[0/2] vfio-ccw: support hsch/csch (QEMU part)

Message

Cornelia Huck Nov. 22, 2018, 4:54 p.m. UTC

[This is the QEMU part, git tree is available at
https://github.com/cohuck/qemu vfio-ccw-caps

The companion Linux kernel patches are available at
https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/vfio-ccw.git vfio-ccw-caps]

Currently, vfio-ccw only relays START SUBCHANNEL requests to the real
device. This tends to work well for the most common 'good path' scenarios;
however, as we emulate {HALT,CLEAR} SUBCHANNEL in QEMU, things like
clearing pending requests at the device is currently not supported.
This may be a problem for e.g. error recovery.

This patch series makes use of the newly introduced async command region
to issue hsch/csch; if it is not present, continue to emulate hsch/csch,
as before.

[I'm not quite happy with how this async processing hooks up in css.c;
ideas welcome.]

Very lightly tested (I can interact with a dasd as before; I have not
found a reliable way to trigger hsch/csch in the Linux dasd guest driver.)

Cornelia Huck (2):
  vfio-ccw: new capability chain support
  vfio-ccw: support async command subregion

 hw/s390x/css.c                 |  27 ++++++--
 hw/vfio/ccw.c                  | 109 ++++++++++++++++++++++++++++++++-
 include/hw/s390x/s390-ccw.h    |   3 +
 linux-headers/linux/vfio.h     |   4 ++
 linux-headers/linux/vfio_ccw.h |  12 ++++
 5 files changed, 149 insertions(+), 6 deletions(-)