#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/MemEncryptSevLib.h>
#include <Library/MemEncryptTdxLib.h>
#include <Library/PcdLib.h>
#include <Library/SynchronizationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include "IoMmuInternal.h"

Macros
#define	SIZE_OF_MEM_RANGE(MemRange) (MemRange->HeaderSize + MemRange->DataSize)

#define	RESERVED_MEM_BITMAP_4K_MASK 0xf

#define	RESERVED_MEM_BITMAP_32K_MASK 0xff0

#define	RESERVED_MEM_BITMAP_128K_MASK 0x3000

#define	RESERVED_MEM_BITMAP_1M_MASK 0x40000

#define	RESERVED_MEM_BITMAP_2M_MASK 0x180000

#define	RESERVED_MEM_BITMAP_MASK 0x1fffff

Functions
STATIC UINT32	CalcuateReservedMemSize (VOID)

EFI_STATUS	IoMmuInitReservedSharedMem (VOID)

EFI_STATUS	IoMmuReleaseReservedSharedMem (BOOLEAN MemoryMapLocked)

STATIC EFI_STATUS	InternalAllocateBuffer (IN EFI_ALLOCATE_TYPE Type, IN EFI_MEMORY_TYPE MemoryType, IN UINTN Pages, OUT UINT32 ReservedMemBit, IN OUT EFI_PHYSICAL_ADDRESS PhysicalAddress)

EFI_STATUS	IoMmuAllocateBounceBuffer (IN EFI_ALLOCATE_TYPE Type, IN EFI_MEMORY_TYPE MemoryType, IN OUT MAP_INFO *MapInfo)

STATIC VOID	ClearReservedMemBit (IN UINT32 ReservedMemBit)

EFI_STATUS	IoMmuFreeBounceBuffer (IN OUT MAP_INFO *MapInfo)

EFI_STATUS	IoMmuAllocateCommonBuffer (IN EFI_MEMORY_TYPE MemoryType, IN UINTN CommonBufferPages, OUT EFI_PHYSICAL_ADDRESS PhysicalAddress, OUT UINT32 ReservedMemBitmap)

EFI_STATUS	IoMmuFreeCommonBuffer (IN COMMON_BUFFER_HEADER *CommonBufferHeader, IN UINTN CommonBufferPages)

Variables
BOOLEAN	mReservedSharedMemSupported

STATIC IOMMU_RESERVED_MEM_RANGE	mReservedMemRanges []

STATIC UINT32	mReservedMemBitmap = 0

STATIC EFI_PHYSICAL_ADDRESS	mReservedSharedMemAddress = 0

STATIC UINT32	mReservedSharedMemSize = 0

Detailed Description

SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file IoMmuBuffer.c.

Macro Definition Documentation

◆ RESERVED_MEM_BITMAP_128K_MASK

#define RESERVED_MEM_BITMAP_128K_MASK 0x3000

Definition at line 25 of file IoMmuBuffer.c.

◆ RESERVED_MEM_BITMAP_1M_MASK

#define RESERVED_MEM_BITMAP_1M_MASK 0x40000

Definition at line 26 of file IoMmuBuffer.c.

◆ RESERVED_MEM_BITMAP_2M_MASK

#define RESERVED_MEM_BITMAP_2M_MASK 0x180000

Definition at line 27 of file IoMmuBuffer.c.

◆ RESERVED_MEM_BITMAP_32K_MASK

#define RESERVED_MEM_BITMAP_32K_MASK 0xff0

Definition at line 24 of file IoMmuBuffer.c.

◆ RESERVED_MEM_BITMAP_4K_MASK

#define RESERVED_MEM_BITMAP_4K_MASK 0xf

Definition at line 23 of file IoMmuBuffer.c.

◆ RESERVED_MEM_BITMAP_MASK

#define RESERVED_MEM_BITMAP_MASK 0x1fffff

Definition at line 28 of file IoMmuBuffer.c.

◆ SIZE_OF_MEM_RANGE

#define SIZE_OF_MEM_RANGE ( MemRange ) (MemRange->HeaderSize + MemRange->DataSize)

Definition at line 21 of file IoMmuBuffer.c.

Function Documentation

◆ CalcuateReservedMemSize()

STATIC UINT32 CalcuateReservedMemSize ( VOID )

Calculate the size of reserved memory.

Return values

UINT32 Size of the reserved memory

Definition at line 94 of file IoMmuBuffer.c.

◆ ClearReservedMemBit()

STATIC VOID ClearReservedMemBit ( IN UINT32 ReservedMemBit )

Clear a bit in the reserved memory bitmap in a thread safe manner

Parameters

ReservedMemBit The bit to clear

Definition at line 399 of file IoMmuBuffer.c.

