1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141
// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
//! PCAT BIOS helper device.
//!
//! A bespoke virtual device that works in-tandem with the custom Hyper-V PCAT
//! BIOS running within the guest.
//!
//! Provides interfaces to fetch various bits of VM machine topology and
//! configuration, along with hooks into various VMM runtime services (e.g:
//! event logging, efficient busy-waiting, generation ID, etc...).
#![warn(missing_docs)]
#![forbid(unsafe_code)]
mod bios_boot_order;
mod default_cmos_values;
mod root_cpu_data;
pub use default_cmos_values::default_cmos_values;
use self::bios_boot_order::bios_boot_order;
use chipset_device::io::deferred::defer_write;
use chipset_device::io::deferred::DeferredToken;
use chipset_device::io::deferred::DeferredWrite;
use chipset_device::io::IoError;
use chipset_device::io::IoResult;
use chipset_device::mmio::MmioIntercept;
use chipset_device::pio::ControlPortIoIntercept;
use chipset_device::pio::PortIoIntercept;
use chipset_device::pio::RegisterPortIoIntercept;
use chipset_device::poll_device::PollDevice;
use chipset_device::ChipsetDevice;
use guestmem::GuestMemory;
use guestmem::MapRom;
use guestmem::UnmapRom;
use inspect::Inspect;
use inspect::InspectMut;
use std::fmt::Debug;
use std::ops::RangeInclusive;
use std::task::Context;
use std::time::Duration;
use thiserror::Error;
use vm_topology::memory::MemoryLayout;
use vm_topology::processor::VpIndex;
use vmcore::device_state::ChangeDeviceState;
use vmcore::vmtime::VmTimeAccess;
use vmcore::vmtime::VmTimeSource;
use zerocopy::AsBytes;
/// Static config info which gets queried by the PCAT BIOS.
pub mod config {
use guid::Guid;
use inspect::Inspect;
use vm_topology::memory::MemoryLayout;
use vm_topology::processor::x86::X86Topology;
use vm_topology::processor::ProcessorTopology;
/// Subset of SMBIOS v2.4 CPU Information structure.
#[derive(Debug, Inspect)]
#[allow(missing_docs)] // self-explanatory fields
pub struct SmbiosProcessorInfoBundle {
pub processor_family: u8,
pub voltage: u8,
pub external_clock: u16,
pub max_speed: u16,
pub current_speed: u16,
}
/// A collection of SMBIOS constants that get reflected into the guest.
///
/// There is a lot of info here, but empirically, it's not _super_ important
/// to make these values 100% accurate...
#[allow(missing_docs)] // self-explanatory fields
#[derive(Debug, Inspect)]
pub struct SmbiosConstants {
pub bios_guid: Guid,
#[inspect(with = "String::from_utf8_lossy")]
pub system_serial_number: Vec<u8>,
#[inspect(with = "String::from_utf8_lossy")]
pub base_board_serial_number: Vec<u8>,
#[inspect(with = "String::from_utf8_lossy")]
pub chassis_serial_number: Vec<u8>,
#[inspect(with = "String::from_utf8_lossy")]
pub chassis_asset_tag: Vec<u8>,
#[inspect(with = "String::from_utf8_lossy")]
pub bios_lock_string: Vec<u8>,
#[inspect(with = "String::from_utf8_lossy")]
pub processor_manufacturer: Vec<u8>,
#[inspect(with = "String::from_utf8_lossy")]
pub processor_version: Vec<u8>,
/// If set to `None`, default UNKNOWN values are used
pub cpu_info_bundle: Option<SmbiosProcessorInfoBundle>,
}
/// A particular kind of boot device PCAT understands.
#[derive(Debug, Clone, Copy, Inspect)]
#[allow(missing_docs)] // self-explanatory variants
pub enum BootDevice {
Floppy = 0,
Optical = 1,
HardDrive = 2,
Network = 3,
}
/// Determines if a boot device is connected or not.
#[derive(Debug, Clone, Copy, Inspect)]
pub struct BootDeviceStatus {
/// Boot device
pub kind: BootDevice,
/// Whether it is physically attached to the system
pub attached: bool,
}
/// PCAT device static configuration data.
