/*
 * VMware VMCI Driver
 *
 * Copyright (C) 2012 VMware, Inc. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation version 2 and no later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 */

#ifndef _VMW_VMCI_DEF_H_
#define _VMW_VMCI_DEF_H_

#include <linux/atomic.h>

/* Register offsets. */
#define VMCI_STATUS_ADDR      0x00
#define VMCI_CONTROL_ADDR     0x04
#define VMCI_ICR_ADDR         0x08
#define VMCI_IMR_ADDR         0x0c
#define VMCI_DATA_OUT_ADDR    0x10
#define VMCI_DATA_IN_ADDR     0x14
#define VMCI_CAPS_ADDR        0x18
#define VMCI_RESULT_LOW_ADDR  0x1c
#define VMCI_RESULT_HIGH_ADDR 0x20

/* Max number of devices. */
#define VMCI_MAX_DEVICES 1

/* Status register bits. */
#define VMCI_STATUS_INT_ON     0x1

/* Control register bits. */
#define VMCI_CONTROL_RESET        0x1
#define VMCI_CONTROL_INT_ENABLE   0x2
#define VMCI_CONTROL_INT_DISABLE  0x4

/* Capabilities register bits. */
#define VMCI_CAPS_HYPERCALL     0x1
#define VMCI_CAPS_GUESTCALL     0x2
#define VMCI_CAPS_DATAGRAM      0x4
#define VMCI_CAPS_NOTIFICATIONS 0x8

/* Interrupt Cause register bits. */
#define VMCI_ICR_DATAGRAM      0x1
#define VMCI_ICR_NOTIFICATION  0x2

/* Interrupt Mask register bits. */
#define VMCI_IMR_DATAGRAM      0x1
#define VMCI_IMR_NOTIFICATION  0x2

/* Interrupt type. */
enum {
        VMCI_INTR_TYPE_INTX = 0,
        VMCI_INTR_TYPE_MSI = 1,
        VMCI_INTR_TYPE_MSIX = 2,
};

/* Maximum MSI/MSI-X interrupt vectors in the device. */
#define VMCI_MAX_INTRS 2

/*
 * Supported interrupt vectors.  There is one for each ICR value above,
 * but here they indicate the position in the vector array/message ID.
 */
enum {
        VMCI_INTR_DATAGRAM = 0,
        VMCI_INTR_NOTIFICATION = 1,
};

/*
 * A single VMCI device has an upper limit of 128MB on the amount of
 * memory that can be used for queue pairs.
 */
#define VMCI_MAX_GUEST_QP_MEMORY (128 * 1024 * 1024)

/*
 * Queues with pre-mapped data pages must be small, so that we don't pin
 * too much kernel memory (especially on vmkernel).  We limit a queuepair to
 * 32 KB, or 16 KB per queue for symmetrical pairs.
 */
#define VMCI_MAX_PINNED_QP_MEMORY (32 * 1024)

/*
 * We have a fixed set of resource IDs available in the VMX.
 * This allows us to have a very simple implementation since we statically
 * know how many will create datagram handles. If a new caller arrives and
 * we have run out of slots we can manually increment the maximum size of
 * available resource IDs.
 *
 * VMCI reserved hypervisor datagram resource IDs.
 */
enum {
        VMCI_RESOURCES_QUERY = 0,
        VMCI_GET_CONTEXT_ID = 1,
        VMCI_SET_NOTIFY_BITMAP = 2,
        VMCI_DOORBELL_LINK = 3,
        VMCI_DOORBELL_UNLINK = 4,
        VMCI_DOORBELL_NOTIFY = 5,
        /*
         * VMCI_DATAGRAM_REQUEST_MAP and VMCI_DATAGRAM_REMOVE_MAP are
         * obsoleted by the removal of VM to VM communication.
         */
        VMCI_DATAGRAM_REQUEST_MAP = 6,
        VMCI_DATAGRAM_REMOVE_MAP = 7,
        VMCI_EVENT_SUBSCRIBE = 8,
        VMCI_EVENT_UNSUBSCRIBE = 9,
        VMCI_QUEUEPAIR_ALLOC = 10,
        VMCI_QUEUEPAIR_DETACH = 11,

        /*
         * VMCI_VSOCK_VMX_LOOKUP was assigned to 12 for Fusion 3.0/3.1,
         * WS 7.0/7.1 and ESX 4.1
         */
        VMCI_HGFS_TRANSPORT = 13,
        VMCI_UNITY_PBRPC_REGISTER = 14,
        VMCI_RPC_PRIVILEGED = 15,
        VMCI_RPC_UNPRIVILEGED = 16,
        VMCI_RESOURCE_MAX = 17,
};

