Re: [PATCH v7 02/13] blkio: add libblkio block driver

[Stefano Garzarella <sgarzare@redhat.com>]

On Thu, Oct 13, 2022 at 02:58:57PM -0400, Stefan Hajnoczi wrote:
>libblkio (https://gitlab.com/libblkio/libblkio/) is a library for
>high-performance disk I/O. It currently supports io_uring,
>virtio-blk-vhost-user, and virtio-blk-vhost-vdpa with additional drivers
>under development.
>
>One of the reasons for developing libblkio is that other applications
>besides QEMU can use it. This will be particularly useful for
>virtio-blk-vhost-user which applications may wish to use for connecting
>to qemu-storage-daemon.
>
>libblkio also gives us an opportunity to develop in Rust behind a C API
>that is easy to consume from QEMU.
>
>This commit adds io_uring, nvme-io_uring, virtio-blk-vhost-user, and
>virtio-blk-vhost-vdpa BlockDrivers to QEMU using libblkio. It will be
>easy to add other libblkio drivers since they will share the majority of
>code.
>
>For now I/O buffers are copied through bounce buffers if the libblkio
>driver requires it. Later commits add an optimization for
>pre-registering guest RAM to avoid bounce buffers.
>
>The syntax is:
>
>  --blockdev io_uring,node-name=drive0,filename=test.img,readonly=on|off,cache.direct=on|off
>
>  --blockdev nvme-io_uring,node-name=drive0,filename=/dev/ng0n1,readonly=on|off,cache.direct=on
>
>  --blockdev virtio-blk-vhost-vdpa,node-name=drive0,path=/dev/vdpa...,readonly=on|off,cache.direct=on
>
>  --blockdev virtio-blk-vhost-user,node-name=drive0,path=vhost-user-blk.sock,readonly=on|off,cache.direct=on
>
>Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
>Acked-by: Markus Armbruster <armbru@redhat.com>
>---
> MAINTAINERS                   |   6 +
> meson_options.txt             |   2 +
> qapi/block-core.json          |  77 +++-
> meson.build                   |   9 +
> block/blkio.c                 | 831 ++++++++++++++++++++++++++++++++++
> tests/qtest/modules-test.c    |   3 +
> block/meson.build             |   1 +
> scripts/meson-buildoptions.sh |   3 +
> 8 files changed, 928 insertions(+), 4 deletions(-)
> create mode 100644 block/blkio.c

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>