On Fri, 1 Mar 2019 10:38:56 +0100 Cornelia Huck <cohuck@xxxxxxxxxx> 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-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 > Queued (with the touchups discussed in the thread) to the vfio-ccw branch on kernel.org.
