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path: root/drivers/vhost
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-rw-r--r--drivers/vhost/Kconfig18
-rw-r--r--drivers/vhost/scsi.c132
-rw-r--r--drivers/vhost/vhost.c247
-rw-r--r--drivers/vhost/vhost.h22
4 files changed, 366 insertions, 53 deletions
diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
index b455d9ab6f3d..a4730217bfb6 100644
--- a/drivers/vhost/Kconfig
+++ b/drivers/vhost/Kconfig
@@ -94,4 +94,22 @@ config VHOST_CROSS_ENDIAN_LEGACY
If unsure, say "N".
+config VHOST_ENABLE_FORK_OWNER_CONTROL
+ bool "Enable VHOST_ENABLE_FORK_OWNER_CONTROL"
+ default y
+ help
+ This option enables two IOCTLs: VHOST_SET_FORK_FROM_OWNER and
+ VHOST_GET_FORK_FROM_OWNER. These allow userspace applications
+ to modify the vhost worker mode for vhost devices.
+
+ Also expose module parameter 'fork_from_owner_default' to allow users
+ to configure the default mode for vhost workers.
+
+ By default, `VHOST_ENABLE_FORK_OWNER_CONTROL` is set to `y`,
+ users can change the worker thread mode as needed.
+ If this config is disabled (n),the related IOCTLs and parameters will
+ be unavailable.
+
+ If unsure, say "Y".
+
endif
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 718fa4e0b31e..88f213d1106f 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -571,6 +571,9 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
int ret;
llnode = llist_del_all(&svq->completion_list);
+
+ mutex_lock(&svq->vq.mutex);
+
llist_for_each_entry_safe(cmd, t, llnode, tvc_completion_list) {
se_cmd = &cmd->tvc_se_cmd;
@@ -604,6 +607,8 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
vhost_scsi_release_cmd_res(se_cmd);
}
+ mutex_unlock(&svq->vq.mutex);
+
if (signal)
vhost_signal(&svq->vs->dev, &svq->vq);
}
@@ -630,7 +635,7 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,
tag = sbitmap_get(&svq->scsi_tags);
if (tag < 0) {
- pr_err("Unable to obtain tag for vhost_scsi_cmd\n");
+ pr_warn_once("Guest sent too many cmds. Returning TASK_SET_FULL.\n");
return ERR_PTR(-ENOMEM);
}
@@ -757,7 +762,7 @@ vhost_scsi_copy_iov_to_sgl(struct vhost_scsi_cmd *cmd, struct iov_iter *iter,
size_t len = iov_iter_count(iter);
unsigned int nbytes = 0;
struct page *page;
- int i;
+ int i, ret;
if (cmd->tvc_data_direction == DMA_FROM_DEVICE) {
cmd->saved_iter_addr = dup_iter(&cmd->saved_iter, iter,
@@ -770,6 +775,7 @@ vhost_scsi_copy_iov_to_sgl(struct vhost_scsi_cmd *cmd, struct iov_iter *iter,
page = alloc_page(GFP_KERNEL);
if (!page) {
i--;
+ ret = -ENOMEM;
goto err;
}
@@ -777,8 +783,10 @@ vhost_scsi_copy_iov_to_sgl(struct vhost_scsi_cmd *cmd, struct iov_iter *iter,
sg_set_page(&sg[i], page, nbytes, 0);
if (cmd->tvc_data_direction == DMA_TO_DEVICE &&
- copy_page_from_iter(page, 0, nbytes, iter) != nbytes)
+ copy_page_from_iter(page, 0, nbytes, iter) != nbytes) {
+ ret = -EFAULT;
goto err;
+ }
len -= nbytes;
}
@@ -793,7 +801,7 @@ err:
for (; i >= 0; i--)
