/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2022 Beckhoff Automation GmbH & Co. KG
 */

#include <sys/param.h>
#include <sys/endian.h>
#include <sys/errno.h>
#include <sys/queue.h>
#include <sys/stat.h>

#include <machine/vmm.h>

#include <assert.h>
#include <err.h>
#include <libutil.h>
#include <stddef.h>
#include <stdio.h>
#include <vmmapi.h>

#include "basl.h"
#include "config.h"
#include "qemu_loader.h"

struct basl_table_checksum {
        STAILQ_ENTRY(basl_table_checksum) chain;
        uint32_t off;
        uint32_t start;
        uint32_t len;
};

struct basl_table_length {
        STAILQ_ENTRY(basl_table_length) chain;
        uint32_t off;
        uint8_t size;
};

struct basl_table_pointer {
        STAILQ_ENTRY(basl_table_pointer) chain;
        uint8_t src_signature[ACPI_NAMESEG_SIZE];
        uint32_t off;
        uint8_t size;
};

struct basl_table {
        STAILQ_ENTRY(basl_table) chain;
        struct vmctx *ctx;
        uint8_t fwcfg_name[QEMU_FWCFG_MAX_NAME];
        void *data;
        uint32_t len;
        uint32_t off;
        uint32_t alignment;
        STAILQ_HEAD(basl_table_checksum_list, basl_table_checksum) checksums;
        STAILQ_HEAD(basl_table_length_list, basl_table_length) lengths;
        STAILQ_HEAD(basl_table_pointer_list, basl_table_pointer) pointers;
};
static STAILQ_HEAD(basl_table_list, basl_table) basl_tables = STAILQ_HEAD_INITIALIZER(
    basl_tables);

static struct qemu_loader *basl_loader;
static struct basl_table *rsdt;
static struct basl_table *xsdt;
static bool load_into_memory;

static __inline uint64_t
basl_le_dec(void *pp, size_t len)
{
        assert(len <= 8);

        switch (len) {
        case 1:
                return ((uint8_t *)pp)[0];
        case 2:
                return le16dec(pp);
        case 4:
                return le32dec(pp);
        case 8:
                return le64dec(pp);
        }

        return 0;
}

static __inline void
basl_le_enc(void *pp, uint64_t val, size_t len)
{
        char buf[8];

        assert(len <= 8);

        le64enc(buf, val);
        memcpy(pp, buf, len);
}

static int
basl_dump_table(const struct basl_table *const table, const bool mem)
{
        const ACPI_TABLE_HEADER *const header = table->data;
        const uint8_t *data;

        if (!mem) {
                data = table->data;
        } else {
                data = vm_map_gpa(table->ctx, BHYVE_ACPI_BASE + table->off,
                    table->len);
                if (data == NULL) {
                        return (ENOMEM);
                }
        }

        printf("%.4s @ %8x (%s)\n", header->Signature,
            BHYVE_ACPI_BASE + table->off, mem ? "Memory" : "FwCfg");
        hexdump(data, table->len, NULL, 0);

        return (0);
}

static int __unused
basl_dump(const bool mem)
{
        struct basl_table *table;

        STAILQ_FOREACH(table, &basl_tables, chain) {
                BASL_EXEC(basl_dump_table(table, mem));
        }

        return (0);
}

void
basl_fill_gas(ACPI_GENERIC_ADDRESS *const gas, const uint8_t space_id,
    const uint8_t bit_width, const uint8_t bit_offset,
    const uint8_t access_width, const uint64_t address)
{
        assert(gas != NULL);

        gas->SpaceId = space_id;
        gas->BitWidth = bit_width;
        gas->BitOffset = bit_offset;
        gas->AccessWidth = access_width;
        gas->Address = htole64(address);
}

static int
basl_finish_install_guest_tables(struct basl_table *const table, uint32_t *const off)
{
        void *gva;

        table->off = roundup2(*off, table->alignment);
        *off = table->off + table->len;
        if (*off <= table->off) {
                warnx("%s: invalid table length 0x%8x @ offset 0x%8x", __func__,
                    table->len, table->off);
                return (EFAULT);
        }

