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2024-08-12block/blkio: use FUA flag on write zeroes only if supportedStefano Garzarella
libblkio supports BLKIO_REQ_FUA with write zeros requests only since version 1.4.0, so let's inform the block layer that the blkio driver supports it only in this case. Otherwise we can have runtime errors as reported in https://issues.redhat.com/browse/RHEL-32878 Fixes: fd66dbd424 ("blkio: add libblkio block driver") Cc: qemu-stable@nongnu.org Buglink: https://issues.redhat.com/browse/RHEL-32878 Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Message-id: 20240808080545.40744-1-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2024-06-28block: rename former bdrv_file_open callbacksPaolo Bonzini
Since there is no bdrv_file_open callback anymore, rename the implementations so that they end with "_open" instead of "_file_open". NFS is the exception because all the functions are named nfs_file_*. Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-28block: remove separate bdrv_file_open callbackPaolo Bonzini
bdrv_file_open and bdrv_open are completely equivalent, they are never checked except to see which one to invoke. So merge them into a single one. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-02-07blkio: Respect memory-alignment for bounce buffer allocationsKevin Wolf
blkio_alloc_mem_region() requires that the requested buffer size is a multiple of the memory-alignment property. If it isn't, the allocation fails with a return value of -EINVAL. Fix the call in blkio_resize_bounce_pool() to make sure the requested size is properly aligned. I observed this problem with vhost-vdpa, which requires page aligned memory. As the virtio-blk device behind it still had 512 byte blocks, we got bs->bl.request_alignment = 512, but actually any request that needed a bounce buffer and was not aligned to 4k would fail without this fix. Suggested-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20240131173140.42398-1-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2024-01-30block/blkio: Make s->mem_region_alignment be 64 bitsRichard W.M. Jones
With GCC 14 the code failed to compile on i686 (and was wrong for any version of GCC): ../block/blkio.c: In function ‘blkio_file_open’: ../block/blkio.c:857:28: error: passing argument 3 of ‘blkio_get_uint64’ from incompatible pointer type [-Wincompatible-pointer-types] 857 | &s->mem_region_alignment); | ^~~~~~~~~~~~~~~~~~~~~~~~ | | | size_t * {aka unsigned int *} In file included from ../block/blkio.c:12: /usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long long unsigned int *’} but argument is of type ‘size_t *’ {aka ‘unsigned int *’} 49 | int blkio_get_uint64(struct blkio *b, const char *name, uint64_t *value); | ~~~~~~~~~~^~~~~ Signed-off-by: Richard W.M. Jones <rjones@redhat.com> Message-id: 20240130122006.2977938-1-rjones@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-10-31util/defer-call: move defer_call() to util/Stefan Hajnoczi
The networking subsystem may wish to use defer_call(), so move the code to util/ where it can be reused. As a reminder of what defer_call() does: This API defers a function call within a defer_call_begin()/defer_call_end() section, allowing multiple calls to batch up. This is a performance optimization that is used in the block layer to submit several I/O requests at once instead of individually: defer_call_begin(); <-- start of section ... defer_call(my_func, my_obj); <-- deferred my_func(my_obj) call defer_call(my_func, my_obj); <-- another defer_call(my_func, my_obj); <-- another ... defer_call_end(); <-- end of section, my_func(my_obj) is called once Suggested-by: Ilya Maximets <i.maximets@ovn.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20230913200045.1024233-3-stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-31block: rename blk_io_plug_call() API to defer_call()Stefan Hajnoczi
Prepare to move the blk_io_plug_call() API out of the block layer so that other subsystems call use this deferred call mechanism. Rename it to defer_call() but leave the code in block/plug.c. The next commit will move the code out of the block layer. Suggested-by: Ilya Maximets <i.maximets@ovn.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Paul Durrant <paul@xen.org> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20230913200045.1024233-2-stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-08-03block/blkio: add more comments on the fd passing handlingStefano Garzarella
As Hanna pointed out, it is not clear in the code why qemu_open() can fail, and why blkio_set_int("fd") is not enough to discover the `fd` property support. Let's fix them by adding more details in the code comments. Suggested-by: Hanna Czenczek <hreitz@redhat.com> Reviewed-by: Hanna Czenczek <hreitz@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20230803082825.25293-3-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-08-03block/blkio: close the fd when blkio_connect() failsStefano Garzarella
libblkio drivers take ownership of `fd` only after a successful blkio_connect(), so if it fails, we are still the owners. Fixes: cad2ccc395 ("block/blkio: use qemu_open() to support fd passing for virtio-blk") Suggested-by: Hanna Czenczek <hreitz@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Hanna Czenczek <hreitz@redhat.com> Message-id: 20230803082825.25293-2-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-07-27block/blkio: use blkio_set_int("fd") to check fd supportStefano Garzarella
