> On Sep 20, 2024, at 23:09, Maxime Coquelin <maxime.coque...@redhat.com> wrote:
>
> External email: Use caution opening links or attachments
>
>
> This patch enables VDUSE reconnection support making use of
> the newly introduced reconnection mechanism in Vhost
> library.
>
> At DPDK VDUSE device creation time, there are two
> possibilities:
> 1. The Kernel VDUSE device does not exist:
> a. A reconnection file named after the VUDSE device name
> is created in VDUSE tmpfs.
> b. The file is truncated to 'struct vhost_reconnect_data'
> size, and mmapped.
> c. Negotiated features, Virtio status... are saved for
> sanity checks at reconnect time.
> 2. The Kernel VDUSE device already exists:
> a. Exit with failure if no reconnect file exists for
> this device.
> b. Open and mmap the reconnect file.
> c. Perform sanity check to ensure features are compatible.
> d. Restore virtqueues' available indexes at startup time.
>
> Then at runtime, the virtqueues' available index are logged by
> the Vhost reconnection mechanism.
>
> At DPDK VDUSE device destruction time, there are two
> possibilities:
> 1. The Kernel VDUSE device destruction succeed, which
> means it is no more attached to the vDPA bus. The
> reconnection file is unmapped and then removed.
> 2. The Kernel VDUSE device destruction failed, meaning it
> is no more attached to the vDPA bus. The reconnection
> file is unmapped but not removed to make possible later
> reconnection.
>
> Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
> ---
> lib/vhost/vduse.c | 308 ++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 268 insertions(+), 40 deletions(-)
>
> diff --git a/lib/vhost/vduse.c b/lib/vhost/vduse.c
> index c66602905c..f9ac317438 100644
> --- a/lib/vhost/vduse.c
> +++ b/lib/vhost/vduse.c
> @@ -136,7 +136,7 @@ vduse_control_queue_event(int fd, void *arg, int *remove
> __rte_unused)
> }
>
> static void
> -vduse_vring_setup(struct virtio_net *dev, unsigned int index)
> +vduse_vring_setup(struct virtio_net *dev, unsigned int index, bool reconnect)
> {
> struct vhost_virtqueue *vq = dev->virtqueue[index];
> struct vhost_vring_addr *ra = &vq->ring_addrs;
> @@ -152,6 +152,19 @@ vduse_vring_setup(struct virtio_net *dev, unsigned int
> index)
> return;
> }
>
> + if (reconnect) {
> + vq->last_avail_idx = vq->reconnect_log->last_avail_idx;
> + vq->last_used_idx = vq->reconnect_log->last_avail_idx;
> + } else {
> + vq->last_avail_idx = vq_info.split.avail_index;
> + vq->last_used_idx = vq_info.split.avail_index;
> + }
> + vq->size = vq_info.num;
> + vq->ready = true;
> + vq->enabled = vq_info.ready;
> + ra->desc_user_addr = vq_info.desc_addr;
> + ra->avail_user_addr = vq_info.driver_addr;
> + ra->used_user_addr = vq_info.device_addr;
> VHOST_CONFIG_LOG(dev->ifname, INFO, "VQ %u info:", index);
> VHOST_CONFIG_LOG(dev->ifname, INFO, "\tnum: %u", vq_info.num);
> VHOST_CONFIG_LOG(dev->ifname, INFO, "\tdesc_addr: %llx",
> @@ -160,17 +173,9 @@ vduse_vring_setup(struct virtio_net *dev, unsigned int
> index)
> (unsigned long long)vq_info.driver_addr);