#[derive(Debug, Inspect)]
pub struct PcatBiosConfig {
/// Number of VCPUs
pub processor_topology: ProcessorTopology<X86Topology>,
/// The VM's memory layout
pub mem_layout: MemoryLayout,
/// The SRAT ACPI table reflected into the guest
pub srat: Vec<u8>,
/// Initial [Generation Id](generation_id) value
pub initial_generation_id: [u8; 16],
/// Hibernation support
pub hibernation_enabled: bool,
/// Boot device order
#[inspect(iter_by_index)]
pub boot_order: [BootDeviceStatus; 4],
/// If num-lock is enabled at boot
pub num_lock_enabled: bool,
/// Bundle of SMBIOS constants
pub smbios: SmbiosConstants,
}
}
/// PCAT event
#[derive(Debug)]
pub enum PcatEvent {
/// Failed to boot via any boot medium
BootFailure,
/// Attempted to boot (INT19) via BIOS
BootAttempt,
}
/// Platform interface to emit PCAT events.
pub trait PcatLogger: Send {
/// Emit a log corresponding to the provided event.
fn log_event(&self, event: PcatEvent);
}
#[derive(Debug, Inspect)]
struct PcatBiosState {
#[inspect(hex)]
address: u32,
#[inspect(hex)]
read_count: u32,
#[inspect(hex)]
e820_entry: u8,
#[inspect(hex)]
srat_offset: u32,
#[inspect(hex)]
srat_size: u32,
#[inspect(hex)]
port80: u32,
#[inspect(skip)]
entropy: [u8; 64],
entropy_placed: bool,
}
impl PcatBiosState {
fn new() -> Self {
let mut entropy = [0; 64];
getrandom::getrandom(&mut entropy).expect("rng failure");
Self {
address: 0,
read_count: 0,
e820_entry: 0,
srat_offset: 0,
srat_size: 0,
port80: 0,
entropy,
entropy_placed: false,
}
}
}
/// PCAT device runtime dependencies.
#[allow(missing_docs)] // self-explanatory fields
pub struct PcatBiosRuntimeDeps<'a> {
pub gm: GuestMemory,
pub logger: Box<dyn PcatLogger>,
pub generation_id_deps: generation_id::GenerationIdRuntimeDeps,
pub vmtime: &'a VmTimeSource,
/// The BIOS ROM.
///
/// If missing, then assume the ROM is already in memory.
pub rom: Option<Box<dyn MapRom>>,
pub register_pio: &'a mut dyn RegisterPortIoIntercept,
/// Replays the initial MTRRs on all VPs.
pub replay_mtrrs: Box<dyn Send + FnMut()>,
}
/// PCAT BIOS helper device.
#[derive(InspectMut)]
pub struct PcatBiosDevice {
// Fixed configuration
config: config::PcatBiosConfig,
// Runtime glue
vmtime_wait: VmTimeAccess,
gm: GuestMemory,
#[inspect(skip)]
logger: Box<dyn PcatLogger>,
#[inspect(skip)]
_rom_mems: Vec<Box<dyn UnmapRom>>,
pre_boot_pio: PreBootStubbedPio,
#[inspect(skip)]
replay_mtrrs: Box<dyn Send + FnMut()>,
// Sub-emulators
#[inspect(mut)]
generation_id: generation_id::GenerationId,
// Runtime book-keeping
#[inspect(skip)]
deferred_wait: Option<DeferredWrite>,
// Volatile state
state: PcatBiosState,
}
// Begin and end range are inclusive.
const IO_PORT_RANGE_BEGIN: u16 = 0x28;
const IO_PORT_RANGE_END: u16 = 0x2f;
const IO_PORT_ADDR_OFFSET: u16 = 0x0;
const IO_PORT_DATA_OFFSET: u16 = 0x4;
// Reports BIOS POST status.
const POST_IO_PORT: u16 = 0x80;
/// Errors which may occur during PCAT BIOS helper device initialization.
#[derive(Debug, Error)]
#[allow(missing_docs)] // self-explanatory variants
pub enum PcatBiosDeviceInitError {
#[error("expected exactly 2 mmio holes, found {0}")]
IncorrectMmioHoles(usize),
#[error("invalid ROM size {0:x} bytes, expected 256KB")]
InvalidRomSize(u64),
#[error("error mapping ROM")]
Rom(#[source] std::io::Error),
}
impl PcatBiosDevice {
/// Create a new instance of the PCAT BIOS helper device.
pub fn new(
runtime_deps: PcatBiosRuntimeDeps<'_>,
config: config::PcatBiosConfig,
) -> Result<PcatBiosDevice, PcatBiosDeviceInitError> {
let PcatBiosRuntimeDeps {
gm,
logger,
generation_id_deps,
vmtime,
rom,
register_pio,
replay_mtrrs,
} = runtime_deps;
let initial_generation_id = config.initial_generation_id;
if config.mem_layout.mmio().len() != 2 {
return Err(PcatBiosDeviceInitError::IncorrectMmioHoles(
config.mem_layout.mmio().len(),
));
}
let mut rom_mems = Vec::new();
if let Some(rom) = rom {
let rom_size = rom.len();
if rom_size != 0x40000 {
return Err(PcatBiosDeviceInitError::InvalidRomSize(rom_size));
}
// Map the ROM at both high and low memory.
