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>
---
MAINTAINERS | 6 +
meson_options.txt | 2 +
qapi/block-core.json | 37 +-
meson.build | 9 +
block/blkio.c | 659 ++++++++++++++++++++++++++++++++++
tests/qtest/modules-test.c | 3 +
block/meson.build | 1 +
scripts/meson-buildoptions.sh | 3 +
8 files changed, 718 insertions(+), 2 deletions(-)
create mode 100644 block/blkio.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 450abd0252..50f340d9ee 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3395,6 +3395,12 @@ 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 97c38109b1..b0b2e0c9b5 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..aa63d5e9bd 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2951,11 +2951,15 @@
'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-vdpa', 'if': 'CONFIG_BLKIO' },
+ 'vmdk', 'vpc', 'vvfat' ] }
##
# @BlockdevOptionsFile:
@@ -3678,6 +3682,30 @@
'*debug': 'int',
'*logfile': 'str' } }
+##
+# @BlockdevOptionsIoUring:
+#
+# Driver specific block device options for the io_uring backend.
+#
+# @filename: path to the image file
+#
+# Since: 7.1
+##
+{ 'struct': 'BlockdevOptionsIoUring',
+ 'data': { 'filename': 'str' } }
+
+##
+# @BlockdevOptionsVirtioBlkVhostVdpa:
+#
+# Driver specific block device options for the virtio-blk-vhost-vdpa backend.
+#
+# @path: path to the vhost-vdpa character device.
+#
+# Since: 7.1
+##
+{ 'struct': 'BlockdevOptionsVirtioBlkVhostVdpa',
+ 'data': { 'path': 'str' } }
+
##
# @IscsiTransport:
#
@@ -4305,6 +4333,8 @@
'if': 'HAVE_HOST_BLOCK_DEVICE' },
'http': 'BlockdevOptionsCurlHttp',
'https': 'BlockdevOptionsCurlHttps',
+ 'io_uring': { 'type': 'BlockdevOptionsIoUring',
+ 'if': 'CONFIG_BLKIO' },
'iscsi': 'BlockdevOptionsIscsi',
'luks': 'BlockdevOptionsLUKS',
'nbd': 'BlockdevOptionsNbd',
@@ -4327,6 +4357,9 @@
'throttle': 'BlockdevOptionsThrottle',
'vdi': 'BlockdevOptionsGenericFormat',
'vhdx': 'BlockdevOptionsGenericFormat',
+ 'virtio-blk-vhost-vdpa':
+ { 'type': 'BlockdevOptionsVirtioBlkVhostVdpa',
+ 'if': 'CONFIG_BLKIO' },
'vmdk': 'BlockdevOptionsGenericCOWFormat',
'vpc': 'BlockdevOptionsGenericFormat',
'vvfat': 'BlockdevOptionsVVFAT'
diff --git a/meson.build b/meson.build
index bc5569ace1..f09b009428 100644
--- a/meson.build
+++ b/meson.build
@@ -713,6 +713,13 @@ if not get_option('virglrenderer').auto() or have_system
or have_vhost_user_gpu
required: get_option('virglrenderer'),
kwargs: static_kwargs)
endif
+blkio = not_found
+if not get_option('blkio').auto() or have_block
+ blkio = dependency('blkio',
+ method: 'pkg-config',
+ required: get_option('blkio'),
+ kwargs: static_kwargs)
+endif
curl = not_found
if not get_option('curl').auto() or have_block
curl = dependency('libcurl', version: '>=7.29.0',
@@ -1755,6 +1762,7 @@ config_host_data.set('CONFIG_LIBUDEV', libudev.found())
config_host_data.set('CONFIG_LZO', lzo.found())
config_host_data.set('CONFIG_MPATH', mpathpersist.found())
config_host_data.set('CONFIG_MPATH_NEW_API', mpathpersist_new_api)
+config_host_data.set('CONFIG_BLKIO', blkio.found())
config_host_data.set('CONFIG_CURL', curl.found())