/*
 * struct vmci_handle - Ownership information structure
 * @context:    The VMX context ID.
 * @resource:   The resource ID (used for locating in resource hash).
 *
 * The vmci_handle structure is used to track resources used within
 * vmw_vmci.
 */
struct vmci_handle {
        u32 context;
        u32 resource;
};

#define vmci_make_handle(_cid, _rid) \
        (struct vmci_handle){ .context = _cid, .resource = _rid }

static inline bool vmci_handle_is_equal(struct vmci_handle h1,
                                        struct vmci_handle h2)
{
        return h1.context == h2.context && h1.resource == h2.resource;
}

#define VMCI_INVALID_ID ~0
static const struct vmci_handle VMCI_INVALID_HANDLE = {
        .context = VMCI_INVALID_ID,
        .resource = VMCI_INVALID_ID
};

static inline bool vmci_handle_is_invalid(struct vmci_handle h)
{
        return vmci_handle_is_equal(h, VMCI_INVALID_HANDLE);
}

/*
 * The below defines can be used to send anonymous requests.
 * This also indicates that no response is expected.
 */
#define VMCI_ANON_SRC_CONTEXT_ID   VMCI_INVALID_ID
#define VMCI_ANON_SRC_RESOURCE_ID  VMCI_INVALID_ID
static const struct vmci_handle VMCI_ANON_SRC_HANDLE = {
        .context = VMCI_ANON_SRC_CONTEXT_ID,
        .resource = VMCI_ANON_SRC_RESOURCE_ID
};

/* The lowest 16 context ids are reserved for internal use. */
#define VMCI_RESERVED_CID_LIMIT ((u32) 16)

/*
 * Hypervisor context id, used for calling into hypervisor
 * supplied services from the VM.
 */
#define VMCI_HYPERVISOR_CONTEXT_ID 0

/*
 * Well-known context id, a logical context that contains a set of
 * well-known services. This context ID is now obsolete.
 */
#define VMCI_WELL_KNOWN_CONTEXT_ID 1

/*
 * Context ID used by host endpoints.
 */
#define VMCI_HOST_CONTEXT_ID  2

#define VMCI_CONTEXT_IS_VM(_cid) (VMCI_INVALID_ID != (_cid) &&          \
                                  (_cid) > VMCI_HOST_CONTEXT_ID)

/*
 * The VMCI_CONTEXT_RESOURCE_ID is used together with vmci_make_handle to make
 * handles that refer to a specific context.
 */
#define VMCI_CONTEXT_RESOURCE_ID 0

/*
 * VMCI error codes.
 */
enum {
        VMCI_SUCCESS_QUEUEPAIR_ATTACH   = 5,
        VMCI_SUCCESS_QUEUEPAIR_CREATE   = 4,
        VMCI_SUCCESS_LAST_DETACH        = 3,
        VMCI_SUCCESS_ACCESS_GRANTED     = 2,
        VMCI_SUCCESS_ENTRY_DEAD         = 1,
        VMCI_SUCCESS                     = 0,
        VMCI_ERROR_INVALID_RESOURCE      = (-1),
        VMCI_ERROR_INVALID_ARGS          = (-2),
        VMCI_ERROR_NO_MEM                = (-3),
        VMCI_ERROR_DATAGRAM_FAILED       = (-4),
        VMCI_ERROR_MORE_DATA             = (-5),
        VMCI_ERROR_NO_MORE_DATAGRAMS     = (-6),
        VMCI_ERROR_NO_ACCESS             = (-7),
        VMCI_ERROR_NO_HANDLE             = (-8),
        VMCI_ERROR_DUPLICATE_ENTRY       = (-9),
        VMCI_ERROR_DST_UNREACHABLE       = (-10),
        VMCI_ERROR_PAYLOAD_TOO_LARGE     = (-11),
        VMCI_ERROR_INVALID_PRIV          = (-12),
        VMCI_ERROR_GENERIC               = (-13),
        VMCI_ERROR_PAGE_ALREADY_SHARED   = (-14),
        VMCI_ERROR_CANNOT_SHARE_PAGE     = (-15),
        VMCI_ERROR_CANNOT_UNSHARE_PAGE   = (-16),
        VMCI_ERROR_NO_PROCESS            = (-17),
        VMCI_ERROR_NO_DATAGRAM           = (-18),
        VMCI_ERROR_NO_RESOURCES          = (-19),
        VMCI_ERROR_UNAVAILABLE           = (-20),
        VMCI_ERROR_NOT_FOUND             = (-21),
        VMCI_ERROR_ALREADY_EXISTS        = (-22),
        VMCI_ERROR_NOT_PAGE_ALIGNED      = (-23),
        VMCI_ERROR_INVALID_SIZE          = (-24),
        VMCI_ERROR_REGION_ALREADY_SHARED = (-25),
        VMCI_ERROR_TIMEOUT               = (-26),
        VMCI_ERROR_DATAGRAM_INCOMPLETE   = (-27),
        VMCI_ERROR_INCORRECT_IRQL        = (-28),
        VMCI_ERROR_EVENT_UNKNOWN         = (-29),
        VMCI_ERROR_OBSOLETE              = (-30),
        VMCI_ERROR_QUEUEPAIR_MISMATCH    = (-31),
        VMCI_ERROR_QUEUEPAIR_NOTSET      = (-32),
        VMCI_ERROR_QUEUEPAIR_NOTOWNER    = (-33),
        VMCI_ERROR_QUEUEPAIR_NOTATTACHED = (-34),
        VMCI_ERROR_QUEUEPAIR_NOSPACE     = (-35),
        VMCI_ERROR_QUEUEPAIR_NODATA      = (-36),
        VMCI_ERROR_BUSMEM_INVALIDATION   = (-37),
        VMCI_ERROR_MODULE_NOT_LOADED     = (-38),
        VMCI_ERROR_DEVICE_NOT_FOUND      = (-39),
        VMCI_ERROR_QUEUEPAIR_NOT_READY   = (-40),
        VMCI_ERROR_WOULD_BLOCK           = (-41),