Setting the `fd` property fails with virtio-blk-* libblkio drivers that do not support fd passing since https://gitlab.com/libblkio/libblkio/-/merge_requests/208. Getting the `fd` property, on the other hand, always succeeds for virtio-blk-* libblkio drivers even when they don't support fd passing. This patch switches to setting the `fd` property because it is a better mechanism for probing fd passing support than getting the `fd` property. Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20230727161020.84213-5-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-07-27block/blkio: fall back on using `path` when `fd` setting failsStefano Garzarella
qemu_open() fails if called with an unix domain socket in this way: -blockdev node-name=drive0,driver=virtio-blk-vhost-user,path=vhost-user-blk.sock,cache.direct=on: Could not open 'vhost-user-blk.sock': No such device or address Since virtio-blk-vhost-user does not support fd passing, let`s always fall back on using `path` if we fail the fd passing. Fixes: cad2ccc395 ("block/blkio: use qemu_open() to support fd passing for virtio-blk") Reported-by: Qing Wang <qinwang@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20230727161020.84213-4-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-07-27block/blkio: retry blkio_connect() if it fails using `fd`Stefano Garzarella
libblkio 1.3.0 added support of "fd" property for virtio-blk-vhost-vdpa driver. In QEMU, starting from commit cad2ccc395 ("block/blkio: use qemu_open() to support fd passing for virtio-blk") we are using `blkio_get_int(..., "fd")` to check if the "fd" property is supported for all the virtio-blk-* driver. Unfortunately that property is also available for those driver that do not support it, such as virtio-blk-vhost-user. So, `blkio_get_int()` is not enough to check whether the driver supports the `fd` property or not. This is because the virito-blk common libblkio driver only checks whether or not `fd` is set during `blkio_connect()` and fails with -EINVAL for those transports that do not support it (all except vhost-vdpa for now). So let's handle the `blkio_connect()` failure, retrying it using `path` directly. Fixes: cad2ccc395 ("block/blkio: use qemu_open() to support fd passing for virtio-blk") Suggested-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20230727161020.84213-3-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-07-27block/blkio: move blkio_connect() in the drivers functionsStefano Garzarella
This is in preparation for the next patch, where for virtio-blk drivers we need to handle the failure of blkio_connect(). Let's also rename the *_open() functions to *_connect() to make the code reflect the changes applied. Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20230727161020.84213-2-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-07-26block/blkio: do not use open flags in qemu_open()Stefano Garzarella
qemu_open() in blkio_virtio_blk_common_open() is used to open the character device (e.g. /dev/vhost-vdpa-0 or /dev/vfio/vfio) or in the future eventually the unix socket. In all these cases we cannot open the path in read-only mode, when the `read-only` option of blockdev is on, because the exchange of IOCTL commands for example will fail. In order to open the device read-only, we have to use the `read-only` property of the libblkio driver as we already do in blkio_file_open(). Fixes: cad2ccc395 ("block/blkio: use qemu_open() to support fd passing for virtio-blk") Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2225439 Reported-by: Qing Wang <qinwang@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Message-id: 20230726074807.14041-1-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-07-25block/blkio: enable the completion eventfdStefano Garzarella
Until libblkio 1.3.0, virtio-blk drivers had completion eventfd notifications enabled from the start, but from the next releases this is no longer the case, so we have to explicitly enable them. In fact, the libblkio documentation says they could be disabled, so we should always enable them at the start if we want to be sure to get completion eventfd notifications: By default, the driver might not generate completion events for requests so it is necessary to explicitly enable the completion file descriptor before use: void blkioq_set_completion_fd_enabled(struct blkioq *q, bool enable); I discovered this while trying a development version of libblkio: the guest kernel hangs during boot, while probing the device. Fixes: fd66dbd424f5 ("blkio: add libblkio block driver") Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20230725103744.77343-1-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-07-04block/blkio: fix module_block.py parsingStefan Hajnoczi
