From 9359c459889fce1804c4e1b2a2ff8f182b4a9ae8 Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Tue, 25 Jul 2023 12:37:44 +0200 Subject: [PATCH 1/8] block/blkio: enable the completion eventfd 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 Message-id: 20230725103744.77343-1-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi --- block/blkio.c | 1 + 1 file changed, 1 insertion(+) diff --git a/block/blkio.c b/block/blkio.c index 1798648134..bc1fac48b7 100644 --- a/block/blkio.c +++ b/block/blkio.c @@ -845,6 +845,7 @@ static int blkio_file_open(BlockDriverState *bs, QDict *options, int flags, QLIST_INIT(&s->bounce_bufs); s->blkioq = blkio_get_queue(s->blkio, 0); s->completion_fd = blkioq_get_completion_fd(s->blkioq); + blkioq_set_completion_fd_enabled(s->blkioq, true); blkio_attach_aio_context(bs, bdrv_get_aio_context(bs)); return 0; From a5942c177b7bcc1357e496b7d68668befcfc2bb9 Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Wed, 26 Jul 2023 09:48:07 +0200 Subject: [PATCH 2/8] block/blkio: do not use open flags in qemu_open() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Stefano Garzarella Reviewed-by: Daniel P. Berrangé Message-id: 20230726074807.14041-1-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi --- block/blkio.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/block/blkio.c b/block/blkio.c index bc1fac48b7..7eb1b94820 100644 --- a/block/blkio.c +++ b/block/blkio.c @@ -686,15 +686,18 @@ static int blkio_virtio_blk_common_open(BlockDriverState *bs, * layer through the "/dev/fdset/N" special path. */ if (fd_supported) { - int open_flags; - - if (flags & BDRV_O_RDWR) { - open_flags = O_RDWR; - } else { - open_flags = O_RDONLY; - } - - fd = qemu_open(path, open_flags, errp); + /* + * `path` can contain the path of a character device + * (e.g. /dev/vhost-vdpa-0 or /dev/vfio/vfio) or a unix socket. + * + * So, we should always open it with O_RDWR flag, also if BDRV_O_RDWR + * is not set in the open flags, because the exchange of IOCTL commands + * for example will fail. + * + * In order to open the device read-only, we are using the `read-only` + * property of the libblkio driver in blkio_file_open(). + */ + fd = qemu_open(path, O_RDWR, errp); if (fd < 0) { return -EINVAL; } From 29a242e165610df9b158bdb8d6b84e83d8733fc4 Mon Sep 17 00:00:00 2001 From: Sam Li Date: Thu, 27 Jul 2023 19:58:44 +0800 Subject: [PATCH 3/8] block/file-posix: fix g_file_get_contents return path MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The g_file_get_contents() function returns a g_boolean. If it fails, the returned value will be 0 instead of -1. Solve the issue by skipping assigning ret value. This issue was found by Matthew Rosato using virtio-blk-{pci,ccw} backed by an NVMe partition e.g. /dev/nvme0n1p1 on s390x. Signed-off-by: Sam Li Reviewed-by: Matthew Rosato Reviewed-by: Stefan Hajnoczi Reviewed-by: Daniel P. Berrangé Message-id: 20230727115844.8480-1-faithilikerun@gmail.com Signed-off-by: Stefan Hajnoczi --- block/file-posix.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index 9e8e3d8ca5..b16e9c21a1 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1232,7 +1232,6 @@ static int hdev_get_max_hw_transfer(int fd, struct stat *st) static int get_sysfs_str_val(struct stat *st, const char *attribute, char **val) { g_autofree char *sysfspath = NULL; - int ret; size_t len; if (!S_ISBLK(st->st_mode)) { @@ -1242,8 +1241,7 @@ static int get_sysfs_str_val(struct stat *st, const char *attribute, sysfspath = g_strdup_printf("/sys/dev/block/%u:%u/queue/%s", major(st->st_rdev), minor(st->st_rdev), attribute); - ret = g_file_get_contents(sysfspath, val, &len, NULL); - if (ret == -1) { + if (!g_file_get_contents(sysfspath, val, &len, NULL)) { return -ENOENT; } @@ -1253,7 +1251,7 @@ static int get_sysfs_str_val(struct stat *st, const char *attribute, if (*(p + len - 1) == '\n') { *(p + len - 1) = '\0'; } - return ret; + return 0; } #endif From ef256751e970bff435d40a8348dd51d81e67e52e Mon Sep 17 00:00:00 2001 From: Hanna Czenczek Date: Fri, 14 Jul 2023 10:59:38 +0200 Subject: [PATCH 4/8] block: Fix pad_request's request restriction bdrv_pad_request() relies on requests' lengths not to exceed SIZE_MAX, which bdrv_check_qiov_request() does not guarantee. bdrv_check_request32() however will guarantee this, and both of bdrv_pad_request()'s callers (bdrv_co_preadv_part() and bdrv_co_pwritev_part()) already run it before calling bdrv_pad_request(). Therefore, bdrv_pad_request() can safely call bdrv_check_request32() without expecting error, too. In effect, this patch will not change guest-visible behavior. It is a clean-up to tighten a condition to match what is guaranteed by our callers, and which exists purely to show clearly why the subsequent assertion (`assert(*bytes <= SIZE_MAX)`) is always true. Note there is a difference between the interfaces of bdrv_check_qiov_request() and bdrv_check_request32(): The former takes an errp, the latter does not, so we can no longer just pass &error_abort. Instead, we need to check the returned value. While we do expect success (because the callers have already run this function), an assert(ret == 0) is not much simpler than just to return an error if it occurs, so let us handle errors by returning them up the stack now. Reported-by: Peter Maydell Signed-off-by: Hanna Czenczek Message-id: 20230714085938.202730-1-hreitz@redhat.com Fixes: 18743311b829cafc1737a5f20bc3248d5f91ee2a ("block: Collapse padded I/O vecs exceeding IOV_MAX") Signed-off-by: Hanna Czenczek Signed-off-by: Stefan Hajnoczi --- block/io.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/block/io.c b/block/io.c index e8293d6b26..055fcf7438 100644 --- a/block/io.c +++ b/block/io.c @@ -1710,7 +1710,11 @@ static int bdrv_pad_request(BlockDriverState *bs, int sliced_niov; size_t sliced_head, sliced_tail; - bdrv_check_qiov_request(*offset, *bytes, *qiov, *qiov_offset, &error_abort); + /* Should have been checked by the caller already */ + ret = bdrv_check_request32(*offset, *bytes, *qiov, *qiov_offset); + if (ret < 0) { + return ret; + } if (!bdrv_init_padding(bs, *offset, *bytes, write, pad)) { if (padded) { @@ -1723,7 +1727,7 @@ static int bdrv_pad_request(BlockDriverState *bs, &sliced_head, &sliced_tail, &sliced_niov); - /* Guaranteed by bdrv_check_qiov_request() */ + /* Guaranteed by bdrv_check_request32() */ assert(*bytes <= SIZE_MAX); ret = bdrv_create_padded_qiov(bs, pad, sliced_iov, sliced_niov, sliced_head, *bytes); From 69785d66ae1ec43f77fc65109a21721992bead9f Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Thu, 27 Jul 2023 18:10:17 +0200 Subject: [PATCH 5/8] block/blkio: move blkio_connect() in the drivers functions 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 Message-id: 20230727161020.84213-2-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi --- block/blkio.c | 67 ++++++++++++++++++++++++++++++--------------------- 1 file changed, 40 insertions(+), 27 deletions(-) diff --git a/block/blkio.c b/block/blkio.c index 7eb1b94820..8ad7c0b575 100644 --- a/block/blkio.c +++ b/block/blkio.c @@ -603,8 +603,8 @@ static void blkio_unregister_buf(BlockDriverState *bs, void *host, size_t size) } } -static int