for gpa in [0xfffc0000, 0xf0000] {
let rom_offset = (gpa + rom_size) & 0xfffff;
let len = rom_size - rom_offset;
let mem = rom
.map_rom(gpa, rom_offset, len)
.map_err(PcatBiosDeviceInitError::Rom)?;
rom_mems.push(mem);
}
}
Ok(PcatBiosDevice {
gm,
logger,
config,
state: PcatBiosState::new(),
generation_id: generation_id::GenerationId::new(
initial_generation_id,
generation_id_deps,
),
vmtime_wait: vmtime.access("pcat-wait"),
deferred_wait: None,
_rom_mems: rom_mems,
pre_boot_pio: PreBootStubbedPio::new(register_pio),
replay_mtrrs,
})
}
fn index_using_read_count(&self, data: &[u8]) -> u32 {
let index = (self.state.read_count % 8) as usize * 4;
let mut buffer = [0u8; 4];
for i in 0..4_usize {
if index + i < data.len() {
buffer[i] = data[index + i];
} else {
buffer[i] = b' ';
}
}
u32::from_ne_bytes(buffer)
}
fn read_data(&mut self, addr: u32) -> u32 {
let mut buffer = [0u8; 4];
match PcatAddress(addr) {
PcatAddress::FIRST_MEMORY_BLOCK_SIZE => {
// Consumers: PCAT BIOS in source/bsp/OEM.ASM
//
// Report only the first memory block here as the BIOS really
// isn't structured to deal with gaps between memory blocks.
// This will bound where the BIOS puts things, including the
// ACPI tables, answers to INT 15 E820, etc.
self.config.mem_layout.ram()[0].range.len().to_kb()
}
PcatAddress::NUM_LOCK_ENABLED => self.config.num_lock_enabled as u32,
PcatAddress::BIOS_GUID => {
let index = (self.state.read_count % 4) as usize;
buffer.copy_from_slice(&self.config.smbios.bios_guid.as_bytes()[index * 4..][..4]);
u32::from_ne_bytes(buffer)
}
PcatAddress::BIOS_SYSTEM_SERIAL_NUMBER => {
self.index_using_read_count(self.config.smbios.system_serial_number.as_bytes())
}
PcatAddress::BIOS_BASE_SERIAL_NUMBER => {
self.index_using_read_count(self.config.smbios.base_board_serial_number.as_bytes())
}
PcatAddress::BIOS_CHASSIS_SERIAL_NUMBER => {
self.index_using_read_count(self.config.smbios.chassis_serial_number.as_bytes())
}
PcatAddress::BIOS_CHASSIS_ASSET_TAG => {
self.index_using_read_count(self.config.smbios.chassis_asset_tag.as_bytes())
}
PcatAddress::BOOT_DEVICE_ORDER => bios_boot_order(&self.config.boot_order),
PcatAddress::BIOS_PROCESSOR_COUNT => self.config.processor_topology.vp_count(),
PcatAddress::PROCESSOR_LOCAL_APIC_ID => {
if self.state.read_count < self.config.processor_topology.vp_count() {
self.config
.processor_topology
.vp_arch(VpIndex::new(self.state.read_count))
.apic_id
} else {
!0
}
}
PcatAddress::SRAT_SIZE => self.config.srat.len() as u32,
PcatAddress::SRAT_DATA => {
let srat_chunk = (self.state.srat_offset + self.state.read_count * 4) as usize;
if let Some(data) = self.config.srat.get(srat_chunk..).and_then(|c| c.get(..4)) {
u32::from_ne_bytes(data.try_into().unwrap())
} else {
tracelimit::warn_ratelimited!(
"invalid SRAT offset: {} + {} * 4 < {} - 4",
self.state.srat_offset,
self.state.read_count,
self.config.srat.len()
);
0
}
}
PcatAddress::MEMORY_AMOUNT_ABOVE_4GB => {
// Consumers:
// - vmbios/source/bsp/em/smbios/Smbport.asm,
// - core/src/MEM.ASM.
self.config.mem_layout.ram_above_4gb().to_mb()
}
PcatAddress::SLEEP_STATES => {
// The AMI BIOS wants to read a byte value of flags to determine
// what sleep states (S1...S4) are supported. In the original
// AMI BIOS code, S4 was enabled as:
//
// or aml_buff.AMLDATA.dSx, 8
//
// Our data register is 4-bytes wide, we just fill in the low
// byte (al) here with the S4 flag if it should be set
if self.config.hibernation_enabled {
8
} else {
0
}
}
PcatAddress::PCI_IO_GAP_START => {
self.config.mem_layout.mmio()[0].start().try_into().unwrap()
}
PcatAddress::PROCESSOR_STA_ENABLE => {
// Read by the ACPI _STA (status) method in the Processor
// objects in the PCAT BIOS DSDT. Return zero (not active) for
// any processor whose index exceeds the current active
// processor count.
