[edk2-devel] [PATCH V1 1/3] OvmfPkg/IoMmuDxe: Reserve shared memory region for DMA operation
Yao, Jiewen
jiewen.yao at intel.com
Fri Dec 9 14:28:28 UTC 2022
Hi Min
Thanks for the contribution.
It is good performance improvement.
Would you please add more description for below ReservedMemRanges?
---------
STATIC IOMMU_RESERVED_MEM_RANGE mReservedMemRanges[] = {
---------
Please add comment to describe:
1) How the pre-allocated memory is managed?
2) What if the pre-allocated memory is used up?
With comment change, patch 1~3 from Min Xu: reviewed-by Jiewen Yao <Jiewen.yao at intel.com>
SEV patch (OvmfPkg/IoMmuDxe: Add SEV support for reserved shared memory) from Tom Lendacky: acked-by: Jiewen Yao <jiewen.yao at intel.com>
Thank you
Yao, Jiewen
> -----Original Message-----
> From: Yao, Jiewen
> Sent: Tuesday, December 6, 2022 1:21 AM
> To: Tom Lendacky <thomas.lendacky at amd.com>; Xu, Min M
> <min.m.xu at intel.com>; devel at edk2.groups.io
> Cc: Aktas, Erdem <erdemaktas at google.com>; James Bottomley
> <jejb at linux.ibm.com>; Gerd Hoffmann <kraxel at redhat.com>
> Subject: RE: [PATCH V1 1/3] OvmfPkg/IoMmuDxe: Reserve shared memory
> region for DMA operation
>
> I suggest it be in same PR, and different patch. (E.g. the last one for SEV)
>
>
>
> > -----Original Message-----
> > From: Tom Lendacky <thomas.lendacky at amd.com>
> > Sent: Tuesday, December 6, 2022 12:48 AM
> > To: Xu, Min M <min.m.xu at intel.com>; devel at edk2.groups.io
> > Cc: Aktas, Erdem <erdemaktas at google.com>; James Bottomley
> > <jejb at linux.ibm.com>; Yao, Jiewen <jiewen.yao at intel.com>; Gerd
> > Hoffmann <kraxel at redhat.com>
> > Subject: Re: [PATCH V1 1/3] OvmfPkg/IoMmuDxe: Reserve shared
> memory
> > region for DMA operation
> >
> > On 12/5/22 02:08, Min Xu wrote:
> > > From: Min M Xu <min.m.xu at intel.com>
> > >
> > > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4171
> > >
> > > A typical QEMU fw_cfg read bytes with IOMMU for td guest is that:
> > > (QemuFwCfgReadBytes at QemuFwCfgLib.c is the example)
> > > 1) Allocate DMA Access buffer
> > > 2) Map actual data buffer
> > > 3) start the transfer and wait for the transfer to complete
> > > 4) Free DMA Access buffer
> > > 5) Un-map actual data buffer
> > >
> > > In step 1/2, Private memories are allocated, converted to shared
> > memories.
> > > In Step 4/5 the shared memories are converted to private memories
> and
> > > accepted again. The final step is to free the pages.
> > >
> > > This is time-consuming and impacts td guest's boot perf (both direct
> boot
> > > and grub boot) badly.
> > >
> > > In a typical grub boot, there are about 5000 calls of page allocation and
> > > private/share conversion. Most of page size is less than 32KB.
> > >
> > > This patch allocates a memory region and initializes it into pieces of
> > > memory with different sizes. A piece of such memory consists of 2 parts:
> > > the first page is of private memory, and the other pages are shared
> > > memory. This is to meet the layout of common buffer.
> > >
> > > When allocating bounce buffer in IoMmuMap(),
> > IoMmuAllocateBounceBuffer()
> > > is called to allocate the buffer. Accordingly when freeing bounce buffer
> > > in IoMmuUnmapWorker(), IoMmuFreeBounceBuffer() is called to free
> the
> > > bounce buffer. CommonBuffer is allocated by
> > IoMmuAllocateCommonBuffer
> > > and accordingly freed by IoMmuFreeCommonBuffer.
