/*
 *
 * Copyright (c) 2011, Microsoft Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 * Authors:
 *   Haiyang Zhang <haiyangz@microsoft.com>
 *   Hank Janssen  <hjanssen@microsoft.com>
 *   K. Y. Srinivasan <kys@microsoft.com>
 *
 */

#ifndef _HYPERV_H
#define _HYPERV_H

#include <linux/types.h>

/*
 * An implementation of HyperV key value pair (KVP) functionality for Linux.
 *
 *
 * Copyright (C) 2010, Novell, Inc.
 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
 *
 */

/*
 * Maximum value size - used for both key names and value data, and includes
 * any applicable NULL terminators.
 *
 * Note:  This limit is somewhat arbitrary, but falls easily within what is
 * supported for all native guests (back to Win 2000) and what is reasonable
 * for the IC KVP exchange functionality.  Note that Windows Me/98/95 are
 * limited to 255 character key names.
 *
 * MSDN recommends not storing data values larger than 2048 bytes in the
 * registry.
 *
 * Note:  This value is used in defining the KVP exchange message - this value
 * cannot be modified without affecting the message size and compatibility.
 */

/*
 * bytes, including any null terminators
 */
#define HV_KVP_EXCHANGE_MAX_VALUE_SIZE          (2048)


/*
 * Maximum key size - the registry limit for the length of an entry name
 * is 256 characters, including the null terminator
 */

#define HV_KVP_EXCHANGE_MAX_KEY_SIZE            (512)

/*
 * In Linux, we implement the KVP functionality in two components:
 * 1) The kernel component which is packaged as part of the hv_utils driver
 * is responsible for communicating with the host and responsible for
 * implementing the host/guest protocol. 2) A user level daemon that is
 * responsible for data gathering.
 *
 * Host/Guest Protocol: The host iterates over an index and expects the guest
 * to assign a key name to the index and also return the value corresponding to
 * the key. The host will have atmost one KVP transaction outstanding at any
 * given point in time. The host side iteration stops when the guest returns
 * an error. Microsoft has specified the following mapping of key names to
 * host specified index:
 *
 *      Index           Key Name
 *      0               FullyQualifiedDomainName
 *      1               IntegrationServicesVersion
 *      2               NetworkAddressIPv4
 *      3               NetworkAddressIPv6
 *      4               OSBuildNumber
 *      5               OSName
 *      6               OSMajorVersion
 *      7               OSMinorVersion
 *      8               OSVersion
 *      9               ProcessorArchitecture
 *
 * The Windows host expects the Key Name and Key Value to be encoded in utf16.
 *
 * Guest Kernel/KVP Daemon Protocol: As noted earlier, we implement all of the
 * data gathering functionality in a user mode daemon. The user level daemon
 * is also responsible for binding the key name to the index as well. The
 * kernel and user-level daemon communicate using a connector channel.
 *
 * The user mode component first registers with the
 * the kernel component. Subsequently, the kernel component requests, data
 * for the specified keys. In response to this message the user mode component
 * fills in the value corresponding to the specified key. We overload the
 * sequence field in the cn_msg header to define our KVP message types.
 *
 *
 * The kernel component simply acts as a conduit for communication between the
 * Windows host and the user-level daemon. The kernel component passes up the
 * index received from the Host to the user-level daemon. If the index is
 * valid (supported), the corresponding key as well as its
 * value (both are strings) is returned. If the index is invalid
 * (not supported), a NULL key string is returned.
 */


/*
 * Registry value types.
 */

#define REG_SZ 1
#define REG_U32 4
#define REG_U64 8

enum hv_kvp_exchg_op {
        KVP_OP_GET = 0,
        KVP_OP_SET,
        KVP_OP_DELETE,
        KVP_OP_ENUMERATE,
        KVP_OP_REGISTER,
        KVP_OP_COUNT /* Number of operations, must be last. */
};

enum hv_kvp_exchg_pool {
        KVP_POOL_EXTERNAL = 0,
        KVP_POOL_GUEST,
        KVP_POOL_AUTO,
        KVP_POOL_AUTO_EXTERNAL,
        KVP_POOL_AUTO_INTERNAL,
        KVP_POOL_COUNT /* Number of pools, must be last. */
};

