CSMWrap Version 3.1.1

Changelog since CSMWrap 3.1.0

Miscellaneous bug fixes, mostly surrounding the SeaBIOS storage driver code.

Full Changelog: 3.1.0...3.1.1

CSMWrap Version 3.1.0

Changelog since CSMWrap 3.0.1

New Features

• Non-VGA option ROM dispatch - CSMWrap now enumerates legacy x86 option ROMs from non-VGA PCI devices (NIC PXE ROMs, RAID/storage ROMs, etc.) and dispatches them through the CSM, mirroring what a real CSM would do.
• $PIR table synthesis - A PCI BIOS Specification 2.1 $PIR table is now synthesized from ACPI _PRT/_PRS and handed to SeaBIOS so legacy OSes can get non-ACPI PCI IRQ routing.
• Working APM shutdown and reboot - APM Set Power State (off/reboot) now trampolines through the helper core into UEFI's ResetSystem runtime service. Previously these calls were no-ops.
• CPU visibility configuration - Three new csmwrap.ini options (system_thread, cpu_allowlist, cpu_blocklist) let you pin the BIOS proxy helper core to a specific APIC ID and hide arbitrary APs.
• Auto-select GPU with working OpROM - When the primary GPU's option ROM can't be claimed (VGA arbitration fails, no legacy image, oversized ROM), CSMWrap now falls through to the next VGA-class device instead of giving up.
• And more!

Bug Fixes

• Many bug fixes and improvements across PCI, APIC/x2APIC/MP tables, AMD MTRR and PAM unlocking, AMD IOMMU teardown order, GOP/VGA arbitration, e820 generation, and more.

SeaBIOS

• Many bug fixes and improvements across xHCI/EHCI/OHCI/UHCI, AHCI/NVMe/eMMC, and more.

Full Changelog: 3.0.1...3.1.0

CSMWrap Version 3.0.1

Changelog since CSMWrap 3.0.0

Bug Fixes

• ap_trampoline: Skip APIC disable when x2APIC is active, preventing #GP on systems with locked x2APIC (e.g. Nova Lake xAPIC deprecation).
• apic: Clear stale vector bits when configuring LINT0/LINT1 for ExtINT/NMI.
• mptable: Read LAPIC address and version from MSR instead of MADT, fixing x2APIC mode where MMIO LAPIC reads don't work.
• video: Backport GOP quirks and fixes from Limine - reject PixelBltOnly/unknown pixel formats, validate all-zero PixelBitMask, check PixelsPerScanLine, and calculate correct BPP for non-32bpp PixelBitMask modes.

SeaBIOS

• mptable: Use x2APIC MSR for APIC version read when in x2APIC mode.

Full Changelog: 3.0.0...3.0.1

CSMWrap Version 3.0.0

Changelog since CSMWrap 2.1.0

New Features

• INI configuration file support - CSMWrap now reads an optional csmwrap.ini placed alongside the EFI executable. See README.md for available options.
• Runtime-configurable serial output - Serial debug is now controlled via the config file instead of a compile-time flag.
• VGA device selection - A non-primary video card can be selected by PCI address for multi-GPU setups.
• Verbose mode - Screen output is suppressed by default; banner and panics always shown.

Bug Fixes

• Fix framebuffer address double-adjustment during BAR relocation - A PCI bridge's prefetchable and non-prefetchable windows could alias after relocation, causing the framebuffer address to be adjusted twice to a wrong address.
• Fix BIOS proxy helper ready signal race (SeaBIOS) - The helper core now signals ready only after its first mailbox check, eliminating a startup race condition.

Other Changes

• README.md updated with clearer instructions and new FAQ entries and more.

Full Changelog: 2.1.0...3.0.0

CSMWrap Version 2.1.0

Changelog since CSMWrap 2.0.0

Bug Fixes

• Fix heap buffer overflow in uacpi_kernel_io_map() bounds tracking
• Fix find_table buffer overread and add VBIOS size bounds check
• Fix SMBIOS 2.1 entry point checksum covering wrong range
• Fix printf format specifier for EFI_PHYSICAL_ADDRESS on ia32
• Fix off-by-one page count in thunk data allocation
• Fix BAR type check to match exactly type 2 (64-bit) instead of any bit-2-set value
• Fix division by zero in get_nanoseconds_since_boot for sub-1GHz TSC
• Fix get_nanoseconds_since_boot() intermediate overflow
• Fix uACPI-to-MADT interrupt flag conversion for PCI link device routing
• Fix ExitBootServices retry to re-call GetMemoryMap to avoid stale map key
• Guard vbios_loc memcpy against NULL
• Guard __builtin_ffs against zero PixelBitMask to avoid bogus mask position
• Reject extended config space offsets in PIO fallback
• Use -1ULL for EfiAcpiAddressRangeHole to ensure consistent width on ia32
• Widen get_unix_epoch nanosecond parameter to uint32_t to match EFI_TIME
• Re-hide P2SB before early return on ia32 BARH overflow

New Features & Enhancements

• Add TSC calibration, delay functions, and CPUID-based frequency detection (time.c/h)
• Use TSC-based timing for uACPI instead of low-resolution RTC
• Add RDNA 4 (Navi 48/44, 0x75xx) to AMD discrete GPU detection
• Add Lunar Lake (model 0xBD) PIT clock gating workaround
• Initialize CMOS memory registers for legacy software compatibility
• Add panic() function
• Add bounds check for PCI interrupt routing entries
• Warn when pci_early_initialize fails
• Check acpi_init() return value

