Re: [Qemu-devel] [PATCH 7/8] pseries: savevm support for PAPR virtual SCSI

[Paolo Bonzini]

Il 27/05/2013 08:48, Alexey Kardashevskiy ha scritto:
>> > 
>> > This is only true when the rerror and werror options have the values
>> > "ignore" or "report".  See virtio-scsi for an example of how to save the
>> > requests using the save_request and load_request callbacks in SCSIBusInfo.
> 
> Sigh.

?

> How do you test that requests are saved/restored correctly? What does
> happen to requests which were already sent to the real hardware (real block
> device, etc) but have not completed at the moment of the end of migration?

They aren't saved, there is a bdrv_drain_all() in the migration code.

This is only used for rerror=stop or werror=stop.  To test it you can
use blkdebug (also a bit underdocumented) or hack block/raw-posix.c with
code that makes it fail the 100th write or something like that.  Start
the VM and migrate it while paused to a QEMU that doesn't have the hack.

Paolo