struct hv_kvp_hdr {
        __u8 operation;
        __u8 pool;
        __u16 pad;
} __attribute__((packed));

struct hv_kvp_exchg_msg_value {
        __u32 value_type;
        __u32 key_size;
        __u32 value_size;
        __u8 key[HV_KVP_EXCHANGE_MAX_KEY_SIZE];
        union {
                __u8 value[HV_KVP_EXCHANGE_MAX_VALUE_SIZE];
                __u32 value_u32;
                __u64 value_u64;
        };
} __attribute__((packed));

struct hv_kvp_msg_enumerate {
        __u32 index;
        struct hv_kvp_exchg_msg_value data;
} __attribute__((packed));

struct hv_kvp_msg_get {
        struct hv_kvp_exchg_msg_value data;
};

struct hv_kvp_msg_set {
        struct hv_kvp_exchg_msg_value data;
};

struct hv_kvp_msg_delete {
        __u32 key_size;
        __u8 key[HV_KVP_EXCHANGE_MAX_KEY_SIZE];
};

struct hv_kvp_register {
        __u8 version[HV_KVP_EXCHANGE_MAX_KEY_SIZE];
};

struct hv_kvp_msg {
        struct hv_kvp_hdr       kvp_hdr;
        union {
                struct hv_kvp_msg_get           kvp_get;
                struct hv_kvp_msg_set           kvp_set;
                struct hv_kvp_msg_delete        kvp_delete;
                struct hv_kvp_msg_enumerate     kvp_enum_data;
                struct hv_kvp_register          kvp_register;
        } body;
} __attribute__((packed));

#ifdef __KERNEL__
#include <linux/scatterlist.h>
#include <linux/list.h>
#include <linux/uuid.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/mod_devicetable.h>


#define MAX_PAGE_BUFFER_COUNT                           19
#define MAX_MULTIPAGE_BUFFER_COUNT                      32 /* 128K */

#pragma pack(push, 1)

/* Single-page buffer */
struct hv_page_buffer {
        u32 len;
        u32 offset;
        u64 pfn;
};

/* Multiple-page buffer */
struct hv_multipage_buffer {
        /* Length and Offset determines the # of pfns in the array */
        u32 len;
        u32 offset;
        u64 pfn_array[MAX_MULTIPAGE_BUFFER_COUNT];
};

/* 0x18 includes the proprietary packet header */
#define MAX_PAGE_BUFFER_PACKET          (0x18 +                 \
                                        (sizeof(struct hv_page_buffer) * \
                                         MAX_PAGE_BUFFER_COUNT))
#define MAX_MULTIPAGE_BUFFER_PACKET     (0x18 +                 \
                                         sizeof(struct hv_multipage_buffer))


#pragma pack(pop)

struct hv_ring_buffer {
        /* Offset in bytes from the start of ring data below */
        u32 write_index;

        /* Offset in bytes from the start of ring data below */
        u32 read_index;

        u32 interrupt_mask;

        /* Pad it to PAGE_SIZE so that data starts on page boundary */
        u8      reserved[4084];

        /* NOTE:
         * The interrupt_mask field is used only for channels but since our
         * vmbus connection also uses this data structure and its data starts
         * here, we commented out this field.
         */

        /*
         * Ring data starts here + RingDataStartOffset
         * !!! DO NOT place any fields below this !!!
         */
        u8 buffer[0];
} __packed;

struct hv_ring_buffer_info {
        struct hv_ring_buffer *ring_buffer;
        u32 ring_size;                  /* Include the shared header */
        spinlock_t ring_lock;

        u32 ring_datasize;              /* < ring_size */
        u32 ring_data_startoffset;
};

struct hv_ring_buffer_debug_info {
        u32 current_interrupt_mask;
        u32 current_read_index;
        u32 current_write_index;
        u32 bytes_avail_toread;
        u32 bytes_avail_towrite;
};


/*
 *
 * hv_get_ringbuffer_availbytes()
 *
 * Get number of bytes available to read and to write to
 * for the specified ring buffer
 */
static inline void
hv_get_ringbuffer_availbytes(struct hv_ring_buffer_info *rbi,
                          u32 *read, u32 *write)
{
        u32 read_loc, write_loc, dsize;

        smp_read_barrier_depends();

