[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-eagain-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. New in v2 are two patches dealing with concurrency. 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 v1->v2: - New patch 1: make it safe to use the cp accessors at any time; this should avoid problems with unsolicited interrupt handling - New patch 2: handle concurrent accesses to the io region; the idea is to return -EAGAIN to userspace more often (so it can simply retry) - also handle concurrent accesses to the async io region - change VFIO_REGION_TYPE_CCW - merge events for halt and clear to a single async event; this turned out to make the code quite a bit simpler - probably some small changes I forgot to note down Cornelia Huck (5): vfio-ccw: make it safe to access channel programs vfio-ccw: concurrent I/O handling vfio-ccw: add capabilities chain s390/cio: export hsch to modules vfio-ccw: add handling for async channel instructions drivers/s390/cio/Makefile | 3 +- drivers/s390/cio/ioasm.c | 1 + drivers/s390/cio/vfio_ccw_async.c | 91 ++++++++++++ drivers/s390/cio/vfio_ccw_cp.c | 3 + drivers/s390/cio/vfio_ccw_cp.h | 2 + drivers/s390/cio/vfio_ccw_drv.c | 46 ++++-- drivers/s390/cio/vfio_ccw_fsm.c | 122 +++++++++++++++- drivers/s390/cio/vfio_ccw_ops.c | 211 +++++++++++++++++++++++----- drivers/s390/cio/vfio_ccw_private.h | 45 ++++++ include/uapi/linux/vfio.h | 4 + include/uapi/linux/vfio_ccw.h | 12 ++ 11 files changed, 487 insertions(+), 53 deletions(-) create mode 100644 drivers/s390/cio/vfio_ccw_async.c -- 2.17.2