◆ InternalAllocateBuffer()

STATIC EFI_STATUS InternalAllocateBuffer	(	IN EFI_ALLOCATE_TYPE	Type,
		IN EFI_MEMORY_TYPE	MemoryType,
		IN UINTN	Pages,
		OUT UINT32 *	ReservedMemBit,
		IN OUT EFI_PHYSICAL_ADDRESS *	PhysicalAddress
	)

Allocate from the reserved memory pool. If the reserved shared memory is exausted or there is no suitalbe size, it turns to the LegacyAllocateBuffer.

Parameters

Type	Allocate type
MemoryType	The memory type to be allocated
Pages	Pages to be allocated.
ReservedMemBitmap	Bitmap of the allocated memory region
PhysicalAddress	Pointer to the data part of allocated memory region

Return values

EFI_SUCCESS	Successfully allocate the buffer
Other	As the error code indicates

Definition at line 268 of file IoMmuBuffer.c.

◆ IoMmuAllocateBounceBuffer()

EFI_STATUS IoMmuAllocateBounceBuffer	(	IN EFI_ALLOCATE_TYPE	Type,
		IN EFI_MEMORY_TYPE	MemoryType,
		IN OUT MAP_INFO *	MapInfo
	)

Allocate reserved shared memory for bounce buffer.

Parameters

Type	Allocate type
MemoryType	The memory type to be allocated
MapInfo	Pointer to the MAP_INFO

Return values

EFI_SUCCESS	Successfully allocate the bounce buffer
Other	As the error code indicates

Definition at line 372 of file IoMmuBuffer.c.

◆ IoMmuAllocateCommonBuffer()

EFI_STATUS IoMmuAllocateCommonBuffer	(	IN EFI_MEMORY_TYPE	MemoryType,
		IN UINTN	CommonBufferPages,
		OUT EFI_PHYSICAL_ADDRESS *	PhysicalAddress,
		OUT UINT32 *	ReservedMemBitmap
	)

Allocate CommonBuffer from pre-allocated shared memory.

Parameters

MemoryType	Memory type
CommonBufferPages	Pages of CommonBuffer
PhysicalAddress	Allocated physical address
ReservedMemBitmap	Bitmap which indicates the allocation of reserved memory

Return values

EFI_SUCCESS	Successfully allocate the common buffer
Other	As the error code indicates

Definition at line 457 of file IoMmuBuffer.c.

◆ IoMmuFreeBounceBuffer()

EFI_STATUS IoMmuFreeBounceBuffer ( IN OUT MAP_INFO * MapInfo )

Free the bounce buffer allocated in IoMmuAllocateBounceBuffer.

Parameters

MapInfo Pointer to the MAP_INFO

Returns: EFI_SUCCESS Successfully free the bounce buffer.

Definition at line 421 of file IoMmuBuffer.c.

◆ IoMmuFreeCommonBuffer()

EFI_STATUS IoMmuFreeCommonBuffer	(	IN COMMON_BUFFER_HEADER *	CommonBufferHeader,
		IN UINTN	CommonBufferPages
	)

Free CommonBuffer which is allocated by IoMmuAllocateCommonBuffer().

Parameters

CommonBufferHeader	Pointer to the CommonBufferHeader
CommonBufferPages	Pages of CommonBuffer

Return values

EFI_SUCCESS	Successfully free the common buffer
Other	As the error code indicates

Definition at line 492 of file IoMmuBuffer.c.

◆ IoMmuInitReservedSharedMem()

EFI_STATUS IoMmuInitReservedSharedMem ( VOID )

Allocate a memory region and convert it to be shared. This memory region will be used in the DMA operation.

The pre-alloc memory contains pieces of memory regions with different size. The allocation of the shared memory regions are indicated by a 32-bit bitmap (mReservedMemBitmap).

The memory regions are consumed by IoMmuAllocateBuffer (in which CommonBuffer is allocated) and IoMmuMap (in which bounce buffer is allocated).

The CommonBuffer contains 2 parts, one page for CommonBufferHeader which is private memory, the other part is shared memory. So the layout of a piece of memory region after initialization looks like:

|------------|----------------------------|
| Header     |    Data                    |  <-- a piece of pre-alloc memory region
| 4k, private| 4k/32k/128k/etc, shared    |
|-----------------------------------------|

Return values

EFI_SUCCESS	Successfully initialize the reserved memory.
EFI_UNSUPPORTED	This feature is not supported.

Definition at line 136 of file IoMmuBuffer.c.

