include/linux/vhost.h

   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