blkio_io_uring_open(BlockDriverState *bs, QDict *options, int flags, - Error **errp) +static int blkio_io_uring_connect(BlockDriverState *bs, QDict *options, + int flags, Error **errp) { const char *filename = qdict_get_str(options, "filename"); BDRVBlkioState *s = bs->opaque; @@ -627,11 +627,18 @@ static int blkio_io_uring_open(BlockDriverState *bs, QDict *options, int flags, } } + ret = blkio_connect(s->blkio); + if (ret < 0) { + error_setg_errno(errp, -ret, "blkio_connect failed: %s", + blkio_get_error_msg()); + return ret; + } + return 0; } -static int blkio_nvme_io_uring(BlockDriverState *bs, QDict *options, int flags, - Error **errp) +static int blkio_nvme_io_uring_connect(BlockDriverState *bs, QDict *options, + int flags, Error **errp) { const char *path = qdict_get_try_str(options, "path"); BDRVBlkioState *s = bs->opaque; @@ -655,11 +662,18 @@ static int blkio_nvme_io_uring(BlockDriverState *bs, QDict *options, int flags, return -EINVAL; } + ret = blkio_connect(s->blkio); + if (ret < 0) { + error_setg_errno(errp, -ret, "blkio_connect failed: %s", + blkio_get_error_msg()); + return ret; + } + return 0; } -static int blkio_virtio_blk_common_open(BlockDriverState *bs, - QDict *options, int flags, Error **errp) +static int blkio_virtio_blk_connect(BlockDriverState *bs, QDict *options, + int flags, Error **errp) { const char *path = qdict_get_try_str(options, "path"); BDRVBlkioState *s = bs->opaque; @@ -718,6 +732,13 @@ static int blkio_virtio_blk_common_open(BlockDriverState *bs, } } + ret = blkio_connect(s->blkio); + if (ret < 0) { + error_setg_errno(errp, -ret, "blkio_connect failed: %s", + blkio_get_error_msg()); + return ret; + } + qdict_del(options, "path"); return 0; @@ -737,24 +758,6 @@ static int blkio_file_open(BlockDriverState *bs, QDict *options, int flags, return ret; } - if (strcmp(blkio_driver, "io_uring") == 0) { - ret = blkio_io_uring_open(bs, options, flags, errp); - } else if (strcmp(blkio_driver, "nvme-io_uring") == 0) { - ret = blkio_nvme_io_uring(bs, options, flags, errp); - } else if (strcmp(blkio_driver, "virtio-blk-vfio-pci") == 0) { - ret = blkio_virtio_blk_common_open(bs, options, flags, errp); - } else if (strcmp(blkio_driver, "virtio-blk-vhost-user") == 0) { - ret = blkio_virtio_blk_common_open(bs, options, flags, errp); - } else if (strcmp(blkio_driver, "virtio-blk-vhost-vdpa") == 0) { - ret = blkio_virtio_blk_common_open(bs, options, flags, errp); - } else { - g_assert_not_reached(); - } - if (ret < 0) { - blkio_destroy(&s->blkio); - return ret; - } - if (!(flags & BDRV_O_RDWR)) { ret = blkio_set_bool(s->blkio, "read-only", true); if (ret < 0) { @@ -765,10 +768,20 @@ static int blkio_file_open(BlockDriverState *bs, QDict *options, int flags, } } - ret = blkio_connect(s->blkio); + if (strcmp(blkio_driver, "io_uring") == 0) { + ret = blkio_io_uring_connect(bs, options, flags, errp); + } else if (strcmp(blkio_driver, "nvme-io_uring") == 0) { + ret = blkio_nvme_io_uring_connect(bs, options, flags, errp); + } else if (strcmp(blkio_driver, "virtio-blk-vfio-pci") == 0) { + ret = blkio_virtio_blk_connect(bs, options, flags, errp); + } else if (strcmp(blkio_driver, "virtio-blk-vhost-user") == 0) { + ret = blkio_virtio_blk_connect(bs, options, flags, errp); + } else if (strcmp(blkio_driver, "virtio-blk-vhost-vdpa") == 0) { + ret = blkio_virtio_blk_connect(bs, options, flags, errp); + } else { + g_assert_not_reached(); + } if (ret < 0) { - error_setg_errno(errp, -ret, "blkio_connect failed: %s", - blkio_get_error_msg()); blkio_destroy(&s->blkio); return ret; } From 809c319f8a089fbc49223dc29e1cc2b978beeada Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Thu, 27 Jul 2023 18:10:18 +0200 Subject: [PATCH 6/8] block/blkio: retry blkio_connect() if it fails using `fd` 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 Signed-off-by: Stefano Garzarella Message-id: 20230727161020.84213-3-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi --- block/blkio.