Re: [PATCH] vhost: Move vhost.h to allow vhost driver out-of-tree compilation

["Guillaume Missonnier" <guillaume.missonnier@atos.net>]

On Fri, Mar 10, 2017 at 06:25:51PM +0200, Michael S. Tsirkin wrote:
> On Tue, Mar 07, 2017 at 10:47:05AM +0100, Guillaume Missonnier wrote:
> > Move vhost.h to include/linux to allow vhost driver out-of-tree compilation.
> > Currently, this cannot be done properly because the vhost header file is in
> > driver/vhost.
> > 
> > To distribute a new vhost driver before it is included in the kernel tree,
> > we need to package it using kmod, dkms, ..., and to compile it out-of-tree
> > using headers provided by the distribution's kernel development package.
> > 
> > Signed-off-by: Guillaume Missonnier <guillaume.missonnier@atos.net>
> 
> FYI, I won't merge infrastructure patches before the first user was even
> posted.  Let's see that new driver first.
> 
Ok, I will eventually resend this patch when our driver is ready.

Thanks

> > ---
> >  MAINTAINERS                |   1 +
> >  drivers/vhost/net.c        |   2 -
> >  drivers/vhost/scsi.c       |   2 -
> >  drivers/vhost/test.c       |   1 -
> >  drivers/vhost/vhost.c      |   2 -
> >  drivers/vhost/vhost.h      | 292 --------------------------------------------
> >  drivers/vhost/vsock.c      |   1 -
> >  include/linux/vhost.h      | 293 +++++++++++++++++++++++++++++++++++++++++++++
> >  include/uapi/linux/vhost.h |   4 +-
> >  9 files changed, 296 insertions(+), 302 deletions(-)
> >  delete mode 100644 drivers/vhost/vhost.h
> >  create mode 100644 include/linux/vhost.h
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 527d137..0788737 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -13113,6 +13113,7 @@ L:	netdev@vger.kernel.org
> >  T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git
> >  S:	Maintained
> >  F:	drivers/vhost/
> > +F:	include/linux/vhost.h
> >  F:	include/uapi/linux/vhost.h
> >  
> >  VIRTIO INPUT DRIVER
> > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> > index 5dc3465..5de59ad 100644
> > --- a/drivers/vhost/net.c
> > +++ b/drivers/vhost/net.c
> > @@ -28,8 +28,6 @@
> >  
> >  #include <net/sock.h>
> >  
> > -#include "vhost.h"
> > -
> >  static int experimental_zcopytx = 1;
> >  module_param(experimental_zcopytx, int, 0444);
> >  MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
> > diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> > index fd6c8b6..5b41456 100644
> > --- a/drivers/vhost/scsi.c
> > +++ b/drivers/vhost/scsi.c
> > @@ -48,8 +48,6 @@
> >  #include <linux/bitmap.h>
> >  #include <linux/percpu_ida.h>
> >  
> > -#include "vhost.h"
> > -
> >  #define VHOST_SCSI_VERSION  "v0.1"
> >  #define VHOST_SCSI_NAMELEN 256
> >  #define VHOST_SCSI_MAX_CDB_SIZE 32
> > diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
> > index 3cc98c0..d515cbd 100644
> > --- a/drivers/vhost/test.c
> > +++ b/drivers/vhost/test.c
> > @@ -17,7 +17,6 @@
> >  #include <linux/slab.h>
> >  
> >  #include "test.h"
> > -#include "vhost.h"
> >  
> >  /* Max number of bytes transferred before requeueing the job.