        /* Capture the read/write indices before they changed */
        read_loc = rbi->ring_buffer->read_index;
        write_loc = rbi->ring_buffer->write_index;
        dsize = rbi->ring_datasize;

        *write = write_loc >= read_loc ? dsize - (write_loc - read_loc) :
                read_loc - write_loc;
        *read = dsize - *write;
}


/*
 * We use the same version numbering for all Hyper-V modules.
 *
 * Definition of versioning is as follows;
 *
 *      Major Number    Changes for these scenarios;
 *                      1.      When a new version of Windows Hyper-V
 *                              is released.
 *                      2.      A Major change has occurred in the
 *                              Linux IC's.
 *                      (For example the merge for the first time
 *                      into the kernel) Every time the Major Number
 *                      changes, the Revision number is reset to 0.
 *      Minor Number    Changes when new functionality is added
 *                      to the Linux IC's that is not a bug fix.
 *
 * 3.1 - Added completed hv_utils driver. Shutdown/Heartbeat/Timesync
 */
#define HV_DRV_VERSION           "3.1"


/*
 * A revision number of vmbus that is used for ensuring both ends on a
 * partition are using compatible versions.
 */
#define VMBUS_REVISION_NUMBER           13

/* Make maximum size of pipe payload of 16K */
#define MAX_PIPE_DATA_PAYLOAD           (sizeof(u8) * 16384)

/* Define PipeMode values. */
#define VMBUS_PIPE_TYPE_BYTE            0x00000000
#define VMBUS_PIPE_TYPE_MESSAGE         0x00000004

/* The size of the user defined data buffer for non-pipe offers. */
#define MAX_USER_DEFINED_BYTES          120

/* The size of the user defined data buffer for pipe offers. */
#define MAX_PIPE_USER_DEFINED_BYTES     116

/*
 * At the center of the Channel Management library is the Channel Offer. This
 * struct contains the fundamental information about an offer.
 */
struct vmbus_channel_offer {
        uuid_le if_type;
        uuid_le if_instance;
        u64 int_latency; /* in 100ns units */
        u32 if_revision;
        u32 server_ctx_size;    /* in bytes */
        u16 chn_flags;
        u16 mmio_megabytes;             /* in bytes * 1024 * 1024 */

        union {
                /* Non-pipes: The user has MAX_USER_DEFINED_BYTES bytes. */
                struct {
                        unsigned char user_def[MAX_USER_DEFINED_BYTES];
                } std;

                /*
                 * Pipes:
                 * The following sructure is an integrated pipe protocol, which
                 * is implemented on top of standard user-defined data. Pipe
                 * clients have MAX_PIPE_USER_DEFINED_BYTES left for their own
                 * use.
                 */
                struct {
                        u32  pipe_mode;
                        unsigned char user_def[MAX_PIPE_USER_DEFINED_BYTES];
                } pipe;
        } u;
        u32 padding;
} __packed;

/* Server Flags */
#define VMBUS_CHANNEL_ENUMERATE_DEVICE_INTERFACE        1
#define VMBUS_CHANNEL_SERVER_SUPPORTS_TRANSFER_PAGES    2
#define VMBUS_CHANNEL_SERVER_SUPPORTS_GPADLS            4
#define VMBUS_CHANNEL_NAMED_PIPE_MODE                   0x10
#define VMBUS_CHANNEL_LOOPBACK_OFFER                    0x100
#define VMBUS_CHANNEL_PARENT_OFFER                      0x200
#define VMBUS_CHANNEL_REQUEST_MONITORED_NOTIFICATION    0x400

struct vmpacket_descriptor {
        u16 type;
        u16 offset8;
        u16 len8;
        u16 flags;
        u64 trans_id;
} __packed;

struct vmpacket_header {
        u32 prev_pkt_start_offset;
        struct vmpacket_descriptor descriptor;
} __packed;

struct vmtransfer_page_range {
        u32 byte_count;
        u32 byte_offset;
} __packed;

struct vmtransfer_page_packet_header {
        struct vmpacket_descriptor d;
        u16 xfer_pageset_id;
        bool sender_owns_set;
        u8 reserved;
        u32 range_cnt;
        struct vmtransfer_page_range ranges[1];
} __packed;

struct vmgpadl_packet_header {
        struct vmpacket_descriptor d;
        u32 gpadl;
        u32 reserved;
} __packed;

struct vmadd_remove_transfer_page_set {
        struct vmpacket_descriptor d;
        u32 gpadl;
        u16 xfer_pageset_id;
        u16 reserved;
} __packed;