> > >
> > > This feature is tested in Intel TDX pre-production platform. It saves up
> > > to hundreds of ms in a grub boot.
> >
> > This crashes SEV guests. I presume because the call to
> > IoMmuReleaseReservedSharedMem() is not bracketed by a check for TDX.
> >
> > I plan to add support for SEV, which would avoid the crash, not sure if
> > you want to integrate it into a single series or not. Here's the patch I
> > was looking to add that should be pretty easy to integrate. Let me know if
> > you would like to integrate it in your series or just have me submit it as
> > a reply to your series:
> >
> >
> > OvmfPkg/IoMmuDxe: Add SEV support for reserved shared memory
> >
> > From: Tom Lendacky <thomas.lendacky at amd.com>
> >
> > Add support to use the reserved shared memory within the IoMmu
> library.
> > This improves boot times for all SEV guests, with SEV-SNP benefiting the
> > most as it avoids the page state change call to the hypervisor.
> >
> > Signed-off-by: Tom Lendacky <thomas.lendacky at amd.com>
> > ---
> > OvmfPkg/IoMmuDxe/CcIoMmu.c | 82 ++++++++++++++++++++-------
> --
> > -----------
> > OvmfPkg/IoMmuDxe/IoMmuBuffer.c | 54 ++++++++++++++++++++-----
> -
> > 2 files changed, 83 insertions(+), 53 deletions(-)
> >
> > diff --git a/OvmfPkg/IoMmuDxe/CcIoMmu.c
> > b/OvmfPkg/IoMmuDxe/CcIoMmu.c
> > index 1479af469881..7c2843cd238a 100644
> > --- a/OvmfPkg/IoMmuDxe/CcIoMmu.c
> > +++ b/OvmfPkg/IoMmuDxe/CcIoMmu.c
> > @@ -223,30 +223,32 @@ IoMmuMap (
> > goto FreeMapInfo;
> > }
> >
> > - if (CC_GUEST_IS_SEV (PcdGet64 (PcdConfidentialComputingGuestAttr)))
> {
> > + if (MapInfo->ReservedMemBitmap == 0) {
> > //
> > - // Clear the memory encryption mask on the plaintext buffer.
> > - //
> > - Status = MemEncryptSevClearPageEncMask (
> > - 0,
> > - MapInfo->PlainTextAddress,
> > - MapInfo->NumberOfPages
> > - );
> > - } else if (CC_GUEST_IS_TDX (PcdGet64
> > (PcdConfidentialComputingGuestAttr))) {
> > - //
> > - // Set the memory shared bit.
> > // If MapInfo->ReservedMemBitmap is 0, it means the bounce buffer
> is
> > not allocated
> > // from the pre-allocated shared memory, so it must be converted to
> > shared memory here.
> > //
> > - if (MapInfo->ReservedMemBitmap == 0) {
> > + if (CC_GUEST_IS_SEV (PcdGet64
> (PcdConfidentialComputingGuestAttr)))
> > {
> > + //
> > + // Clear the memory encryption mask on the plaintext buffer.
> > + //
> > + Status = MemEncryptSevClearPageEncMask (
> > + 0,
> > + MapInfo->PlainTextAddress,
> > + MapInfo->NumberOfPages
> > + );
> > + } else if (CC_GUEST_IS_TDX (PcdGet64
> > (PcdConfidentialComputingGuestAttr))) {
> > + //
> > + // Set the memory shared bit.
> > + //
> > Status = MemEncryptTdxSetPageSharedBit (
> > 0,
> > MapInfo->PlainTextAddress,
> > MapInfo->NumberOfPages
> > );
> > + } else {
> > + ASSERT (FALSE);
> > }
> > - } else {
> > - ASSERT (FALSE);
> > }
> >
> > ASSERT_EFI_ERROR (Status);
> > @@ -396,30 +398,30 @@ IoMmuUnmapWorker (
> > break;
> > }
> >
> > - if (CC_GUEST_IS_SEV (PcdGet64 (PcdConfidentialComputingGuestAttr)))
> {
> > - //
> > - // Restore the memory encryption mask on the area we used to hold
> the
> > - // plaintext.