if self.state.read_count < self.config.processor_topology.vp_count() {
1
} else {
0
}
}
PcatAddress::BIOS_LOCK_STRING => {
self.index_using_read_count(self.config.smbios.bios_lock_string.as_bytes())
}
PcatAddress::MEMORY_ABOVE_HIGH_MMIO => {
// Consumers:
// - vmbios/source/bsp/em/smbios/Smbport.asm,
// - core/src/MEM.ASM.
self.config
.mem_layout
.ram_above_high_mmio()
.expect("validated exactly 2 mmio ranges")
.to_mb()
}
PcatAddress::HIGH_MMIO_GAP_BASE_IN_MB => {
// Consumers:
// - vmbios/source/bsp/em/smbios/Smbport.asm,
// - core/src/MEM.ASM.
self.config.mem_layout.mmio()[1].start().to_mb()
}
PcatAddress::HIGH_MMIO_GAP_LENGTH_IN_MB => {
// Consumers:
// - vmbios/source/bsp/em/smbios/Smbport.asm,
// - core/src/MEM.ASM.
//
// In a classic case of "two wrongs make a right", PCAT expects
// to get _one less_ than the true MMIO region length , as when
// this code was written in Hyper-V, the `end - start`
// calculation used an _inclusive_ `start..=end` range from the
// MMIO gaps API, which wasn't properly compensated for here.
self.config.mem_layout.mmio()[1].len().to_mb() - 1
}
PcatAddress::E820_ENTRY => handle_int15_e820_query(
&self.config.mem_layout,
self.state.e820_entry,
self.state.read_count,
),
PcatAddress::INITIAL_MEGABYTES_BELOW_GAP => {
// Consumers: vmbios/source/bsp/em/smbios/smbios/Smbport.asm
self.config.mem_layout.ram_below_4gb().to_mb()
}
_ => {
tracelimit::warn_ratelimited!(?addr, "unknown bios read");
0xffffffff
}
}
}
fn write_data(
&mut self,
addr: u32,
data: u32,
) -> Result<Option<DeferredToken>, guestmem::GuestMemoryError> {
match PcatAddress(addr) {
PcatAddress::BIOS_PROCESSOR_COUNT => {
// gets poked by the bios for some reason...
}
PcatAddress::SRAT_SIZE => {
if self.config.srat.len() > (data as usize) {
tracelimit::warn_ratelimited!(
data,
len = self.config.srat.len(),
"improper SRAT_SIZE write",
);
}
self.state.srat_size = data;
}
PcatAddress::SRAT_OFFSET => {
if (data as usize) >= self.config.srat.len() || data >= self.state.srat_size {
tracelimit::warn_ratelimited!(
data,
len = self.config.srat.len(),
"improper SRAT_OFFSET write",
);
}
self.state.srat_offset = data;
}
PcatAddress::SRAT_DATA => {
if data == 0 || data == 0xffffffff {
tracelimit::warn_ratelimited!(data, "improper SRAT_DATA write");
}
self.gm.write_at(data as u64, &self.config.srat)?;
}
PcatAddress::BOOT_FINALIZE => {
// The BIOS trashes the originally set MTRRs. Reset them.
(self.replay_mtrrs)();
}
PcatAddress::ENTROPY_TABLE => {
if data == 0 || data == 0xffffffff {
tracelimit::warn_ratelimited!(data, "improper ENTROPY_TABLE write");
}
if !self.state.entropy_placed {
self.gm.write_plain(data as u64, &self.state.entropy)?;
self.state.entropy_placed = true;
}
}
PcatAddress::PROCESSOR_DMTF_TABLE => {
if data == 0 || data == 0xffffffff {
tracelimit::warn_ratelimited!(data, "improper PROCESSOR_DMTF_TABLE write");
}
let cpu_info_legacy = root_cpu_data::get_vp_dmi_info(
self.config.smbios.cpu_info_bundle.as_ref(),
&self.config.smbios.processor_manufacturer,
&self.config.smbios.processor_version,
);
self.gm.write_plain(data as u64, &cpu_info_legacy)?;
}
PcatAddress::PROCESSOR_STA_ENABLE => {
// NOTE: doesn't make a whole lot of sense, but that's what our
// old impl did, so better safe than sorry...
