hw/i386/pc: Document pc_system_ovmf_table_find

[qemu/kevin.git] / hw / i386 / pc_sysfw.c

/*
 * QEMU PC System Firmware
 *
 * Copyright (c) 2003-2004 Fabrice Bellard
 * Copyright (c) 2011-2012 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qapi/error.h"
#include "sysemu/block-backend.h"
#include "qemu/error-report.h"
#include "qemu/option.h"
#include "qemu/units.h"
#include "hw/sysbus.h"
#include "hw/i386/x86.h"
#include "hw/i386/pc.h"
#include "hw/loader.h"
#include "hw/qdev-properties.h"
#include "hw/block/flash.h"
#include "sysemu/kvm.h"
#include "sysemu/sev.h"

#define FLASH_SECTOR_SIZE 4096

static void pc_isa_bios_init(MemoryRegion *rom_memory,
                             MemoryRegion *flash_mem,
                             int ram_size)
{
    int isa_bios_size;
    MemoryRegion *isa_bios;
    uint64_t flash_size;
    void *flash_ptr, *isa_bios_ptr;

    flash_size = memory_region_size(flash_mem);

    /* map the last 128KB of the BIOS in ISA space */
    isa_bios_size = MIN(flash_size, 128 * KiB);
    isa_bios = g_malloc(sizeof(*isa_bios));
    memory_region_init_ram(isa_bios, NULL, "isa-bios", isa_bios_size,
                           &error_fatal);
    memory_region_add_subregion_overlap(rom_memory,
                                        0x100000 - isa_bios_size,
                                        isa_bios,
                                        1);

    /* copy ISA rom image from top of flash memory */
    flash_ptr = memory_region_get_ram_ptr(flash_mem);
    isa_bios_ptr = memory_region_get_ram_ptr(isa_bios);
    memcpy(isa_bios_ptr,
           ((uint8_t*)flash_ptr) + (flash_size - isa_bios_size),
           isa_bios_size);

    memory_region_set_readonly(isa_bios, true);
}

static PFlashCFI01 *pc_pflash_create(PCMachineState *pcms,
                                     const char *name,
                                     const char *alias_prop_name)
{
    DeviceState *dev = qdev_new(TYPE_PFLASH_CFI01);

    qdev_prop_set_uint64(dev, "sector-length", FLASH_SECTOR_SIZE);
    qdev_prop_set_uint8(dev, "width", 1);
    qdev_prop_set_string(dev, "name", name);
    object_property_add_child(OBJECT(pcms), name, OBJECT(dev));
    object_property_add_alias(OBJECT(pcms), alias_prop_name,
                              OBJECT(dev), "drive");
    /*
     * The returned reference is tied to the child property and
     * will be removed with object_unparent.
     */
    object_unref(OBJECT(dev));
    return PFLASH_CFI01(dev);
}

void pc_system_flash_create(PCMachineState *pcms)
{
    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);

    if (pcmc->pci_enabled) {
        pcms->flash[0] = pc_pflash_create(pcms, "system.flash0",
                                          "pflash0");
        pcms->flash[1] = pc_pflash_create(pcms, "system.flash1",
                                          "pflash1");
    }
}

void pc_system_flash_cleanup_unused(PCMachineState *pcms)
{
    char *prop_name;
    int i;
    Object *dev_obj;

    assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);

    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
        dev_obj = OBJECT(pcms->flash[i]);
        if (!object_property_get_bool(dev_obj, "realized", &error_abort)) {
            prop_name = g_strdup_printf("pflash%d", i);
            object_property_del(OBJECT(pcms), prop_name);
            g_free(prop_name);
            object_unparent(dev_obj);
            pcms->flash[i] = NULL;
        }
    }
}

#define OVMF_TABLE_FOOTER_GUID "96b582de-1fb2-45f7-baea-a366c55a082d"

static bool ovmf_flash_parsed;
static uint8_t *ovmf_table;
static int ovmf_table_len;

static void pc_system_parse_ovmf_flash(uint8_t *flash_ptr, size_t flash_size)
{
    uint8_t *ptr;
    QemuUUID guid;
    int tot_len;

