On Tue, Aug 30, 2022 at 09:30:16AM +0200, Markus Armbruster wrote: > Stefan Hajnoczi <stefa...@redhat.com> writes: > > > 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, 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 > > > > and: > > > > --blockdev > > virtio-blk-vhost-vdpa,node-name=drive0,path=/dev/vdpa...,readonly=on|off > > > > Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> > > --- > > MAINTAINERS | 6 + > > meson_options.txt | 2 + > > qapi/block-core.json | 53 ++- > > meson.build | 9 + > > block/blkio.c | 725 ++++++++++++++++++++++++++++++++++ > > tests/qtest/modules-test.c | 3 + > > block/meson.build | 1 + > > scripts/meson-buildoptions.sh | 3 + > > 8 files changed, 800 insertions(+), 2 deletions(-) > > create mode 100644 block/blkio.c > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > index 5ce4227ff6..f8ccd5954c 100644 > > --- a/MAINTAINERS > > +++ b/MAINTAINERS > > @@ -3397,6 +3397,12 @@ L: qemu-block@nongnu.org > > S: Maintained > > F: block/vdi.c > > > > +blkio > > +M: Stefan Hajnoczi <stefa...@redhat.com> > > +L: qemu-block@nongnu.org > > +S: Maintained > > +F: block/blkio.c > > + > > iSCSI > > M: Ronnie Sahlberg <ronniesahlb...@gmail.com> > > M: Paolo Bonzini <pbonz...@redhat.com> > > diff --git a/meson_options.txt b/meson_options.txt > > index e58e158396..67d841a8d2 100644 > > --- a/meson_options.txt > > +++ b/meson_options.txt > > @@ -117,6 +117,8 @@ option('bzip2', type : 'feature', value : 'auto', > > description: 'bzip2 support for DMG images') > > option('cap_ng', type : 'feature', value : 'auto', > > description: 'cap_ng support') > > +option('blkio', type : 'feature', value : 'auto', > > + description: 'libblkio block device driver') > > option('bpf', type : 'feature', value : 'auto', > > description: 'eBPF support') > > option('cocoa', type : 'feature', value : 'auto', > > diff --git a/qapi/block-core.json b/qapi/block-core.json > > index 2173e7734a..c8d217b50c 100644 > > --- a/qapi/block-core.json > > +++ b/qapi/block-core.json > > @@ -2951,11 +2951,16 @@ > > 'file', 'snapshot-access', 'ftp', 'ftps', 'gluster', > > {'name': 'host_cdrom', 'if': 'HAVE_HOST_BLOCK_DEVICE' }, > > {'name': 'host_device', 'if': 'HAVE_HOST_BLOCK_DEVICE' }, > > - 'http', 'https', 'iscsi', > > + 'http', 'https', > > + { 'name': 'io_uring', 'if': 'CONFIG_BLKIO' }, > > + 'iscsi', > > 'luks', 'nbd', 'nfs', 'null-aio', 'null-co', 'nvme', > > 'parallels', > > 'preallocate', 'qcow', 'qcow2', 'qed', 'quorum', 'raw', 'rbd', > > { 'name': 'replication', 'if': 'CONFIG_REPLICATION' }, > > - 'ssh', 'throttle', 'vdi', 'vhdx', 'vmdk', 'vpc', 'vvfat' ] } > > + 'ssh', 'throttle', 'vdi', 'vhdx', > > + { 'name': 'virtio-blk-vhost-user', 'if': 'CONFIG_BLKIO' }, > > + { 'name': 'virtio-blk-vhost-vdpa', 'if': 'CONFIG_BLKIO' }, > > + 'vmdk', 'vpc', 'vvfat' ] } > > > > ## > > # @BlockdevOptionsFile: > > @@ -3678,6 +3683,42 @@ > > '*debug': 'int', > > '*logfile': 'str' } } > > > > +## > > +# @BlockdevOptionsIoUring: > > +# > > +# Driver specific block device options for the io_uring backend. > > +# > > +# @filename: path to the image file > > +# > > +# Since: 7.2 > > +## > > +{ 'struct': 'BlockdevOptionsIoUring', > > + 'data': { 'filename': 'str' } } > > + > > +## > > +# @BlockdevOptionsVirtioBlkVhostUser: > > +# > > +# Driver specific block device options for the virtio-blk-vhost-user > > backend. > > +# > > +# @path: path to the vhost-user UNIX domain socket. > > +# > > +# Since: 7.2 > > +## > > +{ 'struct': 'BlockdevOptionsVirtioBlkVhostUser', > > + 'data': { 'path': 'str' } } > > + > > +## > > +# @BlockdevOptionsVirtioBlkVhostVdpa: > > +# > > +# Driver specific block device options for the virtio-blk-vhost-vdpa > > backend. > > +# > > +# @path: path to the vhost-vdpa character device. > > +# > > +# Since: 7.2 > > +## > > +{ 'struct': 'BlockdevOptionsVirtioBlkVhostVdpa', > > + 'data': { 'path': 'str' } } > > + > > We seem to be evenly split between 'filename' and 'path'. Before the > patch we have four uses of 'filename' in this schema file (ImageInfo, > ImageCheck, BlockDriverOptionsFile, BlockdevCreateOptionsFile), and > three of 'path' (BlockdevOptionsSsh, BlockdevOptionsGluster, > BlockdevOptionsNfs). There's also 'backing-file', 'data-file', > 'backing-filename', 'file', and probably more (I stopped looking). > > I dislike 'path'. For what it's worth, POSIX calls this "pathname", and > the components "filename". Everyday use hardly ever distinguishes > between the two. Plain "path", however, is commonly used for lists of > directories.
Yes :/ Stefan
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