[PATCH v3 0/6] Support exporting BDSs via VDUSE

[Xie Yongji <xieyongji@bytedance.com>]

Hi all,

Last few months ago, VDUSE (vDPA Device in Userspace) [1] has
been merged into Linux kernel as a framework that make it
possible to emulate a vDPA device in userspace. This series
aimed at implementing a VDUSE block backend based on the
qemu-storage-daemon infrastructure.

To support that, we firstly introduce a VDUSE library as a
subproject (like what libvhost-user does) to help implementing
VDUSE backends in QEMU. Then a VDUSE block export is implemented
based on this library. At last, we add resize and reconnect support
to the VDUSE block export and VDUSE library.

Since we don't support vdpa-blk in QEMU currently, the VM case is
tested with my previous patchset [2].

[1] https://www.kernel.org/doc/html/latest/userspace-api/vduse.html
[2] https://www.mail-archive.com/qemu-devel@nongnu.org/msg797569.html

Please review, thanks!

V2 to V3:
- Introduce vduse_get_virtio_features() [Stefan]
- Update MAINTAINERS file [Stefan]
- Fix handler of VIRTIO_BLK_T_GET_ID request [Stefan]
- Add barrier for vduse_queue_inflight_get() [Stefan]

V1 to V2:
- Move vduse header to linux-headers [Stefan]
- Add two new API to support creating device from /dev/vduse/$NAME or
  file descriptor [Stefan]
- Check VIRTIO_F_VERSION_1 during intialization [Stefan]
- Replace malloc() + memset to calloc() [Stefan]
- Increase default queue size to 256 for vduse-blk [Stefan]
- Zero-initialize virtio-blk config space [Stefan]
- Add a patch to support reset blk->dev_ops
- Validate vq->log->inflight fields [Stefan]
- Add vduse_set_reconnect_log_file() API to support specifing the
  reconnect log file
- Fix some bugs [Stefan]

Xie Yongji (6):
  block: Support passing NULL ops to blk_set_dev_ops()
  linux-headers: Add vduse.h
  libvduse: Add VDUSE (vDPA Device in Userspace) library
  vduse-blk: implements vduse-blk export
  vduse-blk: Add vduse-blk resize support
  libvduse: Add support for reconnecting

 MAINTAINERS                                 |    7 +
 block/block-backend.c                       |    2 +-
 block/export/export.c                       |    6 +
 block/export/meson.build                    |    5 +
 block/export/vduse-blk.c                    |  459 ++++++
 block/export/vduse-blk.h                    |   20 +
 linux-headers/linux/vduse.h                 |  306 ++++
 meson.build                                 |   28 +
 meson_options.txt                           |    4 +
 qapi/block-export.json                      |   24 +-
 scripts/meson-buildoptions.sh               |    7 +
 scripts/update-linux-headers.sh             |    2 +-
 subprojects/libvduse/include/atomic.h       |    1 +
 subprojects/libvduse/libvduse.c             | 1386 +++++++++++++++++++
 subprojects/libvduse/libvduse.h             |  247 ++++
 subprojects/libvduse/linux-headers/linux    |    1 +
 subprojects/libvduse/meson.build            |   10 +
 subprojects/libvduse/standard-headers/linux |    1 +
 18 files changed, 2512 insertions(+), 4 deletions(-)
 create mode 100644 block/export/vduse-blk.c
 create mode 100644 block/export/vduse-blk.h
 create mode 100644 linux-headers/linux/vduse.h
 create mode 120000 subprojects/libvduse/include/atomic.h
 create mode 100644 subprojects/libvduse/libvduse.c
 create mode 100644 subprojects/libvduse/libvduse.h
 create mode 120000 subprojects/libvduse/linux-headers/linux
 create mode 100644 subprojects/libvduse/meson.build
 create mode 120000 subprojects/libvduse/standard-headers/linux

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2.20.1