When QEMU is built with --enable-modules, the module_block.py script parses block/*.c to find block drivers that are built as modules. The script generates a table of block drivers called block_driver_modules[]. This table is used for block driver module loading. The blkio.c driver uses macros to define its BlockDriver structs. This was done to avoid code duplication but the module_block.py script is unable to parse the macro. The result is that libblkio-based block drivers can be built as modules but will not be found at runtime. One fix is to make the module_block.py script or build system fancier so it can parse C macros (e.g. by parsing the preprocessed source code). I chose not to do this because it raises the complexity of the build, making future issues harder to debug. Keep things simple: use the macro to avoid duplicating BlockDriver function pointers but define .format_name and .protocol_name manually for each BlockDriver. This way the module_block.py is able to parse the code. Also get rid of the block driver name macros (e.g. DRIVER_IO_URING) because module_block.py cannot parse them either. Fixes: fd66dbd424f5 ("blkio: add libblkio block driver") Reported-by: Qing Wang <qinwang@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20230704123436.187761-1-stefanha@redhat.com Cc: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-06-01block/blkio: use qemu_open() to support fd passing for virtio-blkStefano Garzarella
Some virtio-blk drivers (e.g. virtio-blk-vhost-vdpa) supports the fd passing. Let's expose this to the user, so the management layer can pass the file descriptor of an already opened path. If the libblkio virtio-blk driver supports fd passing, let's always use qemu_open() to open the `path`, so we can handle fd passing from the management layer through the "/dev/fdset/N" special path. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20230530071941.8954-2-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-06-01block/blkio: convert to blk_io_plug_call() APIStefan Hajnoczi
Stop using the .bdrv_co_io_plug() API because it is not multi-queue block layer friendly. Use the new blk_io_plug_call() API to batch I/O submission instead. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com> Message-id: 20230530180959.1108766-4-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-05-30aio: remove aio_disable_external() APIStefan Hajnoczi
All callers now pass is_external=false to aio_set_fd_handler() and aio_set_event_notifier(). The aio_disable_external() API that temporarily disables fd handlers that were registered is_external=true is therefore dead code. Remove aio_disable_external(), aio_enable_external(), and the is_external arguments to aio_set_fd_handler() and aio_set_event_notifier(). The entire test-fdmon-epoll test is removed because its sole purpose was testing aio_disable_external(). Parts of this patch were generated using the following coccinelle (https://coccinelle.lip6.fr/) semantic patch: @@ expression ctx, fd, is_external, io_read, io_write, io_poll, io_poll_ready, opaque; @@ - aio_set_fd_handler(ctx, fd, is_external, io_read, io_write, io_poll, io_poll_ready, opaque) + aio_set_fd_handler(ctx, fd, io_read, io_write, io_poll, io_poll_ready, opaque) @@ expression ctx, notifier, is_external, io_read, io_poll, io_poll_ready; @@ - aio_set_event_notifier(ctx, notifier, is_external, io_read, io_poll, io_poll_ready) + aio_set_event_notifier(ctx, notifier, io_read, io_poll, io_poll_ready) Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20230516190238.8401-21-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-01block: Convert bdrv_get_info() to co_wrapper_mixedEmanuele Giuseppe Esposito
bdrv_get_info() is categorized as an I/O function, and it currently doesn't run in a coroutine. We should let it take a graph rdlock since it traverses the block nodes graph, which however is only possible in a coroutine. Therefore turn it into a co_wrapper to move the actual function into a coroutine where the lock can be taken. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230113204212.359076-11-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-01block: Convert bdrv_refresh_total_sectors() to co_wrapper_mixedEmanuele Giuseppe Esposito
BlockDriver->bdrv_getlength is categorized as IO callback, and it currently doesn't run in a coroutine. We should let it take a graph rdlock since the callback traverses the block nodes graph, which however is only possible in a coroutine. Therefore turn it into a co_wrapper to move the actual function into a coroutine where the lock can be taken. Because now this function creates a new coroutine and polls, we need to take the AioContext lock where it is missing, for the only reason that internally co_wrapper calls AIO_WAIT_WHILE and it expects to release the AioContext lock. This is especially messy when a co_wrapper creates a coroutine and polls in bdrv_open_driver, because this function has so many callers in so many context that it can easily lead to deadlocks. Therefore the new rule for bdrv_open_driver is that the caller must always hold the AioContext lock of the given bs (except if it is a coroutine), because the function calls bdrv_refresh_total_sectors() which is now a co_wrapper. Once the rwlock is ultimated and placed in every place it needs to be, we will poll using AIO_WAIT_WHILE_UNLOCKED and remove the AioContext lock. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230113204212.359076-7-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-01block: Convert bdrv_io_unplug() to co_wrapperEmanuele Giuseppe Esposito
