Yes. We had this problem until we cleared the flag in
>>> On 16.03.11 at 11:11, Ian Campbell <Ian.Campbell@xxxxxxxxxx
> On Wed, 2011-03-16 at 09:34 +0000, Jan Beulich wrote:
>> >>> On 16.03.11 at 04:20, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx
>> > On Thu, Mar 10, 2011 at 12:25:55PM +0100, Olivier Hanesse wrote:
>> >> [469390.126691] alignment check: 0000 [#1] SMP
>> > aligment check? Was there anything else in the log before this? Was there
>> > anything in the Dom0 log?
>> This together with
>> >> [469390.126795] RSP: e02b:ffff88001ec3f9b8 EFLAGS: 00050286
>> makes me wonder if either eflags got restored from a corrupted
>> stack slot somewhere, or whether something in the kernel or one
>> of the modules intentionally played with EFLAGS.AC
> Can a PV kernel running in ring-3 change AC?
do_iret() isn't increasing privilege, and hence restoring whatever
> The hypervisor appears to clear the guest's EFLAGS.AC
on context switch
> to a guest and failsafe bounce but not in e.g. do_iret so it's not
> entirely clear what his policy is...