/*
 * This structure defines a range in guest physical space that can be made to
 * look virtually contiguous.
 */
struct gpa_range {
        u32 byte_count;
        u32 byte_offset;
        u64 pfn_array[0];
};

/*
 * This is the format for an Establish Gpadl packet, which contains a handle by
 * which this GPADL will be known and a set of GPA ranges associated with it.
 * This can be converted to a MDL by the guest OS.  If there are multiple GPA
 * ranges, then the resulting MDL will be "chained," representing multiple VA
 * ranges.
 */
struct vmestablish_gpadl {
        struct vmpacket_descriptor d;
        u32 gpadl;
        u32 range_cnt;
        struct gpa_range range[1];
} __packed;

/*
 * This is the format for a Teardown Gpadl packet, which indicates that the
 * GPADL handle in the Establish Gpadl packet will never be referenced again.
 */
struct vmteardown_gpadl {
        struct vmpacket_descriptor d;
        u32 gpadl;
        u32 reserved;   /* for alignment to a 8-byte boundary */
} __packed;

/*
 * This is the format for a GPA-Direct packet, which contains a set of GPA
 * ranges, in addition to commands and/or data.
 */
struct vmdata_gpa_direct {
        struct vmpacket_descriptor d;
        u32 reserved;
        u32 range_cnt;
        struct gpa_range range[1];
} __packed;

/* This is the format for a Additional Data Packet. */
struct vmadditional_data {
        struct vmpacket_descriptor d;
        u64 total_bytes;
        u32 offset;
        u32 byte_cnt;
        unsigned char data[1];
} __packed;

union vmpacket_largest_possible_header {
        struct vmpacket_descriptor simple_hdr;
        struct vmtransfer_page_packet_header xfer_page_hdr;
        struct vmgpadl_packet_header gpadl_hdr;
        struct vmadd_remove_transfer_page_set add_rm_xfer_page_hdr;
        struct vmestablish_gpadl establish_gpadl_hdr;
        struct vmteardown_gpadl teardown_gpadl_hdr;
        struct vmdata_gpa_direct data_gpa_direct_hdr;
};

#define VMPACKET_DATA_START_ADDRESS(__packet)   \
        (void *)(((unsigned char *)__packet) +  \
         ((struct vmpacket_descriptor)__packet)->offset8 * 8)

#define VMPACKET_DATA_LENGTH(__packet)          \
        ((((struct vmpacket_descriptor)__packet)->len8 -        \
          ((struct vmpacket_descriptor)__packet)->offset8) * 8)

#define VMPACKET_TRANSFER_MODE(__packet)        \
        (((struct IMPACT)__packet)->type)

enum vmbus_packet_type {
        VM_PKT_INVALID                          = 0x0,
        VM_PKT_SYNCH                            = 0x1,
        VM_PKT_ADD_XFER_PAGESET                 = 0x2,
        VM_PKT_RM_XFER_PAGESET                  = 0x3,
        VM_PKT_ESTABLISH_GPADL                  = 0x4,
        VM_PKT_TEARDOWN_GPADL                   = 0x5,
        VM_PKT_DATA_INBAND                      = 0x6,
        VM_PKT_DATA_USING_XFER_PAGES            = 0x7,
        VM_PKT_DATA_USING_GPADL                 = 0x8,
        VM_PKT_DATA_USING_GPA_DIRECT            = 0x9,
        VM_PKT_CANCEL_REQUEST                   = 0xa,
        VM_PKT_COMP                             = 0xb,
        VM_PKT_DATA_USING_ADDITIONAL_PKT        = 0xc,
        VM_PKT_ADDITIONAL_DATA                  = 0xd
};