> >   * Using this limit prevents one virtqueue from starving others. */
> > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> > index 998bed5..d5c5f3c 100644
> > --- a/drivers/vhost/vhost.c
> > +++ b/drivers/vhost/vhost.c
> > @@ -29,8 +29,6 @@
> >  #include <linux/sort.h>
> >  #include <linux/interval_tree_generic.h>
> >  
> > -#include "vhost.h"
> > -
> >  static ushort max_mem_regions = 64;
> >  module_param(max_mem_regions, ushort, 0444);
> >  MODULE_PARM_DESC(max_mem_regions,
> > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> > deleted file mode 100644
> > index f55671d..0000000
> > --- a/drivers/vhost/vhost.h
> > +++ /dev/null
> > @@ -1,292 +0,0 @@
> > -#ifndef _VHOST_H
> > -#define _VHOST_H
> > -
> > -#include <linux/eventfd.h>
> > -#include <linux/vhost.h>
> > -#include <linux/mm.h>
> > -#include <linux/mutex.h>
> > -#include <linux/poll.h>
> > -#include <linux/file.h>
> > -#include <linux/uio.h>
> > -#include <linux/virtio_config.h>
> > -#include <linux/virtio_ring.h>
> > -#include <linux/atomic.h>
> > -
> > -struct vhost_work;
> > -typedef void (*vhost_work_fn_t)(struct vhost_work *work);
> > -
> > -#define VHOST_WORK_QUEUED 1
> > -struct vhost_work {
> > -	struct llist_node	  node;
> > -	vhost_work_fn_t		  fn;
> > -	wait_queue_head_t	  done;
> > -	int			  flushing;
> > -	unsigned		  queue_seq;
> > -	unsigned		  done_seq;
> > -	unsigned long		  flags;
> > -};
> > -
> > -/* Poll a file (eventfd or socket) */
> > -/* Note: there's nothing vhost specific about this structure. */
> > -struct vhost_poll {
> > -	poll_table                table;
> > -	wait_queue_head_t        *wqh;
> > -	wait_queue_t              wait;
> > -	struct vhost_work	  work;
> > -	unsigned long		  mask;
> > -	struct vhost_dev	 *dev;
> > -};
> > -
> > -void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
> > -void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
> > -bool vhost_has_work(struct vhost_dev *dev);
> > -
> > -void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
> > -		     unsigned long mask, struct vhost_dev *dev);
> > -int vhost_poll_start(struct vhost_poll *poll, struct file *file);
> > -void vhost_poll_stop(struct vhost_poll *poll);
> > -void vhost_poll_flush(struct vhost_poll *poll);
> > -void vhost_poll_queue(struct vhost_poll *poll);
> > -void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work);
> > -long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
> > -
> > -struct vhost_log {
> > -	u64 addr;
> > -	u64 len;
> > -};
> > -
> > -#define START(node) ((node)->start)
> > -#define LAST(node) ((node)->last)
> > -
> > -struct vhost_umem_node {
> > -	struct rb_node rb;
> > -	struct list_head link;
> > -	__u64 start;
> > -	__u64 last;
> > -	__u64 size;
> > -	__u64 userspace_addr;
> > -	__u32 perm;
> > -	__u32 flags_padding;
> > -	__u64 __subtree_last;
> > -};
> > -
> > -struct vhost_umem {
> > -	struct rb_root umem_tree;
> > -	struct list_head umem_list;
> > -	int numem;
> > -};
> > -
> > -enum vhost_uaddr_type {
> > -	VHOST_ADDR_DESC = 0,
> > -	VHOST_ADDR_AVAIL = 1,
> > -	VHOST_ADDR_USED = 2,
> > -	VHOST_NUM_ADDRS = 3,
> > -};
> > -
> > -/* The virtqueue structure describes a queue attached to a device. */
> > -struct vhost_virtqueue {
> > -	struct vhost_dev *dev;
> > -
> > -	/* The actual ring of buffers. */
> > -	struct mutex mutex;
> > -	unsigned int num;
> > -	struct vring_desc __user *desc;
> > -	struct vring_avail __user *avail;
> > -	struct vring_used __user *used;
> > -	const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS];
> > -	struct file *kick;
> > -	struct file *call;
> > -	struct file *error;
> > -	struct eventfd_ctx *call_ctx;
> > -	struct eventfd_ctx *error_ctx;
> > -	struct eventfd_ctx *log_ctx;
> > -
> > -	struct vhost_poll poll;
> > -
> > -	/* The routine to call when the Guest pings us, or timeout. */
> > -	vhost_work_fn_t handle_kick;
> > -
> > -	/* Last available index we saw. */
> > -	u16 last_avail_idx;
> > -
> > -	/* Caches available index value from user. */
> > -	u16 avail_idx;
> > -
> > -	/* Last index we used. */
> > -	u16 last_used_idx;
> > -
> > -	/* Last used evet we've seen */
> > -	u16 last_used_event;
> > -
> > -	/* Used flags */
> > -	u16 used_flags;
> > -
> > -	/* Last used index value we have signalled on */
> > -	u16 signalled_used;
> > -
> > -	/* Last used index value we have signalled on */
> > -	bool signalled_used_valid;
> > -
> > -	/* Log writes to used structure. */
> > -	bool log_used;
> > -	u64 log_addr;
> > -
> > -	struct iovec iov[UIO_MAXIOV];
> > -	struct iovec iotlb_iov[64];
> > -	struct iovec *indirect;
> > -	struct vring_used_elem *heads;
> > -	/* Protected by virtqueue mutex. */
> > -	struct vhost_umem *umem;
> > -	struct vhost_umem *iotlb;
> > -	void *private_data;
> > -	u64 acked_features;
> > -	/* Log write descriptors */
> > -	void __user *log_base;
> > -	struct vhost_log *log;
> > -
> > -	/* Ring endianness. Defaults to legacy native endianness.
