[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-v3 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. 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 v3->v4: - shrunk the capability offset, we don't need to accommodate as much as pci - make checks in patch 1 more consistent and less buggy - rebased on top of my current vfio-ccw branch Changes v2->v3: - Unb0rked patch 1, improved scope - Split out the new mutex from patch 2 into new patch 3; added missing locking and hopefully improved description - Patch 2 now reworks the state handling by splitting the BUSY state into CP_PROCESSING and CP_PENDING - Patches 3 and 5 adapted on top of the reworked patches; hsch/csch are allowed in CP_PENDING, but not in CP_PROCESSING (did not add any R-b due to that) - Added missing free in patch 5 - Probably some small changes I forgot to note down 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 (6): vfio-ccw: make it safe to access channel programs vfio-ccw: rework ssch state handling vfio-ccw: protect the I/O region 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 | 88 ++++++++++++ drivers/s390/cio/vfio_ccw_cp.c | 21 ++- drivers/s390/cio/vfio_ccw_cp.h | 2 + drivers/s390/cio/vfio_ccw_drv.c | 57 ++++++-- drivers/s390/cio/vfio_ccw_fsm.c | 143 +++++++++++++++++- drivers/s390/cio/vfio_ccw_ops.c | 215 +++++++++++++++++++++++----- drivers/s390/cio/vfio_ccw_private.h | 48 ++++++- include/uapi/linux/vfio.h | 4 + include/uapi/linux/vfio_ccw.h | 12 ++ 11 files changed, 537 insertions(+), 57 deletions(-) create mode 100644 drivers/s390/cio/vfio_ccw_async.c -- 2.17.2
