Re: [RFC PATCH v1 00/10] s390/vfio-ccw: Channel Path Handling

[Cornelia Huck <cohuck@redhat.com>]

On Fri, 15 Nov 2019 03:56:10 +0100
Eric Farman <farman@linux.ibm.com> wrote:

> Here is a first pass at the channel-path handling code for vfio-ccw.
> This was initially developed by Farhan Ali this past summer, and
> picked up by me.  For my own benefit/sanity, I made a small changelog
> in the commit message for each patch, describing the changes I've
> made to his original code beyond just rebasing to master.
> 
> I did split a couple of his patches, to (hopefully) make them a little
> more understandable.  The entire series is based on top of the trace
> rework patches from a few weeks ago, which are currently pending.
> But really, the only cause for overlap is the trace patch here.
> The bulk of it is really self-contained.
> 
> With this, and the corresponding QEMU series (to be posted momentarily),
> applied I am able to configure off/on a CHPID (for example, by issuing
> "chchp -c 0/1 xx" on the host), and the guest is able to see both the
> events and reflect the updated path masks in its structures.

Nice.

> 
> For reasons that are hopefully obvious, issuing chchp within the guest
> only works for the logical vary.  Configuring it off/on does not work,
> which I think is fine.

Yes, I think that's completely ok.

> 
> Eric Farman (4):
>   vfio-ccw: Refactor the unregister of the async regions
>   vfio-ccw: Refactor IRQ handlers
>   vfio-ccw: Add trace for CRW event
>   vfio-ccw: Remove inline get_schid() routine
> 
> Farhan Ali (6):
>   vfio-ccw: Introduce new helper functions to free/destroy regions
>   vfio-ccw: Register a chp_event callback for vfio-ccw
>   vfio-ccw: Use subchannel lpm in the orb
>   vfio-ccw: Introduce a new schib region
>   vfio-ccw: Introduce a new CRW region
>   vfio-ccw: Wire up the CRW irq and CRW region
> 
>  drivers/s390/cio/Makefile           |   2 +-
>  drivers/s390/cio/vfio_ccw_chp.c     | 128 +++++++++++++++++++++++++
>  drivers/s390/cio/vfio_ccw_cp.c      |   4 +-
>  drivers/s390/cio/vfio_ccw_drv.c     | 140 ++++++++++++++++++++++++++--
>  drivers/s390/cio/vfio_ccw_fsm.c     |   8 +-
>  drivers/s390/cio/vfio_ccw_ops.c     |  65 +++++++++----
>  drivers/s390/cio/vfio_ccw_private.h |  11 +++
>  drivers/s390/cio/vfio_ccw_trace.c   |   1 +
>  drivers/s390/cio/vfio_ccw_trace.h   |  30 ++++++
>  include/uapi/linux/vfio.h           |   3 +
>  include/uapi/linux/vfio_ccw.h       |  10 ++
>  11 files changed, 366 insertions(+), 36 deletions(-)
>  create mode 100644 drivers/s390/cio/vfio_ccw_chp.c

I just glanced at the general approach taken here, which seems sane to
me. I'm, however, currently a bit short on free cycles for reviewing
this, so I'd appreciate if other folks could take a look at this as
well.

(Same applies to the QEMU patches.)