self.state.read_count = data;
}
PcatAddress::WAIT_NANO100 => {
return Ok(Some(
self.defer_wait(Duration::from_nanos(data as u64 * 100)),
))
}
PcatAddress::GENERATION_ID_PTR_LOW => self.generation_id.write_generation_id_low(data),
PcatAddress::GENERATION_ID_PTR_HIGH => {
self.generation_id.write_generation_id_high(data)
}
PcatAddress::E820_ENTRY => {
self.state.e820_entry = data as u8;
}
_ => tracelimit::warn_ratelimited!(addr, data, "unknown bios write"),
}
Ok(None)
}
fn write_address(&mut self, addr: u32) -> Option<DeferredToken> {
// As a side effect of setting the address register, we also reset the
// data register read counter.
self.state.address = addr;
self.state.read_count = 0;
// Some commands do not write to the data register, only the address
// register (so as to save an additional VMEXIT).
match PcatAddress(addr) {
PcatAddress::WAIT1_MILLISECOND => {
return Some(self.defer_wait(Duration::from_millis(1)))
}
PcatAddress::WAIT10_MILLISECONDS => {
return Some(self.defer_wait(Duration::from_millis(10)))
}
PcatAddress::WAIT2_MILLISECOND => {
return Some(self.defer_wait(Duration::from_millis(2)))
}
PcatAddress::REPORT_BOOT_FAILURE => {
tracelimit::info_ratelimited!("pcat boot: failure");
self.stop_pre_boot_pio();
self.logger.log_event(PcatEvent::BootFailure)
}
PcatAddress::REPORT_BOOT_ATTEMPT => {
tracelimit::info_ratelimited!("pcat boot: attempt");
self.stop_pre_boot_pio();
self.logger.log_event(PcatEvent::BootAttempt)
}
_ => {}
}
None
}
fn defer_wait(&mut self, duration: Duration) -> DeferredToken {
tracing::trace!(?duration, "deferring wait request");
self.vmtime_wait
.set_timeout(self.vmtime_wait.now().wrapping_add(duration));
let (write, token) = defer_write();
self.deferred_wait = Some(write);
token
}
/// Unmap the pre-boot PIO stubs if they are active.
/// This should be called before booting into an OS, since
/// the BIOS should no longer try to access these ports.
fn stop_pre_boot_pio(&mut self) {
if self.pre_boot_pio.is_active() {
tracing::info!("disabling pre-boot legacy port-io stubs");
self.pre_boot_pio.unmap();
}
}
}
open_enum::open_enum! {
/// Must match constants in VMCONFIG.EQU
enum PcatAddress: u32 {
FIRST_MEMORY_BLOCK_SIZE = 0x00,
NUM_LOCK_ENABLED = 0x01,
BIOS_GUID = 0x02,
BIOS_SYSTEM_SERIAL_NUMBER = 0x03,
BIOS_BASE_SERIAL_NUMBER = 0x04,
BIOS_CHASSIS_SERIAL_NUMBER = 0x05,
BIOS_CHASSIS_ASSET_TAG = 0x06,
BOOT_DEVICE_ORDER = 0x07,
BIOS_PROCESSOR_COUNT = 0x08,
PROCESSOR_LOCAL_APIC_ID = 0x09,
SRAT_SIZE = 0x0A,
SRAT_OFFSET = 0x0B,
SRAT_DATA = 0x0C,
MEMORY_AMOUNT_ABOVE_4GB = 0x0D,
GENERATION_ID_PTR_LOW = 0x0E,
GENERATION_ID_PTR_HIGH = 0x0F,
SLEEP_STATES = 0x10,
PCI_IO_GAP_START = 0x12,
PROCESSOR_STA_ENABLE = 0x16,
WAIT_NANO100 = 0x17,
WAIT1_MILLISECOND = 0x18,
WAIT10_MILLISECONDS = 0x19,
BOOT_FINALIZE = 0x1A,
WAIT2_MILLISECOND = 0x1B,
BIOS_LOCK_STRING = 0x1C,
PROCESSOR_DMTF_TABLE = 0x1D,
ENTROPY_TABLE = 0x1E,
MEMORY_ABOVE_HIGH_MMIO = 0x1F,
HIGH_MMIO_GAP_BASE_IN_MB = 0x20,
HIGH_MMIO_GAP_LENGTH_IN_MB = 0x21,
E820_ENTRY = 0x22,
INITIAL_MEGABYTES_BELOW_GAP = 0x23,
REPORT_BOOT_FAILURE = 0x3A,
REPORT_BOOT_ATTEMPT = 0x3B,
}
}
/// Handler for PCAT BIOS e820 Enlightenment
///
/// The following documentation is copied wholesale from the OS repo.
///
/// * * *
///
/// The guest OS will discover the parts of GPA space that are populated with
/// usable RAM by using the INT 15 E820 interface. This interface returns one
/// entry of the table per invocation, with an iterator value passed back and
/// forth through EBX.