        /* Cause guest BIOS to copy the ACPI table into guest memory. */
        BASL_EXEC(
            qemu_fwcfg_add_file(table->fwcfg_name, table->len, table->data));
        BASL_EXEC(qemu_loader_alloc(basl_loader, table->fwcfg_name,
            table->alignment, QEMU_LOADER_ALLOC_HIGH));

        if (!load_into_memory) {
                return (0);
        }

        /*
         * Install ACPI tables directly in guest memory for use by guests which
         * do not boot via EFI. EFI ROMs provide a pointer to the firmware
         * generated ACPI tables instead, but it doesn't hurt to install the
         * tables always.
         */
        gva = vm_map_gpa(table->ctx, BHYVE_ACPI_BASE + table->off, table->len);
        if (gva == NULL) {
                warnx("%s: could not map gpa [ 0x%16lx, 0x%16lx ]", __func__,
                    (uint64_t)BHYVE_ACPI_BASE + table->off,
                    (uint64_t)BHYVE_ACPI_BASE + table->off + table->len);
                return (ENOMEM);
        }
        memcpy(gva, table->data, table->len);

        return (0);
}

static int
basl_finish_patch_checksums(struct basl_table *const table)
{
        struct basl_table_checksum *checksum;

        STAILQ_FOREACH(checksum, &table->checksums, chain) {
                uint8_t *gva, *checksum_gva;
                uint64_t gpa;
                uint32_t len;
                uint8_t sum;
                
                len = checksum->len;
                if (len == BASL_TABLE_CHECKSUM_LEN_FULL_TABLE) {
                        len = table->len;
                }

                assert(checksum->off < table->len);
                assert(checksum->start < table->len);
                assert(checksum->start + len <= table->len);

                /* Cause guest BIOS to patch the checksum. */
                BASL_EXEC(qemu_loader_add_checksum(basl_loader,
                    table->fwcfg_name, checksum->off, checksum->start, len));

                if (!load_into_memory) {
                        continue;
                }

                /*
                 * Install ACPI tables directly in guest memory for use by
                 * guests which do not boot via EFI. EFI ROMs provide a pointer
                 * to the firmware generated ACPI tables instead, but it doesn't
                 * hurt to install the tables always.
                 */
                gpa = BHYVE_ACPI_BASE + table->off + checksum->start;
                if ((gpa < BHYVE_ACPI_BASE) ||
                    (gpa < BHYVE_ACPI_BASE + table->off)) {
                        warnx("%s: invalid gpa (off 0x%8x start 0x%8x)",
                            __func__, table->off, checksum->start);
                        return (EFAULT);
                }

                gva = vm_map_gpa(table->ctx, gpa, len);
                if (gva == NULL) {
                        warnx("%s: could not map gpa [ 0x%16lx, 0x%16lx ]",
                            __func__, gpa, gpa + len);
                        return (ENOMEM);
                }
        
                checksum_gva = gva + checksum->off;
                if (checksum_gva < gva) {
                        warnx("%s: invalid checksum offset 0x%8x", __func__,
                            checksum->off);
                        return (EFAULT);
                }

                sum = 0;
                for (uint32_t i = 0; i < len; ++i) {
                        sum += *(gva + i);
                }
                *checksum_gva = -sum;
        }

        return (0);
}

static struct basl_table *
basl_get_table_by_signature(const uint8_t signature[ACPI_NAMESEG_SIZE])
{
        struct basl_table *table;

        STAILQ_FOREACH(table, &basl_tables, chain) {
                const ACPI_TABLE_HEADER *const header =
                    (const ACPI_TABLE_HEADER *)table->data;

                if (strncmp(header->Signature, signature,
                        sizeof(header->Signature)) == 0) {
                        return (table);
                }
        }

        warnx("%s: %.4s not found", __func__, signature);
        return (NULL);
}

static int
basl_finish_patch_pointers(struct basl_table *const table)
{
        struct basl_table_pointer *pointer;

        STAILQ_FOREACH(pointer, &table->pointers, chain) {
                const struct basl_table *src_table;
                uint8_t *gva;
                uint64_t gpa, val;

                assert(pointer->off < table->len);
                assert(pointer->off + pointer->size <= table->len);

                src_table = basl_get_table_by_signature(pointer->src_signature);
                if (src_table == NULL) {
                        warnx("%s: could not find ACPI table %.4s", __func__,
                            pointer->src_signature);
                        return (EFAULT);
                }