#define VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED     1


/* Version 1 messages */
enum vmbus_channel_message_type {
        CHANNELMSG_INVALID                      =  0,
        CHANNELMSG_OFFERCHANNEL         =  1,
        CHANNELMSG_RESCIND_CHANNELOFFER =  2,
        CHANNELMSG_REQUESTOFFERS                =  3,
        CHANNELMSG_ALLOFFERS_DELIVERED  =  4,
        CHANNELMSG_OPENCHANNEL          =  5,
        CHANNELMSG_OPENCHANNEL_RESULT           =  6,
        CHANNELMSG_CLOSECHANNEL         =  7,
        CHANNELMSG_GPADL_HEADER         =  8,
        CHANNELMSG_GPADL_BODY                   =  9,
        CHANNELMSG_GPADL_CREATED                = 10,
        CHANNELMSG_GPADL_TEARDOWN               = 11,
        CHANNELMSG_GPADL_TORNDOWN               = 12,
        CHANNELMSG_RELID_RELEASED               = 13,
        CHANNELMSG_INITIATE_CONTACT             = 14,
        CHANNELMSG_VERSION_RESPONSE             = 15,
        CHANNELMSG_UNLOAD                       = 16,
#ifdef VMBUS_FEATURE_PARENT_OR_PEER_MEMORY_MAPPED_INTO_A_CHILD
        CHANNELMSG_VIEWRANGE_ADD                = 17,
        CHANNELMSG_VIEWRANGE_REMOVE             = 18,
#endif
        CHANNELMSG_COUNT
};

struct vmbus_channel_message_header {
        enum vmbus_channel_message_type msgtype;
        u32 padding;
} __packed;

/* Query VMBus Version parameters */
struct vmbus_channel_query_vmbus_version {
        struct vmbus_channel_message_header header;
        u32 version;
} __packed;

/* VMBus Version Supported parameters */
struct vmbus_channel_version_supported {
        struct vmbus_channel_message_header header;
        bool version_supported;
} __packed;

/* Offer Channel parameters */
struct vmbus_channel_offer_channel {
        struct vmbus_channel_message_header header;
        struct vmbus_channel_offer offer;
        u32 child_relid;
        u8 monitorid;
        bool monitor_allocated;
} __packed;

/* Rescind Offer parameters */
struct vmbus_channel_rescind_offer {
        struct vmbus_channel_message_header header;
        u32 child_relid;
} __packed;

/*
 * Request Offer -- no parameters, SynIC message contains the partition ID
 * Set Snoop -- no parameters, SynIC message contains the partition ID
 * Clear Snoop -- no parameters, SynIC message contains the partition ID
 * All Offers Delivered -- no parameters, SynIC message contains the partition
 *                         ID
 * Flush Client -- no parameters, SynIC message contains the partition ID
 */

/* Open Channel parameters */
struct vmbus_channel_open_channel {
        struct vmbus_channel_message_header header;

        /* Identifies the specific VMBus channel that is being opened. */
        u32 child_relid;

        /* ID making a particular open request at a channel offer unique. */
        u32 openid;

        /* GPADL for the channel's ring buffer. */
        u32 ringbuffer_gpadlhandle;

        /* GPADL for the channel's server context save area. */
        u32 server_contextarea_gpadlhandle;

        /*
        * The upstream ring buffer begins at offset zero in the memory
        * described by RingBufferGpadlHandle. The downstream ring buffer
        * follows it at this offset (in pages).
        */
        u32 downstream_ringbuffer_pageoffset;

        /* User-specific data to be passed along to the server endpoint. */
        unsigned char userdata[MAX_USER_DEFINED_BYTES];
} __packed;

/* Open Channel Result parameters */
struct vmbus_channel_open_result {
        struct vmbus_channel_message_header header;
        u32 child_relid;
        u32 openid;
        u32 status;
} __packed;

/* Close channel parameters; */
struct vmbus_channel_close_channel {
        struct vmbus_channel_message_header header;
        u32 child_relid;
} __packed;

/* Channel Message GPADL */
#define GPADL_TYPE_RING_BUFFER          1
#define GPADL_TYPE_SERVER_SAVE_AREA     2
#define GPADL_TYPE_TRANSACTION          8

/*
 * The number of PFNs in a GPADL message is defined by the number of
 * pages that would be spanned by ByteCount and ByteOffset.  If the
 * implied number of PFNs won't fit in this packet, there will be a
 * follow-up packet that contains more.
 */
struct vmbus_channel_gpadl_header {
        struct vmbus_channel_message_header header;
        u32 child_relid;
        u32 gpadl;
        u16 range_buflen;
        u16 rangecount;
        struct gpa_range range[0];
} __packed;

