Re: HVM domains crash after upgrade from XEN 4.5.1 to 4.5.2

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

On 12/11/15 12:52, Jan Beulich wrote:
>>>> On 12.11.15 at 02:08, <ariel.atom2@web2web.at> wrote:
>> After the upgrade HVM domUs appear to no longer work - regardless of the 
>> dom0 kernel (tested with both 3.18.9 and 4.1.7 as the dom0 kernel); PV 
>> domUs, however, work just fine as before on both dom0 kernels.
>>
>> xl dmesg shows the following information after the first crashed HVM 
>> domU which is started as part of the machine booting up:
>> [...]
>> (XEN) Failed vm entry (exit reason 0x80000021) caused by invalid guest 
>> state (0).
>> (XEN) ************* VMCS Area **************
>> (XEN) *** Guest State ***
>> (XEN) CR0: actual=0x0000000000000039, shadow=0x0000000000000011, 
>> gh_mask=ffffffffffffffff
>> (XEN) CR4: actual=0x0000000000002050, shadow=0x0000000000000000, 
>> gh_mask=ffffffffffffffff
>> (XEN) CR3: actual=0x0000000000800000, target_count=0
>> (XEN)      target0=0000000000000000, target1=0000000000000000
>> (XEN)      target2=0000000000000000, target3=0000000000000000
>> (XEN) RSP = 0x0000000000006fdc (0x0000000000006fdc)  RIP = 
>> 0x0000000100000000 (0x0000000100000000)
> Other than RIP looking odd for a guest still in non-paged protected
> mode I can't seem to spot anything wrong with guest state.

odd? That will be the source of the failure.

Out of long mode, the upper 32bit of %rip should all be zero, and it
should not be possible to set any of them.

I suspect that the guest has exited for emulation, and there has been a
bad update to %rip.  The alternative (which I hope is not the case) is
that there is a hardware errata which allows the guest to accidentally
get it self into this condition.

Are you able to rerun with a debug build of the hypervisor?

~Andrew