///
/// Our virtual AMI BIOS is constructed in a way that's difficult to change
/// without odd side effects, as many things look at the E820 table entries
/// internally, and it's not always clear which parts are switched on or off,
/// making changes hard to validate.
///
/// Extending the AMI BIOS to understand an unbounded number of memory blocks,
/// each with a small gap between them is more difficult than just calling out
/// to the worker process and handing it here. On the other hand, some
/// parameters, such as the location of the Extended BIOS Data Area (EBDA) are
/// really BIOS-internal things and moving them to the worker process would be
/// fragile. So the algorithm here is that the BIOS responds to queries about
/// everything involving the first memory block. The BIOS sets itself up within
/// that. Any subsequent memory block is handled here within the worker process.
///
/// From the ACPI spec:
///
/// ```text
/// Input:
///
/// Register | Parameter | Description
/// | |
/// EAX | Function Code | E820
/// | |
/// EBX | Continuation | Contains the loop counter.
/// | |
/// ES:DI | Buffer Ptr | Pointer to a buffer with the table entry.
/// | |
/// ECX | Buffer Size | Size of passed in struct.
/// | |
/// EDX | Signature | 'SMAP'
///
/// Output:
///
/// EAX | Signature | 'SMAP'
/// | |
/// ES:DI | Buffer Ptr | same as input
/// | |
/// ECX | Size | 20 bytes
/// | |
/// EBX | Continuation | Value that the caller should use to get
/// | | the next entry.
///```
///
/// In order to avoid opening an aperture to the guest here, the BIOS takes
/// register contents modified by this function and unpacks them into the
/// caller's buffer.
///
/// The AMI BIOS will subtract the number of entries that it wants to handle
/// internally from EBX before writing it to the BIOS port, so that this
/// function will see indices starting with 0.
///
/// So we return to the guest using this port as a FIFO. Each successive read
/// returns a different part of the data:
///
/// ```text
/// 0 (b:0) | 1 == "entry exists"
/// 0 (b:1) | 0 == "memory", 1 == "reserved"
/// 0 (b:2) | 0 == "last entry", 1 == "there's more data"
/// 0 (31:3) | Length in megabytes low (48:20)
/// 1 | Base Address Low
/// 2 | Base Address High
/// ```
fn handle_int15_e820_query(mem_layout: &MemoryLayout, e820_entry: u8, read_count: u32) -> u32 {
// The first memory range is the one that the BIOS itself knows about, and
// the one for which the BIOS will answer the guest OS's questions. This is
// done because the BIOS places various tables (EBDA, ACPI "reclaim", ACPI
// NVS, etc.) in this memory block, carving things out of it.
//
// The BIOS, on the other hand, has no idea, at least in the core BIOS code,
// that the other memory blocks exist. This is necessary because there can
// be a series of gaps between memory blocks that are hard to accommodate
// within the BIOS. For reporting things above the gaps, this function looks
// at the upper memory blocks.
let index = (e820_entry + 1) as usize;
// Special case: if there is only a single RAM range, no error should be
// logged + zero should be returned, indicating that there are no further
// RAM regions.
if e820_entry == 0 && mem_layout.ram().len() == 1 {
return 0;
}
let Some(ram) = mem_layout.ram().get(index) else {
tracelimit::warn_ratelimited!(?e820_entry, "unexpected e820 entry");
return 0;
};
match read_count {
0 => {
let mut data = 1; // entry exists
data |= if index + 1 != mem_layout.ram().len() {
0b100 // more data
} else {
0 // last entry
};
data |= ram.range.len().to_mb() << 3; // clamp reported RAM to the nearest megabyte
data
}
1 => ram.range.start() as u32,
2 => (ram.range.start() >> 32) as u32,
_ => {
tracelimit::warn_ratelimited!(?read_count, "invalid E820 read count");
0
}
}
}
impl ChangeDeviceState for PcatBiosDevice {
fn start(&mut self) {}
async fn stop(&mut self) {}
async fn reset(&mut self) {
self.generation_id.reset();
self.state = PcatBiosState::new();
}
}
impl ChipsetDevice for PcatBiosDevice {
fn supports_pio(&mut self) -> Option<&mut dyn PortIoIntercept> {
Some(self)
}
fn supports_mmio(&mut self) -> Option<&mut dyn MmioIntercept> {
Some(self)
}
fn supports_poll_device(&mut self) -> Option<&mut dyn PollDevice> {
Some(self)
}
}
impl PollDevice for PcatBiosDevice {
fn poll_device(&mut self, cx: &mut Context<'_>) {
self.generation_id.poll(cx);
while self.vmtime_wait.poll_timeout(cx).is_ready() {
if let Some(deferred) = self.deferred_wait.take() {
tracing::trace!("releasing deferred wait");
deferred.complete();
}
}
}
}
impl MmioIntercept for PcatBiosDevice {
fn mmio_read(&mut self, _addr: u64, _data: &mut [u8]) -> IoResult {
tracelimit::error_ratelimited!("firmware should be mapped, should not be visible as MMIO");
IoResult::Ok
}
fn mmio_write(&mut self, addr: u64, _data: &[u8]) -> IoResult {
match addr {
0xf5bea | 0xf5bfa => {
// There is a bug in the firmware's throttle_getchar_FAR
// enlightenment: it expects to write to a value in the ROM
// segment, but this is not writable after POST. Just ignore
// this, it means that getchar is not actually throttled after
// POST (e.g. in DOS).