    /* should only be called once */
    if (ovmf_flash_parsed) {
        return;
    }

    ovmf_flash_parsed = true;

    if (flash_size < TARGET_PAGE_SIZE) {
        return;
    }

    /*
     * if this is OVMF there will be a table footer
     * guid 48 bytes before the end of the flash file.  If it's
     * not found, silently abort the flash parsing.
     */
    qemu_uuid_parse(OVMF_TABLE_FOOTER_GUID, &guid);
    guid = qemu_uuid_bswap(guid); /* guids are LE */
    ptr = flash_ptr + flash_size - 48;
    if (!qemu_uuid_is_equal((QemuUUID *)ptr, &guid)) {
        return;
    }

    /* if found, just before is two byte table length */
    ptr -= sizeof(uint16_t);
    tot_len = le16_to_cpu(*(uint16_t *)ptr) - sizeof(guid) - sizeof(uint16_t);

    if (tot_len <= 0) {
        return;
    }

    ovmf_table = g_malloc(tot_len);
    ovmf_table_len = tot_len;

    /*
     * ptr is the foot of the table, so copy it all to the newly
     * allocated ovmf_table and then set the ovmf_table pointer
     * to the table foot
     */
    memcpy(ovmf_table, ptr - tot_len, tot_len);
    ovmf_table += tot_len;
}

/**
 * pc_system_ovmf_table_find - Find the data associated with an entry in OVMF's
 * reset vector GUIDed table.
 *
 * @entry: GUID string of the entry to lookup
 * @data: Filled with a pointer to the entry's value (if not NULL)
 * @data_len: Filled with the length of the entry's value (if not NULL). Pass
 *            NULL here if the length of data is known.
 *
 * Return: true if the entry was found in the OVMF table; false otherwise.
 */
bool pc_system_ovmf_table_find(const char *entry, uint8_t **data,
                               int *data_len)
{
    uint8_t *ptr = ovmf_table;
    int tot_len = ovmf_table_len;
    QemuUUID entry_guid;

    assert(ovmf_flash_parsed);

    if (qemu_uuid_parse(entry, &entry_guid) < 0) {
        return false;
    }

    if (!ptr) {
        return false;
    }

    entry_guid = qemu_uuid_bswap(entry_guid); /* guids are LE */
    while (tot_len >= sizeof(QemuUUID) + sizeof(uint16_t)) {
        int len;
        QemuUUID *guid;

        /*
         * The data structure is
         *   arbitrary length data
         *   2 byte length of entire entry
         *   16 byte guid
         */
        guid = (QemuUUID *)(ptr - sizeof(QemuUUID));
        len = le16_to_cpu(*(uint16_t *)(ptr - sizeof(QemuUUID) -
                                        sizeof(uint16_t)));

        /*
         * just in case the table is corrupt, wouldn't want to spin in
         * the zero case
         */
        if (len < sizeof(QemuUUID) + sizeof(uint16_t)) {
            return false;
        } else if (len > tot_len) {
            return false;
        }

        ptr -= len;
        tot_len -= len;
        if (qemu_uuid_is_equal(guid, &entry_guid)) {
            if (data) {
                *data = ptr;
            }
            if (data_len) {
                *data_len = len - sizeof(QemuUUID) - sizeof(uint16_t);
            }
            return true;
        }
    }
    return false;
}

/*
 * Map the pcms->flash[] from 4GiB downward, and realize.
 * Map them in descending order, i.e. pcms->flash[0] at the top,
 * without gaps.
 * Stop at the first pcms->flash[0] lacking a block backend.
 * Set each flash's size from its block backend.  Fatal error if the
 * size isn't a non-zero multiple of 4KiB, or the total size exceeds
 * pcms->max_fw_size.
 *
 * If pcms->flash[0] has a block backend, its memory is passed to
 * pc_isa_bios_init().  Merging several flash devices for isa-bios is
 * not supported.
 */
static void pc_system_flash_map(PCMachineState *pcms,
                                MemoryRegion *rom_memory)
{
    hwaddr total_size = 0;
    int i;
    BlockBackend *blk;
    int64_t size;
    PFlashCFI01 *system_flash;
    MemoryRegion *flash_mem;
    void *flash_ptr;
    int flash_size;
    int ret;

    assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);