        /* VMCI clients should return error code within this range */
        VMCI_ERROR_CLIENT_MIN            = (-500),
        VMCI_ERROR_CLIENT_MAX            = (-550),

        /* Internal error codes. */
        VMCI_SHAREDMEM_ERROR_BAD_CONTEXT = (-1000),
};

/* VMCI reserved events. */
enum {
        /* Only applicable to guest endpoints */
        VMCI_EVENT_CTX_ID_UPDATE  = 0,

        /* Applicable to guest and host */
        VMCI_EVENT_CTX_REMOVED    = 1,

        /* Only applicable to guest endpoints */
        VMCI_EVENT_QP_RESUMED     = 2,

        /* Applicable to guest and host */
        VMCI_EVENT_QP_PEER_ATTACH = 3,

        /* Applicable to guest and host */
        VMCI_EVENT_QP_PEER_DETACH = 4,

        /*
         * Applicable to VMX and vmk.  On vmk,
         * this event has the Context payload type.
         */
        VMCI_EVENT_MEM_ACCESS_ON  = 5,

        /*
         * Applicable to VMX and vmk.  Same as
         * above for the payload type.
         */
        VMCI_EVENT_MEM_ACCESS_OFF = 6,
        VMCI_EVENT_MAX            = 7,
};

/*
 * Of the above events, a few are reserved for use in the VMX, and
 * other endpoints (guest and host kernel) should not use them. For
 * the rest of the events, we allow both host and guest endpoints to
 * subscribe to them, to maintain the same API for host and guest
 * endpoints.
 */
#define VMCI_EVENT_VALID_VMX(_event) ((_event) == VMCI_EVENT_MEM_ACCESS_ON || \
                                      (_event) == VMCI_EVENT_MEM_ACCESS_OFF)

#define VMCI_EVENT_VALID(_event) ((_event) < VMCI_EVENT_MAX &&          \
                                  !VMCI_EVENT_VALID_VMX(_event))

/* Reserved guest datagram resource ids. */
#define VMCI_EVENT_HANDLER 0

/*
 * VMCI coarse-grained privileges (per context or host
 * process/endpoint. An entity with the restricted flag is only
 * allowed to interact with the hypervisor and trusted entities.
 */
enum {
        VMCI_NO_PRIVILEGE_FLAGS = 0,
        VMCI_PRIVILEGE_FLAG_RESTRICTED = 1,
        VMCI_PRIVILEGE_FLAG_TRUSTED = 2,
        VMCI_PRIVILEGE_ALL_FLAGS = (VMCI_PRIVILEGE_FLAG_RESTRICTED |
                                    VMCI_PRIVILEGE_FLAG_TRUSTED),
        VMCI_DEFAULT_PROC_PRIVILEGE_FLAGS = VMCI_NO_PRIVILEGE_FLAGS,
        VMCI_LEAST_PRIVILEGE_FLAGS = VMCI_PRIVILEGE_FLAG_RESTRICTED,
        VMCI_MAX_PRIVILEGE_FLAGS = VMCI_PRIVILEGE_FLAG_TRUSTED,
};