> > - //
> > - Status = MemEncryptSevSetPageEncMask (
> > - 0,
> > - MapInfo->PlainTextAddress,
> > - MapInfo->NumberOfPages
> > - );
> > - } else if (CC_GUEST_IS_TDX (PcdGet64
> > (PcdConfidentialComputingGuestAttr))) {
> > - //
> > - // Restore the memory shared bit mask on the area we used to hold
> the
> > - // plaintext.
> > - //
> > - if (MapInfo->ReservedMemBitmap == 0) {
> > + if (MapInfo->ReservedMemBitmap == 0) {
> > + if (CC_GUEST_IS_SEV (PcdGet64
> (PcdConfidentialComputingGuestAttr)))
> > {
> > + //
> > + // Restore the memory encryption mask on the area we used to hold
> > the
> > + // plaintext.
> > + //
> > + Status = MemEncryptSevSetPageEncMask (
> > + 0,
> > + MapInfo->PlainTextAddress,
> > + MapInfo->NumberOfPages
> > + );
> > + } else if (CC_GUEST_IS_TDX (PcdGet64
> > (PcdConfidentialComputingGuestAttr))) {
> > + //
> > + // Restore the memory shared bit mask on the area we used to hold
> > the
> > + // plaintext.
> > + //
> > Status = MemEncryptTdxClearPageSharedBit (
> > 0,
> > MapInfo->PlainTextAddress,
> > MapInfo->NumberOfPages
> > );
> > + } else {
> > + ASSERT (FALSE);
> > }
> > - } else {
> > - ASSERT (FALSE);
> > }
> >
> > ASSERT_EFI_ERROR (Status);
> > @@ -924,16 +926,14 @@ InstallIoMmuProtocol (
> > }
> >
> > //
> > - // Currently only Tdx guest support Reserved shared memory for DMA
> > operation.
> > + // For CC guests, use reserved shared memory for DMA operation.
> > //
> > - if (CC_GUEST_IS_TDX (PcdGet64 (PcdConfidentialComputingGuestAttr)))
> {
> > - mReservedSharedMemSupported = TRUE;
> > - Status = IoMmuInitReservedSharedMem ();
> > - if (EFI_ERROR (Status)) {
> > - mReservedSharedMemSupported = FALSE;
> > - } else {
> > - DEBUG ((DEBUG_INFO, "%a: Feature of reserved memory for DMA is
> > supported.\n", __FUNCTION__));
> > - }
> > + mReservedSharedMemSupported = TRUE;
> > + Status = IoMmuInitReservedSharedMem ();
> > + if (EFI_ERROR (Status)) {
> > + mReservedSharedMemSupported = FALSE;
> > + } else {
> > + DEBUG ((DEBUG_INFO, "%a: Feature of reserved memory for DMA is
> > supported.\n", __FUNCTION__));
> > }
> >
> > return EFI_SUCCESS;
> > diff --git a/OvmfPkg/IoMmuDxe/IoMmuBuffer.c
> > b/OvmfPkg/IoMmuDxe/IoMmuBuffer.c
> > index 5ada8e9d57bd..d69969b6b763 100644
> > --- a/OvmfPkg/IoMmuDxe/IoMmuBuffer.c
> > +++ b/OvmfPkg/IoMmuDxe/IoMmuBuffer.c
> > @@ -9,7 +9,9 @@
> > #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/UefiBootServicesTableLib.h>
> > #include "IoMmuInternal.h"
> >
> > @@ -105,6 +107,7 @@ IoMmuInitReservedSharedMem (
> > UINTN TotalPages;
> > IOMMU_RESERVED_MEM_RANGE *MemRange;
> > EFI_PHYSICAL_ADDRESS PhysicalAddress;
> > + UINT64 SharedAddress;
> >
> > if (!mReservedSharedMemSupported) {
> > return EFI_UNSUPPORTED;
> > @@ -129,12 +132,25 @@ IoMmuInitReservedSharedMem (
> > MemRange->StartAddressOfMemRange = PhysicalAddress;
> >
> > for (Index2 = 0; Index2 < MemRange->Slots; Index2++) {
> > - Status = MemEncryptTdxSetPageSharedBit (
> > - 0,
