On Thu, 19 May 2022 14:33:10 -0400 Matthew Rosato <mjrosato@xxxxxxxxxxxxx> wrote: > As discussed in this thread: > > https://lore.kernel.org/kvm/20220516172734.GE1343366@xxxxxxxxxx/ > > Let's remove VFIO_GROUP_NOTIFY_SET_KVM and instead assume the association > has already been established prior to device_open. For the types today > that need a KVM (GVT, vfio-ap) these will fail if a KVM is not found. > Looking ahead, vfio-pci-zdev will optionally want the KVM association > (enable hardware assists) but it will not be a hard requirement (still > want to allow other, non-KVM userspace usage). > > This is built on top of vfio-next and tested with s390x-pci > (zdev-kvm series) and vfio-ap (GVT changes are compile-tested only) > > Changes for v3: > - merge branches under if (device->open_count == 1) (Kevin) > - move device->open_count-- out from group_rwsem (Kevin) > - drop null KVM check (Christoph) > - remove extra kvm_{get,put}_kvm from vfio_ap_ops, it was already getting > a reference (Jason) > - Add comment about kvm reference in vfio.h (Jason) > - Return -EINVAL if !kvm for vfio-ap (Tony) > > Changes for v2: > - gvt no longer needs release_work, get rid of it (Christoph) > - a few compile fixes for gvt > - update commit to mention fixes gvt oops (Jason) > - s/down_write/down_read/ in a few spots (Jason) > - avoid kvm build dependency by holding group read lock over device > open/close and put the onus on the driver to obtain a reference if > it will actually use the kvm pointer. Document the requirement, > use lockdep_assert to ensure lock is held during register_notifer; > today all callers are from driver open_device. > > Matthew Rosato (1): > vfio: remove VFIO_GROUP_NOTIFY_SET_KVM > > drivers/gpu/drm/i915/gvt/gtt.c | 4 +- > drivers/gpu/drm/i915/gvt/gvt.h | 3 - > drivers/gpu/drm/i915/gvt/kvmgt.c | 82 ++++++-------------------- > drivers/s390/crypto/vfio_ap_ops.c | 35 ++--------- > drivers/s390/crypto/vfio_ap_private.h | 3 - > drivers/vfio/vfio.c | 83 ++++++++++----------------- > include/linux/vfio.h | 6 +- > 7 files changed, 57 insertions(+), 159 deletions(-) Applied to vfio next branch for v5.19. Thanks, Alex