> > -	 * Set to true when starting a modern virtio device. */
> > -	bool is_le;
> > -#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
> > -	/* Ring endianness requested by userspace for cross-endian support. */
> > -	bool user_be;
> > -#endif
> > -	u32 busyloop_timeout;
> > -};
> > -
> > -struct vhost_msg_node {
> > -  struct vhost_msg msg;
> > -  struct vhost_virtqueue *vq;
> > -  struct list_head node;
> > -};
> > -
> > -struct vhost_dev {
> > -	struct mm_struct *mm;
> > -	struct mutex mutex;
> > -	struct vhost_virtqueue **vqs;
> > -	int nvqs;
> > -	struct file *log_file;
> > -	struct eventfd_ctx *log_ctx;
> > -	struct llist_head work_list;
> > -	struct task_struct *worker;
> > -	struct vhost_umem *umem;
> > -	struct vhost_umem *iotlb;
> > -	spinlock_t iotlb_lock;
> > -	struct list_head read_list;
> > -	struct list_head pending_list;
> > -	wait_queue_head_t wait;
> > -};
> > -
> > -void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
> > -long vhost_dev_set_owner(struct vhost_dev *dev);
> > -bool vhost_dev_has_owner(struct vhost_dev *dev);
> > -long vhost_dev_check_owner(struct vhost_dev *);
> > -struct vhost_umem *vhost_dev_reset_owner_prepare(void);
> > -void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_umem *);
> > -void vhost_dev_cleanup(struct vhost_dev *, bool locked);
> > -void vhost_dev_stop(struct vhost_dev *);
> > -long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
> > -long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
> > -int vhost_vq_access_ok(struct vhost_virtqueue *vq);
> > -int vhost_log_access_ok(struct vhost_dev *);
> > -
> > -int vhost_get_vq_desc(struct vhost_virtqueue *,
> > -		      struct iovec iov[], unsigned int iov_count,
> > -		      unsigned int *out_num, unsigned int *in_num,
> > -		      struct vhost_log *log, unsigned int *log_num);
> > -void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
> > -
> > -int vhost_vq_init_access(struct vhost_virtqueue *);
> > -int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
> > -int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
> > -		     unsigned count);
> > -void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
> > -			       unsigned int id, int len);
> > -void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
> > -			       struct vring_used_elem *heads, unsigned count);
> > -void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
> > -void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
> > -bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
> > -bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
> > -
> > -int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
> > -		    unsigned int log_num, u64 len);
> > -int vq_iotlb_prefetch(struct vhost_virtqueue *vq);
> > -
> > -struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
> > -void vhost_enqueue_msg(struct vhost_dev *dev,
> > -		       struct list_head *head,
> > -		       struct vhost_msg_node *node);
> > -struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
> > -					 struct list_head *head);
> > -unsigned int vhost_chr_poll(struct file *file, struct vhost_dev *dev,
> > -			    poll_table *wait);
> > -ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
> > -			    int noblock);
> > -ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
> > -			     struct iov_iter *from);
> > -int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