config_host_data.set('CONFIG_CURSES', curses.found())
config_host_data.set('CONFIG_GBM', gbm.found())
@@ -3909,6 +3917,7 @@ summary_info += {'PAM': pam}
summary_info += {'iconv support': iconv}
summary_info += {'curses support': curses}
summary_info += {'virgl support': virgl}
+summary_info += {'blkio support': blkio}
summary_info += {'curl support': curl}
summary_info += {'Multipath support': mpathpersist}
summary_info += {'PNG support': png}
diff --git a/block/blkio.c b/block/blkio.c
new file mode 100644
index 0000000000..7fbdbd7fae
--- /dev/null
+++ b/block/blkio.c
@@ -0,0 +1,659 @@
+#include "qemu/osdep.h"
+#include <blkio.h>
+#include "block/block_int.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
+#include "qemu/module.h"
+
+typedef struct BlkAIOCB {
+ BlockAIOCB common;
+ struct blkio_mem_region mem_region;
+ QEMUIOVector qiov;
+ struct iovec bounce_iov;
+} BlkioAIOCB;
+
+typedef struct {
+ /* Protects ->blkio and request submission on ->blkioq */
+ QemuMutex lock;
+
+ struct blkio *blkio;
+ struct blkioq *blkioq; /* this could be multi-queue in the future */
+ int completion_fd;
+
+ /* Polling fetches the next completion into this field */
+ struct blkio_completion poll_completion;
+
+ /* The value of the "mem-region-alignment" property */
+ size_t mem_region_alignment;
+
+ /* Can we skip adding/deleting blkio_mem_regions? */
+ bool needs_mem_regions;
+} BDRVBlkioState;
+
+static void blkio_aiocb_complete(BlkioAIOCB *acb, int ret)
+{
+ /* Copy bounce buffer back to qiov */
+ if (acb->qiov.niov > 0) {
+ qemu_iovec_from_buf(&acb->qiov, 0,
+ acb->bounce_iov.iov_base,
+ acb->bounce_iov.iov_len);
+ qemu_iovec_destroy(&acb->qiov);
+ }
+
+ acb->common.cb(acb->common.opaque, ret);
+
+ if (acb->mem_region.len > 0) {
+ BDRVBlkioState *s = acb->common.bs->opaque;
+
+ WITH_QEMU_LOCK_GUARD(&s->lock) {
+ blkio_free_mem_region(s->blkio, &acb->mem_region);
+ }
+ }
+
+ qemu_aio_unref(&acb->common);
+}
+
+/*
+ * Only the thread that calls aio_poll() invokes fd and poll handlers.
+ * Therefore locks are not necessary except when accessing s->blkio.
+ *
+ * No locking is performed around blkioq_get_completions() although other
+ * threads may submit I/O requests on s->blkioq. We're assuming there is no
+ * inteference between blkioq_get_completions() and other s->blkioq APIs.
+ */
+
+static void blkio_completion_fd_read(void *opaque)
+{
+ BlockDriverState *bs = opaque;
+ BDRVBlkioState *s = bs->opaque;
+ struct blkio_completion completion;
+ uint64_t val;
+ ssize_t ret __attribute__((unused));
+
+ /* Polling may have already fetched a completion */
+ if (s->poll_completion.user_data != NULL) {
+ completion = s->poll_completion;
+
+ /* Clear it in case blkio_aiocb_complete() has a nested event loop */
+ s->poll_completion.user_data = NULL;
+
+ blkio_aiocb_complete(completion.user_data, completion.ret);
+ }
+
+ /* Reset completion fd status */
+ ret = read(s->completion_fd, &val, sizeof(val));
+
+ /*
+ * Reading one completion at a time makes nested event loop re-entrancy
+ * simple. Change this loop to get multiple completions in one go if it
+ * becomes a performance bottleneck.