__free_page(sg_page(&sg[i]));
kfree(cmd->saved_iter_addr);
- return -ENOMEM;
+ return ret;
}
static int
@@ -930,24 +938,69 @@ static void vhost_scsi_target_queue_cmd(struct vhost_scsi_cmd *cmd)
}
static void
-vhost_scsi_send_bad_target(struct vhost_scsi *vs,
- struct vhost_virtqueue *vq,
- int head, unsigned out)
+vhost_scsi_send_status(struct vhost_scsi *vs, struct vhost_virtqueue *vq,
+ struct vhost_scsi_ctx *vc, u8 status)
{
- struct virtio_scsi_cmd_resp __user *resp;
struct virtio_scsi_cmd_resp rsp;
+ struct iov_iter iov_iter;
int ret;
memset(&rsp, 0, sizeof(rsp));
- rsp.response = VIRTIO_SCSI_S_BAD_TARGET;
- resp = vq->iov[out].iov_base;
- ret = __copy_to_user(resp, &rsp, sizeof(rsp));
- if (!ret)
- vhost_add_used_and_signal(&vs->dev, vq, head, 0);
+ rsp.status = status;
+
+ iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[vc->out], vc->in,
+ sizeof(rsp));
+
+ ret = copy_to_iter(&rsp, sizeof(rsp), &iov_iter);
+
+ if (likely(ret == sizeof(rsp)))
+ vhost_add_used_and_signal(&vs->dev, vq, vc->head, 0);
else
pr_err("Faulted on virtio_scsi_cmd_resp\n");
}
+#define TYPE_IO_CMD 0
+#define TYPE_CTRL_TMF 1
+#define TYPE_CTRL_AN 2
+
+static void
+vhost_scsi_send_bad_target(struct vhost_scsi *vs,
+ struct vhost_virtqueue *vq,
+ struct vhost_scsi_ctx *vc, int type)
+{
+ union {
+ struct virtio_scsi_cmd_resp cmd;
+ struct virtio_scsi_ctrl_tmf_resp tmf;
+ struct virtio_scsi_ctrl_an_resp an;
+ } rsp;
+ struct iov_iter iov_iter;
+ size_t rsp_size;
+ int ret;
+
+ memset(&rsp, 0, sizeof(rsp));
+
+ if (type == TYPE_IO_CMD) {
+ rsp_size = sizeof(struct virtio_scsi_cmd_resp);
+ rsp.cmd.response = VIRTIO_SCSI_S_BAD_TARGET;
+ } else if (type == TYPE_CTRL_TMF) {
+ rsp_size = sizeof(struct virtio_scsi_ctrl_tmf_resp);
+ rsp.tmf.response = VIRTIO_SCSI_S_BAD_TARGET;
+ } else {
+ rsp_size = sizeof(struct virtio_scsi_ctrl_an_resp);
+ rsp.an.response = VIRTIO_SCSI_S_BAD_TARGET;
+ }
+
+ iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[vc->out], vc->in,
+ rsp_size);
+
+ ret = copy_to_iter(&rsp, rsp_size, &iov_iter);
+
+ if (likely(ret == rsp_size))
+ vhost_add_used_and_signal(&vs->dev, vq, vc->head, 0);
+ else
+ pr_err("Faulted on virtio scsi type=%d\n", type);
+}
+
static int
vhost_scsi_get_desc(struct vhost_scsi *vs, struct vhost_virtqueue *vq,
struct vhost_scsi_ctx *vc)
@@ -1035,10 +1088,8 @@ vhost_scsi_get_req(struct vhost_virtqueue *vq, struct vhost_scsi_ctx *vc,
/* validated at handler entry */
vs_tpg = vhost_vq_get_backend(vq);
tpg = READ_ONCE(vs_tpg[*vc->target]);
- if (unlikely(!tpg)) {
- vq_err(vq, "Target 0x%x does not exist\n", *vc->target);
+ if (unlikely(!tpg))
goto out;
- }
}
if (tpgp)
@@ -1216,8 +1267,8 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
exp_data_len + prot_bytes,
data_direction);
if (IS_ERR(cmd)) {
- vq_err(vq, "vhost_scsi_get_cmd failed %ld\n",
- PTR_ERR(cmd));
+ ret = PTR_ERR(cmd);
+ vq_err(vq, "vhost_scsi_get_tag failed %dd\n", ret);
goto err;
}
