aacdb84413
When AMD's SEV memory encryption is in use, flash memory banks (which are initialed by pc_system_flash_map()) need to be encrypted with the guest's key, so that the guest can read them. That's abstracted via the kvm_memcrypt_encrypt_data() callback in the KVM state.. except, that it doesn't really abstract much at all. For starters, the only call site is in code specific to the 'pc' family of machine types, so it's obviously specific to those and to x86 to begin with. But it makes a bunch of further assumptions that need not be true about an arbitrary confidential guest system based on memory encryption, let alone one based on other mechanisms: * it assumes that the flash memory is defined to be encrypted with the guest key, rather than being shared with hypervisor * it assumes that that hypervisor has some mechanism to encrypt data into the guest, even though it can't decrypt it out, since that's the whole point * the interface assumes that this encrypt can be done in place, which implies that the hypervisor can write into a confidential guests's memory, even if what it writes isn't meaningful So really, this "abstraction" is actually pretty specific to the way SEV works. So, this patch removes it and instead has the PC flash initialization code call into a SEV specific callback. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
249 lines
8.5 KiB
C
249 lines
8.5 KiB
C
/*
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* QEMU PC System Firmware
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*
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* Copyright (c) 2003-2004 Fabrice Bellard
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* Copyright (c) 2011-2012 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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#include "qemu-common.h"
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#include "qapi/error.h"
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#include "sysemu/block-backend.h"
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#include "qemu/error-report.h"
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#include "qemu/option.h"
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#include "qemu/units.h"
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#include "hw/sysbus.h"
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#include "hw/i386/x86.h"
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#include "hw/i386/pc.h"
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#include "hw/loader.h"
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#include "hw/qdev-properties.h"
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#include "sysemu/sysemu.h"
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#include "hw/block/flash.h"
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#include "sysemu/kvm.h"
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#include "sysemu/sev.h"
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#define FLASH_SECTOR_SIZE 4096
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static void pc_isa_bios_init(MemoryRegion *rom_memory,
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MemoryRegion *flash_mem,
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int ram_size)
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{
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int isa_bios_size;
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MemoryRegion *isa_bios;
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uint64_t flash_size;
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void *flash_ptr, *isa_bios_ptr;
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flash_size = memory_region_size(flash_mem);
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/* map the last 128KB of the BIOS in ISA space */
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isa_bios_size = MIN(flash_size, 128 * KiB);
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isa_bios = g_malloc(sizeof(*isa_bios));
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memory_region_init_ram(isa_bios, NULL, "isa-bios", isa_bios_size,
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&error_fatal);
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memory_region_add_subregion_overlap(rom_memory,
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0x100000 - isa_bios_size,
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isa_bios,
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1);
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/* copy ISA rom image from top of flash memory */
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flash_ptr = memory_region_get_ram_ptr(flash_mem);
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isa_bios_ptr = memory_region_get_ram_ptr(isa_bios);
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memcpy(isa_bios_ptr,
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((uint8_t*)flash_ptr) + (flash_size - isa_bios_size),
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isa_bios_size);
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memory_region_set_readonly(isa_bios, true);
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}
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static PFlashCFI01 *pc_pflash_create(PCMachineState *pcms,
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const char *name,
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const char *alias_prop_name)
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{
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DeviceState *dev = qdev_new(TYPE_PFLASH_CFI01);
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qdev_prop_set_uint64(dev, "sector-length", FLASH_SECTOR_SIZE);
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qdev_prop_set_uint8(dev, "width", 1);
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qdev_prop_set_string(dev, "name", name);
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object_property_add_child(OBJECT(pcms), name, OBJECT(dev));
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object_property_add_alias(OBJECT(pcms), alias_prop_name,
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OBJECT(dev), "drive");
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/*
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* The returned reference is tied to the child property and
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* will be removed with object_unparent.
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*/
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object_unref(OBJECT(dev));
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return PFLASH_CFI01(dev);
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}
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void pc_system_flash_create(PCMachineState *pcms)
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{
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PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
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if (pcmc->pci_enabled) {
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pcms->flash[0] = pc_pflash_create(pcms, "system.flash0",
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"pflash0");
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pcms->flash[1] = pc_pflash_create(pcms, "system.flash1",
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"pflash1");
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}
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}
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void pc_system_flash_cleanup_unused(PCMachineState *pcms)
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{
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char *prop_name;
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int i;
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Object *dev_obj;
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assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);
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for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
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dev_obj = OBJECT(pcms->flash[i]);
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if (!object_property_get_bool(dev_obj, "realized", &error_abort)) {
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prop_name = g_strdup_printf("pflash%d", i);
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object_property_del(OBJECT(pcms), prop_name);
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g_free(prop_name);
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object_unparent(dev_obj);
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pcms->flash[i] = NULL;
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}
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}
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}
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/*
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* Map the pcms->flash[] from 4GiB downward, and realize.
