// SPDX-License-Identifier: GPL-2.0+
/*
 *  EFI variable service via OP-TEE
 *
 *  Copyright (C) 2019 Linaro Ltd. <sughosh.ganu@linaro.org>
 *  Copyright (C) 2019 Linaro Ltd. <ilias.apalodimas@linaro.org>
 */

#include <common.h>
#include <efi.h>
#include <efi_api.h>
#include <efi_loader.h>
#include <efi_variable.h>
#include <tee.h>
#include <malloc.h>
#include <mm_communication.h>

extern struct efi_var_file __efi_runtime_data *efi_var_buf;
static efi_uintn_t max_buffer_size;     /* comm + var + func + data */
static efi_uintn_t max_payload_size;    /* func + data */

struct mm_connection {
        struct udevice *tee;
        u32 session;
};

/**
 * get_connection() - Retrieve OP-TEE session for a specific UUID.
 *
 * @conn:   session buffer to fill
 * Return:  status code
 */
static int get_connection(struct mm_connection *conn)
{
        static const struct tee_optee_ta_uuid uuid = PTA_STMM_UUID;
        struct udevice *tee = NULL;
        struct tee_open_session_arg arg;
        int rc = -ENODEV;

        tee = tee_find_device(tee, NULL, NULL, NULL);
        if (!tee)
                goto out;

        memset(&arg, 0, sizeof(arg));
        tee_optee_ta_uuid_to_octets(arg.uuid, &uuid);
        rc = tee_open_session(tee, &arg, 0, NULL);
        if (rc)
                goto out;

        /* Check the internal OP-TEE result */
        if (arg.ret != TEE_SUCCESS) {
                rc = -EIO;
                goto out;
        }

        conn->tee = tee;
        conn->session = arg.session;

        return 0;
out:
        return rc;
}

/**
 * optee_mm_communicate() - Pass a buffer to StandaloneMM running in OP-TEE
 *
 * @comm_buf:           locally allocted communcation buffer
 * @dsize:              buffer size
 * Return:              status code
 */
static efi_status_t optee_mm_communicate(void *comm_buf, ulong dsize)
{
        ulong buf_size;
        efi_status_t ret;
        struct efi_mm_communicate_header *mm_hdr;
        struct mm_connection conn = { NULL, 0 };
        struct tee_invoke_arg arg;
        struct tee_param param[2];
        struct tee_shm *shm = NULL;
        int rc;

        if (!comm_buf)
                return EFI_INVALID_PARAMETER;

        mm_hdr = (struct efi_mm_communicate_header *)comm_buf;
        buf_size = mm_hdr->message_len + sizeof(efi_guid_t) + sizeof(size_t);

        if (dsize != buf_size)
                return EFI_INVALID_PARAMETER;

        rc = get_connection(&conn);
        if (rc) {
                log_err("Unable to open OP-TEE session (err=%d)\n", rc);
                return EFI_UNSUPPORTED;
        }

        if (tee_shm_register(conn.tee, comm_buf, buf_size, 0, &shm)) {
                log_err("Unable to register shared memory\n");
                tee_close_session(conn.tee, conn.session);
                return EFI_UNSUPPORTED;
        }

        memset(&arg, 0, sizeof(arg));
        arg.func = PTA_STMM_CMDID_COMMUNICATE;
        arg.session = conn.session;

        memset(param, 0, sizeof(param));
        param[0].attr = TEE_PARAM_ATTR_TYPE_MEMREF_INOUT;
        param[0].u.memref.size = buf_size;
        param[0].u.memref.shm = shm;
        param[1].attr = TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT;

        rc = tee_invoke_func(conn.tee, &arg, 2, param);
        tee_shm_free(shm);
        tee_close_session(conn.tee, conn.session);
        if (rc)
                return EFI_DEVICE_ERROR;
        if (arg.ret == TEE_ERROR_EXCESS_DATA)
                log_err("Variable payload too large\n");
        if (arg.ret != TEE_SUCCESS)
                return EFI_DEVICE_ERROR;

        switch (param[1].u.value.a) {
        case ARM_SVC_SPM_RET_SUCCESS:
                ret = EFI_SUCCESS;
                break;