cmd->tvc_vhost = vs;
@@ -1232,9 +1283,9 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
" %d\n", cmd, exp_data_len, prot_bytes, data_direction);
if (data_direction != DMA_NONE) {
- if (unlikely(vhost_scsi_mapal(cmd, prot_bytes,
- &prot_iter, exp_data_len,
- &data_iter))) {
+ ret = vhost_scsi_mapal(cmd, prot_bytes, &prot_iter,
+ exp_data_len, &data_iter);
+ if (unlikely(ret)) {
vq_err(vq, "Failed to map iov to sgl\n");
vhost_scsi_release_cmd_res(&cmd->tvc_se_cmd);
goto err;
@@ -1254,11 +1305,15 @@ err:
* EINVAL: Invalid response buffer, drop the request
* EIO: Respond with bad target
* EAGAIN: Pending request
+ * ENOMEM: Could not allocate resources for request
*/
if (ret == -ENXIO)
break;
else if (ret == -EIO)
- vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out);
+ vhost_scsi_send_bad_target(vs, vq, &vc, TYPE_IO_CMD);
+ else if (ret == -ENOMEM)
+ vhost_scsi_send_status(vs, vq, &vc,
+ SAM_STAT_TASK_SET_FULL);
} while (likely(!vhost_exceeds_weight(vq, ++c, 0)));
out:
mutex_unlock(&vq->mutex);
@@ -1297,8 +1352,11 @@ static void vhost_scsi_tmf_resp_work(struct vhost_work *work)
else
resp_code = VIRTIO_SCSI_S_FUNCTION_REJECTED;
+ mutex_lock(&tmf->svq->vq.mutex);
vhost_scsi_send_tmf_resp(tmf->vhost, &tmf->svq->vq, tmf->in_iovs,
tmf->vq_desc, &tmf->resp_iov, resp_code);
+ mutex_unlock(&tmf->svq->vq.mutex);
+
vhost_scsi_release_tmf_res(tmf);
}
@@ -1488,7 +1546,10 @@ err:
if (ret == -ENXIO)
break;
else if (ret == -EIO)
- vhost_scsi_send_bad_target(vs, vq, vc.head, vc.out);
+ vhost_scsi_send_bad_target(vs, vq, &vc,
+ v_req.type == VIRTIO_SCSI_T_TMF ?
+ TYPE_CTRL_TMF :
+ TYPE_CTRL_AN);
} while (likely(!vhost_exceeds_weight(vq, ++c, 0)));
out:
mutex_unlock(&vq->mutex);
@@ -1699,14 +1760,19 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
}
}
+ if (vs->vs_tpg) {
+ pr_err("vhost-scsi endpoint already set for %s.\n",
+ vs->vs_vhost_wwpn);
+ ret = -EEXIST;
+ goto out;
+ }
+
len = sizeof(vs_tpg[0]) * VHOST_SCSI_MAX_TARGET;
vs_tpg = kzalloc(len, GFP_KERNEL);
if (!vs_tpg) {
ret = -ENOMEM;
goto out;
}
- if (vs->vs_tpg)
- memcpy(vs_tpg, vs->vs_tpg, len);
mutex_lock(&vhost_scsi_mutex);
list_for_each_entry(tpg, &vhost_scsi_list, tv_tpg_list) {
@@ -1722,12 +1788,6 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
tv_tport = tpg->tport;
if (!strcmp(tv_tport->tport_name, t->vhost_wwpn)) {
- if (vs->vs_tpg && vs->vs_tpg[tpg->tport_tpgt]) {
- mutex_unlock(&tpg->tv_tpg_mutex);
- mutex_unlock(&vhost_scsi_mutex);
- ret = -EEXIST;
- goto undepend;
- }
/*
* In order to ensure individual vhost-scsi configfs
* groups cannot be removed while in use by vhost ioctl,
@@ -1774,15 +1834,15 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
}
ret = 0;
} else {
- ret = -EEXIST;
+ ret = -ENODEV;
+ goto free_tpg;
}
/*
- * Act as synchronize_rcu to make sure access to
- * old vs->vs_tpg is finished.
+ * Act as synchronize_rcu to make sure requests after this point
+ * see a fully setup device.