> > - (UINT64)(UINTN)(MemRange->StartAddressOfMemRange +
> > Index2 * SIZE_OF_MEM_RANGE (MemRange) + MemRange->HeaderSize),
> > - EFI_SIZE_TO_PAGES (MemRange->DataSize)
> > - );
> > - ASSERT (!EFI_ERROR (Status));
> > + SharedAddress = (UINT64)(UINTN)(MemRange-
> > >StartAddressOfMemRange + Index2 * SIZE_OF_MEM_RANGE
> (MemRange)
> > + MemRange->HeaderSize);
> > +
> > + if (CC_GUEST_IS_SEV (PcdGet64
> > (PcdConfidentialComputingGuestAttr))) {
> > + Status = MemEncryptSevClearPageEncMask (
> > + 0,
> > + SharedAddress,
> > + EFI_SIZE_TO_PAGES (MemRange->DataSize)
> > + );
> > + ASSERT (!EFI_ERROR (Status));
> > + } else if (CC_GUEST_IS_TDX (PcdGet64
> > (PcdConfidentialComputingGuestAttr))) {
> > + Status = MemEncryptTdxSetPageSharedBit (
> > + 0,
> > + SharedAddress,
> > + EFI_SIZE_TO_PAGES (MemRange->DataSize)
> > + );
> > + ASSERT (!EFI_ERROR (Status));
> > + } else {
> > + ASSERT (FALSE);
> > + }
> > }
> >
> > PhysicalAddress += (MemRange->Slots * SIZE_OF_MEM_RANGE
> > (MemRange));
> > @@ -156,16 +172,30 @@ IoMmuReleaseReservedSharedMem (
> > EFI_STATUS Status;
> > UINT32 Index1, Index2;
> > IOMMU_RESERVED_MEM_RANGE *MemRange;
> > + UINT64 SharedAddress;
> >
> > for (Index1 = 0; Index1 < ARRAY_SIZE (mReservedMemRanges);
> Index1++)
> > {
> > MemRange = &mReservedMemRanges[Index1];
> > for (Index2 = 0; Index2 < MemRange->Slots; Index2++) {
> > - Status = MemEncryptTdxClearPageSharedBit (
> > - 0,
> > - (UINT64)(UINTN)(MemRange->StartAddressOfMemRange +
> > Index2 * SIZE_OF_MEM_RANGE (MemRange) + MemRange->HeaderSize),
> > - EFI_SIZE_TO_PAGES (MemRange->DataSize)
> > - );
> > - ASSERT (!EFI_ERROR (Status));
> > + SharedAddress = (UINT64)(UINTN)(MemRange-
> > >StartAddressOfMemRange + Index2 * SIZE_OF_MEM_RANGE
> (MemRange)
> > + MemRange->HeaderSize);
> > +
> > + if (CC_GUEST_IS_SEV (PcdGet64
> > (PcdConfidentialComputingGuestAttr))) {
> > + Status = MemEncryptSevSetPageEncMask (
> > + 0,
> > + SharedAddress,
> > + EFI_SIZE_TO_PAGES (MemRange->DataSize)
> > + );
> > + ASSERT (!EFI_ERROR (Status));
> > + } else if (CC_GUEST_IS_TDX (PcdGet64
> > (PcdConfidentialComputingGuestAttr))) {
> > + Status = MemEncryptTdxClearPageSharedBit (
> > + 0,
> > + SharedAddress,
> > + EFI_SIZE_TO_PAGES (MemRange->DataSize)
> > + );
> > + ASSERT (!EFI_ERROR (Status));
> > + } else {
> > + ASSERT (FALSE);
> > + }
> > }
> > }
> >
> >
> > >
> > > Cc: Erdem Aktas <erdemaktas at google.com>
> > > Cc: James Bottomley <jejb at linux.ibm.com>
> > > Cc: Jiewen Yao <jiewen.yao at intel.com>
> > > Cc: Tom Lendacky <thomas.lendacky at amd.com>
> > > Cc: Gerd Hoffmann <kraxel at redhat.com>
> > > Signed-off-by: Min Xu <min.m.xu at intel.com>
> > > ---
> > > OvmfPkg/IoMmuDxe/AmdSevIoMmu.c | 142 +++++------
> > > OvmfPkg/IoMmuDxe/IoMmuBuffer.c | 425
> > +++++++++++++++++++++++++++++++
> > > OvmfPkg/IoMmuDxe/IoMmuDxe.inf | 1 +
> > > OvmfPkg/IoMmuDxe/IoMmuInternal.h | 179 +++++++++++++
> > > 4 files changed, 676 insertions(+), 71 deletions(-)