IOMMU

• Disable VT-d interrupt remapping and queued invalidation
• Add pause instruction to VT-d polling loops
• Remove VT-d polling timeout and unnecessary AMD-Vi polling

Legacy Handoff

• Zero CR3, TR, and GDTR before legacy handoff
• Mask stale LVT entries before legacy handoff
• Send second SIPI per Intel MP spec INIT-SIPI-SIPI sequence
• Hardware-disable helper core LAPIC to prevent stale IPIs from legacy OS
• Remove all MADT entries for helper core (both LAPIC and x2APIC)
• Limit helper core selection to xAPIC-addressable APIC IDs (<255)
• Allocate helper stack as RuntimeServicesData to prevent OS reuse
• Align helper signature to 8 bytes and use aligned 64-bit scan
• Move mailbox out of EBDA
• Invalidate ConOut after ExitBootServices to prevent stale access

Dependencies

• Update uACPI from 3.2.0 to 4.0.0
• Update SeaBIOS submodule

Code Quality

• Convert CRLF line endings to LF
• Replace VLA swap buffer in qsort with fixed-size chunked copy
• Use uintptr_t comparison in memmove to avoid relational pointer UB
• Cache CLFLUSH CPUID check to avoid repeated serializing instruction
• Drop CPUID 0x16 TSC frequency fallback
• Round up delay_us() tick count for sub-MHz timer frequencies
• Check add_bar return value for bridge window BARs
• Remove dead type==0 check in e820 (convert_memory_type never returns 0)
• Remove unused AssignedDriveNumber (SeaBIOS uses BootPriority only)
• Fix misleading PAM0 comments
• Remove double semicolon in PCI code

Full Changelog: 2.0.0...2.1.0

CSMWrap Version 2.0.0

Major New Features

• PCI BAR Relocation - Automatically relocate PCI BARs from >4GB to <4GB, eliminating the need to disable "Above 4G Decoding" in UEFI settings.
• PCIe Resizable BAR Support - Shrink large BARs (e.g., 4GB GPU VRAM) to 256MB using PCIe ReBAR capability, eliminating the need to disable "Resizable Bar/Smart Access Memory" in UEFI settings.
• BIOS Proxy Helper Core - Dedicate an AP for BIOS calls from the BSP. This allows usage of CSMWrap with legacy OSes calling BIOS routines from Virtual 8086 Mode and other improvements.
• MP Table Generation - Generate Intel MPS 1.4 tables from ACPI MADT for legacy OSes that don't support ACPI.
• SMBIOS 3.0 → 2.x Synthesis - Generate SMBIOS 2.x entry point when only 3.0 is available.
• Boot Device Detection - Auto-detect boot drive and build BBS table with correct priority.

Platform Support

• IOMMU Disable - Automatically disable Intel VT-d and AMD-Vi before legacy OS handoff.
• x2APIC Handling - Transition to xAPIC mode if possible or configure ExtINT passthrough for PIC interrupts.
• Intel PIT Workaround - Fix timer interrupts on Arrow Lake, Meteor Lake, Panther Lake.
• AMD RDNA+ Detection - Force SeaVGABIOS for RDNA/RDNA2/RDNA3 GPUs with broken legacy OpROMs.

Video

• Flanterm Integration - Faster, better video output via Flanterm library.
• GOP Modesetting Fixes - Handle Intel iGPU where default mode has FrameBufferBase=0.
• VGA Arbitration - Only claim VGA routing when using OpROM path.

Many other minor fixes and improvements!

Full Changelog: 1.3.0...2.0.0

Many bug fixes and improvements, and reapplication of (fixed versions of) previously reverted commits.

Add support for loading a custom VGA Video BIOS from \EFI\CSMWrap\vgabios.bin, if present.

Merged pull requests

• Update video.c by @Gelip in #92

New Contributors

• @Gelip made their first contribution in #92

Full Changelog: 1.2.3...1.3.0

This is a follow-up to fix regression introduced in previous release (#87).

What's Changed

• Remove a potentially unnecessary statement that increments pmm_base by LOW_STACK_SIZE by @Mintsuki in #84

Full Changelog: 1.2.2...1.2.3

New wiki site

Thanks to @FarelRA and other contributors, we now have a comprehensive documentation collection on our GitHub wiki!

What's Changed

• Docs: Update Project Documentation by @FarelRA
• Full uACPI implementation by @48cf and @Mintsuki
• Many many accumulative improvements by @Mintsuki

New Contributors

• @FarelRA made their first contribution in #52
• @48cf made their first contribution in #54
• @FlyGoat made their first contribution in #81

Full Changelog: 1.2.1...1.2.2

What's Changed

• Accumulative fixes (@Mintsuki, @FlyGoat)
• AHCI fixes for SATA on some systems (@FlyGoat)

Full Changelog: 1.2.0...1.2.1

What's Changed

• Replace POSIX-UEFI with Nyu-EFI and various improvements by @Mintsuki
• Get native VGA OpROM working by @FlyGoat
• Various OS/Platform compatibility fixes by @FlyGoat

Full Changelog: 1.1.0...1.2.0

Implement VGA Arbitration mechanism.