}
_ => tracelimit::warn_ratelimited!(addr, "unexpected firmware write"),
}
IoResult::Ok
}
fn get_static_regions(&mut self) -> &[(&str, RangeInclusive<u64>)] {
&[
("rom-low", 0xf0000..=0xfffff),
("rom-high", 0xfffc_0000..=0xffff_ffff),
]
}
}
impl PortIoIntercept for PcatBiosDevice {
fn io_read(&mut self, io_port: u16, data: &mut [u8]) -> IoResult {
if io_port == POST_IO_PORT {
data.copy_from_slice(&self.state.port80.to_ne_bytes()[..data.len()]);
return IoResult::Ok;
}
if self.pre_boot_pio.contains_port(io_port) {
tracing::trace!(?io_port, "stubbed pre-boot pio read");
data.fill(!0);
return IoResult::Ok;
}
// Some OSes probe for an 8-bit superio device at this location,
// silence the logs generated by this.
if io_port == 0x2f && data.len() == 1 {
tracing::trace!(?io_port, "stubbed superio pio read");
data.fill(!0);
return IoResult::Ok;
}
if data.len() != 4 {
return IoResult::Err(IoError::InvalidAccessSize);
}
let offset = io_port - IO_PORT_RANGE_BEGIN;
let v = match offset {
IO_PORT_ADDR_OFFSET => self.state.address,
IO_PORT_DATA_OFFSET => self.read_data(self.state.address),
_ => return IoResult::Err(IoError::InvalidRegister),
};
data.copy_from_slice(&v.to_ne_bytes());
tracing::trace!(
offset,
address = self.state.address,
read_count = self.state.read_count,
value = v,
"bios read",
);
if offset == IO_PORT_DATA_OFFSET {
self.state.read_count += 1;
}
IoResult::Ok
}
fn io_write(&mut self, io_port: u16, data: &[u8]) -> IoResult {
if io_port == POST_IO_PORT {
let mut v = [0; 4];
v[..data.len()].copy_from_slice(data);
let data = u32::from_ne_bytes(v);
tracing::debug!(data, "pcat boot: checkpoint");
// magic number specific to PCAT BIOS
const AT_END_POST_CHECKPOINT: u32 = 0x50ac;
if data == AT_END_POST_CHECKPOINT {
self.stop_pre_boot_pio();
}
// Store the port 80 data. Consider keeping a ring of
// these for inspect in the future.
self.state.port80 = data;
return IoResult::Ok;
}
if self.pre_boot_pio.contains_port(io_port) {
tracing::trace!(?io_port, ?data, "stubbed pre-boot pio write");
return IoResult::Ok;
}
// Some OSes probe for an 8-bit superio device at this location,
// silence the logs generated by this.
if io_port == 0x2e && data.len() == 1 {
tracing::trace!(?io_port, ?data, "stubbed superio pio write");
return IoResult::Ok;
}
if data.len() != 4 {
return IoResult::Err(IoError::InvalidAccessSize);
}
let offset = io_port - IO_PORT_RANGE_BEGIN;
let v = u32::from_ne_bytes(data.try_into().unwrap());
let r = match offset {
IO_PORT_ADDR_OFFSET => Ok(self.write_address(v)),
IO_PORT_DATA_OFFSET => self.write_data(self.state.address, v),
_ => return IoResult::Err(IoError::InvalidRegister),
};
match r {
Ok(Some(token)) => return IoResult::Defer(token),
Ok(None) => {}
Err(err) => {
tracelimit::warn_ratelimited!(
error = &err as &dyn std::error::Error,
"bios command error"
);
}
}
tracing::trace!(
offset,
address = self.state.address,
read_count = self.state.read_count,
data = v,
"bios write",
);
IoResult::Ok
}
fn get_static_regions(&mut self) -> &[(&str, RangeInclusive<u16>)] {
&[
("pcat_bios", IO_PORT_RANGE_BEGIN..=IO_PORT_RANGE_END),
// NOTE: POST port 0x80 might overlap with a an ISA DMA page register.