> > -
> > -#define vq_err(vq, fmt, ...) do {                                  \
> > -		pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
> > -		if ((vq)->error_ctx)                               \
> > -				eventfd_signal((vq)->error_ctx, 1);\
> > -	} while (0)
> > -
> > -enum {
> > -	VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
> > -			 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
> > -			 (1ULL << VIRTIO_RING_F_EVENT_IDX) |
> > -			 (1ULL << VHOST_F_LOG_ALL) |
> > -			 (1ULL << VIRTIO_F_ANY_LAYOUT) |
> > -			 (1ULL << VIRTIO_F_VERSION_1)
> > -};
> > -
> > -static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
> > -{
> > -	return vq->acked_features & (1ULL << bit);
> > -}
> > -
> > -#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
> > -static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
> > -{
> > -	return vq->is_le;
> > -}
> > -#else
> > -static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
> > -{
> > -	return virtio_legacy_is_little_endian() || vq->is_le;
> > -}
> > -#endif
> > -
> > -/* Memory accessors */
> > -static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
> > -{
> > -	return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
> > -}
> > -
> > -static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
> > -{
> > -	return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
> > -}
> > -
> > -static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
> > -{
> > -	return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
> > -}
> > -
> > -static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
> > -{
> > -	return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
> > -}
> > -
> > -static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
> > -{
> > -	return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
> > -}
> > -
> > -static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
> > -{
> > -	return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
> > -}
> > -#endif
> > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> > index ce5e63d..f4c6fd8 100644
> > --- a/drivers/vhost/vsock.c
> > +++ b/drivers/vhost/vsock.c
> > @@ -17,7 +17,6 @@
> >  #include <linux/vhost.h>
> >  
> >  #include <net/af_vsock.h>
> > -#include "vhost.h"
> >  
> >  #define VHOST_VSOCK_DEFAULT_HOST_CID	2
> >  
> > diff --git a/include/linux/vhost.h b/include/linux/vhost.h
> > new file mode 100644
> > index 0000000..7168c40
> > --- /dev/null
> > +++ b/include/linux/vhost.h
> > @@ -0,0 +1,293 @@
> > +#ifndef _LINUX_VHOST_H
> > +#define _LINUX_VHOST_H
> > +
> > +#include <uapi/linux/vhost.h>
> > +
> > +#include <linux/eventfd.h>
> > +#include <linux/mm.h>
> > +#include <linux/mutex.h>
> > +#include <linux/poll.h>
> > +#include <linux/file.h>
> > +#include <linux/uio.h>
> > +#include <linux/virtio_config.h>
> > +#include <linux/virtio_ring.h>
> > +#include <linux/atomic.h>
> > +
> > +struct vhost_work;
> > +typedef void (*vhost_work_fn_t)(struct vhost_work *work);
> > +
> > +#define VHOST_WORK_QUEUED 1
> > +struct vhost_work {
> > +	struct llist_node	  node;
> > +	vhost_work_fn_t		  fn;
> > +	wait_queue_head_t	  done;
> > +	int			  flushing;
> > +	unsigned		  queue_seq;
> > +	unsigned		  done_seq;
> > +	unsigned long		  flags;
> > +};
> > +
> > +/* Poll a file (eventfd or socket) */
> > +/* Note: there's nothing vhost specific about this structure. */
> > +struct vhost_poll {