> > > create mode 100644 OvmfPkg/IoMmuDxe/IoMmuBuffer.c
> > > create mode 100644 OvmfPkg/IoMmuDxe/IoMmuInternal.h
> > >
> > > diff --git a/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c
> > b/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c
> > > index 6b65897f032a..77e46bbf4a60 100644
> > > --- a/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c
> > > +++ b/OvmfPkg/IoMmuDxe/AmdSevIoMmu.c
> > > @@ -15,18 +15,7 @@
> > > #include <Library/PcdLib.h>
> > > #include <ConfidentialComputingGuestAttr.h>
> > > #include "AmdSevIoMmu.h"
> > > -
> > > -#define MAP_INFO_SIG SIGNATURE_64 ('M', 'A', 'P', '_', 'I', 'N', 'F', 'O')
> > > -
> > > -typedef struct {
> > > - UINT64 Signature;
> > > - LIST_ENTRY Link;
> > > - EDKII_IOMMU_OPERATION Operation;
> > > - UINTN NumberOfBytes;
> > > - UINTN NumberOfPages;
> > > - EFI_PHYSICAL_ADDRESS CryptedAddress;
> > > - EFI_PHYSICAL_ADDRESS PlainTextAddress;
> > > -} MAP_INFO;
> > > +#include "IoMmuInternal.h"
> > >
> > > //
> > > // List of the MAP_INFO structures that have been set up by
> > IoMmuMap() and not
> > > @@ -35,7 +24,10 @@ typedef struct {
> > > //
> > > STATIC LIST_ENTRY mMapInfos = INITIALIZE_LIST_HEAD_VARIABLE
> > (mMapInfos);
> > >
> > > -#define COMMON_BUFFER_SIG SIGNATURE_64 ('C', 'M', 'N', 'B', 'U', 'F',
> > 'F', 'R')
> > > +//
> > > +// Indicate if the feature of reserved memory is supported in DMA
> > operation.
> > > +//
> > > +BOOLEAN mReservedSharedMemSupported = FALSE;
> > >
> > > //
> > > // ASCII names for EDKII_IOMMU_OPERATION constants, for debug
> > logging.
> > > @@ -50,30 +42,6 @@
> > mBusMasterOperationName[EdkiiIoMmuOperationMaximum] = {
> > > "CommonBuffer64"
> > > };
> > >
> > > -//
> > > -// The following structure enables Map() and Unmap() to perform in-
> > place
> > > -// decryption and encryption, respectively, for
> > BusMasterCommonBuffer[64]
> > > -// operations, without dynamic memory allocation or release.
> > > -//
> > > -// Both COMMON_BUFFER_HEADER and
> > COMMON_BUFFER_HEADER.StashBuffer are allocated
> > > -// by AllocateBuffer() and released by FreeBuffer().
> > > -//
> > > -#pragma pack (1)
> > > -typedef struct {
> > > - UINT64 Signature;
> > > -
> > > - //
> > > - // Always allocated from EfiBootServicesData type memory, and
> always
> > > - // encrypted.
> > > - //
> > > - VOID *StashBuffer;
> > > -
> > > - //
> > > - // Followed by the actual common buffer, starting at the next page.
> > > - //
> > > -} COMMON_BUFFER_HEADER;
> > > -#pragma pack ()
> > > -
> > > /**
> > > Provides the controller-specific addresses required to access system
> > memory
> > > from a DMA bus master. On SEV/TDX guest, the DMA operations
> must
> > be performed on
> > > @@ -139,6 +107,8 @@ IoMmuMap (
> > > return EFI_INVALID_PARAMETER;
> > > }
> > >
> > > + Status = EFI_SUCCESS;
> > > +
> > > //
> > > // Allocate a MAP_INFO structure to remember the mapping when
> > Unmap() is
> > > // called later.
