On 11/22/2018 11:54 AM, Cornelia Huck wrote:
[This is the Linux kernel part, git tree is available at https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/vfio-ccw.git vfio-ccw-caps The companion QEMU patches are available at https://github.com/cohuck/qemu 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 introduces capabilities (similar to what vfio-pci uses) and exposes a new async region for handling hsch/csch. 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.)
I was able to trigger the guest DASD driver to issue a csch instruction, and from my brief testing it seems to be working just like it would on the LPAR. (I basically tested with 2 threads trying to issue DASD device reserve and release ioctls, on the same DASD device, in a busy loop).
I am going to spend some time doing a deeper review. Thanks Farhan
Cornelia Huck (3): vfio-ccw: add capabilities chain s390/cio: export hsch to modules vfio-ccw: add handling for asnyc channel instructions drivers/s390/cio/Makefile | 3 +- drivers/s390/cio/ioasm.c | 1 + drivers/s390/cio/vfio_ccw_async.c | 88 +++++++++++++ drivers/s390/cio/vfio_ccw_drv.c | 48 +++++-- drivers/s390/cio/vfio_ccw_fsm.c | 158 +++++++++++++++++++++- drivers/s390/cio/vfio_ccw_ops.c | 195 ++++++++++++++++++++++++---- drivers/s390/cio/vfio_ccw_private.h | 44 +++++++ include/uapi/linux/vfio.h | 5 + include/uapi/linux/vfio_ccw.h | 12 ++ 9 files changed, 509 insertions(+), 45 deletions(-) create mode 100644 drivers/s390/cio/vfio_ccw_async.c