> VHOST_CONFIG_LOG(dev->ifname, INFO, "\tdevice_addr: %llx",
> (unsigned long long)vq_info.device_addr);
> - VHOST_CONFIG_LOG(dev->ifname, INFO, "\tavail_idx: %u",
> vq_info.split.avail_index);
> + VHOST_CONFIG_LOG(dev->ifname, INFO, "\tavail_idx: %u",
> vq->last_avail_idx);
> + VHOST_CONFIG_LOG(dev->ifname, INFO, "\tused_idx: %u",
> vq->last_used_idx);
> VHOST_CONFIG_LOG(dev->ifname, INFO, "\tready: %u", vq_info.ready);
> -
> - vq->last_avail_idx = vq_info.split.avail_index;
> - vq->size = vq_info.num;
> - vq->ready = true;
> - vq->enabled = vq_info.ready;
> - ra->desc_user_addr = vq_info.desc_addr;
> - ra->avail_user_addr = vq_info.driver_addr;
> - ra->used_user_addr = vq_info.device_addr;
> -
> vq->kickfd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
> if (vq->kickfd < 0) {
> VHOST_CONFIG_LOG(dev->ifname, ERR, "Failed to init kickfd for
> VQ %u: %s",
> @@ -267,7 +272,7 @@ vduse_vring_cleanup(struct virtio_net *dev, unsigned int
> index)
> }
>
> static void
> -vduse_device_start(struct virtio_net *dev)
> +vduse_device_start(struct virtio_net *dev, bool reconnect)
> {
> unsigned int i, ret;
>
> @@ -287,6 +292,15 @@ vduse_device_start(struct virtio_net *dev)
> return;
> }
>
> + if (reconnect && dev->features != dev->reconnect_log->features) {
> + VHOST_CONFIG_LOG(dev->ifname, ERR,
> + "Mismatch between reconnect file features
> 0x%" PRIx64 " & device features 0x%" PRIx64,
> + dev->reconnect_log->features, dev->features);
> + return;
> + }
> +
> + dev->reconnect_log->features = dev->features;
> +
> VHOST_CONFIG_LOG(dev->ifname, INFO, "Negotiated Virtio features: 0x%"
> PRIx64,
> dev->features);
>
> @@ -300,7 +314,7 @@ vduse_device_start(struct virtio_net *dev)
> }
>
> for (i = 0; i < dev->nr_vring; i++)
> - vduse_vring_setup(dev, i);
> + vduse_vring_setup(dev, i, reconnect);
>
> dev->flags |= VIRTIO_DEV_READY;
>
> @@ -373,6 +387,7 @@ vduse_events_handler(int fd, void *arg, int *remove
> __rte_unused)
> req.s.status);
> old_status = dev->status;
> dev->status = req.s.status;
> + dev->reconnect_log->status = dev->status;
> resp.result = VDUSE_REQ_RESULT_OK;
> break;
> case VDUSE_UPDATE_IOTLB:
> @@ -398,7 +413,7 @@ vduse_events_handler(int fd, void *arg, int *remove
> __rte_unused)
>
> if ((old_status ^ dev->status) & VIRTIO_DEVICE_STATUS_DRIVER_OK) {
> if (dev->status & VIRTIO_DEVICE_STATUS_DRIVER_OK)
> - vduse_device_start(dev);
> + vduse_device_start(dev, false);
> else
> vduse_device_stop(dev);
> }
> @@ -407,10 +422,64 @@ vduse_events_handler(int fd, void *arg, int *remove
> __rte_unused)
> vduse_req_id_to_str(req.type), req.type);
> }
>
> +static char vduse_reconnect_dir[PATH_MAX];
> +static bool vduse_reconnect_path_set;
> +
> +static int
> +vduse_reconnect_path_init(void)
> +{
> + const char *directory;
> + int ret;
> +
> + /* from RuntimeDirectory= see systemd.exec */
> + directory = getenv("RUNTIME_DIRECTORY");
> + if (directory == NULL) {
> + /*
> + * Used standard convention defined in
> + * XDG Base Directory Specification and
> + * Filesystem Hierarchy Standard.
