[PATCH v3 0/2] rpmb: add virtio RPMB driver

[Haruka Kuze]

This adds a driver on top of the rpmb subsystem for virtio-rpmb devices.

Alex Bennée had an earlier virtio-rpmb driver in his RPMB series [1]
but that stalled due to the user space API.

The one that merged later has no user space API and OP-TEE routes frames
through it so this driver only needs to implement route_frames().

I added patch 1 to fix a use-after-free that I hit while testing
removing the device (OP-TEE can still route frames after driver unregisters
the rpmb device).

I tested this with UML (virtio_uml) and a vhost-user backend I wrote
for this on top of rust-vmm's vhost-device with KASAN, lockdep:

 - key programming
 - write counter
 - single and multi block write and read
 - MAC and counter failures
 - max_wr_cnt
 - unbinding the driver when the rpmb device is held

With OP-TEE 4.11 on QEMU virt arm64 the secure_storage example TA keeps
its objects in RPMB through the driver and an object written to in one
boot is found in the one after.

I have added myself in MAINTAINERS. I would like to maintain the driver.

Changes in v3:
- Take a spinlock around the virtqueue operations, so the completion
  callback can not call virtqueue_get_buf() while a new request is
  added (sashiko)
- Do not delete the virtqueue twice when restore failed (sashiko)
- Explain the reliable_wr_count calculation in a comment
- v2: https://lore.kernel.org/all/20261029124132.2354314-1-harukak@xxxxxxxxxxx/

Changes in v2:
- Use guard() and scoped_guard() for the locks in both patches (Greg)
- Call virtio_device_ready() before vr->vq is set, so a request on
  restore can not kick the queue before DRIVER_OK (sashiko)
- v1: https://lore.kernel.org/all/20261029081317.2264887-1-harukak@xxxxxxxxxxx/

- haruka

[1] https://lore.kernel.org/all/20220405093759.1126835-1-alex.bennee@xxxxxxxxxx/

Haruka Kuze (2):
  rpmb: stop the routing after unregister
  rpmb: add a virtio RPMB device driver

 MAINTAINERS                      |   7 +
 drivers/misc/Kconfig             |  10 ++
 drivers/misc/Makefile            |   1 +
 drivers/misc/rpmb-core.c         |  14 +-
 drivers/misc/virtio_rpmb.c       | 300 +++++++++++++++++++++++++++++++
 include/linux/rpmb.h             |   4 +
 include/uapi/linux/virtio_rpmb.h |  56 ++++++
 7 files changed, 391 insertions(+), 1 deletion(-)
 create mode 100644 drivers/misc/virtio_rpmb.c
 create mode 100644 include/uapi/linux/virtio_rpmb.h


base-commit: c339f4010dea8b0d754f84ace70cd1b089878ef8
-- 
2.55.0