable test] 33690: regressions - FAIL

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 26/01/15 11:38, Jan Beulich wrote:
>>>> On 26.01.15 at 12:04, <JBeulich@suse.com> wrote:
>>>>> On 24.01.15 at 13:54, <Ian.Jackson@eu.citrix.com> wrote:
>>>  test-amd64-amd64-xl-qemut-win7-amd64  7 windows-install   fail REGR. vs. 33637
>> Jan 24 00:35:16.262627 (XEN) ----[ Xen-4.6-unstable  x86_64  debug=y  Not tainted ]----
>> Jan 24 00:35:16.478599 (XEN) CPU:    1
>> Jan 24 00:35:16.478624 (XEN) RIP:    e008:[<0000000000000000>] 0000000000000000
>> Jan 24 00:35:16.486596 (XEN) RFLAGS: 0000000000010082   CONTEXT: hypervisor
>> ...
>> Jan 24 00:35:16.678620 (XEN) Xen call trace:
>> Jan 24 00:35:16.678650 (XEN)    [<ffff82d0801d36d0>] vpmu_do_interrupt+0x2f/0x8a
>> Jan 24 00:35:16.686605 (XEN)    [<ffff82d08015e242>] pmu_apic_interrupt+0x33/0x35
>> Jan 24 00:35:16.698582 (XEN)    [<ffff82d080171bf0>] do_IRQ+0x9c/0x624
>> Jan 24 00:35:16.698615 (XEN)    [<ffff82d080234062>] common_interrupt+0x62/0x70
>> Jan 24 00:35:16.698653 (XEN)    [<ffff82d08012c6fe>] _spin_unlock_irq+0x30/0x31
>> Jan 24 00:35:16.706604 (XEN)    [<ffff82d08012bcf1>] __do_softirq+0x81/0x8c
>> Jan 24 00:35:16.706638 (XEN)    [<ffff82d08012bd49>] do_softirq+0x13/0x15
>> Jan 24 00:35:16.718591 (XEN)    [<ffff82d0801ec4da>] vmx_asm_do_vmentry+0x2a/0x50
> I think I see what the problem here is: Commit 8097616fbd
> ("x86/VPMU: handle APIC_LVTPC accesses") gives the guest
> control over LVTPC.mask regardless of whether the vPMU was
> actually initialized for it. Supposedly in the case above the
> guest is being run with core2_no_vpmu_ops, which in
> particular has .do_interrupt == NULL. It's not immediately
> clear whether vpmu_lvtpc_update() should do the check or its
> (sole) caller. In any event I'm going to revert that commit as
> the primary suspect for causing the regression.

I have just fallen over this as well.  I second a revert in the absence
of a clear way to fix the patch.

~Andrew