/* This is the followup packet that contains more PFNs. */
struct vmbus_channel_gpadl_body {
        struct vmbus_channel_message_header header;
        u32 msgnumber;
        u32 gpadl;
        u64 pfn[0];
} __packed;

struct vmbus_channel_gpadl_created {
        struct vmbus_channel_message_header header;
        u32 child_relid;
        u32 gpadl;
        u32 creation_status;
} __packed;

struct vmbus_channel_gpadl_teardown {
        struct vmbus_channel_message_header header;
        u32 child_relid;
        u32 gpadl;
} __packed;

struct vmbus_channel_gpadl_torndown {
        struct vmbus_channel_message_header header;
        u32 gpadl;
} __packed;

#ifdef VMBUS_FEATURE_PARENT_OR_PEER_MEMORY_MAPPED_INTO_A_CHILD
struct vmbus_channel_view_range_add {
        struct vmbus_channel_message_header header;
        PHYSICAL_ADDRESS viewrange_base;
        u64 viewrange_length;
        u32 child_relid;
} __packed;

struct vmbus_channel_view_range_remove {
        struct vmbus_channel_message_header header;
        PHYSICAL_ADDRESS viewrange_base;
        u32 child_relid;
} __packed;
#endif

struct vmbus_channel_relid_released {
        struct vmbus_channel_message_header header;
        u32 child_relid;
} __packed;

struct vmbus_channel_initiate_contact {
        struct vmbus_channel_message_header header;
        u32 vmbus_version_requested;
        u32 padding2;
        u64 interrupt_page;
        u64 monitor_page1;
        u64 monitor_page2;
} __packed;

struct vmbus_channel_version_response {
        struct vmbus_channel_message_header header;
        bool version_supported;
} __packed;

enum vmbus_channel_state {
        CHANNEL_OFFER_STATE,
        CHANNEL_OPENING_STATE,
        CHANNEL_OPEN_STATE,
};

struct vmbus_channel_debug_info {
        u32 relid;
        enum vmbus_channel_state state;
        uuid_le interfacetype;
        uuid_le interface_instance;
        u32 monitorid;
        u32 servermonitor_pending;
        u32 servermonitor_latency;
        u32 servermonitor_connectionid;
        u32 clientmonitor_pending;
        u32 clientmonitor_latency;
        u32 clientmonitor_connectionid;

        struct hv_ring_buffer_debug_info inbound;
        struct hv_ring_buffer_debug_info outbound;
};

/*
 * Represents each channel msg on the vmbus connection This is a
 * variable-size data structure depending on the msg type itself
 */
struct vmbus_channel_msginfo {
        /* Bookkeeping stuff */
        struct list_head msglistentry;

        /* So far, this is only used to handle gpadl body message */
        struct list_head submsglist;

        /* Synchronize the request/response if needed */
        struct completion  waitevent;
        union {
                struct vmbus_channel_version_supported version_supported;
                struct vmbus_channel_open_result open_result;
                struct vmbus_channel_gpadl_torndown gpadl_torndown;
                struct vmbus_channel_gpadl_created gpadl_created;
                struct vmbus_channel_version_response version_response;
        } response;

        u32 msgsize;
        /*
         * The channel message that goes out on the "wire".
         * It will contain at minimum the VMBUS_CHANNEL_MESSAGE_HEADER header
         */
        unsigned char msg[0];
};

struct vmbus_close_msg {
        struct vmbus_channel_msginfo info;
        struct vmbus_channel_close_channel msg;
};

struct vmbus_channel {
        struct list_head listentry;

        struct hv_device *device_obj;

        struct work_struct work;

        enum vmbus_channel_state state;

        struct vmbus_channel_offer_channel offermsg;
        /*
         * These are based on the OfferMsg.MonitorId.
         * Save it here for easy access.
         */
        u8 monitor_grp;
        u8 monitor_bit;

        u32 ringbuffer_gpadlhandle;