BlockDriver->bdrv_io_unplug is categorized as IO callback, and it currently doesn't run in a coroutine. We should let it take a graph rdlock since the callback traverses the block nodes graph, which however is only possible in a coroutine. The only caller of this function is blk_io_unplug(), therefore make blk_io_unplug() a co_wrapper, so that we're always running in a coroutine where the lock can be taken. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230113204212.359076-4-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-01-23block/blkio: Fix inclusion of required headersPeter Krempa
After recent header file inclusion rework the build fails when the blkio module is enabled: ../block/blkio.c: In function ‘blkio_detach_aio_context’: ../block/blkio.c:321:24: error: implicit declaration of function ‘bdrv_get_aio_context’; did you mean ‘qemu_get_aio_context’? [-Werror=implicit-function-declaration] 321 | aio_set_fd_handler(bdrv_get_aio_context(bs), | ^~~~~~~~~~~~~~~~~~~~ | qemu_get_aio_context ../block/blkio.c:321:24: error: nested extern declaration of ‘bdrv_get_aio_context’ [-Werror=nested-externs] ../block/blkio.c:321:24: error: passing argument 1 of ‘aio_set_fd_handler’ makes pointer from integer without a cast [-Werror=int-conversion] 321 | aio_set_fd_handler(bdrv_get_aio_context(bs), | ^~~~~~~~~~~~~~~~~~~~~~~~ | | | int In file included from /home/pipo/git/qemu.git/include/qemu/job.h:33, from /home/pipo/git/qemu.git/include/block/blockjob.h:30, from /home/pipo/git/qemu.git/include/block/block_int-global-state.h:28, from /home/pipo/git/qemu.git/include/block/block_int.h:27, from ../block/blkio.c:13: /home/pipo/git/qemu.git/include/block/aio.h:476:37: note: expected ‘AioContext *’ but argument is of type ‘int’ 476 | void aio_set_fd_handler(AioContext *ctx, | ~~~~~~~~~~~~^~~ ../block/blkio.c: In function ‘blkio_file_open’: ../block/blkio.c:821:34: error: passing argument 2 of ‘blkio_attach_aio_context’ makes pointer from integer without a cast [-Werror=int-conversion] 821 | blkio_attach_aio_context(bs, bdrv_get_aio_context(bs)); | ^~~~~~~~~~~~~~~~~~~~~~~~ | | | int Fix it by including 'block/block-io.h' which contains the required declarations. Fixes: e2c1c34f139f49ef909bb4322607fb8b39002312 Signed-off-by: Peter Krempa <pkrempa@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-id: 2bc956011404a1ab03342aefde0087b5b4762562.1674477350.git.pkrempa@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-11-10block/blkio: Set BlockDriver::has_variable_length to falseAlberto Faria
Setting it to true can cause the device size to be queried from libblkio in otherwise fast paths, degrading performance. Set it to false and require users to refresh the device size explicitly instead. Fixes: 4c8f4fda0504 ("block/blkio: Tolerate device size changes") Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Alberto Faria <afaria@redhat.com> Message-Id: <20221108144433.1334074-1-afaria@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-10-31block/blkio: Make driver nvme-io_uring take a "path" instead of a "filename"Alberto Faria
The nvme-io_uring driver expects a character special file such as /dev/ng0n1. Follow the convention of having a "filename" option when a regular file is expected, and a "path" option otherwise. This makes io_uring the only libblkio-based driver with a "filename" option, as it accepts a regular file (even though it can also take a block special file). Signed-off-by: Alberto Faria <afaria@redhat.com> Message-id: 20221028233854.839933-1-afaria@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-10-31block/blkio: Tolerate device size changesAlberto Faria
Some libblkio drivers may be able to work with regular files (e.g., io_uring) or otherwise resizable devices. Conservatively set BlockDriver::has_variable_length to true to ensure bdrv_nb_sectors() always gives up-to-date results. Also implement BlockDriver::bdrv_co_truncate for the case where no preallocation is needed and the device already has a size compatible with what was requested. Signed-off-by: Alberto Faria <afaria@redhat.com> Message-id: 20221029122031.975273-1-afaria@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-10-31block/blkio: Add virtio-blk-vfio-pci BlockDriverAlberto Faria
libblkio 1.1.0 [1] introduces a virtio-blk-vfio-pci driver, which accesses a virtio-blk PCI device using VFIO. Add a corresponding BlockDriver. [1] https://gitlab.com/libblkio/libblkio/-/tree/v1.1.0 Signed-off-by: Alberto Faria <afaria@redhat.com> Message-id: 20221028131635.710267-1-afaria@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-10-26blkio: implement BDRV_REQ_REGISTERED_BUF optimizationStefan Hajnoczi
Avoid bounce buffers when QEMUIOVector elements are within previously registered bdrv_register_buf() buffers. The idea is that emulated storage controllers will register guest RAM using bdrv_register_buf() and set the BDRV_REQ_REGISTERED_BUF on I/O requests. Therefore no blkio_map_mem_region() calls are necessary in the performance-critical I/O code path. This optimization doesn't apply if the I/O buffer is internally allocated by QEMU (e.g. qcow2 metadata). There we still take the slow path because BDRV_REQ_REGISTERED_BUF is not set. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20221013185908.1297568-13-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-10-26blkio: add libblkio block driverStefan Hajnoczi
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> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20221013185908.1297568-3-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>