        case ARM_SVC_SPM_RET_INVALID_PARAMS:
                ret = EFI_INVALID_PARAMETER;
                break;

        case ARM_SVC_SPM_RET_DENIED:
                ret = EFI_ACCESS_DENIED;
                break;

        case ARM_SVC_SPM_RET_NO_MEMORY:
                ret = EFI_OUT_OF_RESOURCES;
                break;

        default:
                ret = EFI_ACCESS_DENIED;
        }

        return ret;
}

/**
 * mm_communicate() - Adjust the cmonnucation buffer to StandAlonneMM and send
 * it to OP-TEE
 *
 * @comm_buf:           locally allocted communcation buffer
 * @dsize:              buffer size
 * Return:              status code
 */
static efi_status_t mm_communicate(u8 *comm_buf, efi_uintn_t dsize)
{
        efi_status_t ret;
        struct efi_mm_communicate_header *mm_hdr;
        struct smm_variable_communicate_header *var_hdr;

        dsize += MM_COMMUNICATE_HEADER_SIZE + MM_VARIABLE_COMMUNICATE_SIZE;
        mm_hdr = (struct efi_mm_communicate_header *)comm_buf;
        var_hdr = (struct smm_variable_communicate_header *)mm_hdr->data;

        ret = optee_mm_communicate(comm_buf, dsize);
        if (ret != EFI_SUCCESS) {
                log_err("%s failed!\n", __func__);
                return ret;
        }

        return var_hdr->ret_status;
}

/**
 * setup_mm_hdr() -     Allocate a buffer for StandAloneMM and initialize the
 *                      header data.
 *
 * @dptr:               pointer address of the corresponding StandAloneMM
 *                      function
 * @payload_size:       buffer size
 * @func:               standAloneMM function number
 * @ret:                EFI return code
 * Return:              buffer or NULL
 */
static u8 *setup_mm_hdr(void **dptr, efi_uintn_t payload_size,
                        efi_uintn_t func, efi_status_t *ret)
{
        const efi_guid_t mm_var_guid = EFI_MM_VARIABLE_GUID;
        struct efi_mm_communicate_header *mm_hdr;
        struct smm_variable_communicate_header *var_hdr;
        u8 *comm_buf;

        /* In the init function we initialize max_buffer_size with
         * get_max_payload(). So skip the test if max_buffer_size is initialized
         * StandAloneMM will perform similar checks and drop the buffer if it's
         * too long
         */
        if (max_buffer_size && max_buffer_size <
                        (MM_COMMUNICATE_HEADER_SIZE +
                         MM_VARIABLE_COMMUNICATE_SIZE +
                         payload_size)) {
                *ret = EFI_INVALID_PARAMETER;
                return NULL;
        }

        comm_buf = calloc(1, MM_COMMUNICATE_HEADER_SIZE +
                          MM_VARIABLE_COMMUNICATE_SIZE +
                          payload_size);
        if (!comm_buf) {
                *ret = EFI_OUT_OF_RESOURCES;
                return NULL;
        }

        mm_hdr = (struct efi_mm_communicate_header *)comm_buf;
        guidcpy(&mm_hdr->header_guid, &mm_var_guid);
        mm_hdr->message_len = MM_VARIABLE_COMMUNICATE_SIZE + payload_size;

        var_hdr = (struct smm_variable_communicate_header *)mm_hdr->data;
        var_hdr->function = func;
        if (dptr)
                *dptr = var_hdr->data;
        *ret = EFI_SUCCESS;

        return comm_buf;
}

/**
 * get_max_payload() - Get variable payload size from StandAloneMM.
 *
 * @size:    size of the variable in storage
 * Return:   status code
 */
efi_status_t EFIAPI get_max_payload(efi_uintn_t *size)
{
        struct smm_variable_payload_size *var_payload = NULL;
        efi_uintn_t payload_size;
        u8 *comm_buf = NULL;
        efi_status_t ret;

        if (!size) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }

        payload_size = sizeof(*var_payload);
        comm_buf = setup_mm_hdr((void **)&var_payload, payload_size,
                                SMM_VARIABLE_FUNCTION_GET_PAYLOAD_SIZE, &ret);
        if (!comm_buf)
                goto out;

        ret = mm_communicate(comm_buf, payload_size);
        if (ret != EFI_SUCCESS)
                goto out;