*/
vhost_scsi_flush(vs);
- kfree(vs->vs_tpg);
vs->vs_tpg = vs_tpg;
goto out;
@@ -1802,6 +1862,7 @@ undepend:
target_undepend_item(&tpg->se_tpg.tpg_group.cg_item);
}
}
+free_tpg:
kfree(vs_tpg);
out:
mutex_unlock(&vs->dev.mutex);
@@ -1904,6 +1965,7 @@ free_vs_tpg:
vhost_scsi_flush(vs);
kfree(vs->vs_tpg);
vs->vs_tpg = NULL;
+ memset(vs->vs_vhost_wwpn, 0, sizeof(vs->vs_vhost_wwpn));
WARN_ON(vs->vs_events_nr);
mutex_unlock(&vs->dev.mutex);
return 0;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 9ac25d08f473..71604668e53f 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -22,6 +22,7 @@
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/kthread.h>
+#include <linux/cgroup.h>
#include <linux/module.h>
#include <linux/sort.h>
#include <linux/sched/mm.h>
@@ -41,6 +42,13 @@ static int max_iotlb_entries = 2048;
module_param(max_iotlb_entries, int, 0444);
MODULE_PARM_DESC(max_iotlb_entries,
"Maximum number of iotlb entries. (default: 2048)");
+static bool fork_from_owner_default = VHOST_FORK_OWNER_TASK;
+
+#ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_CONTROL
+module_param(fork_from_owner_default, bool, 0444);
+MODULE_PARM_DESC(fork_from_owner_default,
+ "Set task mode as the default(default: Y)");
+#endif
enum {
VHOST_MEMORY_F_LOG = 0x1,
@@ -242,7 +250,7 @@ static void vhost_worker_queue(struct vhost_worker *worker,
* test_and_set_bit() implies a memory barrier.
*/
llist_add(&work->node, &worker->work_list);
- vhost_task_wake(worker->vtsk);
+ worker->ops->wakeup(worker);
}
}
@@ -388,6 +396,44 @@ static void vhost_vq_reset(struct vhost_dev *dev,
__vhost_vq_meta_reset(vq);
}
+static int vhost_run_work_kthread_list(void *data)
+{
+ struct vhost_worker *worker = data;
+ struct vhost_work *work, *work_next;
+ struct vhost_dev *dev = worker->dev;
+ struct llist_node *node;
+
+ kthread_use_mm(dev->mm);
+
+ for (;;) {
+ /* mb paired w/ kthread_stop */
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ if (kthread_should_stop()) {
+ __set_current_state(TASK_RUNNING);
+ break;
+ }
+ node = llist_del_all(&worker->work_list);
+ if (!node)
+ schedule();
+
+ node = llist_reverse_order(node);
+ /* make sure flag is seen after deletion */
+ smp_wmb();
+ llist_for_each_entry_safe(work, work_next, node, node) {
+ clear_bit(VHOST_WORK_QUEUED, &work->flags);
+ __set_current_state(TASK_RUNNING);
+ kcov_remote_start_common(worker->kcov_handle);
+ work->fn(work);
+ kcov_remote_stop();
+ cond_resched();
+ }
+ }
+ kthread_unuse_mm(dev->mm);
+
+ return 0;
+}
+
static bool vhost_run_work_list(void *data)
{
struct vhost_worker *worker = data;
@@ -552,6 +598,7 @@ void vhost_dev_init(struct vhost_dev *dev,
dev->byte_weight = byte_weight;
dev->use_worker = use_worker;
dev->msg_handler = msg_handler;
+ dev->fork_owner = fork_from_owner_default;
init_waitqueue_head(&dev->wait);
INIT_LIST_HEAD(&dev->read_list);
INIT_LIST_HEAD(&dev->pending_list);
@@ -581,6 +628,46 @@ long vhost_dev_check_owner(struct vhost_dev *dev)
}
EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
+struct vhost_attach_cgroups_struct {
+ struct vhost_work work;
+ struct task_struct *owner;
+ int ret;
+};
+
+static void vhost_attach_cgroups_work(struct vhost_work *work)
+{
+ struct vhost_attach_cgroups_struct *s;
+
+ s = container_of(work, struct vhost_attach_cgroups_struct, work);
+ s->ret = cgroup_attach_task_all(s->owner, current);
+}
+
+static int vhost_attach_task_to_cgroups(struct vhost_worker *worker)
+{
+ struct vhost_attach_cgroups_struct attach;
+ int saved_cnt;
+
+ attach.owner = current;
+
+ vhost_work_init(&attach.work, vhost_attach_cgroups_work);
+ vhost_worker_queue(worker, &attach.work);
+
+ mutex_lock(&worker->mutex);
+
+ /*
+ * Bypass attachment_cnt check in __vhost_worker_flush:
+ * Temporarily change it to INT_MAX to bypass the check
+ */
+ saved_cnt = worker->attachment_cnt;