+ */
+ while (blkioq_do_io(s->blkioq, &completion, 0, 1, NULL) == 1) {
+ blkio_aiocb_complete(completion.user_data, completion.ret);
+ }
+}
+
+static bool blkio_completion_fd_poll(void *opaque)
+{
+ BlockDriverState *bs = opaque;
+ BDRVBlkioState *s = bs->opaque;
+
+ /* Just in case we already fetched a completion */
+ if (s->poll_completion.user_data != NULL) {
+ return true;
+ }
+
+ return blkioq_do_io(s->blkioq, &s->poll_completion, 0, 1, NULL) == 1;
+}
+
+static void blkio_completion_fd_poll_ready(void *opaque)
+{
+ blkio_completion_fd_read(opaque);
+}
+
+static void blkio_attach_aio_context(BlockDriverState *bs,
+ AioContext *new_context)
+{
+ BDRVBlkioState *s = bs->opaque;
+
+ aio_set_fd_handler(new_context,
+ s->completion_fd,
+ false,
+ blkio_completion_fd_read,
+ NULL,
+ blkio_completion_fd_poll,
+ blkio_completion_fd_poll_ready,
+ bs);
+}
+
+static void blkio_detach_aio_context(BlockDriverState *bs)
+{
+ BDRVBlkioState *s = bs->opaque;
+
+ aio_set_fd_handler(bdrv_get_aio_context(bs),
+ s->completion_fd,
+ false, NULL, NULL, NULL, NULL, NULL);
+}
+
+static const AIOCBInfo blkio_aiocb_info = {
+ .aiocb_size = sizeof(BlkioAIOCB),
+};
+
+/* Create a BlkioAIOCB */
+static BlkioAIOCB *blkio_aiocb_get(BlockDriverState *bs,
+ BlockCompletionFunc *cb,
+ void *opaque)
+{
+ BlkioAIOCB *acb = qemu_aio_get(&blkio_aiocb_info, bs, cb, opaque);
+
+ /* A few fields need to be initialized, leave the rest... */
+ acb->qiov.niov = 0;
+ acb->mem_region.len = 0;
+ return acb;
+}
+
+/* s->lock must be held */
+static int blkio_aiocb_init_mem_region_locked(BlkioAIOCB *acb, size_t len)
+{
+ BDRVBlkioState *s = acb->common.bs->opaque;
+ size_t mem_region_len = QEMU_ALIGN_UP(len, s->mem_region_alignment);
+ int ret;
+
+ ret = blkio_alloc_mem_region(s->blkio, &acb->mem_region, mem_region_len);
+ if (ret < 0) {
+ return ret;
+ }
+
+ acb->bounce_iov.iov_base = acb->mem_region.addr;
+ acb->bounce_iov.iov_len = len;
+ return 0;
+}
+
+/* Call this to submit I/O after enqueuing a new request */
+static void blkio_submit_io(BlockDriverState *bs)
+{
+ if (qatomic_read(&bs->io_plugged) == 0) {
+ BDRVBlkioState *s = bs->opaque;
+
+ blkioq_do_io(s->blkioq, NULL, 0, 0, NULL);
+ }
+}
+
+static BlockAIOCB *blkio_aio_pdiscard(BlockDriverState *bs, int64_t offset,
+ int bytes, BlockCompletionFunc *cb, void *opaque)
+{
+ BDRVBlkioState *s = bs->opaque;
+ BlkioAIOCB *acb;
+
+ QEMU_LOCK_GUARD(&s->lock);
+
+ acb = blkio_aiocb_get(bs, cb, opaque);
+ blkioq_discard(s->blkioq, offset, bytes, acb, 0);
+ blkio_submit_io(bs);
+ return &acb->common;
+}
+
+static BlockAIOCB *blkio_aio_preadv(BlockDriverState *bs, int64_t offset,
+ int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags,
+ BlockCompletionFunc *cb, void *opaque)
+{
+ BDRVBlkioState *s = bs->opaque;
+ struct iovec *iov = qiov->iov;
+ int iovcnt = qiov->niov;
+ BlkioAIOCB *acb;
+
+ QEMU_LOCK_GUARD(&s->lock);
+
+ acb = blkio_aiocb_get(bs, cb, opaque);
+
+ if (s->needs_mem_regions) {
+ if (blkio_aiocb_init_mem_region_locked(acb, bytes) < 0) {
+ qemu_aio_unref(&acb->common);
+ return NULL;
+ }
+
+ /* Copy qiov because we'll call qemu_iovec_from_buf() on completion */
+ qemu_iovec_init_slice(&acb->qiov, qiov, 0, qiov->size);
+
+ iov = &acb->bounce_iov;
+ iovcnt = 1;
+ }
+
+ blkioq_readv(s->blkioq, offset, iov, iovcnt, acb, 0);
+ blkio_submit_io(bs);
+ return &acb->common;
+}
+
+static BlockAIOCB *blkio_aio_pwritev(BlockDriverState *bs, int64_t offset,