/* 0 through VMCI_RESERVED_RESOURCE_ID_MAX are reserved. */
#define VMCI_RESERVED_RESOURCE_ID_MAX 1023

/*
 * Driver version.
 *
 * Increment major version when you make an incompatible change.
 * Compatibility goes both ways (old driver with new executable
 * as well as new driver with old executable).
 */

/* Never change VMCI_VERSION_SHIFT_WIDTH */
#define VMCI_VERSION_SHIFT_WIDTH 16
#define VMCI_MAKE_VERSION(_major, _minor)                       \
        ((_major) << VMCI_VERSION_SHIFT_WIDTH | (u16) (_minor))

#define VMCI_VERSION_MAJOR(v)  ((u32) (v) >> VMCI_VERSION_SHIFT_WIDTH)
#define VMCI_VERSION_MINOR(v)  ((u16) (v))

/*
 * VMCI_VERSION is always the current version.  Subsequently listed
 * versions are ways of detecting previous versions of the connecting
 * application (i.e., VMX).
 *
 * VMCI_VERSION_NOVMVM: This version removed support for VM to VM
 * communication.
 *
 * VMCI_VERSION_NOTIFY: This version introduced doorbell notification
 * support.
 *
 * VMCI_VERSION_HOSTQP: This version introduced host end point support
 * for hosted products.
 *
 * VMCI_VERSION_PREHOSTQP: This is the version prior to the adoption of
 * support for host end-points.
 *
 * VMCI_VERSION_PREVERS2: This fictional version number is intended to
 * represent the version of a VMX which doesn't call into the driver
 * with ioctl VERSION2 and thus doesn't establish its version with the
 * driver.
 */

#define VMCI_VERSION                VMCI_VERSION_NOVMVM
#define VMCI_VERSION_NOVMVM         VMCI_MAKE_VERSION(11, 0)
#define VMCI_VERSION_NOTIFY         VMCI_MAKE_VERSION(10, 0)
#define VMCI_VERSION_HOSTQP         VMCI_MAKE_VERSION(9, 0)
#define VMCI_VERSION_PREHOSTQP      VMCI_MAKE_VERSION(8, 0)
#define VMCI_VERSION_PREVERS2       VMCI_MAKE_VERSION(1, 0)

#define VMCI_SOCKETS_MAKE_VERSION(_p)                                   \
        ((((_p)[0] & 0xFF) << 24) | (((_p)[1] & 0xFF) << 16) | ((_p)[2]))

/*
 * The VMCI IOCTLs.  We use identity code 7, as noted in ioctl-number.h, and
 * we start at sequence 9f.  This gives us the same values that our shipping
 * products use, starting at 1951, provided we leave out the direction and
 * structure size.  Note that VMMon occupies the block following us, starting
 * at 2001.
 */
#define IOCTL_VMCI_VERSION                      _IO(7, 0x9f)    /* 1951 */
#define IOCTL_VMCI_INIT_CONTEXT                 _IO(7, 0xa0)
#define IOCTL_VMCI_QUEUEPAIR_SETVA              _IO(7, 0xa4)
#define IOCTL_VMCI_NOTIFY_RESOURCE              _IO(7, 0xa5)
#define IOCTL_VMCI_NOTIFICATIONS_RECEIVE        _IO(7, 0xa6)
#define IOCTL_VMCI_VERSION2                     _IO(7, 0xa7)
#define IOCTL_VMCI_QUEUEPAIR_ALLOC              _IO(7, 0xa8)
#define IOCTL_VMCI_QUEUEPAIR_SETPAGEFILE        _IO(7, 0xa9)
#define IOCTL_VMCI_QUEUEPAIR_DETACH             _IO(7, 0xaa)
#define IOCTL_VMCI_DATAGRAM_SEND                _IO(7, 0xab)
#define IOCTL_VMCI_DATAGRAM_RECEIVE             _IO(7, 0xac)
#define IOCTL_VMCI_CTX_ADD_NOTIFICATION         _IO(7, 0xaf)
#define IOCTL_VMCI_CTX_REMOVE_NOTIFICATION      _IO(7, 0xb0)
#define IOCTL_VMCI_CTX_GET_CPT_STATE            _IO(7, 0xb1)
#define IOCTL_VMCI_CTX_SET_CPT_STATE            _IO(7, 0xb2)
#define IOCTL_VMCI_GET_CONTEXT_ID               _IO(7, 0xb3)
#define IOCTL_VMCI_SOCKETS_VERSION              _IO(7, 0xb4)
#define IOCTL_VMCI_SOCKETS_GET_AF_VALUE         _IO(7, 0xb8)
#define IOCTL_VMCI_SOCKETS_GET_LOCAL_CID        _IO(7, 0xb9)
#define IOCTL_VMCI_SET_NOTIFY                   _IO(7, 0xcb)    /* 1995 */
/*IOCTL_VMMON_START                             _IO(7, 0xd1)*/  /* 2001 */