        /* Make sure the buffer is big enough for storing variables */
        if (var_payload->size < MM_VARIABLE_ACCESS_HEADER_SIZE + 0x20) {
                ret = EFI_DEVICE_ERROR;
                goto out;
        }
        *size = var_payload->size;
        /*
         * There seems to be a bug in EDK2 miscalculating the boundaries and
         * size checks, so deduct 2 more bytes to fulfill this requirement. Fix
         * it up here to ensure backwards compatibility with older versions
         * (cf. StandaloneMmPkg/Drivers/StandaloneMmCpu/AArch64/EventHandle.c.
         * sizeof (EFI_MM_COMMUNICATE_HEADER) instead the size minus the
         * flexible array member).
         *
         * size is guaranteed to be > 2 due to checks on the beginning.
         */
        *size -= 2;
out:
        free(comm_buf);
        return ret;
}

/*
 * StMM can store internal attributes and properties for variables, i.e enabling
 * R/O variables
 */
static efi_status_t set_property_int(const u16 *variable_name,
                                     efi_uintn_t name_size,
                                     const efi_guid_t *vendor,
                                     struct var_check_property *var_property)
{
        struct smm_variable_var_check_property *smm_property;
        efi_uintn_t payload_size;
        u8 *comm_buf = NULL;
        efi_status_t ret;

        payload_size = sizeof(*smm_property) + name_size;
        if (payload_size > max_payload_size) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }
        comm_buf = setup_mm_hdr((void **)&smm_property, payload_size,
                                SMM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_SET,
                                &ret);
        if (!comm_buf)
                goto out;

        guidcpy(&smm_property->guid, vendor);
        smm_property->name_size = name_size;
        memcpy(&smm_property->property, var_property,
               sizeof(smm_property->property));
        memcpy(smm_property->name, variable_name, name_size);

        ret = mm_communicate(comm_buf, payload_size);

out:
        free(comm_buf);
        return ret;
}

static efi_status_t get_property_int(const u16 *variable_name,
                                     efi_uintn_t name_size,
                                     const efi_guid_t *vendor,
                                     struct var_check_property *var_property)
{
        struct smm_variable_var_check_property *smm_property;
        efi_uintn_t payload_size;
        u8 *comm_buf = NULL;
        efi_status_t ret;

        memset(var_property, 0, sizeof(*var_property));
        payload_size = sizeof(*smm_property) + name_size;
        if (payload_size > max_payload_size) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }
        comm_buf = setup_mm_hdr((void **)&smm_property, payload_size,
                                SMM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_GET,
                                &ret);
        if (!comm_buf)
                goto out;

        guidcpy(&smm_property->guid, vendor);
        smm_property->name_size = name_size;
        memcpy(smm_property->name, variable_name, name_size);

        ret = mm_communicate(comm_buf, payload_size);
        /*
         * Currently only R/O property is supported in StMM.
         * Variables that are not set to R/O will not set the property in StMM
         * and the call will return EFI_NOT_FOUND. We are setting the
         * properties to 0x0 so checking against that is enough for the
         * EFI_NOT_FOUND case.
         */
        if (ret == EFI_NOT_FOUND)
                ret = EFI_SUCCESS;
        if (ret != EFI_SUCCESS)
                goto out;
        memcpy(var_property, &smm_property->property, sizeof(*var_property));

out:
        free(comm_buf);
        return ret;
}

efi_status_t efi_get_variable_int(const u16 *variable_name,
                                  const efi_guid_t *vendor,
                                  u32 *attributes, efi_uintn_t *data_size,
                                  void *data, u64 *timep)
{
        struct var_check_property var_property;
        struct smm_variable_access *var_acc;
        efi_uintn_t payload_size;
        efi_uintn_t name_size;
        efi_uintn_t tmp_dsize;
        u8 *comm_buf = NULL;
        efi_status_t ret, tmp;

        if (!variable_name || !vendor || !data_size) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }

        /* Check payload size */
        name_size = u16_strsize(variable_name);
        if (name_size > max_payload_size - MM_VARIABLE_ACCESS_HEADER_SIZE) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }

        /* Trim output buffer size */
        tmp_dsize = *data_size;
        if (name_size + tmp_dsize >
                        max_payload_size - MM_VARIABLE_ACCESS_HEADER_SIZE) {
                tmp_dsize = max_payload_size -
                                MM_VARIABLE_ACCESS_HEADER_SIZE -
                                name_size;
        }

        /* Get communication buffer and initialize header */
        payload_size = MM_VARIABLE_ACCESS_HEADER_SIZE + name_size + tmp_dsize;
        comm_buf = setup_mm_hdr((void **)&var_acc, payload_size,
                                SMM_VARIABLE_FUNCTION_GET_VARIABLE, &ret);
        if (!comm_buf)
                goto out;

        /* Fill in contents */
        guidcpy(&var_acc->guid, vendor);
        var_acc->data_size = tmp_dsize;
        var_acc->name_size = name_size;
        var_acc->attr = attributes ? *attributes : 0;
        memcpy(var_acc->name, variable_name, name_size);

        /* Communicate */
        ret = mm_communicate(comm_buf, payload_size);
        if (ret != EFI_SUCCESS && ret != EFI_BUFFER_TOO_SMALL)
                goto out;

        /* Update with reported data size for trimmed case */
        *data_size = var_acc->data_size;
        /*
         * UEFI > 2.7 needs the attributes set even if the buffer is
         * smaller
         */
        if (attributes) {
                tmp = get_property_int(variable_name, name_size, vendor,
                                       &var_property);
                if (tmp != EFI_SUCCESS) {
                        ret = tmp;
                        goto out;
                }
                *attributes = var_acc->attr;
                if (var_property.property &
                    VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY)
                        *attributes |= EFI_VARIABLE_READ_ONLY;
        }

        /* return if ret is EFI_BUFFER_TOO_SMALL */
        if (ret != EFI_SUCCESS)
                goto out;

        if (data)
                memcpy(data, (u8 *)var_acc->name + var_acc->name_size,
                       var_acc->data_size);
        else
                ret = EFI_INVALID_PARAMETER;

out:
        free(comm_buf);
        return ret;
}

efi_status_t efi_get_next_variable_name_int(efi_uintn_t *variable_name_size,
                                            u16 *variable_name,
                                            efi_guid_t *guid)
{
        struct smm_variable_getnext *var_getnext;
        efi_uintn_t payload_size;
        efi_uintn_t out_name_size;
        efi_uintn_t in_name_size;
        u8 *comm_buf = NULL;
        efi_status_t ret;

        if (!variable_name_size || !variable_name || !guid) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }

        out_name_size = *variable_name_size;
        in_name_size = u16_strsize(variable_name);

        if (out_name_size < in_name_size) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }

        if (in_name_size > max_payload_size - MM_VARIABLE_GET_NEXT_HEADER_SIZE) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }

        /* Trim output buffer size */
        if (out_name_size > max_payload_size - MM_VARIABLE_GET_NEXT_HEADER_SIZE)
                out_name_size = max_payload_size - MM_VARIABLE_GET_NEXT_HEADER_SIZE;

        payload_size = MM_VARIABLE_GET_NEXT_HEADER_SIZE + out_name_size;
        comm_buf = setup_mm_hdr((void **)&var_getnext, payload_size,
                                SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME,
                                &ret);
        if (!comm_buf)
                goto out;

        /* Fill in contents */
        guidcpy(&var_getnext->guid, guid);
        var_getnext->name_size = out_name_size;
        memcpy(var_getnext->name, variable_name, in_name_size);
        memset((u8 *)var_getnext->name + in_name_size, 0x0,
               out_name_size - in_name_size);

