RE: PV resume failed after self migration failed

["James Harper" <james.harper@bendigoit.com.au>]

> Hi James:
> 
>     I found another issue during test.
>     When migrating VM from host A to B, it contains following process.
>     1) memory copy
>     2) suspend VM on A
>     3) transfer some other thing to B such as tsc state.
> 
>     If step (3) failed,  VM will be resumed on host A.
>     Well, from the test of view,  the resume cannot be completed
successfully.
> 
>     Out test is migrating 12VMs between twn host over again and again.
>     The attached log doing exactly below things
>     1) Migrate from Host B, so fisrt resuming (line 25 to 474)
>     2) Later want to migrating to B again, so suspending (line 474 to
line
> 1116)
>     3) Migrating failed and enter into resuming again  (line 1118 to
line
> 1399).
> 
>      line 1383 is waiting vbd state to be changed but can not get the
> response.
> And 1392 show a "Unacknowledged event word ". From the log, it looks
like
> this is due to XenVbd_HwScsiResetBus in line 1397.
> 
>       Question is what trigger the XenVbd_HwScsiResetBus during
resuming?
> 

Windows will invoke a scsi reset if a request takes too long to complete
(5 seconds I think). It will also issue a reset when a crash dump
starts, just to make sure all previous requests are flushed etc.

James