Linux Virtualization - Mar 2017 - [PATCH] vhost: Move vhost.h to allow vhost driver out-of-tree compilation

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 at atos.net>
---
 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 at 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

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 at
atos.net>
FYI, I won't merge infrastructure patches before the first user was even
posted.  Let's see that new driver first.
> ---
>  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 at 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

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 at
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 at 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