Re: [RFC PATCH v2 7/9] vfio-ccw: Wire up the CRW irq and CRW region

[Eric Farman <farman@linux.ibm.com>]

On 4/6/20 9:52 AM, Cornelia Huck wrote:
> On Thu,  6 Feb 2020 22:38:23 +0100
> Eric Farman <farman@linux.ibm.com> wrote:
> 
>> From: Farhan Ali <alifm@linux.ibm.com>
>>
>> Use an IRQ to notify userspace that there is a CRW
>> pending in the region, related to path-availability
>> changes on the passthrough subchannel.
>>
>> Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
>> Signed-off-by: Eric Farman <farman@linux.ibm.com>
>> ---
>>
>> Notes:
>>     v1->v2:
>>      - Remove extraneous 0x0 in crw.rsid assignment [CH]
>>      - Refactor the building/queueing of a crw into its own routine [EF]
>>     
>>     v0->v1: [EF]
>>      - Place the non-refactoring changes from the previous patch here
>>      - Clean up checkpatch (whitespace) errors
>>      - s/chp_crw/crw/
>>      - Move acquire/release of io_mutex in vfio_ccw_crw_region_read()
>>        into patch that introduces that region
>>      - Remove duplicate include from vfio_ccw_drv.c
>>      - Reorder include in vfio_ccw_private.h
>>
>>  drivers/s390/cio/vfio_ccw_chp.c     |  5 ++
>>  drivers/s390/cio/vfio_ccw_drv.c     | 73 +++++++++++++++++++++++++++++
>>  drivers/s390/cio/vfio_ccw_ops.c     |  4 ++
>>  drivers/s390/cio/vfio_ccw_private.h |  9 ++++
>>  include/uapi/linux/vfio.h           |  1 +
>>  5 files changed, 92 insertions(+)
> 
> [I may have gotten all muddled up from staring at this, but please bear
> with me...]
> 
...snip...
> 
> Aren't we missing copying in a new queued crw after userspace had done
> a read?
> 

Um, huh.  I'll doublecheck that after dinner, but it sure looks like
you're right.

(Might not get back to you tomorrow, because I don't have much time
until Wednesday.)