                /* Cause guest BIOS to patch the pointer. */
                BASL_EXEC(
                    qemu_loader_add_pointer(basl_loader, table->fwcfg_name,
                        src_table->fwcfg_name, pointer->off, pointer->size));

                if (!load_into_memory) {
                        continue;
                }

                /*
                 * Install ACPI tables directly in guest memory for use by
                 * guests which do not boot via EFI. EFI ROMs provide a pointer
                 * to the firmware generated ACPI tables instead, but it doesn't
                 * hurt to install the tables always.
                 */
                gpa = BHYVE_ACPI_BASE + table->off;
                if (gpa < BHYVE_ACPI_BASE) {
                        warnx("%s: table offset of 0x%8x is too large",
                            __func__, table->off);
                        return (EFAULT);
                }

                gva = vm_map_gpa(table->ctx, gpa, table->len);
                if (gva == NULL) {
                        warnx("%s: could not map gpa [ 0x%16lx, 0x%16lx ]",
                            __func__, gpa, gpa + table->len);
                        return (ENOMEM);
                }

                val = basl_le_dec(gva + pointer->off, pointer->size);
                val += BHYVE_ACPI_BASE + src_table->off;
                basl_le_enc(gva + pointer->off, val, pointer->size);
        }

        return (0);
}

static int
basl_finish_set_length(struct basl_table *const table)
{
        struct basl_table_length *length;

        STAILQ_FOREACH(length, &table->lengths, chain) {
                assert(length->off < table->len);
                assert(length->off + length->size <= table->len);

                basl_le_enc((uint8_t *)table->data + length->off, table->len,
                    length->size);
        }

        return (0);
}

int
basl_finish(void)
{
        struct basl_table *table;
        uint32_t off = 0;

        if (STAILQ_EMPTY(&basl_tables)) {
                warnx("%s: no ACPI tables found", __func__);
                return (EINVAL);
        }

        /*
         * If we install ACPI tables by FwCfg and by memory, Windows will use
         * the tables from memory. This can cause issues when using advanced
         * features like a TPM log because we aren't able to patch the memory
         * tables accordingly.
         */
        load_into_memory = get_config_bool_default("acpi_tables_in_memory",
            true);

        /*
         * We have to install all tables before we can patch them. Therefore,
         * use two loops. The first one installs all tables and the second one
         * patches them.
         */
        STAILQ_FOREACH(table, &basl_tables, chain) {
                BASL_EXEC(basl_finish_set_length(table));
                BASL_EXEC(basl_finish_install_guest_tables(table, &off));
        }
        STAILQ_FOREACH(table, &basl_tables, chain) {
                BASL_EXEC(basl_finish_patch_pointers(table));

                /*
                 * Calculate the checksum as last step!
                 */
                BASL_EXEC(basl_finish_patch_checksums(table));
        }
        BASL_EXEC(qemu_loader_finish(basl_loader));

        return (0);
}

static int
basl_init_rsdt(struct vmctx *const ctx)
{
        BASL_EXEC(
            basl_table_create(&rsdt, ctx, ACPI_SIG_RSDT, BASL_TABLE_ALIGNMENT));

        /* Header */
        BASL_EXEC(basl_table_append_header(rsdt, ACPI_SIG_RSDT, 1, 1));
        /* Pointers (added by basl_table_register_to_rsdt) */

        return (0);
}

static int
basl_init_xsdt(struct vmctx *const ctx)
{
        BASL_EXEC(
            basl_table_create(&xsdt, ctx, ACPI_SIG_XSDT, BASL_TABLE_ALIGNMENT));

        /* Header */
        BASL_EXEC(basl_table_append_header(xsdt, ACPI_SIG_XSDT, 1, 1));
        /* Pointers (added by basl_table_register_to_rsdt) */

        return (0);
}

int
basl_init(struct vmctx *const ctx)
{
        BASL_EXEC(basl_init_rsdt(ctx));
        BASL_EXEC(basl_init_xsdt(ctx));
        BASL_EXEC(
            qemu_loader_create(&basl_loader, QEMU_FWCFG_FILE_TABLE_LOADER));

        return (0);
}

int
basl_table_add_checksum(struct basl_table *const table, const uint32_t off,
    const uint32_t start, const uint32_t len)
{
        struct basl_table_checksum *checksum;

        assert(table != NULL);

        checksum = calloc(1, sizeof(struct basl_table_checksum));
        if (checksum == NULL) {
                warnx("%s: failed to allocate checksum", __func__);
                return (ENOMEM);
        }

        checksum->off = off;
        checksum->start = start;
        checksum->len = len;