("post", POST_IO_PORT..=POST_IO_PORT),
]
}
}
/// Helper trait to convert bytes to various other units
trait ConvertBytes {
/// Convert from bytes to megabytes
fn to_mb(self) -> u32;
/// Convert from bytes to kiloytes
fn to_kb(self) -> u32;
}
impl ConvertBytes for u64 {
fn to_mb(self) -> u32 {
(self >> 20).try_into().unwrap()
}
fn to_kb(self) -> u32 {
(self >> 10).try_into().unwrap()
}
}
/// Encapsulates ownership over various legacy port io locations that the PCAT
/// BIOS attempts to access during init.
///
/// We don't implement any of the devices backing these ports, so in order to
/// cut down on the large amount of "unknown device" logging, we claim these
/// ports for the PCAT BIOS helper device during pre-boot, and then release
/// ownership post-boot.
#[derive(Inspect)]
struct PreBootStubbedPio {
#[inspect(iter_by_index)]
ranges: Vec<Box<dyn ControlPortIoIntercept>>,
}
impl PreBootStubbedPio {
const LEN_PORT: &'static [(u16, u16)] = &[
// ISA PnP
(1, 0x279), // index
(1, 0xa79), // write data port
(1, 0x20b), // initial value for read data port
(1, 0x20f), // ...which PCAT will increment by 4
(1, 0x213),
(1, 0x217),
(1, 0x21b),
(1, 0x21f),
(1, 0x223),
(1, 0x227), // ...until it gives up (after 8x tries)
// something to do with archaic dual VGA init?
(2, 0x102),
(2, 0x46e8),
// something to do with piix4 "routing ports"?
(1, 0xeb),
// (1, 0xed), // gets claimed as part of the 0xED IO port delay device
(1, 0xee),
// no idea ¯\_(ツ)_/¯
(1, 0x6f0),
];
fn new(register_pio: &mut dyn RegisterPortIoIntercept) -> PreBootStubbedPio {
let mut ranges = Vec::new();
for &(len, port) in Self::LEN_PORT {
let mut control = register_pio.new_io_region("legacy-port-stub", len);
control.map(port);
ranges.push(control)
}
PreBootStubbedPio { ranges }
}
fn is_active(&self) -> bool {
!self.ranges.is_empty()
}
fn unmap(&mut self) {
for mut range in self.ranges.drain(..) {
range.unmap()
}
}
fn contains_port(&self, port: u16) -> bool {
if !self.is_active() {
return false;
}
Self::LEN_PORT
.iter()
.any(|&(len, p)| (p..p + len).contains(&port))
}
}
mod save_restore {
use super::*;
use vmcore::save_restore::RestoreError;
use vmcore::save_restore::SaveError;
use vmcore::save_restore::SaveRestore;
mod state {
use generation_id::GenerationId;
use mesh::payload::Protobuf;
use vmcore::save_restore::SaveRestore;
use vmcore::save_restore::SavedStateRoot;
#[derive(Protobuf, SavedStateRoot)]
#[mesh(package = "firmware.pcat")]
pub struct SavedState {
#[mesh(1)]
pub address: u32,
#[mesh(2)]
pub read_count: u32,
#[mesh(3)]
pub e820_entry: u8,
#[mesh(4)]
pub srat_offset: u32,
#[mesh(5)]
pub srat_size: u32,
#[mesh(6)]
pub port80: u32,
#[mesh(7)]
pub entropy: [u8; 64],
#[mesh(8)]
pub entropy_placed: bool,
#[mesh(9)]
pub genid: <GenerationId as SaveRestore>::SavedState,
}
}
impl SaveRestore for PcatBiosDevice {
type SavedState = state::SavedState;
fn save(&mut self) -> Result<Self::SavedState, SaveError> {
let PcatBiosState {
address,
read_count,
e820_entry,
srat_offset,
srat_size,
port80,
entropy,
entropy_placed,
} = self.state;
let saved_state = state::SavedState {
address,
read_count,
e820_entry,
srat_offset,
srat_size,
port80,
entropy,
entropy_placed,
genid: self.generation_id.save()?,
};
// sanity check that there aren't any outstanding deferred IOs
assert!(self.deferred_wait.is_none());
Ok(saved_state)
}
fn restore(&mut self, state: Self::SavedState) -> Result<(), RestoreError> {
let state::SavedState {
address,
read_count,
e820_entry,
srat_offset,
srat_size,
port80,
entropy,
entropy_placed,
genid,
} = state;
self.state = PcatBiosState {
address,
read_count,
e820_entry,
srat_offset,
srat_size,
port80,
entropy,
entropy_placed,
};
self.generation_id.restore(genid)?;
Ok(())
}
}
}