/*
 * struct vmci_queue_header - VMCI Queue Header information.
 *
 * A Queue cannot stand by itself as designed.  Each Queue's header
 * contains a pointer into itself (the producer_tail) and into its peer
 * (consumer_head).  The reason for the separation is one of
 * accessibility: Each end-point can modify two things: where the next
 * location to enqueue is within its produce_q (producer_tail); and
 * where the next dequeue location is in its consume_q (consumer_head).
 *
 * An end-point cannot modify the pointers of its peer (guest to
 * guest; NOTE that in the host both queue headers are mapped r/w).
 * But, each end-point needs read access to both Queue header
 * structures in order to determine how much space is used (or left)
 * in the Queue.  This is because for an end-point to know how full
 * its produce_q is, it needs to use the consumer_head that points into
 * the produce_q but -that- consumer_head is in the Queue header for
 * that end-points consume_q.
 *
 * Thoroughly confused?  Sorry.
 *
 * producer_tail: the point to enqueue new entrants.  When you approach
 * a line in a store, for example, you walk up to the tail.
 *
 * consumer_head: the point in the queue from which the next element is
 * dequeued.  In other words, who is next in line is he who is at the
 * head of the line.
 *
 * Also, producer_tail points to an empty byte in the Queue, whereas
 * consumer_head points to a valid byte of data (unless producer_tail ==
 * consumer_head in which case consumer_head does not point to a valid
 * byte of data).
 *
 * For a queue of buffer 'size' bytes, the tail and head pointers will be in
 * the range [0, size-1].
 *
 * If produce_q_header->producer_tail == consume_q_header->consumer_head
 * then the produce_q is empty.
 */
struct vmci_queue_header {
        /* All fields are 64bit and aligned. */
        struct vmci_handle handle;      /* Identifier. */
        atomic64_t producer_tail;       /* Offset in this queue. */
        atomic64_t consumer_head;       /* Offset in peer queue. */
};

/*
 * struct vmci_datagram - Base struct for vmci datagrams.
 * @dst:        A vmci_handle that tracks the destination of the datagram.
 * @src:        A vmci_handle that tracks the source of the datagram.
 * @payload_size:       The size of the payload.
 *
 * vmci_datagram structs are used when sending vmci datagrams.  They include
 * the necessary source and destination information to properly route
 * the information along with the size of the package.
 */
struct vmci_datagram {
        struct vmci_handle dst;
        struct vmci_handle src;
        u64 payload_size;
};

/*
 * Second flag is for creating a well-known handle instead of a per context
 * handle.  Next flag is for deferring datagram delivery, so that the
 * datagram callback is invoked in a delayed context (not interrupt context).
 */
#define VMCI_FLAG_DG_NONE          0
#define VMCI_FLAG_WELLKNOWN_DG_HND 0x1
#define VMCI_FLAG_ANYCID_DG_HND    0x2
#define VMCI_FLAG_DG_DELAYED_CB    0x4

/*
 * Maximum supported size of a VMCI datagram for routable datagrams.
 * Datagrams going to the hypervisor are allowed to be larger.
 */
#define VMCI_MAX_DG_SIZE (17 * 4096)
#define VMCI_MAX_DG_PAYLOAD_SIZE (VMCI_MAX_DG_SIZE - \
                                  sizeof(struct vmci_datagram))
#define VMCI_DG_PAYLOAD(_dg) (void *)((char *)(_dg) +                   \
                                      sizeof(struct vmci_datagram))
#define VMCI_DG_HEADERSIZE sizeof(struct vmci_datagram)
#define VMCI_DG_SIZE(_dg) (VMCI_DG_HEADERSIZE + (size_t)(_dg)->payload_size)
#define VMCI_DG_SIZE_ALIGNED(_dg) ((VMCI_DG_SIZE(_dg) + 7) & (~((size_t) 0x7)))
#define VMCI_MAX_DATAGRAM_QUEUE_SIZE (VMCI_MAX_DG_SIZE * 2)

struct vmci_event_payload_qp {
        struct vmci_handle handle;  /* queue_pair handle. */
        u32 peer_id;                /* Context id of attaching/detaching VM. */
        u32 _pad;
};

