Re: [Qemu-devel] KVM "fake DAX" flushing interface - discussion

[Paolo Bonzini]

On 24/11/2017 14:02, Pankaj Gupta wrote:
> 
>>>    - Suggestion by Paolo & Stefan(previously) to use virtio-blk makes sense
>>>    if just
>>>      want a flush vehicle to send guest commands to host and get reply
>>>      after asynchronous
>>>      execution. There was previous discussion [1] with Rik & Dan on this.
>>>
>>>     [1] https://lists.gnu.org/archive/html/qemu-devel/2017-07/msg08373.html
>>
>> ... in fact, the virtio-blk device _could_ actually accept regular I/O
>> too.  That would make it easier to boot from pmem.  Is there anything
>> similar in regular hardware?
> 
> there is existing block device associated(hard bind) with the pmem range.
> Also, comment by Christoph [1], about removing block device with DAX support.
> Still I am not clear about this. Am I missing anything here?

The I/O part of the blk device would only be used by the firmware.  In
Linux, the different device id would bind the device to a different
driver that would only be used for flushing.

But maybe this idea makes no sense. :)

Paolo