> + */
> + if (getuid() == 0)
> + directory = "/var/run";
> + else
> + directory = getenv("XDG_RUNTIME_DIR") ? : "/tmp";
> + }
> +
> + ret = snprintf(vduse_reconnect_dir, sizeof(vduse_reconnect_dir),
> "%s/vduse",
> + directory);
> + if (ret < 0 || ret == sizeof(vduse_reconnect_dir)) {
> + VHOST_CONFIG_LOG("vduse", ERR, "Error creating VDUSE
> reconnect path name");
> + return -1;
> + }
> +
> + ret = mkdir(vduse_reconnect_dir, 0700);
> + if (ret < 0 && errno != EEXIST) {
> + VHOST_CONFIG_LOG("vduse", ERR, "Error creating '%s': %s",
> + vduse_reconnect_dir, strerror(errno));
> + return -1;
> + }
> +
> + VHOST_CONFIG_LOG("vduse", INFO, "Created VDUSE reconnect directory in
> %s",
> + vduse_reconnect_dir);
> +
> + return 0;
> +}
> +
> +static void
> +vduse_reconnect_handler(int fd, void *arg, int *remove)
> +{
> + struct virtio_net *dev = arg;
> +
> + vduse_device_start(dev, true);
> +
> + close(fd);
> + *remove = 1;
> +}
> +
> int
> vduse_device_create(const char *path, bool compliant_ol_flags)
> {
> - int control_fd, dev_fd, vid, ret;
> + int control_fd, dev_fd, vid, ret, reco_fd;
> uint32_t i, max_queue_pairs, total_queues;
> struct virtio_net *dev;
> struct virtio_net_config vnet_config = {{ 0 }};
> @@ -418,6 +487,9 @@ vduse_device_create(const char *path, bool
> compliant_ol_flags)
> uint64_t features;
> struct vduse_dev_config *dev_config = NULL;
> const char *name = path + strlen("/dev/vduse/");
> + char reconnect_file[PATH_MAX];
> + struct vhost_reconnect_data *reconnect_log = NULL;
> + bool reconnect = false;
>
> if (vduse.fdset == NULL) {
> vduse.fdset = fdset_init("vduse-evt");
> @@ -427,6 +499,20 @@ vduse_device_create(const char *path, bool
> compliant_ol_flags)
> }
> }
>
> + if (vduse_reconnect_path_set == false) {
> + if (vduse_reconnect_path_init() < 0) {
> + VHOST_CONFIG_LOG(path, ERR, "failed to initialize
> reconnect path");
> + return -1;
> + }
> + vduse_reconnect_path_set = true;
> + }
> +
> + ret = snprintf(reconnect_file, sizeof(reconnect_file), "%s/%s",
> vduse_reconnect_dir, name);
> + if (ret < 0 || ret == sizeof(reconnect_file)) {
> + VHOST_CONFIG_LOG(name, ERR, "Failed to create vduse reconnect
> path name");
> + return -1;
> + }
> +
> control_fd = open(VDUSE_CTRL_PATH, O_RDWR);
> if (control_fd < 0) {
> VHOST_CONFIG_LOG(name, ERR, "Failed to open %s: %s",
> @@ -441,14 +527,6 @@ vduse_device_create(const char *path, bool
> compliant_ol_flags)
> goto out_ctrl_close;
> }
>
> - dev_config = malloc(offsetof(struct vduse_dev_config, config) +
> - sizeof(vnet_config));
> - if (!dev_config) {
> - VHOST_CONFIG_LOG(name, ERR, "Failed to allocate VDUSE
> config");
> - ret = -1;
> - goto out_ctrl_close;
> - }
> -
> ret = rte_vhost_driver_get_features(path, &features);
> if (ret < 0) {
> VHOST_CONFIG_LOG(name, ERR, "Failed to get backend features");
> @@ -469,23 +547,118 @@ vduse_device_create(const char *path, bool
> compliant_ol_flags)
> else
> total_queues += 1; /* Includes ctrl queue */
>
> - vnet_config.max_virtqueue_pairs = max_queue_pairs;
> - memset(dev_config, 0, sizeof(struct vduse_dev_config));
> + if (access(path, F_OK) == 0) {
> + VHOST_CONFIG_LOG(name, INFO, "Device already exists,
> reconnecting...");
> + reconnect = true;
> +
> + reco_fd = open(reconnect_file, O_RDWR, 0600);
> + if (reco_fd < 0) {
> + if (errno == ENOENT)
> + VHOST_CONFIG_LOG(name, ERR, "Missing
> reconnect file (%s)",
> + reconnect_file);
> + else
> + VHOST_CONFIG_LOG(name, ERR, "Failed to open
> reconnect file %s (%s)",