/* Flags for VMCI queue_pair API. */
enum {
        /* Fail alloc if QP not created by peer. */
        VMCI_QPFLAG_ATTACH_ONLY = 1 << 0,

        /* Only allow attaches from local context. */
        VMCI_QPFLAG_LOCAL = 1 << 1,

        /* Host won't block when guest is quiesced. */
        VMCI_QPFLAG_NONBLOCK = 1 << 2,

        /* Pin data pages in ESX.  Used with NONBLOCK */
        VMCI_QPFLAG_PINNED = 1 << 3,

        /* Update the following flag when adding new flags. */
        VMCI_QP_ALL_FLAGS = (VMCI_QPFLAG_ATTACH_ONLY | VMCI_QPFLAG_LOCAL |
                             VMCI_QPFLAG_NONBLOCK | VMCI_QPFLAG_PINNED),

        /* Convenience flags */
        VMCI_QP_ASYMM = (VMCI_QPFLAG_NONBLOCK | VMCI_QPFLAG_PINNED),
        VMCI_QP_ASYMM_PEER = (VMCI_QPFLAG_ATTACH_ONLY | VMCI_QP_ASYMM),
};

/*
 * We allow at least 1024 more event datagrams from the hypervisor past the
 * normally allowed datagrams pending for a given context.  We define this
 * limit on event datagrams from the hypervisor to guard against DoS attack
 * from a malicious VM which could repeatedly attach to and detach from a queue
 * pair, causing events to be queued at the destination VM.  However, the rate
 * at which such events can be generated is small since it requires a VM exit
 * and handling of queue pair attach/detach call at the hypervisor.  Event
 * datagrams may be queued up at the destination VM if it has interrupts
 * disabled or if it is not draining events for some other reason.  1024
 * datagrams is a grossly conservative estimate of the time for which
 * interrupts may be disabled in the destination VM, but at the same time does
 * not exacerbate the memory pressure problem on the host by much (size of each
 * event datagram is small).
 */
#define VMCI_MAX_DATAGRAM_AND_EVENT_QUEUE_SIZE                          \
        (VMCI_MAX_DATAGRAM_QUEUE_SIZE +                                 \
         1024 * (sizeof(struct vmci_datagram) +                         \
                 sizeof(struct vmci_event_data_max)))

/*
 * Struct used for querying, via VMCI_RESOURCES_QUERY, the availability of
 * hypervisor resources.  Struct size is 16 bytes. All fields in struct are
 * aligned to their natural alignment.
 */
struct vmci_resource_query_hdr {
        struct vmci_datagram hdr;
        u32 num_resources;
        u32 _padding;
};

/*
 * Convenience struct for negotiating vectors. Must match layout of
 * VMCIResourceQueryHdr minus the struct vmci_datagram header.
 */
struct vmci_resource_query_msg {
        u32 num_resources;
        u32 _padding;
        u32 resources[1];
};

/*
 * The maximum number of resources that can be queried using
 * VMCI_RESOURCE_QUERY is 31, as the result is encoded in the lower 31
 * bits of a positive return value. Negative values are reserved for
 * errors.
 */
#define VMCI_RESOURCE_QUERY_MAX_NUM 31

/* Maximum size for the VMCI_RESOURCE_QUERY request. */
#define VMCI_RESOURCE_QUERY_MAX_SIZE                            \
        (sizeof(struct vmci_resource_query_hdr) +               \
         sizeof(u32) * VMCI_RESOURCE_QUERY_MAX_NUM)

/*
 * Struct used for setting the notification bitmap.  All fields in
 * struct are aligned to their natural alignment.
 */
struct vmci_notify_bm_set_msg {
        struct vmci_datagram hdr;
        u32 bitmap_ppn;
        u32 _pad;
};

/*
 * Struct used for linking a doorbell handle with an index in the
 * notify bitmap. All fields in struct are aligned to their natural
 * alignment.
 */
struct vmci_doorbell_link_msg {
        struct vmci_datagram hdr;
        struct vmci_handle handle;
        u64 notify_idx;
};

/*
 * Struct used for unlinking a doorbell handle from an index in the
 * notify bitmap. All fields in struct are aligned to their natural
 * alignment.
 */
struct vmci_doorbell_unlink_msg {
        struct vmci_datagram hdr;
        struct vmci_handle handle;
};

/*
 * Struct used for generating a notification on a doorbell handle. All
 * fields in struct are aligned to their natural alignment.
 */
struct vmci_doorbell_notify_msg {
        struct vmci_datagram hdr;
        struct vmci_handle handle;
};

