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