935cdee7ee
vring changes already do a flush internally where appropriate, so we do not need a second flush. It's currently not very expensive but a follow-up patch makes flush more heavy-weight, so remove the extra flush here to avoid regressing performance if call or kick fds are changed on data path. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
221 lines
6.7 KiB
C
221 lines
6.7 KiB
C
#ifndef _VHOST_H
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#define _VHOST_H
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#include <linux/eventfd.h>
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#include <linux/vhost.h>
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#include <linux/mm.h>
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#include <linux/mutex.h>
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#include <linux/poll.h>
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#include <linux/file.h>
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#include <linux/uio.h>
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#include <linux/virtio_config.h>
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#include <linux/virtio_ring.h>
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#include <linux/atomic.h>
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struct vhost_device;
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struct vhost_work;
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typedef void (*vhost_work_fn_t)(struct vhost_work *work);
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struct vhost_work {
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struct list_head node;
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vhost_work_fn_t fn;
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wait_queue_head_t done;
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int flushing;
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unsigned queue_seq;
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unsigned done_seq;
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};
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/* Poll a file (eventfd or socket) */
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/* Note: there's nothing vhost specific about this structure. */
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struct vhost_poll {
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poll_table table;
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wait_queue_head_t *wqh;
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wait_queue_t wait;
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struct vhost_work work;
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unsigned long mask;
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struct vhost_dev *dev;
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};
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void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
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void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
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void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
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unsigned long mask, struct vhost_dev *dev);
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void vhost_poll_start(struct vhost_poll *poll, struct file *file);
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void vhost_poll_stop(struct vhost_poll *poll);
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void vhost_poll_flush(struct vhost_poll *poll);
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void vhost_poll_queue(struct vhost_poll *poll);
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struct vhost_log {
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u64 addr;
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u64 len;
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};
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struct vhost_virtqueue;
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struct vhost_ubuf_ref {
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struct kref kref;
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wait_queue_head_t wait;
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struct vhost_virtqueue *vq;
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};
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struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *, bool zcopy);
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void vhost_ubuf_put(struct vhost_ubuf_ref *);
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void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *);
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struct ubuf_info;
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/* The virtqueue structure describes a queue attached to a device. */
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struct vhost_virtqueue {
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struct vhost_dev *dev;
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/* The actual ring of buffers. */
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struct mutex mutex;
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unsigned int num;
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struct vring_desc __user *desc;
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struct vring_avail __user *avail;
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struct vring_used __user *used;
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struct file *kick;
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struct file *call;
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struct file *error;
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struct eventfd_ctx *call_ctx;
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struct eventfd_ctx *error_ctx;
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struct eventfd_ctx *log_ctx;
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struct vhost_poll poll;
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/* The routine to call when the Guest pings us, or timeout. */
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vhost_work_fn_t handle_kick;
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/* Last available index we saw. */
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u16 last_avail_idx;
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/* Caches available index value from user. */
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u16 avail_idx;
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/* Last index we used. */
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u16 last_used_idx;
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/* Used flags */
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u16 used_flags;
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/* Last used index value we have signalled on */
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u16 signalled_used;
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/* Last used index value we have signalled on */
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bool signalled_used_valid;
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/* Log writes to used structure. */
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bool log_used;
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u64 log_addr;
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struct iovec iov[UIO_MAXIOV];
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/* hdr is used to store the virtio header.
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* Since each iovec has >= 1 byte length, we never need more than
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* header length entries to store the header. */
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struct iovec hdr[sizeof(struct virtio_net_hdr_mrg_rxbuf)];
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struct iovec *indirect;
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size_t vhost_hlen;
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size_t sock_hlen;
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struct vring_used_elem *heads;
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/* We use a kind of RCU to access private pointer.
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* All readers access it from worker, which makes it possible to
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* flush the vhost_work instead of synchronize_rcu. Therefore readers do
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* not need to call rcu_read_lock/rcu_read_unlock: the beginning of
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* vhost_work execution acts instead of rcu_read_lock() and the end of
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* vhost_work execution acts instead of rcu_read_unlock().
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* Writers use virtqueue mutex. */
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void __rcu *private_data;
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/* Log write descriptors */
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void __user *log_base;
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struct vhost_log *log;
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/* vhost zerocopy support fields below: */
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/* last used idx for outstanding DMA zerocopy buffers */
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int upend_idx;
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/* first used idx for DMA done zerocopy buffers */
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int done_idx;
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/* an array of userspace buffers info */
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struct ubuf_info *ubuf_info;
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/* Reference counting for outstanding ubufs.
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* Protected by vq mutex. Writers must also take device mutex. */
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struct vhost_ubuf_ref *ubufs;
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};
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struct vhost_dev {
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/* Readers use RCU to access memory table pointer
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* log base pointer and features.
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* Writers use mutex below.*/
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struct vhost_memory __rcu *memory;
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struct mm_struct *mm;
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struct mutex mutex;
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unsigned acked_features;
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struct vhost_virtqueue *vqs;
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int nvqs;
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struct file *log_file;
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struct eventfd_ctx *log_ctx;
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spinlock_t work_lock;
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struct list_head work_list;
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struct task_struct *worker;
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};
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long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
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long vhost_dev_check_owner(struct vhost_dev *);
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long vhost_dev_reset_owner(struct vhost_dev *);
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void vhost_dev_cleanup(struct vhost_dev *, bool locked);
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void vhost_dev_stop(struct vhost_dev *);
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long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
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long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
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int vhost_vq_access_ok(struct vhost_virtqueue *vq);
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int vhost_log_access_ok(struct vhost_dev *);
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int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
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struct iovec iov[], unsigned int iov_count,
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unsigned int *out_num, unsigned int *in_num,
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struct vhost_log *log, unsigned int *log_num);
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void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
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int vhost_init_used(struct vhost_virtqueue *);
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int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
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int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
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unsigned count);
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void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
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unsigned int id, int len);
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void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
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struct vring_used_elem *heads, unsigned count);
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void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
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void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
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bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
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int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
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unsigned int log_num, u64 len);
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#define vq_err(vq, fmt, ...) do { \
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pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
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if ((vq)->error_ctx) \
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eventfd_signal((vq)->error_ctx, 1);\
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} while (0)
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enum {
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VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
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(1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
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(1ULL << VIRTIO_RING_F_EVENT_IDX) |
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(1ULL << VHOST_F_LOG_ALL),
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VHOST_NET_FEATURES = VHOST_FEATURES |
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(1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
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(1ULL << VIRTIO_NET_F_MRG_RXBUF),
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};
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static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
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{
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unsigned acked_features;
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/* TODO: check that we are running from vhost_worker or dev mutex is
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* held? */
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acked_features = rcu_dereference_index_check(dev->acked_features, 1);
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return acked_features & (1 << bit);
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}
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void vhost_enable_zcopy(int vq);
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#endif
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