> > +	poll_table                table;
> > +	wait_queue_head_t        *wqh;
> > +	wait_queue_t              wait;
> > +	struct vhost_work	  work;
> > +	unsigned long		  mask;
> > +	struct vhost_dev	 *dev;
> > +};
> > +
> > +void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
> > +void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
> > +bool vhost_has_work(struct vhost_dev *dev);
> > +
> > +void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
> > +		     unsigned long mask, struct vhost_dev *dev);
> > +int vhost_poll_start(struct vhost_poll *poll, struct file *file);
> > +void vhost_poll_stop(struct vhost_poll *poll);
> > +void vhost_poll_flush(struct vhost_poll *poll);
> > +void vhost_poll_queue(struct vhost_poll *poll);
> > +void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work);
> > +long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
> > +
> > +struct vhost_log {
> > +	u64 addr;
> > +	u64 len;
> > +};
> > +
> > +#define START(node) ((node)->start)
> > +#define LAST(node) ((node)->last)
> > +
> > +struct vhost_umem_node {
> > +	struct rb_node rb;
> > +	struct list_head link;
> > +	__u64 start;
> > +	__u64 last;
> > +	__u64 size;
> > +	__u64 userspace_addr;
> > +	__u32 perm;
> > +	__u32 flags_padding;
> > +	__u64 __subtree_last;
> > +};
> > +
> > +struct vhost_umem {
> > +	struct rb_root umem_tree;
> > +	struct list_head umem_list;
> > +	int numem;
> > +};
> > +
> > +enum vhost_uaddr_type {
> > +	VHOST_ADDR_DESC = 0,
> > +	VHOST_ADDR_AVAIL = 1,
> > +	VHOST_ADDR_USED = 2,
> > +	VHOST_NUM_ADDRS = 3,
> > +};
> > +
> > +/* The virtqueue structure describes a queue attached to a device. */
> > +struct vhost_virtqueue {
> > +	struct vhost_dev *dev;
> > +
> > +	/* The actual ring of buffers. */
> > +	struct mutex mutex;
> > +	unsigned int num;
> > +	struct vring_desc __user *desc;
> > +	struct vring_avail __user *avail;
> > +	struct vring_used __user *used;
> > +	const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS];
> > +	struct file *kick;
> > +	struct file *call;
> > +	struct file *error;
> > +	struct eventfd_ctx *call_ctx;
> > +	struct eventfd_ctx *error_ctx;
> > +	struct eventfd_ctx *log_ctx;
> > +
> > +	struct vhost_poll poll;
> > +
> > +	/* The routine to call when the Guest pings us, or timeout. */
> > +	vhost_work_fn_t handle_kick;
> > +
> > +	/* Last available index we saw. */
> > +	u16 last_avail_idx;
> > +
> > +	/* Caches available index value from user. */
> > +	u16 avail_idx;
> > +
> > +	/* Last index we used. */
> > +	u16 last_used_idx;
> > +
> > +	/* Last used evet we've seen */
> > +	u16 last_used_event;
> > +
> > +	/* Used flags */
> > +	u16 used_flags;
> > +
> > +	/* Last used index value we have signalled on */
> > +	u16 signalled_used;
> > +
> > +	/* Last used index value we have signalled on */
> > +	bool signalled_used_valid;
> > +
> > +	/* Log writes to used structure. */
> > +	bool log_used;
> > +	u64 log_addr;
> > +
> > +	struct iovec iov[UIO_MAXIOV];
> > +	struct iovec iotlb_iov[64];
> > +	struct iovec *indirect;
> > +	struct vring_used_elem *heads;
> > +	/* Protected by virtqueue mutex. */
> > +	struct vhost_umem *umem;
> > +	struct vhost_umem *iotlb;
> > +	void *private_data;
> > +	u64 acked_features;
> > +	/* Log write descriptors */
> > +	void __user *log_base;
> > +	struct vhost_log *log;
> > +
> > +	/* Ring endianness. Defaults to legacy native endianness.