+ int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags,
+ BlockCompletionFunc *cb, void *opaque)
+{
+ uint32_t blkio_flags = (flags & BDRV_REQ_FUA) ? BLKIO_REQ_FUA : 0;
+ BDRVBlkioState *s = bs->opaque;
+ struct iovec *iov = qiov->iov;
+ int iovcnt = qiov->niov;
+ BlkioAIOCB *acb;
+
+ QEMU_LOCK_GUARD(&s->lock);
+
+ acb = blkio_aiocb_get(bs, cb, opaque);
+
+ if (s->needs_mem_regions) {
+ if (blkio_aiocb_init_mem_region_locked(acb, bytes) < 0) {
+ qemu_aio_unref(&acb->common);
+ return NULL;
+ }
+
+ qemu_iovec_to_buf(qiov, 0, acb->bounce_iov.iov_base, bytes);
+
+ iov = &acb->bounce_iov;
+ iovcnt = 1;
+ }
+
+ blkioq_writev(s->blkioq, offset, iov, iovcnt, acb, blkio_flags);
+ blkio_submit_io(bs);
+ return &acb->common;
+}
+
+static BlockAIOCB *blkio_aio_flush(BlockDriverState *bs,
+ BlockCompletionFunc *cb,
+ void *opaque)
+{
+ BDRVBlkioState *s = bs->opaque;
+ BlkioAIOCB *acb;
+
+ QEMU_LOCK_GUARD(&s->lock);
+
+ acb = blkio_aiocb_get(bs, cb, opaque);
+
+ blkioq_flush(s->blkioq, acb, 0);
+ blkio_submit_io(bs);
+ return &acb->common;
+}
+
+/* For async to .bdrv_co_*() conversion */
+typedef struct {
+ Coroutine *coroutine;
+ int ret;
+} BlkioCoData;
+
+static void blkio_co_pwrite_zeroes_complete(void *opaque, int ret)
+{
+ BlkioCoData *data = opaque;
+
+ data->ret = ret;
+ aio_co_wake(data->coroutine);
+}
+
+static int coroutine_fn blkio_co_pwrite_zeroes(BlockDriverState *bs,
+ int64_t offset, int64_t bytes, BdrvRequestFlags flags)
+{
+ BDRVBlkioState *s = bs->opaque;
+ BlkioCoData data = {
+ .coroutine = qemu_coroutine_self(),
+ };
+ uint32_t blkio_flags = 0;
+
+ if (flags & BDRV_REQ_FUA) {
+ blkio_flags |= BLKIO_REQ_FUA;
+ }
+ if (!(flags & BDRV_REQ_MAY_UNMAP)) {
+ blkio_flags |= BLKIO_REQ_NO_UNMAP;
+ }
+ if (flags & BDRV_REQ_NO_FALLBACK) {
+ blkio_flags |= BLKIO_REQ_NO_FALLBACK;
+ }
+
+ WITH_QEMU_LOCK_GUARD(&s->lock) {
+ BlkioAIOCB *acb =
+ blkio_aiocb_get(bs, blkio_co_pwrite_zeroes_complete, &data);
+ blkioq_write_zeroes(s->blkioq, offset, bytes, acb, blkio_flags);
+ blkio_submit_io(bs);
+ }
+
+ qemu_coroutine_yield();
+ return data.ret;
+}
+
+static void blkio_io_unplug(BlockDriverState *bs)
+{
+ BDRVBlkioState *s = bs->opaque;
+
+ WITH_QEMU_LOCK_GUARD(&s->lock) {
+ blkio_submit_io(bs);
+ }
+}
+
+static void blkio_parse_filename_io_uring(const char *filename, QDict *options,
+ Error **errp)
+{
+ bdrv_parse_filename_strip_prefix(filename, "io_uring:", options);
+}
+
+static void blkio_parse_filename_virtio_blk_vhost_vdpa(
+ const char *filename,
+ QDict *options,
+ Error **errp)
+{
+ bdrv_parse_filename_strip_prefix(filename, "virtio-blk-vhost-vdpa:",
options);
+}
+
+static int blkio_io_uring_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
+{
+ const char *filename = qdict_get_try_str(options, "filename");
+ BDRVBlkioState *s = bs->opaque;
+ int ret;
+
+ ret = blkio_set_str(s->blkio, "path", filename);
+ qdict_del(options, "filename");
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to set path: %s",
+ blkio_get_error_msg());
+ return ret;
+ }
+
+ if (flags & BDRV_O_NOCACHE) {
+ ret = blkio_set_bool(s->blkio, "direct", true);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to set direct: %s",
+ blkio_get_error_msg());
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static int blkio_virtio_blk_vhost_vdpa_open(BlockDriverState *bs,
+ QDict *options, int flags, Error **errp)
+{
+ const char *path = qdict_get_try_str(options, "path");
+ BDRVBlkioState *s = bs->opaque;
+ int ret;
