AcpiVTD

Function Table

Address	Name	Description
	GetDxeServicesTable
	GetHobList
	CompareGuid
	DebugPrintErrorLevel
	LocateProtocol
	ParseDmarSubTableType
	InsertDmaRemap
	SortDmarSubTables
	GetDmarTable
	InstallDmarTable
	ReadSetupVariableByte
	AcpiVtdDriverEntryPoint
	UefiMain
Global	data (BSS, initialized at driver load)
UEFI	handle and table pointers
EFI_HANDLE	gImageHandle = NULL; // 0x2450
0x2440	*EFI_BOOT_SERVICES gBootServices = NULL; // 0x2448**
0x2458	*VOID gDsServicesTable = NULL; // 0x2478 (DXE Services Table)**
0x2470	(HOB List)
Protocol	pointers (lazy-located)
VOID	*gPcdProtocol = NULL; // 0x2460 (PCD protocol)
0x2490	(ACPI table protocol)
0x2488	*VOID gSetupProtocol = NULL; // 0x2480 (Setup protocol)**
DMAR	table construction globals
DMA_REMAP_CONTAINER	*mDmarContainer = NULL; // 0x24C8 (primary container pointer)
0x24D0	(= mDmarContainer + 2048)
0x24A0	= 'DMAR' (0x52414D44)
Platform	configuration values (read from setup/PCD)
UINT16	mDmarFlags; // 0x24B0 (DMAR flags word: HAW + INTR_REMAP)
0x24B2	//
Function	pointer table for DMAR sub-table construction callbacks
These	entries come from the setup variable configuration describing
typedef	struct {
GUID	identifying the variable (or sub-table type)
Pointer	to platform data for this sub-table
Size	in bytes of the variable data
Index	0: DRHD hardware unit definitions
Index	1: RMRR region definitions
Index	2: ATSR device definitions
Terminator	};
Helper	functions (library-level, inlined in original binary)
Forward	copy (non-overlapping or src > dst)
Count	= Length >> 3;
Backward	copy to handle overlapping regions
Dst8	*= (UINT8 )Destination + Length - 1;**
Protocol	/ table location helpers
UEFI	setup variable reading
Read	CMOS register 0x4B to determine debug configuration
CmosData	= IoRead8 (0x70);
EFI_D_ERROR	if (CmosData == 1) {
EFI_D_INFO	}
Forward	to the debug protocol if installed
Result	= (BOOLEAN)DEBUG (ErrorLevel, Format);
DMAR	sub-table type parsing
SubType	0 + No flag = DRHD entry
This	is actually subtype 1 (RMRR) because SubType=0 but IsDmarUnit=TRUE
means	the first byte was 0x00 and the second byte 0x01 = LE value 0x0100 = 256.
Real	DMAR sub-tables don't have type 256, this is RMRR.
Type	*0: (UINT32* )v8 = 0x100000 -> bytes 00 00 10**
Type	*1: (UINT32* )v8 = 0x180001 -> byte 01 00 18**
So	for sorting: type 0 has WORD=0, type 1 has WORD=1 (but is checked
in	the binary via the n2 flag, not the actual WORD).
The	ReadDmarSubTableType function in the original checks:
DMAR	sub-table construction (InsertDmaRemap)
Validate	container pointer
if	(DmaRemap == NULL) {
Write	cursor: points to the current end of the container data
WriteCursor	*= (UINT8 )DmaRemap + DmaRemap->Length;**
DRHD	- DMA-Remapping Hardware Unit Definition
Write	DRHD header: Type=0, Flags, Segment, BaseAddress
INCLUDE_PCI_ALL	flag
Append	device scope entries
CurrentLength	*= (UINT16* )(WriteCursor + 2);**
Write	device scope type and bus number
Device	type
Minimum	length (header)
Copy	initial 2 bytes of PCI path data
for	(Index = 0; Index < 2; Index++) {
Append	additional PCI path entries until terminator (0xFF)
ScopeSource	*= (UINT8 )SubTableData +* (UINT64 )((UINT8 )SubTableData + 24)**
RMRR	- Reserved Memory Region Reporting
Write	RMRR header: Type=1, Segment, BaseAddress, EndAddress
Write	device scope header data
Type	ScopeEntry[5] = ScopeSource[2]; // Enumeration data
Minimum	length
Append	PCI path entries
