hw/vfio-user/protocol.h

#ifndef VFIO_USER_PROTOCOL_H
#define VFIO_USER_PROTOCOL_H

/*
 * vfio protocol over a UNIX socket.
 *
 * Copyright © 2018, 2021 Oracle and/or its affiliates.
 *
 * Each message has a standard header that describes the command
 * being sent, which is almost always a VFIO ioctl().
 *
 * The header may be followed by command-specific data, such as the
 * region and offset info for read and write commands.
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

typedef struct {
    uint16_t id;
    uint16_t command;
    uint32_t size;
    uint32_t flags;
    uint32_t error_reply;
} VFIOUserHdr;

/* VFIOUserHdr commands */
enum vfio_user_command {
    VFIO_USER_VERSION                   = 1,
    VFIO_USER_DMA_MAP                   = 2,
    VFIO_USER_DMA_UNMAP                 = 3,
    VFIO_USER_DEVICE_GET_INFO           = 4,
    VFIO_USER_DEVICE_GET_REGION_INFO    = 5,
    VFIO_USER_DEVICE_GET_REGION_IO_FDS  = 6,
    VFIO_USER_DEVICE_GET_IRQ_INFO       = 7,
    VFIO_USER_DEVICE_SET_IRQS           = 8,
    VFIO_USER_REGION_READ               = 9,
    VFIO_USER_REGION_WRITE              = 10,
    VFIO_USER_DMA_READ                  = 11,
    VFIO_USER_DMA_WRITE                 = 12,
    VFIO_USER_DEVICE_RESET              = 13,
    VFIO_USER_DIRTY_PAGES               = 14,
    VFIO_USER_MAX,
};

/* VFIOUserHdr flags */
#define VFIO_USER_REQUEST       0x0
#define VFIO_USER_REPLY         0x1
#define VFIO_USER_TYPE          0xF

#define VFIO_USER_NO_REPLY      0x10
#define VFIO_USER_ERROR         0x20


/*
 * VFIO_USER_VERSION
 */
typedef struct {
    VFIOUserHdr hdr;
    uint16_t major;
    uint16_t minor;
    char capabilities[];
} VFIOUserVersion;

#define VFIO_USER_MAJOR_VER     0
#define VFIO_USER_MINOR_VER     0

#define VFIO_USER_CAP           "capabilities"

/* "capabilities" members */
#define VFIO_USER_CAP_MAX_FDS   "max_msg_fds"
#define VFIO_USER_CAP_MAX_XFER  "max_data_xfer_size"
#define VFIO_USER_CAP_PGSIZES   "pgsizes"
#define VFIO_USER_CAP_MAP_MAX   "max_dma_maps"
#define VFIO_USER_CAP_MIGR      "migration"

/* "migration" members */
#define VFIO_USER_CAP_PGSIZE            "pgsize"
#define VFIO_USER_CAP_MAX_BITMAP        "max_bitmap_size"

/*
 * Max FDs mainly comes into play when a device supports multiple interrupts
 * where each ones uses an eventfd to inject it into the guest.
 * It is clamped by the the number of FDs the qio channel supports in a
 * single message.
 */
#define VFIO_USER_DEF_MAX_FDS   8
#define VFIO_USER_MAX_MAX_FDS   16

/*
 * Max transfer limits the amount of data in region and DMA messages.
 * Region R/W will be very small (limited by how much a single instruction
 * can process) so just use a reasonable limit here.
 */
#define VFIO_USER_DEF_MAX_XFER  (1024 * 1024)
#define VFIO_USER_MAX_MAX_XFER  (64 * 1024 * 1024)

/*
 * Default pagesizes supported is 4k.
 */
#define VFIO_USER_DEF_PGSIZE    4096

/*
 * Default max number of DMA mappings is stolen from the
 * linux kernel "dma_entry_limit"
 */
#define VFIO_USER_DEF_MAP_MAX   65535

/*
 * Default max bitmap size is also take from the linux kernel,
 * where usage of signed ints limits the VA range to 2^31 bytes.
 * Dividing that by the number of bits per byte yields 256MB
 */
#define VFIO_USER_DEF_MAX_BITMAP (256 * 1024 * 1024)

/*
 * VFIO_USER_DEVICE_GET_INFO
 * imported from struct vfio_device_info
 */
typedef struct {
    VFIOUserHdr hdr;
    uint32_t argsz;
    uint32_t flags;
    uint32_t num_regions;
    uint32_t num_irqs;
} VFIOUserDeviceInfo;

#endif /* VFIO_USER_PROTOCOL_H */