        STAILQ_INSERT_TAIL(&table->checksums, checksum, chain);

        return (0);
}

int
basl_table_add_length(struct basl_table *const table, const uint32_t off,
    const uint8_t size)
{
        struct basl_table_length *length;

        assert(table != NULL);
        assert(size == 4 || size == 8);

        length = calloc(1, sizeof(struct basl_table_length));
        if (length == NULL) {
                warnx("%s: failed to allocate length", __func__);
                return (ENOMEM);
        }

        length->off = off;
        length->size = size;

        STAILQ_INSERT_TAIL(&table->lengths, length, chain);

        return (0);
}

int
basl_table_add_pointer(struct basl_table *const table,
    const uint8_t src_signature[ACPI_NAMESEG_SIZE], const uint32_t off,
    const uint8_t size)
{
        struct basl_table_pointer *pointer;

        assert(table != NULL);
        assert(size == 4 || size == 8);

        pointer = calloc(1, sizeof(struct basl_table_pointer));
        if (pointer == NULL) {
                warnx("%s: failed to allocate pointer", __func__);
                return (ENOMEM);
        }

        memcpy(pointer->src_signature, src_signature,
            sizeof(pointer->src_signature));
        pointer->off = off;
        pointer->size = size;

        STAILQ_INSERT_TAIL(&table->pointers, pointer, chain);

        return (0);
}

int
basl_table_append_bytes(struct basl_table *const table, const void *const bytes,
    const uint32_t len)
{
        void *end;

        assert(table != NULL);
        assert(bytes != NULL);

        if (table->len + len <= table->len) {
                warnx("%s: table too large (table->len 0x%8x len 0x%8x)",
                    __func__, table->len, len);
                return (EFAULT);
        }

        table->data = reallocf(table->data, table->len + len);
        if (table->data == NULL) {
                warnx("%s: failed to realloc table to length 0x%8x", __func__,
                    table->len + len);
                table->len = 0;
                return (ENOMEM);
        }

        end = (uint8_t *)table->data + table->len;
        table->len += len;

        memcpy(end, bytes, len);

        return (0);
}

int
basl_table_append_checksum(struct basl_table *const table, const uint32_t start,
    const uint32_t len)
{
        assert(table != NULL);

        BASL_EXEC(basl_table_add_checksum(table, table->len, start, len));
        BASL_EXEC(basl_table_append_int(table, 0, 1));

        return (0);
}

int
basl_table_append_content(struct basl_table *table, void *data, uint32_t len)
{
        assert(data != NULL);
        assert(len >= sizeof(ACPI_TABLE_HEADER));

        return (basl_table_append_bytes(table,
            (void *)((uintptr_t)(data) + sizeof(ACPI_TABLE_HEADER)),
            len - sizeof(ACPI_TABLE_HEADER)));
}

int
basl_table_append_fwcfg(struct basl_table *const table,
    const uint8_t *fwcfg_name, const uint32_t alignment, const uint8_t size)
{
        assert(table != NULL);
        assert(fwcfg_name != NULL);
        assert(size <= sizeof(uint64_t));

        BASL_EXEC(qemu_loader_alloc(basl_loader, fwcfg_name, alignment,
            QEMU_LOADER_ALLOC_HIGH));
        BASL_EXEC(qemu_loader_add_pointer(basl_loader, table->fwcfg_name,
            fwcfg_name, table->len, size));
        BASL_EXEC(basl_table_append_int(table, 0, size));

        return (0);
}

int
basl_table_append_gas(struct basl_table *const table, const uint8_t space_id,
    const uint8_t bit_width, const uint8_t bit_offset,
    const uint8_t access_width, const uint64_t address)
{
        ACPI_GENERIC_ADDRESS gas_le = {
                .SpaceId = space_id,
                .BitWidth = bit_width,
                .BitOffset = bit_offset,
                .AccessWidth = access_width,
                .Address = htole64(address),
        };

