[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-eagain-caps-v4]
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.
Note that the kernel side now returns -EAGAIN to trigger a retry in more
cases; QEMU should already be fine with that.
[I'm not quite happy with how this async processing hooks up in css.c;
ideas welcome.]
Lightly tested (I can interact with a dasd as before, and reserve/release
seems to work well.) Not sure if there is a better way to test this, ideas
welcome.
Changes v2->v3:
- update kernel header to v4 of kernel patches
- rebased on master
Changes v1->v2:
- update kernel header to v2 of kernel patches
- rebased on master
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(-)
--
2.17.2