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/block/blkio.c b/block/blkio.c index 8ad7c0b575..60d2d0f129 100644 --- a/block/blkio.c +++ b/block/blkio.c @@ -733,6 +733,35 @@ static int blkio_virtio_blk_connect(BlockDriverState *bs, QDict *options, } ret = blkio_connect(s->blkio); + /* + * If the libblkio driver doesn't support the `fd` property, blkio_connect() + * will fail with -EINVAL. So let's try calling blkio_connect() again by + * directly setting `path`. + */ + if (fd_supported && ret == -EINVAL) { + qemu_close(fd); + + /* + * We need to clear the `fd` property we set previously by setting + * it to -1. + */ + ret = blkio_set_int(s->blkio, "fd", -1); + if (ret < 0) { + error_setg_errno(errp, -ret, "failed to set fd: %s", + blkio_get_error_msg()); + return ret; + } + + ret = blkio_set_str(s->blkio, "path", path); + if (ret < 0) { + error_setg_errno(errp, -ret, "failed to set path: %s", + blkio_get_error_msg()); + return ret; + } + + ret = blkio_connect(s->blkio); + } + if (ret < 0) { error_setg_errno(errp, -ret, "blkio_connect failed: %s", blkio_get_error_msg()); From 723bea27b127969931fa26bc0de79372a3d9e148 Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Thu, 27 Jul 2023 18:10:19 +0200 Subject: [PATCH 7/8] block/blkio: fall back on using `path` when `fd` setting fails 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 Signed-off-by: Stefano Garzarella Message-id: 20230727161020.84213-4-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi --- block/blkio.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/block/blkio.c b/block/blkio.c index 60d2d0f129..72b46d61fd 100644 --- a/block/blkio.c +++ b/block/blkio.c @@ -711,19 +711,19 @@ static int blkio_virtio_blk_connect(BlockDriverState *bs, QDict *options, * In order to open the device read-only, we are using the `read-only` * property of the libblkio driver in blkio_file_open(). */ - fd = qemu_open(path, O_RDWR, errp); + fd = qemu_open(path, O_RDWR, NULL); if (fd < 0) { - return -EINVAL; + fd_supported = false; + } else { + ret = blkio_set_int(s->blkio, "fd", fd); + if (ret < 0) { + fd_supported = false; + qemu_close(fd); + } } + } - ret = blkio_set_int(s->blkio, "fd", fd); - if (ret < 0) { - error_setg_errno(errp, -ret, "failed to set fd: %s", - blkio_get_error_msg()); - qemu_close(fd); - return ret; - } - } else { + if (!fd_supported) { ret = blkio_set_str(s->blkio, "path", path); if (ret < 0) { error_setg_errno(errp, -ret, "failed to set path: %s", From 1c38fe69e2b8a05c1762b122292fa7e3662f06fd Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Thu, 27 Jul 2023 18:10:20 +0200 Subject: [PATCH 8/8] block/blkio: use blkio_set_int("fd") to check fd support 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 Message-id: 20230727161020.84213-5-sgarzare@redhat.com Signed-off-by: Stefan Hajnoczi --- block/blkio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/blkio.c b/block/blkio.c index 72b46d61fd..8e7ce42c79 100644 --- a/block/blkio.c +++ b/block/blkio.c @@ -690,7 +690,7 @@ static int blkio_virtio_blk_connect(BlockDriverState *bs, QDict *options, return -EINVAL; } - if (blkio_get_int(s->blkio, "fd", &fd) == 0) { + if (blkio_set_int(s->blkio, "fd", -1) == 0) { fd_supported = true; }