        /* Allocated memory for ring buffer */
        void *ringbuffer_pages;
        u32 ringbuffer_pagecount;
        struct hv_ring_buffer_info outbound;    /* send to parent */
        struct hv_ring_buffer_info inbound;     /* receive from parent */
        spinlock_t inbound_lock;
        struct workqueue_struct *controlwq;

        struct vmbus_close_msg close_msg;

        /* Channel callback are invoked in this workqueue context */
        /* HANDLE dataWorkQueue; */

        void (*onchannel_callback)(void *context);
        void *channel_callback_context;
};

void vmbus_onmessage(void *context);

int vmbus_request_offers(void);

/* The format must be the same as struct vmdata_gpa_direct */
struct vmbus_channel_packet_page_buffer {
        u16 type;
        u16 dataoffset8;
        u16 length8;
        u16 flags;
        u64 transactionid;
        u32 reserved;
        u32 rangecount;
        struct hv_page_buffer range[MAX_PAGE_BUFFER_COUNT];
} __packed;

/* The format must be the same as struct vmdata_gpa_direct */
struct vmbus_channel_packet_multipage_buffer {
        u16 type;
        u16 dataoffset8;
        u16 length8;
        u16 flags;
        u64 transactionid;
        u32 reserved;
        u32 rangecount;         /* Always 1 in this case */
        struct hv_multipage_buffer range;
} __packed;


extern int vmbus_open(struct vmbus_channel *channel,
                            u32 send_ringbuffersize,
                            u32 recv_ringbuffersize,
                            void *userdata,
                            u32 userdatalen,
                            void(*onchannel_callback)(void *context),
                            void *context);

extern void vmbus_close(struct vmbus_channel *channel);

extern int vmbus_sendpacket(struct vmbus_channel *channel,
                                  const void *buffer,
                                  u32 bufferLen,
                                  u64 requestid,
                                  enum vmbus_packet_type type,
                                  u32 flags);

extern int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
                                            struct hv_page_buffer pagebuffers[],
                                            u32 pagecount,
                                            void *buffer,
                                            u32 bufferlen,
                                            u64 requestid);

extern int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
                                        struct hv_multipage_buffer *mpb,
                                        void *buffer,
                                        u32 bufferlen,
                                        u64 requestid);

extern int vmbus_establish_gpadl(struct vmbus_channel *channel,
                                      void *kbuffer,
                                      u32 size,
                                      u32 *gpadl_handle);

extern int vmbus_teardown_gpadl(struct vmbus_channel *channel,
                                     u32 gpadl_handle);

extern int vmbus_recvpacket(struct vmbus_channel *channel,
                                  void *buffer,
                                  u32 bufferlen,
                                  u32 *buffer_actual_len,
                                  u64 *requestid);

extern int vmbus_recvpacket_raw(struct vmbus_channel *channel,
                                     void *buffer,
                                     u32 bufferlen,
                                     u32 *buffer_actual_len,
                                     u64 *requestid);


extern void vmbus_get_debug_info(struct vmbus_channel *channel,
                                     struct vmbus_channel_debug_info *debug);

extern void vmbus_ontimer(unsigned long data);

struct hv_dev_port_info {
        u32 int_mask;
        u32 read_idx;
        u32 write_idx;
        u32 bytes_avail_toread;
        u32 bytes_avail_towrite;
};

/* Base driver object */
struct hv_driver {
        const char *name;

        /* the device type supported by this driver */
        uuid_le dev_type;
        const struct hv_vmbus_device_id *id_table;

        struct device_driver driver;

        int (*probe)(struct hv_device *, const struct hv_vmbus_device_id *);
        int (*remove)(struct hv_device *);
        void (*shutdown)(struct hv_device *);

};

/* Base device object */
struct hv_device {
        /* the device type id of this device */
        uuid_le dev_type;

        /* the device instance id of this device */
        uuid_le dev_instance;

        struct device device;

        struct vmbus_channel *channel;
};


static inline struct hv_device *device_to_hv_device(struct device *d)
{
        return container_of(d, struct hv_device, device);
}

static inline struct hv_driver *drv_to_hv_drv(struct device_driver *d)
{
        return container_of(d, struct hv_driver, driver);
}

static inline void hv_set_drvdata(struct hv_device *dev, void *data)
{
        dev_set_drvdata(&dev->device, data);
}

static inline void *hv_get_drvdata(struct hv_device *dev)
{
        return dev_get_drvdata(&dev->device);
}