ScopeSource	*= (UINT8 )SubTableData +* (UINT64 )((UINT8 )SubTableData + 32)**
ATSR	- Address Translation Services Reporting
Write	ATSR header: Type=2, Flags, Segment
Type	WriteCursor[4] = Atsr->Flags;
Minimum	length of 8 bytes
Append	device scope entries (only for ATS-capable devices)
for	(DeviceScopeIndex = 0, ScopeDataOffset = 0;
Check	ATS capability mask at SubTableData[16] (UINT32)
if	*((((UINT32* )((UINT8 )SubTableData + 16) >> DeviceScopeIndex) & 1) == 0) {*
Write	device scope header
ScopeSource	+= 16;
RHSA	- Remapping Hardware Status Affinity
Write	RHSA header: Type=3, ProximityDomain, BaseAddress
Type	WriteCursor[16] = (UINT8)(Rhsa->ProximityDomain & 0xFF);
Total	length: 20 bytes
Validate	DMAR table size does not exceed 2KB limit
if	*(DmaRemap->Length >= 2 1024) {**
DMAR	sub-table sorting (SortDmarSubTables)
Skip	DMAR header copy
Start	after header
Sorted	output area
Total	container length
Pass	1: Copy DRHD entries (type 0 where IsDmarUnit is set)
while	(SrcOffset < SrcLength) {
Pass	2: Copy RMRR entries (type 0 where IsDmarUnit is NOT set)
In	the binary, these are the "type 0 entries with !n2 && n21" flag
SrcOffset	= DMAR_HEADER_LENGTH;
Pass	3: Copy RMRR entries (type 1 where IsDmarUnit is NOT set)
This	handles the type-1 entries (actual RMRR)
Pass	4: Copy ATSR entries (type 2 where IsDmarUnit is NOT set)
Pass	5: Copy RHSA entries (type 3)
Get	DMAR Table (GetDmarTable)
Check	if container has sub-table data
if	*((UINT32* )((UINT8 )mDmarContainer + 4) <= DMAR_HEADER_LENGTH) {*
Sort	sub-tables and return pointer to sorted output
SortDmarSubTables	();
DMAR	table installation (InstallDmarTable)
Allocate	DMAR table buffer (6 KB = 0x1800)
DmarBuffer	= AllocateZeroPool (DMAR_TABLE_BUFFER_SIZE);
Initialize	the DMAR table header:
DmarSignature	= DMAR_SIGNATURE;
48	at offset 4
Revision	at offset 8
DmarUnitCount	at offset 24
DeviceScopeCount	at offset 28
Internal	scope count at offset 36
Read	host address width from PCD protocol
if	(GetPcdProtocol () != NULL) {
PCD	protocol offset +32 = Get32 method
PCD	protocol offset +40 = GetN method (returns UINTN)
These	are used to query platform VT-d capability:
PcdVTdHostAddressWidth	-> determines address width field in DMAR
PcdVTdInterruptRemap	-> determines INTR_REMAP flag
PcdValue32	*= ((PCD_PROTOCOL )gPcdProtocol)->Get32 (PcdVTdHostAddressWidth);**
Encode	the address width and interrupt remap capability
into	the DMAR table header fields at offset 10-24
InternalCopyMemChecked	(
Install	the DMAR ACPI table via gBS->InstallAcpiTable
This	corresponds to BootServices[128] (InstallAcpiTable)
with	the registered protocol handle via LocateProtocol(&gAcpiTableGuid)
Signature	used for registration:
Status	= gBootServices->InstallAcpiTable (
Platform	configuration reading (sub_1620 / variable read)
Read	the setup variable
Buffer	= ReadSetupVariable (
Copy	one byte from the buffer
InternalCopyMemChecked	(Variable, Buffer + Offset, 1);
Free	the variable buffer
if	(gAcpiTableProtocolReady) {
Driver	initialization (sub_398 / module entry prologue)
Save	ImageHandle, SystemTable, BootServices, RuntimeServices
gImageHandle	= ImageHandle;
Initialize	HOB list pointer (needed for DMAR table construction)
Status	= GetHobList (&gHobList);
Initialize	DXE Services Table pointer
Status	= GetDxeServicesTable (&gDsServicesTable);
Build	and install the DMAR table
return	InstallDmarTable ();
Module	entry point (UefiMain)

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