        /* Communicate */
        ret = mm_communicate(comm_buf, payload_size);
        if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
                /* Update with reported data size for trimmed case */
                *variable_name_size = var_getnext->name_size;
        }
        if (ret != EFI_SUCCESS)
                goto out;

        guidcpy(guid, &var_getnext->guid);
        memcpy(variable_name, var_getnext->name, var_getnext->name_size);

out:
        free(comm_buf);
        return ret;
}

efi_status_t efi_set_variable_int(const u16 *variable_name,
                                  const efi_guid_t *vendor, u32 attributes,
                                  efi_uintn_t data_size, const void *data,
                                  bool ro_check)
{
        efi_status_t ret, alt_ret = EFI_SUCCESS;
        struct var_check_property var_property;
        struct smm_variable_access *var_acc;
        efi_uintn_t payload_size;
        efi_uintn_t name_size;
        u8 *comm_buf = NULL;
        bool ro;

        if (!variable_name || variable_name[0] == 0 || !vendor) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }
        if (data_size > 0 && !data) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }
        /* Check payload size */
        name_size = u16_strsize(variable_name);
        payload_size = MM_VARIABLE_ACCESS_HEADER_SIZE + name_size + data_size;
        if (payload_size > max_payload_size) {
                ret = EFI_INVALID_PARAMETER;
                goto out;
        }

        /*
         * Allocate the buffer early, before switching to RW (if needed)
         * so we won't need to account for any failures in reading/setting
         * the properties, if the allocation fails
         */
        comm_buf = setup_mm_hdr((void **)&var_acc, payload_size,
                                SMM_VARIABLE_FUNCTION_SET_VARIABLE, &ret);
        if (!comm_buf)
                goto out;

        ro = !!(attributes & EFI_VARIABLE_READ_ONLY);
        attributes &= EFI_VARIABLE_MASK;

        /*
         * The API has the ability to override RO flags. If no RO check was
         * requested switch the variable to RW for the duration of this call
         */
        ret = get_property_int(variable_name, name_size, vendor,
                               &var_property);
        if (ret != EFI_SUCCESS)
                goto out;

        if (var_property.property & VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY) {
                /* Bypass r/o check */
                if (!ro_check) {
                        var_property.property &= ~VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY;
                        ret = set_property_int(variable_name, name_size, vendor, &var_property);
                        if (ret != EFI_SUCCESS)
                                goto out;
                } else {
                        ret = EFI_WRITE_PROTECTED;
                        goto out;
                }
        }

        /* Fill in contents */
        guidcpy(&var_acc->guid, vendor);
        var_acc->data_size = data_size;
        var_acc->name_size = name_size;
        var_acc->attr = attributes;
        memcpy(var_acc->name, variable_name, name_size);
        memcpy((u8 *)var_acc->name + name_size, data, data_size);

        /* Communicate */
        ret = mm_communicate(comm_buf, payload_size);
        if (ret != EFI_SUCCESS)
                alt_ret = ret;

        if (ro && !(var_property.property & VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY)) {
                var_property.revision = VAR_CHECK_VARIABLE_PROPERTY_REVISION;
                var_property.property |= VAR_CHECK_VARIABLE_PROPERTY_READ_ONLY;
                var_property.attributes = attributes;
                var_property.minsize = 1;
                var_property.maxsize = var_acc->data_size;
                ret = set_property_int(variable_name, name_size, vendor, &var_property);
        }

        if (alt_ret != EFI_SUCCESS)
                goto out;

        if (!u16_strcmp(variable_name, u"PK"))
                alt_ret = efi_init_secure_state();
out:
        free(comm_buf);
        return alt_ret == EFI_SUCCESS ? ret : alt_ret;
}

efi_status_t efi_query_variable_info_int(u32 attributes,
                                         u64 *max_variable_storage_size,
                                         u64 *remain_variable_storage_size,
                                         u64 *max_variable_size)
{
        struct smm_variable_query_info *mm_query_info;
        efi_uintn_t payload_size;
        efi_status_t ret;
        u8 *comm_buf;

        payload_size = sizeof(*mm_query_info);
        comm_buf = setup_mm_hdr((void **)&mm_query_info, payload_size,
                                SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO,
                                &ret);
        if (!comm_buf)
                goto out;