/*
 * This struct is used to contain data for events.  Size of this struct is a
 * multiple of 8 bytes, and all fields are aligned to their natural alignment.
 */
struct vmci_event_data {
        u32 event;              /* 4 bytes. */
        u32 _pad;
        /* Event payload is put here. */
};

/*
 * Define the different VMCI_EVENT payload data types here.  All structs must
 * be a multiple of 8 bytes, and fields must be aligned to their natural
 * alignment.
 */
struct vmci_event_payld_ctx {
        u32 context_id; /* 4 bytes. */
        u32 _pad;
};

struct vmci_event_payld_qp {
        struct vmci_handle handle;  /* queue_pair handle. */
        u32 peer_id;        /* Context id of attaching/detaching VM. */
        u32 _pad;
};

/*
 * We define the following struct to get the size of the maximum event
 * data the hypervisor may send to the guest.  If adding a new event
 * payload type above, add it to the following struct too (inside the
 * union).
 */
struct vmci_event_data_max {
        struct vmci_event_data event_data;
        union {
                struct vmci_event_payld_ctx context_payload;
                struct vmci_event_payld_qp qp_payload;
        } ev_data_payload;
};

/*
 * Struct used for VMCI_EVENT_SUBSCRIBE/UNSUBSCRIBE and
 * VMCI_EVENT_HANDLER messages.  Struct size is 32 bytes.  All fields
 * in struct are aligned to their natural alignment.
 */
struct vmci_event_msg {
        struct vmci_datagram hdr;

        /* Has event type and payload. */
        struct vmci_event_data event_data;

        /* Payload gets put here. */
};

/* Event with context payload. */
struct vmci_event_ctx {
        struct vmci_event_msg msg;
        struct vmci_event_payld_ctx payload;
};

/* Event with QP payload. */
struct vmci_event_qp {
        struct vmci_event_msg msg;
        struct vmci_event_payld_qp payload;
};

/*
 * Structs used for queue_pair alloc and detach messages.  We align fields of
 * these structs to 64bit boundaries.
 */
struct vmci_qp_alloc_msg {
        struct vmci_datagram hdr;
        struct vmci_handle handle;
        u32 peer;
        u32 flags;
        u64 produce_size;
        u64 consume_size;
        u64 num_ppns;

        /* List of PPNs placed here. */
};

struct vmci_qp_detach_msg {
        struct vmci_datagram hdr;
        struct vmci_handle handle;
};

/* VMCI Doorbell API. */
#define VMCI_FLAG_DELAYED_CB 0x01

typedef void (*vmci_callback) (void *client_data);

/*
 * struct vmci_qp - A vmw_vmci queue pair handle.
 *
 * This structure is used as a handle to a queue pair created by
 * VMCI.  It is intentionally left opaque to clients.
 */
struct vmci_qp;

/* Callback needed for correctly waiting on events. */
typedef int (*vmci_datagram_recv_cb) (void *client_data,
                                      struct vmci_datagram *msg);

/* VMCI Event API. */
typedef void (*vmci_event_cb) (u32 sub_id, const struct vmci_event_data *ed,
                               void *client_data);

/*
 * We use the following inline function to access the payload data
 * associated with an event data.
 */
static inline const void *
vmci_event_data_const_payload(const struct vmci_event_data *ev_data)
{
        return (const char *)ev_data + sizeof(*ev_data);
}

static inline void *vmci_event_data_payload(struct vmci_event_data *ev_data)
{
        return (void *)vmci_event_data_const_payload(ev_data);
}

/*
 * Helper to read a value from a head or tail pointer. For X86_32, the
 * pointer is treated as a 32bit value, since the pointer value
 * never exceeds a 32bit value in this case. Also, doing an
 * atomic64_read on X86_32 uniprocessor systems may be implemented
 * as a non locked cmpxchg8b, that may end up overwriting updates done
 * by the VMCI device to the memory location. On 32bit SMP, the lock
 * prefix will be used, so correctness isn't an issue, but using a
 * 64bit operation still adds unnecessary overhead.
 */
static inline u64 vmci_q_read_pointer(atomic64_t *var)
{
#if defined(CONFIG_X86_32)
        return atomic_read((atomic_t *)var);
#else
        return atomic64_read(var);
#endif
}

/*
 * Helper to set the value of a head or tail pointer. For X86_32, the
 * pointer is treated as a 32bit value, since the pointer value
 * never exceeds a 32bit value in this case. On 32bit SMP, using a
 * locked cmpxchg8b adds unnecessary overhead.
 */
static inline void vmci_q_set_pointer(atomic64_t *var,
                                      u64 new_val)
{
#if defined(CONFIG_X86_32)
        return atomic_set((atomic_t *)var, (u32)new_val);
#else
        return atomic64_set(var, new_val);
#endif
}

