[PATCH v2 0/6] fs: Add 9P filesystem support over virtio

[Kuan-Wei Chiu <visitorckw@gmail.com>]

Add 9P network filesystem support to U-Boot.

It allows U-Boot to directly mount host directories in virtualization
environments via virtio.

The functionality has been verified on qemu arm64 by successfully
loading a Linux kernel image and an initramfs image via 9P, and booting
to the Linux shell.

To test with QEMU:
  -fsdev local,id=fsdev0,path=/path/to/host/dir,security_model=none \
  -device virtio-9p-device,fsdev=fsdev0,mount_tag=rootfs

U-Boot usage:
  => virtio scan
  => ls 9p rootfs /
  => ls 9p 0 /
  => ls 9p - /
  => load 9p rootfs $kernel_addr_r /Image
  => load 9p rootfs $ramdisk_addr_r /initramfs.cpio
  => booti $kernel_addr_r $ramdisk_addr_r:$filesize $fdtcontroladdr

Changes in v2:
- Introduce DM UCLASS_9P and dm_p9_ops for transport devices.
- Support selecting devices by mount tag, sequence index, or default.
- Integrate 9p into disk/part.c and generic VFS null_dev_desc handling.
- Consistently use 9P2000.L naming across subjects, code, and Kconfig.
- Add kerneldoc comments and separate filesystem header.
- Add timeout handling, feature negotiation, and remove callback.
- Add 9P documentation.
- Add automated pytest and enable in qemu_arm64_defconfig.
- Fix error checking, bounds checks, and memory leaks.

Kuan-Wei Chiu (6):
  net: 9p: Add 9P2000.L protocol support
  fs: 9p: Add 9P filesystem support
  virtio: 9p: Add 9P transport driver
  doc: 9p: Add 9P filesystem documentation
  test: 9p: Add test for 9P filesystem
  MAINTAINERS: Add entry for 9PFS

 MAINTAINERS                    |  11 +
 configs/qemu_arm64_defconfig   |   3 +
 disk/part.c                    |  16 ++
 doc/usage/filesystems/9p.rst   |  55 +++++
 doc/usage/index.rst            |   1 +
 drivers/virtio/Kconfig         |   7 +
 drivers/virtio/Makefile        |   1 +
 drivers/virtio/virtio-uclass.c |   1 +
 drivers/virtio/virtio_9p.c     | 119 ++++++++++
 fs/9p/9p.c                     | 185 +++++++++++++++
 fs/9p/Kconfig                  |   8 +
 fs/9p/Makefile                 |   5 +
 fs/Kconfig                     |   2 +
 fs/Makefile                    |   1 +
 fs/fs.c                        |  25 ++
 include/9p.h                   | 203 ++++++++++++++++
 include/9pfs.h                 |  60 +++++
 include/dm/uclass-id.h         |   1 +
 include/fs.h                   |   1 +
 include/virtio.h               |  12 +-
 net/9p/Kconfig                 |   5 +
 net/9p/Makefile                |   5 +
 net/9p/client.c                | 408 +++++++++++++++++++++++++++++++++
 net/Kconfig                    |   2 +
 net/Makefile                   |   1 +
 test/py/tests/test_9p.py       |  82 +++++++
 26 files changed, 1219 insertions(+), 1 deletion(-)
 create mode 100644 doc/usage/filesystems/9p.rst
 create mode 100644 drivers/virtio/virtio_9p.c
 create mode 100644 fs/9p/9p.c
 create mode 100644 fs/9p/Kconfig
 create mode 100644 fs/9p/Makefile
 create mode 100644 include/9p.h
 create mode 100644 include/9pfs.h
 create mode 100644 net/9p/Kconfig
 create mode 100644 net/9p/Makefile
 create mode 100644 net/9p/client.c
 create mode 100644 test/py/tests/test_9p.py

-- 
2.55.0.897.gb25b4bd76c-goog