1 #ifndef _LINUX_VHOST_H
2 #define _LINUX_VHOST_H
3 /* Userspace interface for in-kernel virtio accelerators. */
4 
5 /* vhost is used to reduce the number of system calls involved in virtio.
6  *
7  * Existing virtio net code is used in the guest without modification.
8  *
9  * This header includes interface used by userspace hypervisor for
10  * device configuration.
11  */
12 
13 #include <linux/types.h>
14 #include <linux/compiler.h>
15 #include <linux/ioctl.h>
16 #include <linux/virtio_config.h>
17 #include <linux/virtio_ring.h>
18 
19 struct vhost_vring_state {
20 	unsigned int index;
21 	unsigned int num;
22 };
23 
24 struct vhost_vring_file {
25 	unsigned int index;
26 	int fd; /* Pass -1 to unbind from file. */
27 
28 };
29 
30 struct vhost_vring_addr {
31 	unsigned int index;
32 	/* Option flags. */
33 	unsigned int flags;
34 	/* Flag values: */
35 	/* Whether log address is valid. If set enables logging. */
36 #define VHOST_VRING_F_LOG 0
37 
38 	/* Start of array of descriptors (virtually contiguous) */
39 	__u64 desc_user_addr;
40 	/* Used structure address. Must be 32 bit aligned */
41 	__u64 used_user_addr;
42 	/* Available structure address. Must be 16 bit aligned */
43 	__u64 avail_user_addr;
44 	/* Logging support. */
45 	/* Log writes to used structure, at offset calculated from specified
46 	 * address. Address must be 32 bit aligned. */
47 	__u64 log_guest_addr;
48 };
49 
50 struct vhost_memory_region {
51 	__u64 guest_phys_addr;
52 	__u64 memory_size; /* bytes */
53 	__u64 userspace_addr;
54 	__u64 flags_padding; /* No flags are currently specified. */
55 };
56 
57 /* All region addresses and sizes must be 4K aligned. */
58 #define VHOST_PAGE_SIZE 0x1000
59 
60 struct vhost_memory {
61 	__u32 nregions;
62 	__u32 padding;
63 	struct vhost_memory_region regions[0];
64 };
65 
66 /* ioctls */
67 
68 #define VHOST_VIRTIO 0xAF
69 
70 /* Features bitmask for forward compatibility.  Transport bits are used for
71  * vhost specific features. */
72 #define VHOST_GET_FEATURES	_IOR(VHOST_VIRTIO, 0x00, __u64)
73 #define VHOST_SET_FEATURES	_IOW(VHOST_VIRTIO, 0x00, __u64)
74 
75 /* Set current process as the (exclusive) owner of this file descriptor.  This
76  * must be called before any other vhost command.  Further calls to
77  * VHOST_OWNER_SET fail until VHOST_OWNER_RESET is called. */
78 #define VHOST_SET_OWNER _IO(VHOST_VIRTIO, 0x01)
79 /* Give up ownership, and reset the device to default values.
80  * Allows subsequent call to VHOST_OWNER_SET to succeed. */
81 #define VHOST_RESET_OWNER _IO(VHOST_VIRTIO, 0x02)
82 
83 /* Set up/modify memory layout */
84 #define VHOST_SET_MEM_TABLE	_IOW(VHOST_VIRTIO, 0x03, struct vhost_memory)
85 
86 /* Write logging setup. */
87 /* Memory writes can optionally be logged by setting bit at an offset
88  * (calculated from the physical address) from specified log base.
89  * The bit is set using an atomic 32 bit operation. */
90 /* Set base address for logging. */
91 #define VHOST_SET_LOG_BASE _IOW(VHOST_VIRTIO, 0x04, __u64)
92 /* Specify an eventfd file descriptor to signal on log write. */
93 #define VHOST_SET_LOG_FD _IOW(VHOST_VIRTIO, 0x07, int)
94 
95 /* Ring setup. */
96 /* Set number of descriptors in ring. This parameter can not
97  * be modified while ring is running (bound to a device). */
98 #define VHOST_SET_VRING_NUM _IOW(VHOST_VIRTIO, 0x10, struct vhost_vring_state)
99 /* Set addresses for the ring. */
100 #define VHOST_SET_VRING_ADDR _IOW(VHOST_VIRTIO, 0x11, struct vhost_vring_addr)
101 /* Base value where queue looks for available descriptors */
102 #define VHOST_SET_VRING_BASE _IOW(VHOST_VIRTIO, 0x12, struct vhost_vring_state)
103 /* Get accessor: reads index, writes value in num */
104 #define VHOST_GET_VRING_BASE _IOWR(VHOST_VIRTIO, 0x12, struct vhost_vring_state)
105 
106 /* The following ioctls use eventfd file descriptors to signal and poll
107  * for events. */
108 
109 /* Set eventfd to poll for added buffers */
110 #define VHOST_SET_VRING_KICK _IOW(VHOST_VIRTIO, 0x20, struct vhost_vring_file)
111 /* Set eventfd to signal when buffers have beed used */
112 #define VHOST_SET_VRING_CALL _IOW(VHOST_VIRTIO, 0x21, struct vhost_vring_file)
113 /* Set eventfd to signal an error */
114 #define VHOST_SET_VRING_ERR _IOW(VHOST_VIRTIO, 0x22, struct vhost_vring_file)
115 
116 /* VHOST_NET specific defines */
117 
118 /* Attach virtio net ring to a raw socket, or tap device.
119  * The socket must be already bound to an ethernet device, this device will be
120  * used for transmit.  Pass fd -1 to unbind from the socket and the transmit
121  * device.  This can be used to stop the ring (e.g. for migration). */
122 #define VHOST_NET_SET_BACKEND _IOW(VHOST_VIRTIO, 0x30, struct vhost_vring_file)
123 
124 /* Feature bits */
125 /* Log all write descriptors. Can be changed while device is active. */
126 #define VHOST_F_LOG_ALL 26
127 /* vhost-net should add virtio_net_hdr for RX, and strip for TX packets. */
128 #define VHOST_NET_F_VIRTIO_NET_HDR 27
129 
130 #endif
131