+ worker->attachment_cnt = INT_MAX;
+ __vhost_worker_flush(worker);
+ worker->attachment_cnt = saved_cnt;
+
+ mutex_unlock(&worker->mutex);
+
+ return attach.ret;
+}
+
/* Caller should have device mutex */
bool vhost_dev_has_owner(struct vhost_dev *dev)
{
@@ -626,7 +713,7 @@ static void vhost_worker_destroy(struct vhost_dev *dev,
WARN_ON(!llist_empty(&worker->work_list));
xa_erase(&dev->worker_xa, worker->id);
- vhost_task_stop(worker->vtsk);
+ worker->ops->stop(worker);
kfree(worker);
}
@@ -649,42 +736,115 @@ static void vhost_workers_free(struct vhost_dev *dev)
xa_destroy(&dev->worker_xa);
}
+static void vhost_task_wakeup(struct vhost_worker *worker)
+{
+ return vhost_task_wake(worker->vtsk);
+}
+
+static void vhost_kthread_wakeup(struct vhost_worker *worker)
+{
+ wake_up_process(worker->kthread_task);
+}
+
+static void vhost_task_do_stop(struct vhost_worker *worker)
+{
+ return vhost_task_stop(worker->vtsk);
+}
+
+static void vhost_kthread_do_stop(struct vhost_worker *worker)
+{
+ kthread_stop(worker->kthread_task);
+}
+
+static int vhost_task_worker_create(struct vhost_worker *worker,
+ struct vhost_dev *dev, const char *name)
+{
+ struct vhost_task *vtsk;
+ u32 id;
+ int ret;
+
+ vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed,
+ worker, name);
+ if (IS_ERR(vtsk))
+ return PTR_ERR(vtsk);
+
+ worker->vtsk = vtsk;
+ vhost_task_start(vtsk);
+ ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
+ if (ret < 0) {
+ vhost_task_do_stop(worker);
+ return ret;
+ }
+ worker->id = id;
+ return 0;
+}
+
+static int vhost_kthread_worker_create(struct vhost_worker *worker,
+ struct vhost_dev *dev, const char *name)
+{
+ struct task_struct *task;
+ u32 id;
+ int ret;
+
+ task = kthread_create(vhost_run_work_kthread_list, worker, "%s", name);
+ if (IS_ERR(task))
+ return PTR_ERR(task);
+
+ worker->kthread_task = task;
+ wake_up_process(task);
+ ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
+ if (ret < 0)
+ goto stop_worker;
+
+ ret = vhost_attach_task_to_cgroups(worker);
+ if (ret)
+ goto stop_worker;
+
+ worker->id = id;
+ return 0;
+
+stop_worker:
+ vhost_kthread_do_stop(worker);
+ return ret;
+}
+
+static const struct vhost_worker_ops kthread_ops = {
+ .create = vhost_kthread_worker_create,
+ .stop = vhost_kthread_do_stop,
+ .wakeup = vhost_kthread_wakeup,
+};
+
+static const struct vhost_worker_ops vhost_task_ops = {
+ .create = vhost_task_worker_create,
+ .stop = vhost_task_do_stop,
+ .wakeup = vhost_task_wakeup,
+};
+
static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
{
struct vhost_worker *worker;
- struct vhost_task *vtsk;
char name[TASK_COMM_LEN];
int ret;
- u32 id;
+ const struct vhost_worker_ops *ops = dev->fork_owner ? &vhost_task_ops :
+ &kthread_ops;
worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT);
if (!worker)
return NULL;
worker->dev = dev;
+ worker->ops = ops;
snprintf(name, sizeof(name), "vhost-%d", current->pid);
- vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed,
- worker, name);
- if (!vtsk)
- goto free_worker;
-
mutex_init(&worker->mutex);
init_llist_head(&worker->work_list);
worker->kcov_handle = kcov_common_handle();
- worker->vtsk = vtsk;
-
- vhost_task_start(vtsk);
-
- ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
+ ret = ops->create(worker, dev, name);
if (ret < 0)
- goto stop_worker;
- worker->id = id;
+ goto free_worker;
return worker;
-stop_worker:
- vhost_task_stop(vtsk);
free_worker:
kfree(worker);
return NULL;
@@ -865,6 +1025,14 @@ long vhost_worker_ioctl(struct vhost_dev *dev, unsigned int ioctl,
switch (ioctl) {
/* dev worker ioctls */
case VHOST_NEW_WORKER:
+ /*
+ * vhost_tasks will account for worker threads under the parent's
+ * NPROC value but kthreads do not. To avoid userspace overflowing
+ * the system with worker threads fork_owner must be true.