/* Vmbus interface */
#define vmbus_driver_register(driver)   \
        __vmbus_driver_register(driver, THIS_MODULE, KBUILD_MODNAME)
int __must_check __vmbus_driver_register(struct hv_driver *hv_driver,
                                         struct module *owner,
                                         const char *mod_name);
void vmbus_driver_unregister(struct hv_driver *hv_driver);

/**
 * VMBUS_DEVICE - macro used to describe a specific hyperv vmbus device
 *
 * This macro is used to create a struct hv_vmbus_device_id that matches a
 * specific device.
 */
#define VMBUS_DEVICE(g0, g1, g2, g3, g4, g5, g6, g7,    \
                     g8, g9, ga, gb, gc, gd, ge, gf)    \
        .guid = { g0, g1, g2, g3, g4, g5, g6, g7,       \
                  g8, g9, ga, gb, gc, gd, ge, gf },

/*
 * Common header for Hyper-V ICs
 */

#define ICMSGTYPE_NEGOTIATE             0
#define ICMSGTYPE_HEARTBEAT             1
#define ICMSGTYPE_KVPEXCHANGE           2
#define ICMSGTYPE_SHUTDOWN              3
#define ICMSGTYPE_TIMESYNC              4
#define ICMSGTYPE_VSS                   5

#define ICMSGHDRFLAG_TRANSACTION        1
#define ICMSGHDRFLAG_REQUEST            2
#define ICMSGHDRFLAG_RESPONSE           4

#define HV_S_OK                         0x00000000
#define HV_E_FAIL                       0x80004005
#define HV_S_CONT                       0x80070103
#define HV_ERROR_NOT_SUPPORTED          0x80070032
#define HV_ERROR_MACHINE_LOCKED         0x800704F7

/*
 * While we want to handle util services as regular devices,
 * there is only one instance of each of these services; so
 * we statically allocate the service specific state.
 */

struct hv_util_service {
        u8 *recv_buffer;
        void (*util_cb)(void *);
        int (*util_init)(struct hv_util_service *);
        void (*util_deinit)(void);
};

struct vmbuspipe_hdr {
        u32 flags;

        u32 msgsize;
} __packed;

struct ic_version {
        u16 major;
        u16 minor;
} __packed;

struct icmsg_hdr {
        struct ic_version icverframe;
        u16 icmsgtype;
        struct ic_version icvermsg;
        u16 icmsgsize;
        u32 status;
        u8 ictransaction_id;
        u8 icflags;
        u8 reserved[2];
} __packed;

struct icmsg_negotiate {
        u16 icframe_vercnt;
        u16 icmsg_vercnt;
        u32 reserved;
        struct ic_version icversion_data[1]; /* any size array */
} __packed;

struct shutdown_msg_data {
        u32 reason_code;
        u32 timeout_seconds;
        u32 flags;
        u8  display_message[2048];
} __packed;

struct heartbeat_msg_data {
        u64 seq_num;
        u32 reserved[8];
} __packed;

/* Time Sync IC defs */
#define ICTIMESYNCFLAG_PROBE    0
#define ICTIMESYNCFLAG_SYNC     1
#define ICTIMESYNCFLAG_SAMPLE   2

#ifdef __x86_64__
#define WLTIMEDELTA     116444736000000000L     /* in 100ns unit */
#else
#define WLTIMEDELTA     116444736000000000LL
#endif

struct ictimesync_data {
        u64 parenttime;
        u64 childtime;
        u64 roundtriptime;
        u8 flags;
} __packed;

struct hyperv_service_callback {
        u8 msg_type;
        char *log_msg;
        uuid_le data;
        struct vmbus_channel *channel;
        void (*callback) (void *context);
};

#define MAX_SRV_VER     0x7ffffff
extern void vmbus_prep_negotiate_resp(struct icmsg_hdr *,
                                        struct icmsg_negotiate *, u8 *, int,
                                        int);

int hv_kvp_init(struct hv_util_service *);
void hv_kvp_deinit(void);
void hv_kvp_onchannelcallback(void *);

#endif /* __KERNEL__ */
#endif /* _HYPERV_H */