        return (basl_table_append_bytes(table, &gas_le, sizeof(gas_le)));
}

int
basl_table_append_header(struct basl_table *const table,
    const uint8_t signature[ACPI_NAMESEG_SIZE], const uint8_t revision,
    const uint32_t oem_revision)
{
        ACPI_TABLE_HEADER header_le;
        /* + 1 is required for the null terminator */
        char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];

        assert(table != NULL);
        assert(table->len == 0);

        memcpy(header_le.Signature, signature, ACPI_NAMESEG_SIZE);
        header_le.Length = 0; /* patched by basl_finish */
        header_le.Revision = revision;
        header_le.Checksum = 0; /* patched by basl_finish */
        memcpy(header_le.OemId, "BHYVE ", ACPI_OEM_ID_SIZE);
        snprintf(oem_table_id, ACPI_OEM_TABLE_ID_SIZE, "BV%.4s  ", signature);
        memcpy(header_le.OemTableId, oem_table_id,
            sizeof(header_le.OemTableId));
        header_le.OemRevision = htole32(oem_revision);
        memcpy(header_le.AslCompilerId, "BASL", ACPI_NAMESEG_SIZE);
        header_le.AslCompilerRevision = htole32(0x20220504);

        BASL_EXEC(
            basl_table_append_bytes(table, &header_le, sizeof(header_le)));

        BASL_EXEC(basl_table_add_length(table,
            offsetof(ACPI_TABLE_HEADER, Length), sizeof(header_le.Length)));
        BASL_EXEC(basl_table_add_checksum(table,
            offsetof(ACPI_TABLE_HEADER, Checksum), 0,
            BASL_TABLE_CHECKSUM_LEN_FULL_TABLE));

        return (0);
}

int
basl_table_append_int(struct basl_table *const table, const uint64_t val,
    const uint8_t size)
{
        char buf[8];

        assert(size <= sizeof(val));

        basl_le_enc(buf, val, size);
        return (basl_table_append_bytes(table, buf, size));
}

int
basl_table_append_length(struct basl_table *const table, const uint8_t size)
{
        assert(table != NULL);
        assert(size <= sizeof(table->len));

        BASL_EXEC(basl_table_add_length(table, table->len, size));
        BASL_EXEC(basl_table_append_int(table, 0, size));

        return (0);
}

int
basl_table_append_pointer(struct basl_table *const table,
    const uint8_t src_signature[ACPI_NAMESEG_SIZE], const uint8_t size)
{
        assert(table != NULL);
        assert(size == 4 || size == 8);

        BASL_EXEC(basl_table_add_pointer(table, src_signature, table->len, size));
        BASL_EXEC(basl_table_append_int(table, 0, size));

        return (0);
}

int
basl_table_create(struct basl_table **const table, struct vmctx *ctx,
    const uint8_t *const name, const uint32_t alignment)
{
        struct basl_table *new_table;

        assert(table != NULL);

        new_table = calloc(1, sizeof(struct basl_table));
        if (new_table == NULL) {
                warnx("%s: failed to allocate table", __func__);
                return (ENOMEM);
        }

        new_table->ctx = ctx;

        snprintf(new_table->fwcfg_name, sizeof(new_table->fwcfg_name),
            "etc/acpi/%s", name);

        new_table->alignment = alignment;

        STAILQ_INIT(&new_table->checksums);
        STAILQ_INIT(&new_table->lengths);
        STAILQ_INIT(&new_table->pointers);

        STAILQ_INSERT_TAIL(&basl_tables, new_table, chain);

        *table = new_table;

        return (0);
}

int
basl_table_register_to_rsdt(struct basl_table *table)
{
        const ACPI_TABLE_HEADER *header;

        assert(table != NULL);

        header = (const ACPI_TABLE_HEADER *)table->data;

        BASL_EXEC(basl_table_append_pointer(rsdt, header->Signature,
            ACPI_RSDT_ENTRY_SIZE));
        BASL_EXEC(basl_table_append_pointer(xsdt, header->Signature,
            ACPI_XSDT_ENTRY_SIZE));

        return (0);
}