/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2016 Flavius Anton
 * Copyright (c) 2016 Mihai Tiganus
 * Copyright (c) 2016-2019 Mihai Carabas
 * Copyright (c) 2017-2019 Darius Mihai
 * Copyright (c) 2017-2019 Elena Mihailescu
 * Copyright (c) 2018-2019 Sergiu Weisz
 * All rights reserved.
 * The bhyve-snapshot feature was developed under sponsorships
 * from Matthew Grooms.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _VMM_SNAPSHOT_
#define _VMM_SNAPSHOT_

#include <sys/errno.h>
#include <sys/types.h>
#ifndef _KERNEL
#include <stdbool.h>
#endif

enum snapshot_req {
        STRUCT_VIOAPIC = 1,
        STRUCT_VM,
        STRUCT_VLAPIC,
        VM_MEM,
        STRUCT_VHPET,
        STRUCT_VMCX,
        STRUCT_VATPIC,
        STRUCT_VATPIT,
        STRUCT_VPMTMR,
        STRUCT_VRTC,
};

struct vm_snapshot_buffer {
        /*
         * R/O for device-specific functions;
         * written by generic snapshot functions.
         */
        uint8_t *const buf_start;
        const size_t buf_size;

        /*
         * R/W for device-specific functions used to keep track of buffer
         * current position and remaining size.
         */
        uint8_t *buf;
        size_t buf_rem;

        /*
         * Length of the snapshot is either determined as (buf_size - buf_rem)
         * or (buf - buf_start) -- the second variation returns a signed value
         * so it may not be appropriate.
         *
         * Use vm_get_snapshot_size(meta).
         */
};

enum vm_snapshot_op {
        VM_SNAPSHOT_SAVE,
        VM_SNAPSHOT_RESTORE,
};

struct vm_snapshot_meta {
        void *dev_data;
        const char *dev_name;      /* identify userspace devices */
        enum snapshot_req dev_req; /* identify kernel structs */

        struct vm_snapshot_buffer buffer;

        enum vm_snapshot_op op;
};

void vm_snapshot_buf_err(const char *bufname, const enum vm_snapshot_op op);
int vm_snapshot_buf(void *data, size_t data_size,
    struct vm_snapshot_meta *meta);
size_t vm_get_snapshot_size(struct vm_snapshot_meta *meta);

#define SNAPSHOT_BUF_OR_LEAVE(DATA, LEN, META, RES, LABEL)                      \
do {                                                                            \
        (RES) = vm_snapshot_buf((DATA), (LEN), (META));                         \
        if ((RES) != 0) {                                                       \
                vm_snapshot_buf_err(#DATA, (META)->op);                         \
                goto LABEL;                                                     \
        }                                                                       \
} while (0)

#define SNAPSHOT_VAR_OR_LEAVE(DATA, META, RES, LABEL)                           \
        SNAPSHOT_BUF_OR_LEAVE(&(DATA), sizeof(DATA), (META), (RES), LABEL)

#ifndef _KERNEL
int vm_snapshot_buf_cmp(void *data, size_t data_size,
    struct vm_snapshot_meta *meta);

/* compare the value in the meta buffer with the data */
#define SNAPSHOT_BUF_CMP_OR_LEAVE(DATA, LEN, META, RES, LABEL)                  \
do {                                                                            \
        (RES) = vm_snapshot_buf_cmp((DATA), (LEN), (META));                     \
        if ((RES) != 0) {                                                       \
                vm_snapshot_buf_err(#DATA, (META)->op);                         \
                goto LABEL;                                                     \
        }                                                                       \
} while (0)

#define SNAPSHOT_VAR_CMP_OR_LEAVE(DATA, META, RES, LABEL)                       \
        SNAPSHOT_BUF_CMP_OR_LEAVE(&(DATA), sizeof(DATA), (META), (RES), LABEL)

#endif  /* _KERNEL */
#endif