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![Jason Wang](/assets/img/avatar_default.png)
Qemu supports up to UIO_MAXIOV s/g so we have to match that because guest drivers may rely on this. Allocate indirect and log arrays dynamically to avoid using too much contigious memory and make the length of hdr array to match the header length since each iovec entry has a least one byte. Test with copying large files w/ and w/o migration in both linux and windows guests. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
178 lines
5.3 KiB
C
178 lines
5.3 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/skbuff.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 <asm/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_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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/* 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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/* 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_lock().
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* Writers use virtqueue mutex. */
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void *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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};
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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 *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 *);
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long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
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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_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_virtqueue *);
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bool vhost_enable_notify(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 = (1 << VIRTIO_F_NOTIFY_ON_EMPTY) |
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(1 << VIRTIO_RING_F_INDIRECT_DESC) |
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(1 << VHOST_F_LOG_ALL) |
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(1 << VHOST_NET_F_VIRTIO_NET_HDR) |
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(1 << 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 = rcu_dereference(dev->acked_features);
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return acked_features & (1 << bit);
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}
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#endif
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