+
+ ret = blkio_set_str(s->blkio, "path", path);
+ qdict_del(options, "path");
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to set path: %s",
+ blkio_get_error_msg());
+ return ret;
+ }
+
+ if (flags & BDRV_O_NOCACHE) {
+ error_setg(errp, "cache.direct=off is not supported");
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int blkio_file_open(BlockDriverState *bs, QDict *options, int flags,
+ Error **errp)
+{
+ const char *blkio_driver = bs->drv->protocol_name;
+ BDRVBlkioState *s = bs->opaque;
+ int ret;
+
+ ret = blkio_create(blkio_driver, &s->blkio);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "blkio_create failed: %s",
+ blkio_get_error_msg());
+ return ret;
+ }
+
+ if (strcmp(blkio_driver, "io_uring") == 0) {
+ ret = blkio_io_uring_open(bs, options, flags, errp);
+ } else if (strcmp(blkio_driver, "virtio-blk-vhost-vdpa") == 0) {
+ ret = blkio_virtio_blk_vhost_vdpa_open(bs, options, flags, errp);
+ }
+ if (ret < 0) {
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+
+ if (!(flags & BDRV_O_RDWR)) {
+ ret = blkio_set_bool(s->blkio, "readonly", true);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to set readonly: %s",
+ blkio_get_error_msg());
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+ }
+
+ ret = blkio_connect(s->blkio);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "blkio_connect failed: %s",
+ blkio_get_error_msg());
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+
+ ret = blkio_get_bool(s->blkio,
+ "needs-mem-regions",
+ &s->needs_mem_regions);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret,
+ "failed to get needs-mem-regions: %s",
+ blkio_get_error_msg());
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+
+ ret = blkio_get_uint64(s->blkio,
+ "mem-region-alignment",
+ &s->mem_region_alignment);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret,
+ "failed to get mem-region-alignment: %s",
+ blkio_get_error_msg());
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+
+ ret = blkio_start(s->blkio);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "blkio_start failed: %s",
+ blkio_get_error_msg());
+ blkio_destroy(&s->blkio);
+ return ret;
+ }
+
+ bs->supported_write_flags = BDRV_REQ_FUA;
+ bs->supported_zero_flags = BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP |
+ BDRV_REQ_NO_FALLBACK;
+
+ qemu_mutex_init(&s->lock);
+ s->blkioq = blkio_get_queue(s->blkio, 0);
+ s->completion_fd = blkioq_get_completion_fd(s->blkioq);
+
+ blkio_attach_aio_context(bs, bdrv_get_aio_context(bs));
+ return 0;
+}
+
+static void blkio_close(BlockDriverState *bs)
+{
+ BDRVBlkioState *s = bs->opaque;
+
+ qemu_mutex_destroy(&s->lock);
+ blkio_destroy(&s->blkio);
+}
+
+static int64_t blkio_getlength(BlockDriverState *bs)
+{
+ BDRVBlkioState *s = bs->opaque;
+ uint64_t capacity;
+ int ret;
+
+ WITH_QEMU_LOCK_GUARD(&s->lock) {
+ ret = blkio_get_uint64(s->blkio, "capacity", &capacity);
+ }
+ if (ret < 0) {
+ return -ret;
+ }
+
+ return capacity;
+}
+
+static int blkio_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
+{
+ return 0;
+}
+
+static void blkio_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+ BDRVBlkioState *s = bs->opaque;
+ int value;
+ int ret;
+
+ ret = blkio_get_int(s->blkio,
+ "request-alignment",
+ (int *)&bs->bl.request_alignment);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to get \"request-alignment\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ if (bs->bl.request_alignment < 1 ||