+ */
+ if (!dev->fork_owner)
+ return -EFAULT;
+
ret = vhost_new_worker(dev, &state);
if (!ret && copy_to_user(argp, &state, sizeof(state)))
ret = -EFAULT;
@@ -982,6 +1150,7 @@ void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *umem)
vhost_dev_cleanup(dev);
+ dev->fork_owner = fork_from_owner_default;
dev->umem = umem;
/* We don't need VQ locks below since vhost_dev_cleanup makes sure
* VQs aren't running.
@@ -2135,6 +2304,45 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
goto done;
}
+#ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_CONTROL
+ if (ioctl == VHOST_SET_FORK_FROM_OWNER) {
+ /* Only allow modification before owner is set */
+ if (vhost_dev_has_owner(d)) {
+ r = -EBUSY;
+ goto done;
+ }
+ u8 fork_owner_val;
+
+ if (get_user(fork_owner_val, (u8 __user *)argp)) {
+ r = -EFAULT;
+ goto done;
+ }
+ if (fork_owner_val != VHOST_FORK_OWNER_TASK &&
+ fork_owner_val != VHOST_FORK_OWNER_KTHREAD) {
+ r = -EINVAL;
+ goto done;
+ }
+ d->fork_owner = !!fork_owner_val;
+ r = 0;
+ goto done;
+ }
+ if (ioctl == VHOST_GET_FORK_FROM_OWNER) {
+ u8 fork_owner_val = d->fork_owner;
+
+ if (fork_owner_val != VHOST_FORK_OWNER_TASK &&
+ fork_owner_val != VHOST_FORK_OWNER_KTHREAD) {
+ r = -EINVAL;
+ goto done;
+ }
+ if (put_user(fork_owner_val, (u8 __user *)argp)) {
+ r = -EFAULT;
+ goto done;
+ }
+ r = 0;
+ goto done;
+ }
+#endif
+
/* You must be the owner to do anything else */
r = vhost_dev_check_owner(d);
if (r)
@@ -2763,6 +2971,9 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
}
r = __vhost_add_used_n(vq, heads, count);
+ if (r < 0)
+ return r;
+
/* Make sure buffer is written before we update index. */
smp_wmb();
if (vhost_put_used_idx(vq)) {
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index bb75a292d50c..ab704d84fb34 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -26,7 +26,18 @@ struct vhost_work {
unsigned long flags;
};
+struct vhost_worker;
+struct vhost_dev;
+
+struct vhost_worker_ops {
+ int (*create)(struct vhost_worker *worker, struct vhost_dev *dev,
+ const char *name);
+ void (*stop)(struct vhost_worker *worker);
+ void (*wakeup)(struct vhost_worker *worker);
+};
+
struct vhost_worker {
+ struct task_struct *kthread_task;
struct vhost_task *vtsk;
struct vhost_dev *dev;
/* Used to serialize device wide flushing with worker swapping. */
@@ -36,6 +47,7 @@ struct vhost_worker {
u32 id;
int attachment_cnt;
bool killed;
+ const struct vhost_worker_ops *ops;
};
/* Poll a file (eventfd or socket) */
@@ -176,6 +188,16 @@ struct vhost_dev {
int byte_weight;
struct xarray worker_xa;
bool use_worker;
+ /*
+ * If fork_owner is true we use vhost_tasks to create
+ * the worker so all settings/limits like cgroups, NPROC,
+ * scheduler, etc are inherited from the owner. If false,
+ * we use kthreads and only attach to the same cgroups
+ * as the owner for compat with older kernels.
+ * here we use true as default value.
+ * The default value is set by fork_from_owner_default
+ */
+ bool fork_owner;
int (*msg_handler)(struct vhost_dev *dev, u32 asid,
struct vhost_iotlb_msg *msg);
};
generated by cgit v1.2.3 (git 2.39.0) at 2025-08-29 13:25:39 +0300