/*
 * Helper to add a given offset to a head or tail pointer. Wraps the
 * value of the pointer around the max size of the queue.
 */
static inline void vmci_qp_add_pointer(atomic64_t *var,
                                       size_t add,
                                       u64 size)
{
        u64 new_val = vmci_q_read_pointer(var);

        if (new_val >= size - add)
                new_val -= size;

        new_val += add;

        vmci_q_set_pointer(var, new_val);
}

/*
 * Helper routine to get the Producer Tail from the supplied queue.
 */
static inline u64
vmci_q_header_producer_tail(const struct vmci_queue_header *q_header)
{
        struct vmci_queue_header *qh = (struct vmci_queue_header *)q_header;
        return vmci_q_read_pointer(&qh->producer_tail);
}

/*
 * Helper routine to get the Consumer Head from the supplied queue.
 */
static inline u64
vmci_q_header_consumer_head(const struct vmci_queue_header *q_header)
{
        struct vmci_queue_header *qh = (struct vmci_queue_header *)q_header;
        return vmci_q_read_pointer(&qh->consumer_head);
}

/*
 * Helper routine to increment the Producer Tail.  Fundamentally,
 * vmci_qp_add_pointer() is used to manipulate the tail itself.
 */
static inline void
vmci_q_header_add_producer_tail(struct vmci_queue_header *q_header,
                                size_t add,
                                u64 queue_size)
{
        vmci_qp_add_pointer(&q_header->producer_tail, add, queue_size);
}

/*
 * Helper routine to increment the Consumer Head.  Fundamentally,
 * vmci_qp_add_pointer() is used to manipulate the head itself.
 */
static inline void
vmci_q_header_add_consumer_head(struct vmci_queue_header *q_header,
                                size_t add,
                                u64 queue_size)
{
        vmci_qp_add_pointer(&q_header->consumer_head, add, queue_size);
}

/*
 * Helper routine for getting the head and the tail pointer for a queue.
 * Both the VMCIQueues are needed to get both the pointers for one queue.
 */
static inline void
vmci_q_header_get_pointers(const struct vmci_queue_header *produce_q_header,
                           const struct vmci_queue_header *consume_q_header,
                           u64 *producer_tail,
                           u64 *consumer_head)
{
        if (producer_tail)
                *producer_tail = vmci_q_header_producer_tail(produce_q_header);

        if (consumer_head)
                *consumer_head = vmci_q_header_consumer_head(consume_q_header);
}

static inline void vmci_q_header_init(struct vmci_queue_header *q_header,
                                      const struct vmci_handle handle)
{
        q_header->handle = handle;
        atomic64_set(&q_header->producer_tail, 0);
        atomic64_set(&q_header->consumer_head, 0);
}

/*
 * Finds available free space in a produce queue to enqueue more
 * data or reports an error if queue pair corruption is detected.
 */
static s64
vmci_q_header_free_space(const struct vmci_queue_header *produce_q_header,
                         const struct vmci_queue_header *consume_q_header,
                         const u64 produce_q_size)
{
        u64 tail;
        u64 head;
        u64 free_space;

        tail = vmci_q_header_producer_tail(produce_q_header);
        head = vmci_q_header_consumer_head(consume_q_header);

        if (tail >= produce_q_size || head >= produce_q_size)
                return VMCI_ERROR_INVALID_SIZE;

        /*
         * Deduct 1 to avoid tail becoming equal to head which causes
         * ambiguity. If head and tail are equal it means that the
         * queue is empty.
         */
        if (tail >= head)
                free_space = produce_q_size - (tail - head) - 1;
        else
                free_space = head - tail - 1;

        return free_space;
}

/*
 * vmci_q_header_free_space() does all the heavy lifting of
 * determing the number of free bytes in a Queue.  This routine,
 * then subtracts that size from the full size of the Queue so
 * the caller knows how many bytes are ready to be dequeued.
 * Results:
 * On success, available data size in bytes (up to MAX_INT64).
 * On failure, appropriate error code.
 */
static inline s64
vmci_q_header_buf_ready(const struct vmci_queue_header *consume_q_header,
                        const struct vmci_queue_header *produce_q_header,
                        const u64 consume_q_size)
{
        s64 free_space;

        free_space = vmci_q_header_free_space(consume_q_header,
                                              produce_q_header, consume_q_size);
        if (free_space < VMCI_SUCCESS)
                return free_space;

        return consume_q_size - free_space - 1;
}


#endif /* _VMW_VMCI_DEF_H_ */