+ bs->bl.request_alignment >= INT_MAX ||
+ !is_power_of_2(bs->bl.request_alignment)) {
+ error_setg(errp, "invalid \"request-alignment\" value %d, must be "
+ "power of 2 less than INT_MAX", bs->bl.request_alignment);
+ return;
+ }
+
+ ret = blkio_get_int(s->blkio,
+ "optimal-io-size",
+ (int *)&bs->bl.opt_transfer);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to get \"buf-alignment\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ if (bs->bl.opt_transfer > INT_MAX ||
+ (bs->bl.opt_transfer % bs->bl.request_alignment)) {
+ error_setg(errp, "invalid \"buf-alignment\" value %d, must be a "
+ "multiple of %d", bs->bl.opt_transfer,
+ bs->bl.request_alignment);
+ return;
+ }
+
+ ret = blkio_get_int(s->blkio,
+ "max-transfer",
+ (int *)&bs->bl.max_transfer);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to get \"max-transfer\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ if ((bs->bl.max_transfer % bs->bl.request_alignment) ||
+ (bs->bl.opt_transfer && (bs->bl.max_transfer % bs->bl.opt_transfer))) {
+ error_setg(errp, "invalid \"max-transfer\" value %d, must be a "
+ "multiple of %d and %d (if non-zero)",
+ bs->bl.max_transfer, bs->bl.request_alignment,
+ bs->bl.opt_transfer);
+ return;
+ }
+
+ ret = blkio_get_int(s->blkio, "buf-alignment", &value);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to get \"buf-alignment\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ if (value < 1) {
+ error_setg(errp, "invalid \"buf-alignment\" value %d, must be "
+ "positive", value);
+ return;
+ }
+ bs->bl.min_mem_alignment = value;
+
+ ret = blkio_get_int(s->blkio, "optimal-buf-alignment", &value);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret,
+ "failed to get \"optimal-buf-alignment\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ if (value < 1) {
+ error_setg(errp, "invalid \"optimal-buf-alignment\" value %d, "
+ "must be positive", value);
+ return;
+ }
+ bs->bl.opt_mem_alignment = value;
+
+ ret = blkio_get_int(s->blkio, "max-segments", &bs->bl.max_iov);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "failed to get \"max-segments\": %s",
+ blkio_get_error_msg());
+ return;
+ }
+ if (value < 1) {
+ error_setg(errp, "invalid \"max-segments\" value %d, must be positive",
+ bs->bl.max_iov);
+ return;
+ }
+}
+
+/*
+ * TODO
+ * Missing libblkio APIs:
+ * - write zeroes
+ * - discard
+ * - block_status
+ * - co_invalidate_cache
+ *
+ * Out of scope?
+ * - create
+ * - truncate
+ */
+
+static BlockDriver bdrv_io_uring = {
+ .format_name = "io_uring",
+ .protocol_name = "io_uring",
+ .instance_size = sizeof(BDRVBlkioState),
+ .bdrv_needs_filename = true,
+ .bdrv_parse_filename = blkio_parse_filename_io_uring,
+ .bdrv_file_open = blkio_file_open,
+ .bdrv_close = blkio_close,
+ .bdrv_getlength = blkio_getlength,
+ .bdrv_get_info = blkio_get_info,
+ .bdrv_attach_aio_context = blkio_attach_aio_context,
+ .bdrv_detach_aio_context = blkio_detach_aio_context,
+ .bdrv_aio_pdiscard = blkio_aio_pdiscard,
+ .bdrv_aio_preadv = blkio_aio_preadv,
+ .bdrv_aio_pwritev = blkio_aio_pwritev,
+ .bdrv_aio_flush = blkio_aio_flush,
+ .bdrv_co_pwrite_zeroes = blkio_co_pwrite_zeroes,
+ .bdrv_io_unplug = blkio_io_unplug,
+ .bdrv_refresh_limits = blkio_refresh_limits,
+};
+
+static BlockDriver bdrv_virtio_blk_vhost_vdpa = {
+ .format_name = "virtio-blk-vhost-vdpa",
+ .protocol_name = "virtio-blk-vhost-vdpa",
+ .instance_size = sizeof(BDRVBlkioState),
+ .bdrv_needs_filename = true,
