On Wed, Jul 27, 2022 at 09:33:40PM +0200, Kevin Wolf wrote: > Am 08.07.2022 um 06:17 hat Stefan Hajnoczi geschrieben: > > libblkio (https://gitlab.com/libblkio/libblkio/) is a library for > > high-performance disk I/O. It currently supports io_uring 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 > > vhost-user-blk 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 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 > > > > and: > > > > --blockdev > > virtio-blk-vhost-vdpa,node-name=drive0,path=/dev/vdpa...,readonly=on|off > > > > Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> > > The subject line implies only io_uring, but you actually add vhost-vdpa > support, too. I think the subject line should be changed. > > I think it would also make sense to already implement support for > vhost-user-blk on the QEMU side even if support isn't compiled in > libblkio by default and opening vhost-user-blk images would therefore > always fail with a default build. > > But then you could run QEMU with a custom build of libblkio to make use > of it without patching QEMU. This is probably useful for getting libvirt > support for using a storage daemon implemented without having to wait > for another QEMU release. (Peter, do you have any opinion on this?)
vhost-user-blk is now supported in all builds of libblkio. I'll add it. Stefan
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