◆ IoMmuReleaseReservedSharedMem()

EFI_STATUS IoMmuReleaseReservedSharedMem ( BOOLEAN MemoryMapLocked )

Release the pre-alloc shared memory.

Return values

EFI_SUCCESS Successfully release the shared memory

Definition at line 203 of file IoMmuBuffer.c.

Variable Documentation

◆ mReservedMemBitmap

STATIC UINT32 mReservedMemBitmap = 0

Definition at line 75 of file IoMmuBuffer.c.

◆ mReservedMemRanges

STATIC IOMMU_RESERVED_MEM_RANGE mReservedMemRanges[]

Initial value:

= {
  { RESERVED_MEM_BITMAP_4K_MASK,   0,  4, SIZE_4KB,   SIZE_4KB, 0 },
  { RESERVED_MEM_BITMAP_32K_MASK,  4,  8, SIZE_32KB,  SIZE_4KB, 0 },
  { RESERVED_MEM_BITMAP_128K_MASK, 12, 2, SIZE_128KB, SIZE_4KB, 0 },
  { RESERVED_MEM_BITMAP_1M_MASK,   14, 1, SIZE_1MB,   SIZE_4KB, 0 },
  { RESERVED_MEM_BITMAP_2M_MASK,   15, 2, SIZE_2MB,   SIZE_4KB, 0 },
}

mReservedMemRanges describes the layout of the reserved memory. The reserved memory consists of disfferent size of memory region. The pieces of memory with the same size are managed by one entry in the mReservedMemRanges. All the pieces of memories are managed by mReservedMemBitmap which is a UINT32. It means it can manage at most 32 pieces of memory. Because of the layout of CommonBuffer (1-page header + n-page data), a piece of reserved memory consists of 2 parts: Header + Data.

So put all these together, mReservedMemRanges and mReservedMemBitmap are designed to manage the reserved memory.

Use the second entry of mReservedMemRanges as an example. { RESERVED_MEM_BITMAP_32K_MASK, 4, 8, SIZE_32KB, SIZE_4KB, 0 },

RESERVED_MEM_BITMAP_32K_MASK is 0xff0. It means bit4-11 in mReservedMemBitmap is reserved for 32K size memory.
4 is the shift of mReservedMemBitmap.
8 means there are 8 pieces of 32K size memory.
SIZE_32KB indicates the size of Data part.
SIZE_4KB is the size of Header part.
0 is the start address of this memory range which will be populated when the reserved memory is initialized.

The size and count of the memory region are derived from the experience. For a typical grub boot, there are about 5100 IoMmu/DMA operation. Most of these DMA operation require the memory with size less than 32K (~5080). But we find in grub boot there may be 2 DMA operation which require for the memory larger than 1M. And these 2 DMA operation occur concurrently. So we reserve 2 pieces of memory with size of SIZE_2MB. This is for the best boot performance.

If all the reserved memory are exausted, then it will fall back to the legacy memory allocation as before.

Definition at line 64 of file IoMmuBuffer.c.

◆ mReservedSharedMemAddress

STATIC EFI_PHYSICAL_ADDRESS mReservedSharedMemAddress = 0

Definition at line 80 of file IoMmuBuffer.c.

◆ mReservedSharedMemSize

STATIC UINT32 mReservedSharedMemSize = 0

Definition at line 85 of file IoMmuBuffer.c.

◆ mReservedSharedMemSupported

BOOLEAN mReservedSharedMemSupported

extern

Definition at line 30 of file CcIoMmu.c.

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ RESERVED_MEM_BITMAP_128K_MASK

◆ RESERVED_MEM_BITMAP_1M_MASK

◆ RESERVED_MEM_BITMAP_2M_MASK

◆ RESERVED_MEM_BITMAP_32K_MASK

◆ RESERVED_MEM_BITMAP_4K_MASK

◆ RESERVED_MEM_BITMAP_MASK

◆ SIZE_OF_MEM_RANGE

Function Documentation

◆ CalcuateReservedMemSize()

◆ ClearReservedMemBit()

◆ InternalAllocateBuffer()

◆ IoMmuAllocateBounceBuffer()

◆ IoMmuAllocateCommonBuffer()

◆ IoMmuFreeBounceBuffer()

◆ IoMmuFreeCommonBuffer()

◆ IoMmuInitReservedSharedMem()

◆ IoMmuReleaseReservedSharedMem()

Variable Documentation

◆ mReservedMemBitmap

◆ mReservedMemRanges

◆ mReservedSharedMemAddress

◆ mReservedSharedMemSize

◆ mReservedSharedMemSupported