        mm_query_info->attr = attributes;
        ret = mm_communicate(comm_buf, payload_size);
        if (ret != EFI_SUCCESS)
                goto out;
        *max_variable_storage_size = mm_query_info->max_variable_storage;
        *remain_variable_storage_size =
                        mm_query_info->remaining_variable_storage;
        *max_variable_size = mm_query_info->max_variable_size;

out:
        free(comm_buf);
        return ret;
}

/**
 * efi_query_variable_info() - get information about EFI variables
 *
 * This function implements the QueryVariableInfo() runtime service.
 *
 * See the Unified Extensible Firmware Interface (UEFI) specification for
 * details.
 *
 * @attributes:                         bitmask to select variables to be
 *                                      queried
 * @maximum_variable_storage_size:      maximum size of storage area for the
 *                                      selected variable types
 * @remaining_variable_storage_size:    remaining size of storage are for the
 *                                      selected variable types
 * @maximum_variable_size:              maximum size of a variable of the
 *                                      selected type
 * Return:                              status code
 */
efi_status_t EFIAPI __efi_runtime
efi_query_variable_info_runtime(u32 attributes, u64 *max_variable_storage_size,
                                u64 *remain_variable_storage_size,
                                u64 *max_variable_size)
{
        return EFI_UNSUPPORTED;
}

/**
 * efi_set_variable_runtime() - runtime implementation of SetVariable()
 *
 * @variable_name:      name of the variable
 * @guid:               vendor GUID
 * @attributes:         attributes of the variable
 * @data_size:          size of the buffer with the variable value
 * @data:               buffer with the variable value
 * Return:              status code
 */
static efi_status_t __efi_runtime EFIAPI
efi_set_variable_runtime(u16 *variable_name, const efi_guid_t *guid,
                         u32 attributes, efi_uintn_t data_size,
                         const void *data)
{
        return EFI_UNSUPPORTED;
}

/**
 * efi_variables_boot_exit_notify() - notify ExitBootServices() is called
 */
void efi_variables_boot_exit_notify(void)
{
        efi_status_t ret;
        u8 *comm_buf;
        loff_t len;
        struct efi_var_file *var_buf;

        comm_buf = setup_mm_hdr(NULL, 0,
                                SMM_VARIABLE_FUNCTION_EXIT_BOOT_SERVICE, &ret);
        if (comm_buf)
                ret = mm_communicate(comm_buf, 0);
        else
                ret = EFI_NOT_FOUND;

        if (ret != EFI_SUCCESS)
                log_err("Unable to notify StMM for ExitBootServices\n");
        free(comm_buf);

        /*
         * Populate the list for runtime variables.
         * asking EFI_VARIABLE_RUNTIME_ACCESS is redundant, since
         * efi_var_mem_notify_exit_boot_services will clean those, but that's fine
         */
        ret = efi_var_collect(&var_buf, &len, EFI_VARIABLE_RUNTIME_ACCESS);
        if (ret != EFI_SUCCESS)
                log_err("Can't populate EFI variables. No runtime variables will be available\n");
        else
                efi_var_buf_update(var_buf);
        free(var_buf);

        /* Update runtime service table */
        efi_runtime_services.query_variable_info =
                        efi_query_variable_info_runtime;
        efi_runtime_services.get_variable = efi_get_variable_runtime;
        efi_runtime_services.get_next_variable_name =
                        efi_get_next_variable_name_runtime;
        efi_runtime_services.set_variable = efi_set_variable_runtime;
        efi_update_table_header_crc32(&efi_runtime_services.hdr);
}

/**
 * efi_init_variables() - initialize variable services
 *
 * Return:      status code
 */
efi_status_t efi_init_variables(void)
{
        efi_status_t ret;

        /* Create a cached copy of the variables that will be enabled on ExitBootServices() */
        ret = efi_var_mem_init();
        if (ret != EFI_SUCCESS)
                return ret;

        ret = get_max_payload(&max_payload_size);
        if (ret != EFI_SUCCESS)
                return ret;

        max_buffer_size = MM_COMMUNICATE_HEADER_SIZE +
                          MM_VARIABLE_COMMUNICATE_SIZE +
                          max_payload_size;

        ret = efi_init_secure_state();
        if (ret != EFI_SUCCESS)
                return ret;

        return EFI_SUCCESS;
}