The idea is to let vfio core manage the vfio_device life cycle instead of duplicating the logic cross drivers. Besides cleaner code in driver side this also allows adding struct device to vfio_device as the first step toward adding cdev uAPI in the future. Another benefit is that user can now look at sysfs to decide whether a device is bound to vfio [1], e.g.: /sys/devices/pci0000\:6f/0000\:6f\:01.0/vfio-dev/vfio0 Though most drivers can fit the new model naturally: - vfio_alloc_device() to allocate and initialize vfio_device - vfio_put_device() to release vfio_device - dev_ops->init() for driver private initialization - dev_ops->release() for driver private cleanup vfio-ccw is the only exception due to a life cycle mess that its private structure mixes both parent and mdev info hence must be alloc/freed outside of the life cycle of vfio device. Per prior discussions this won't be fixed in short term by IBM folks [2]. Instead of waiting this series introduces a few tricks to move forward: - vfio_init_device() to initialize a pre-allocated device structure; - require *EVERY* driver to implement @release and free vfio_device inside. Then vfio-ccw can use a completion mechanism to delay the free to css driver; The second trick is not a real burden to other drivers because they all require a @release for private cleanup anyway. Later once the ccw mess is fixed a simple cleanup can be done by moving free from @release to vfio core. Thanks Kevin [1] https://listman.redhat.com/archives/libvir-list/2022-August/233482.html [2] https://lore.kernel.org/all/0ee29bd6583f17f0ee4ec0769fa50e8ea6703623.camel@xxxxxxxxxxxxx/ v4: - fix use-after-free issue in @release of mtty/mbochs and also change mdpy/ap to free vfio-device as the last thing in @release (Alex) - revert the rename from 'vfio' to 'vfio_group' in procfs (Alex) v3: - https://lore.kernel.org/lkml/20220909102247.67324-1-kevin.tian@xxxxxxxxx/ - rebase to vfio-next after resolving conflicts with Yishai's series - add missing fixes for two checkpatch errors - fix grammar issues (Eric Auger) - add more r-b's v2: - https://lore.kernel.org/lkml/20220901143747.32858-1-kevin.tian@xxxxxxxxx/ - rebase to 6.0-rc3 - fix build warnings (lkp) - patch1: remove unnecessary forward reference (Jason) - patch10: leave device_set released by vfio core (Jason) - patch13: add Suggested-by - patch15: add ABI file sysfs-devices-vfio-dev (Alex) - patch15: rename 'vfio' to 'vfio_group' in procfs (Jason) v1: https://lore.kernel.org/lkml/20220827171037.30297-1-kevin.tian@xxxxxxxxx/ Kevin Tian (6): vfio: Add helpers for unifying vfio_device life cycle drm/i915/gvt: Use the new device life cycle helpers vfio/platform: Use the new device life cycle helpers vfio/amba: Use the new device life cycle helpers vfio/ccw: Use the new device life cycle helpers vfio: Rename vfio_device_put() and vfio_device_try_get() Yi Liu (9): vfio/pci: Use the new device life cycle helpers vfio/mlx5: Use the new device life cycle helpers vfio/hisi_acc: Use the new device life cycle helpers vfio/mdpy: Use the new device life cycle helpers vfio/mtty: Use the new device life cycle helpers vfio/mbochs: Use the new device life cycle helpers vfio/ap: Use the new device life cycle helpers vfio/fsl-mc: Use the new device life cycle helpers vfio: Add struct device to vfio_device .../ABI/testing/sysfs-devices-vfio-dev | 8 + MAINTAINERS | 1 + drivers/gpu/drm/i915/gvt/gvt.h | 5 +- drivers/gpu/drm/i915/gvt/kvmgt.c | 52 ++++-- drivers/gpu/drm/i915/gvt/vgpu.c | 33 ++-- drivers/s390/cio/vfio_ccw_ops.c | 52 +++++- drivers/s390/cio/vfio_ccw_private.h | 3 + drivers/s390/crypto/vfio_ap_ops.c | 50 +++--- drivers/vfio/fsl-mc/vfio_fsl_mc.c | 85 +++++---- .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 80 ++++----- drivers/vfio/pci/mlx5/main.c | 50 ++++-- drivers/vfio/pci/vfio_pci.c | 20 +-- drivers/vfio/pci/vfio_pci_core.c | 23 ++- drivers/vfio/platform/vfio_amba.c | 72 ++++++-- drivers/vfio/platform/vfio_platform.c | 66 +++++-- drivers/vfio/platform/vfio_platform_common.c | 71 +++----- drivers/vfio/platform/vfio_platform_private.h | 18 +- drivers/vfio/vfio_main.c | 164 +++++++++++++++--- include/linux/vfio.h | 28 ++- include/linux/vfio_pci_core.h | 6 +- samples/vfio-mdev/mbochs.c | 73 +++++--- samples/vfio-mdev/mdpy.c | 81 +++++---- samples/vfio-mdev/mtty.c | 67 ++++--- 23 files changed, 728 insertions(+), 380 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-devices-vfio-dev base-commit: f39856aacb078c1c93acef011a37121b17d54fe0 -- 2.21.3