    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
        system_flash = pcms->flash[i];
        blk = pflash_cfi01_get_blk(system_flash);
        if (!blk) {
            break;
        }
        size = blk_getlength(blk);
        if (size < 0) {
            error_report("can't get size of block device %s: %s",
                         blk_name(blk), strerror(-size));
            exit(1);
        }
        if (size == 0 || !QEMU_IS_ALIGNED(size, FLASH_SECTOR_SIZE)) {
            error_report("system firmware block device %s has invalid size "
                         "%" PRId64,
                         blk_name(blk), size);
            info_report("its size must be a non-zero multiple of 0x%x",
                        FLASH_SECTOR_SIZE);
            exit(1);
        }
        if ((hwaddr)size != size
            || total_size > HWADDR_MAX - size
            || total_size + size > pcms->max_fw_size) {
            error_report("combined size of system firmware exceeds "
                         "%" PRIu64 " bytes",
                         pcms->max_fw_size);
            exit(1);
        }

        total_size += size;
        qdev_prop_set_uint32(DEVICE(system_flash), "num-blocks",
                             size / FLASH_SECTOR_SIZE);
        sysbus_realize_and_unref(SYS_BUS_DEVICE(system_flash), &error_fatal);
        sysbus_mmio_map(SYS_BUS_DEVICE(system_flash), 0,
                        0x100000000ULL - total_size);

        if (i == 0) {
            flash_mem = pflash_cfi01_get_memory(system_flash);
            pc_isa_bios_init(rom_memory, flash_mem, size);

            /* Encrypt the pflash boot ROM */
            if (sev_enabled()) {
                flash_ptr = memory_region_get_ram_ptr(flash_mem);
                flash_size = memory_region_size(flash_mem);
                /*
                 * OVMF places a GUIDed structures in the flash, so
                 * search for them
                 */
                pc_system_parse_ovmf_flash(flash_ptr, flash_size);

                ret = sev_es_save_reset_vector(flash_ptr, flash_size);
                if (ret) {
                    error_report("failed to locate and/or save reset vector");
                    exit(1);
                }

                sev_encrypt_flash(flash_ptr, flash_size, &error_fatal);
            }
        }
    }
}

void pc_system_firmware_init(PCMachineState *pcms,
                             MemoryRegion *rom_memory)
{
    PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
    int i;
    BlockBackend *pflash_blk[ARRAY_SIZE(pcms->flash)];

    if (!pcmc->pci_enabled) {
        x86_bios_rom_init(MACHINE(pcms), "bios.bin", rom_memory, true);
        return;
    }

    /* Map legacy -drive if=pflash to machine properties */
    for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
        pflash_cfi01_legacy_drive(pcms->flash[i],
                                  drive_get(IF_PFLASH, 0, i));
        pflash_blk[i] = pflash_cfi01_get_blk(pcms->flash[i]);
    }

    /* Reject gaps */
    for (i = 1; i < ARRAY_SIZE(pcms->flash); i++) {
        if (pflash_blk[i] && !pflash_blk[i - 1]) {
            error_report("pflash%d requires pflash%d", i, i - 1);
            exit(1);
        }
    }

    if (!pflash_blk[0]) {
        /* Machine property pflash0 not set, use ROM mode */
        x86_bios_rom_init(MACHINE(pcms), "bios.bin", rom_memory, false);
    } else {
        if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
            /*
             * Older KVM cannot execute from device memory. So, flash
             * memory cannot be used unless the readonly memory kvm
             * capability is present.
             */
            error_report("pflash with kvm requires KVM readonly memory support");
            exit(1);
        }

        pc_system_flash_map(pcms, rom_memory);
    }

    pc_system_flash_cleanup_unused(pcms);
}