> > +	 * Set to true when starting a modern virtio device. */
> > +	bool is_le;
> > +#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
> > +	/* Ring endianness requested by userspace for cross-endian support. */
> > +	bool user_be;
> > +#endif
> > +	u32 busyloop_timeout;
> > +};
> > +
> > +struct vhost_msg_node {
> > +  struct vhost_msg msg;
> > +  struct vhost_virtqueue *vq;
> > +  struct list_head node;
> > +};
> > +
> > +struct vhost_dev {
> > +	struct mm_struct *mm;
> > +	struct mutex mutex;
> > +	struct vhost_virtqueue **vqs;
> > +	int nvqs;
> > +	struct file *log_file;
> > +	struct eventfd_ctx *log_ctx;
> > +	struct llist_head work_list;
> > +	struct task_struct *worker;
> > +	struct vhost_umem *umem;
> > +	struct vhost_umem *iotlb;
> > +	spinlock_t iotlb_lock;
> > +	struct list_head read_list;
> > +	struct list_head pending_list;
> > +	wait_queue_head_t wait;
> > +};
> > +
> > +void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
> > +long vhost_dev_set_owner(struct vhost_dev *dev);
> > +bool vhost_dev_has_owner(struct vhost_dev *dev);
> > +long vhost_dev_check_owner(struct vhost_dev *);
> > +struct vhost_umem *vhost_dev_reset_owner_prepare(void);
> > +void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_umem *);
> > +void vhost_dev_cleanup(struct vhost_dev *, bool locked);
> > +void vhost_dev_stop(struct vhost_dev *);
> > +long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
> > +long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
> > +int vhost_vq_access_ok(struct vhost_virtqueue *vq);
> > +int vhost_log_access_ok(struct vhost_dev *);
> > +
> > +int vhost_get_vq_desc(struct vhost_virtqueue *,
> > +		      struct iovec iov[], unsigned int iov_count,
> > +		      unsigned int *out_num, unsigned int *in_num,
> > +		      struct vhost_log *log, unsigned int *log_num);
> > +void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
> > +
> > +int vhost_vq_init_access(struct vhost_virtqueue *);
> > +int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
> > +int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
> > +		     unsigned count);
> > +void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
> > +			       unsigned int id, int len);
> > +void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
> > +			       struct vring_used_elem *heads, unsigned count);
> > +void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
> > +void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
> > +bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
> > +bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
> > +
> > +int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
> > +		    unsigned int log_num, u64 len);
> > +int vq_iotlb_prefetch(struct vhost_virtqueue *vq);
> > +
> > +struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
> > +void vhost_enqueue_msg(struct vhost_dev *dev,
> > +		       struct list_head *head,
> > +		       struct vhost_msg_node *node);
> > +struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
> > +					 struct list_head *head);
> > +unsigned int vhost_chr_poll(struct file *file, struct vhost_dev *dev,
> > +			    poll_table *wait);
> > +ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
> > +			    int noblock);
> > +ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
> > +			     struct iov_iter *from);
> > +int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
> > +
> > +#define vq_err(vq, fmt, ...) do {                                  \
> > +		pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
> > +		if ((vq)->error_ctx)                               \
> > +				eventfd_signal((vq)->error_ctx, 1);\
> > +	} while (0)
> > +
> > +enum {
> > +	VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
> > +			 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
> > +			 (1ULL << VIRTIO_RING_F_EVENT_IDX) |
> > +			 (1ULL << VHOST_F_LOG_ALL) |
> > +			 (1ULL << VIRTIO_F_ANY_LAYOUT) |
> > +			 (1ULL << VIRTIO_F_VERSION_1)
> > +};
> > +
> > +static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
> > +{
> > +	return vq->acked_features & (1ULL << bit);
> > +}
> > +
> > +#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
> > +static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
> > +{
> > +	return vq->is_le;
> > +}
> > +#else
> > +static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
> > +{
> > +	return virtio_legacy_is_little_endian() || vq->is_le;
> > +}
> > +#endif
> > +
> > +/* Memory accessors */
> > +static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
> > +{
> > +	return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
> > +}
> > +
> > +static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
> > +{
> > +	return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
> > +}
> > +
> > +static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
> > +{
> > +	return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
> > +}
> > +
> > +static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
> > +{
> > +	return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
> > +}
> > +
> > +static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
> > +{
> > +	return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
> > +}
> > +
> > +static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
> > +{
> > +	return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
> > +}
> > +#endif
> > diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
> > index 60180c0..678a716 100644
> > --- a/include/uapi/linux/vhost.h
> > +++ b/include/uapi/linux/vhost.h
> > @@ -1,5 +1,5 @@
> > -#ifndef _LINUX_VHOST_H
> > -#define _LINUX_VHOST_H
> > +#ifndef _UAPI_LINUX_VHOST_H
> > +#define _UAPI_LINUX_VHOST_H
> >  /* Userspace interface for in-kernel virtio accelerators. */
> >  
> >  /* vhost is used to reduce the number of system calls involved in virtio.
> > -- 
> > 1.8.3.1