> + reconnect_file,
> strerror(errno));
> + ret = -1;
> + goto out_ctrl_close;
> + }
>
> - strncpy(dev_config->name, name, VDUSE_NAME_MAX - 1);
> - dev_config->device_id = VIRTIO_ID_NET;
> - dev_config->vendor_id = 0;
> - dev_config->features = features;
> - dev_config->vq_num = total_queues;
> - dev_config->vq_align = sysconf(_SC_PAGE_SIZE);
> - dev_config->config_size = sizeof(struct virtio_net_config);
> - memcpy(dev_config->config, &vnet_config, sizeof(vnet_config));
> + reconnect_log = mmap(NULL, sizeof(*reconnect_log), PROT_READ
> | PROT_WRITE,
> + MAP_SHARED, reco_fd, 0);
> + close(reco_fd);
> + if (reconnect_log == MAP_FAILED) {
> + VHOST_CONFIG_LOG(name, ERR, "Failed to mmap reconnect
> file %s (%s)",
> + reconnect_file, strerror(errno));
> + ret = -1;
> + goto out_ctrl_close;
> + }
>
> - ret = ioctl(control_fd, VDUSE_CREATE_DEV, dev_config);
> - if (ret < 0) {
> - VHOST_CONFIG_LOG(name, ERR, "Failed to create VDUSE device:
> %s",
> - strerror(errno));
> - goto out_free;
> + if (reconnect_log->version != VHOST_RECONNECT_VERSION) {
> + VHOST_CONFIG_LOG(name, ERR,
> + "Version mismatch between backend
> (0x%x) & reconnection file (0x%x)",
> + VHOST_RECONNECT_VERSION,
> reconnect_log->version);
> + }
> +
> + if ((reconnect_log->features & features) !=
> reconnect_log->features) {
> + VHOST_CONFIG_LOG(name, ERR,
> + "Features mismatch between backend
> (0x%" PRIx64 ") & reconnection file (0x%" PRIx64 ")",
> + features, reconnect_log->features);
> + ret = -1;
> + goto out_ctrl_close;
> + }
> +
> + if (reconnect_log->nr_vrings != total_queues) {
> + VHOST_CONFIG_LOG(name, ERR,
> + "Queues number mismatch between
> backend (%u) and reconnection file (%u)",
> + total_queues,
> reconnect_log->nr_vrings);
> + ret = -1;
> + goto out_ctrl_close;
> + }
> + } else {
> + reco_fd = open(reconnect_file, O_CREAT | O_EXCL | O_RDWR,
> 0600);
> + if (reco_fd < 0) {
> + if (errno == EEXIST) {
> + VHOST_CONFIG_LOG(name, ERR, "Reconnect file
> %s exists but not the device",
> + reconnect_file);
> + } else {
> + VHOST_CONFIG_LOG(name, ERR, "Failed to open
> reconnect file %s (%s)",
> + reconnect_file,
> strerror(errno));
> + }
> + ret = -1;
> + goto out_ctrl_close;
> + }
> +
> + ret = ftruncate(reco_fd, sizeof(*reconnect_log));
> + if (ret < 0) {
> + VHOST_CONFIG_LOG(name, ERR, "Failed to truncate
> reconnect file %s (%s)",
> + reconnect_file, strerror(errno));
> + close(reco_fd);
> + goto out_ctrl_close;
> + }
> +
> + reconnect_log = mmap(NULL, sizeof(*reconnect_log), PROT_READ
> | PROT_WRITE,
> + MAP_SHARED, reco_fd, 0);
> + close(reco_fd);
> + if (reconnect_log == MAP_FAILED) {
> + VHOST_CONFIG_LOG(name, ERR, "Failed to mmap reconnect
> file %s (%s)",
> + reconnect_file, strerror(errno));
> + ret = -1;
> + goto out_ctrl_close;
> + }
> +
> + reconnect_log->version = VHOST_RECONNECT_VERSION;
> +
> + dev_config = malloc(offsetof(struct vduse_dev_config, config)
> +
> + sizeof(vnet_config));
> + if (!dev_config) {
> + VHOST_CONFIG_LOG(name, ERR, "Failed to allocate VDUSE
> config");
> + ret = -1;
> + goto out_ctrl_close;
> + }
> +
> + vnet_config.max_virtqueue_pairs = max_queue_pairs;
> + memset(dev_config, 0, sizeof(struct vduse_dev_config));
> +
> + rte_strscpy(dev_config->name, name, VDUSE_NAME_MAX - 1);
> + dev_config->device_id = VIRTIO_ID_NET;
> + dev_config->vendor_id = 0;
> + dev_config->features = features;
> + dev_config->vq_num = total_queues;
> + dev_config->vq_align = sysconf(_SC_PAGE_SIZE);