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* Map them in descending order, i.e. pcms->flash[0] at the top,
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* without gaps.
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* Stop at the first pcms->flash[0] lacking a block backend.
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* Set each flash's size from its block backend. Fatal error if the
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* size isn't a non-zero multiple of 4KiB, or the total size exceeds
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* pcms->max_fw_size.
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*
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* If pcms->flash[0] has a block backend, its memory is passed to
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* pc_isa_bios_init(). Merging several flash devices for isa-bios is
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* not supported.
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*/
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static void pc_system_flash_map(PCMachineState *pcms,
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MemoryRegion *rom_memory)
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{
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hwaddr total_size = 0;
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int i;
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BlockBackend *blk;
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int64_t size;
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PFlashCFI01 *system_flash;
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MemoryRegion *flash_mem;
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void *flash_ptr;
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int flash_size;
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assert(PC_MACHINE_GET_CLASS(pcms)->pci_enabled);
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for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
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system_flash = pcms->flash[i];
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blk = pflash_cfi01_get_blk(system_flash);
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if (!blk) {
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break;
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}
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size = blk_getlength(blk);
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if (size < 0) {
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error_report("can't get size of block device %s: %s",
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blk_name(blk), strerror(-size));
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exit(1);
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}
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if (size == 0 || !QEMU_IS_ALIGNED(size, FLASH_SECTOR_SIZE)) {
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error_report("system firmware block device %s has invalid size "
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"%" PRId64,
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blk_name(blk), size);
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info_report("its size must be a non-zero multiple of 0x%x",
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FLASH_SECTOR_SIZE);
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exit(1);
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}
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if ((hwaddr)size != size
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|| total_size > HWADDR_MAX - size
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|| total_size + size > pcms->max_fw_size) {
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error_report("combined size of system firmware exceeds "
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"%" PRIu64 " bytes",
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pcms->max_fw_size);
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exit(1);
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}
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total_size += size;
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qdev_prop_set_uint32(DEVICE(system_flash), "num-blocks",
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size / FLASH_SECTOR_SIZE);
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sysbus_realize_and_unref(SYS_BUS_DEVICE(system_flash), &error_fatal);
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sysbus_mmio_map(SYS_BUS_DEVICE(system_flash), 0,
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0x100000000ULL - total_size);
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if (i == 0) {
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flash_mem = pflash_cfi01_get_memory(system_flash);
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pc_isa_bios_init(rom_memory, flash_mem, size);
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/* Encrypt the pflash boot ROM, if necessary */
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flash_ptr = memory_region_get_ram_ptr(flash_mem);
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flash_size = memory_region_size(flash_mem);
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sev_encrypt_flash(flash_ptr, flash_size, &error_fatal);
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}
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}
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}
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void pc_system_firmware_init(PCMachineState *pcms,
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MemoryRegion *rom_memory)
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{
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PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
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int i;
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BlockBackend *pflash_blk[ARRAY_SIZE(pcms->flash)];
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if (!pcmc->pci_enabled) {
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x86_bios_rom_init(MACHINE(pcms), "bios.bin", rom_memory, true);
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return;
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}
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/* Map legacy -drive if=pflash to machine properties */
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for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
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pflash_cfi01_legacy_drive(pcms->flash[i],
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drive_get(IF_PFLASH, 0, i));
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pflash_blk[i] = pflash_cfi01_get_blk(pcms->flash[i]);
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}
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/* Reject gaps */
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for (i = 1; i < ARRAY_SIZE(pcms->flash); i++) {
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if (pflash_blk[i] && !pflash_blk[i - 1]) {
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error_report("pflash%d requires pflash%d", i, i - 1);
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exit(1);
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}
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}
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if (!pflash_blk[0]) {
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/* Machine property pflash0 not set, use ROM mode */
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x86_bios_rom_init(MACHINE(pcms), "bios.bin", rom_memory, false);
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} else {
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if (kvm_enabled() && !kvm_readonly_mem_enabled()) {
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/*
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* Older KVM cannot execute from device memory. So, flash
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* memory cannot be used unless the readonly memory kvm
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* capability is present.
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*/
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error_report("pflash with kvm requires KVM readonly memory support");
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exit(1);
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}
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pc_system_flash_map(pcms, rom_memory);
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}
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pc_system_flash_cleanup_unused(pcms);
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}
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