> + dev_config->config_size = sizeof(struct virtio_net_config);
> + memcpy(dev_config->config, &vnet_config, sizeof(vnet_config));
> +
> + ret = ioctl(control_fd, VDUSE_CREATE_DEV, dev_config);
> + if (ret < 0) {
> + VHOST_CONFIG_LOG(name, ERR, "Failed to create VDUSE
> device: %s",
> + strerror(errno));
> + goto out_free;
> + }
> +
> + memcpy(&reconnect_log->config, &vnet_config,
> sizeof(vnet_config));
> + reconnect_log->nr_vrings = total_queues;
> + free(dev_config);
> + dev_config = NULL;
> }
>
> dev_fd = open(path, O_RDWR);
> @@ -519,10 +692,15 @@ vduse_device_create(const char *path, bool
> compliant_ol_flags)
> strncpy(dev->ifname, path, IF_NAME_SZ - 1);
> dev->vduse_ctrl_fd = control_fd;
> dev->vduse_dev_fd = dev_fd;
> + dev->reconnect_log = reconnect_log;
> + if (reconnect)
> + dev->status = dev->reconnect_log->status;
> +
> vhost_setup_virtio_net(dev->vid, true, compliant_ol_flags, true, true);
>
> for (i = 0; i < total_queues; i++) {
> struct vduse_vq_config vq_cfg = { 0 };
> + struct vhost_virtqueue *vq;
>
> ret = alloc_vring_queue(dev, i);
> if (ret) {
> @@ -530,6 +708,12 @@ vduse_device_create(const char *path, bool
> compliant_ol_flags)
> goto out_dev_destroy;
> }
>
> + vq = dev->virtqueue[i];
> + vq->reconnect_log = &reconnect_log->vring[i];
> +
> + if (reconnect)
> + continue;
> +
> vq_cfg.index = i;
> vq_cfg.max_size = 1024;
>
> @@ -549,7 +733,32 @@ vduse_device_create(const char *path, bool
> compliant_ol_flags)
> goto out_dev_destroy;
> }
>
> - free(dev_config);
> + if (reconnect && dev->status & VIRTIO_DEVICE_STATUS_DRIVER_OK) {
> + /*
> + * Make vduse_device_start() being executed in the same
> + * context for both reconnection and fresh startup.
> + */
> + reco_fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
> + if (reco_fd < 0) {
> + VHOST_CONFIG_LOG(name, ERR, "Failed to create
> reco_fd: %s",
> + strerror(errno));
> + ret = -1;
> + goto out_dev_destroy;
> + }
> +
> + ret = fdset_add(vduse.fdset, reco_fd,
> vduse_reconnect_handler, NULL, dev);
> + if (ret) {
> + VHOST_CONFIG_LOG(name, ERR, "Failed to add reconnect
> fd %d to vduse fdset",
> + reco_fd);
> + goto out_dev_destroy;
> + }
> +
> + ret = eventfd_write(reco_fd, (eventfd_t)1);
> + if (ret < 0) {
> + VHOST_CONFIG_LOG(name, ERR, "Failed to write to
> reconnect eventfd");
> + goto out_dev_destroy;
> + }
> + }
>
> return 0;
>
> @@ -587,6 +796,9 @@ vduse_device_destroy(const char *path)
> if (vid == RTE_MAX_VHOST_DEVICE)
> return -1;
>
> + if (dev->reconnect_log)
> + munmap(dev->reconnect_log, sizeof(*dev->reconnect_log));
> +
> vduse_device_stop(dev);
>
> fdset_del(vduse.fdset, dev->vduse_dev_fd);
> @@ -597,10 +809,26 @@ vduse_device_destroy(const char *path)
> }
>
> if (dev->vduse_ctrl_fd >= 0) {
> + char reconnect_file[PATH_MAX];
> +
> ret = ioctl(dev->vduse_ctrl_fd, VDUSE_DESTROY_DEV, name);
> - if (ret)
> + if (ret) {
> VHOST_CONFIG_LOG(name, ERR, "Failed to destroy VDUSE
> device: %s",
> strerror(errno));
> + } else {
> + /*
> + * VDUSE device was no more attached to the vDPA bus,
> + * so we can remove the reconnect file.
> + */
> + ret = snprintf(reconnect_file,
> sizeof(reconnect_file), "%s/%s",
> + vduse_reconnect_dir, name);
> + if (ret < 0 || ret == sizeof(reconnect_file))
> + VHOST_CONFIG_LOG(name, ERR,
> + "Failed to create vduse
> reconnect path name");
> + else
> + unlink(reconnect_file);
> + }
> +
> close(dev->vduse_ctrl_fd);
> dev->vduse_ctrl_fd = -1;
> }
> --
> 2.46.0
>
Reviewed-by: Chenbo Xia <chen...@nvidia.com>