> > > @@ -153,11 +123,12 @@ IoMmuMap (
> > > // Initialize the MAP_INFO structure, except the PlainTextAddress
> field
> > > //
> > > ZeroMem (&MapInfo->Link, sizeof MapInfo->Link);
> > > - MapInfo->Signature = MAP_INFO_SIG;
> > > - MapInfo->Operation = Operation;
> > > - MapInfo->NumberOfBytes = *NumberOfBytes;
> > > - MapInfo->NumberOfPages = EFI_SIZE_TO_PAGES (MapInfo-
> > >NumberOfBytes);
> > > - MapInfo->CryptedAddress = (UINTN)HostAddress;
> > > + MapInfo->Signature = MAP_INFO_SIG;
> > > + MapInfo->Operation = Operation;
> > > + MapInfo->NumberOfBytes = *NumberOfBytes;
> > > + MapInfo->NumberOfPages = EFI_SIZE_TO_PAGES (MapInfo-
> > >NumberOfBytes);
> > > + MapInfo->CryptedAddress = (UINTN)HostAddress;
> > > + MapInfo->ReservedMemBitmap = 0;
> > >
> > > //
> > > // In the switch statement below, we point "MapInfo-
> > >PlainTextAddress" to the
> > > @@ -185,12 +156,11 @@ IoMmuMap (
> > > //
> > > // Allocate the implicit plaintext bounce buffer.
> > > //
> > > - Status = gBS->AllocatePages (
> > > - AllocateType,
> > > - EfiBootServicesData,
> > > - MapInfo->NumberOfPages,
> > > - &MapInfo->PlainTextAddress
> > > - );
> > > + Status = IoMmuAllocateBounceBuffer (
> > > + AllocateType,
> > > + EfiBootServicesData,
> > > + MapInfo
> > > + );
> > > if (EFI_ERROR (Status)) {
> > > goto FreeMapInfo;
> > > }
> > > @@ -241,7 +211,8 @@ IoMmuMap (
> > > // Point "DecryptionSource" to the stash buffer so that we decrypt
> > > // it to the original location, after the switch statement.
> > > //
> > > - DecryptionSource = CommonBufferHeader->StashBuffer;
> > > + DecryptionSource = CommonBufferHeader->StashBuffer;
> > > + MapInfo->ReservedMemBitmap = CommonBufferHeader-
> > >ReservedMemBitmap;
> > > break;
> > >
> > > default:
> > > @@ -264,12 +235,16 @@ IoMmuMap (
> > > } else if (CC_GUEST_IS_TDX (PcdGet64
> > (PcdConfidentialComputingGuestAttr))) {
> > > //
> > > // Set the memory shared bit.
> > > + // If MapInfo->ReservedMemBitmap is 0, it means the bounce buffer
> > is not allocated
> > > + // from the pre-allocated shared memory, so it must be converted
> to
> > shared memory here.
> > > //
> > > - Status = MemEncryptTdxSetPageSharedBit (
> > > - 0,
> > > - MapInfo->PlainTextAddress,
> > > - MapInfo->NumberOfPages
> > > - );
> > > + if (MapInfo->ReservedMemBitmap == 0) {
> > > + Status = MemEncryptTdxSetPageSharedBit (
> > > + 0,
> > > + MapInfo->PlainTextAddress,
> > > + MapInfo->NumberOfPages
> > > + );
> > > + }
> > > } else {
> > > ASSERT (FALSE);
> > > }
> > > @@ -311,12 +286,13 @@ IoMmuMap (
> > >
> > > DEBUG ((
> > > DEBUG_VERBOSE,
> > > - "%a: Mapping=0x%p Device(PlainText)=0x%Lx Crypted=0x%Lx
> > Pages=0x%Lx\n",
> > > + "%a: Mapping=0x%p Device(PlainText)=0x%Lx Crypted=0x%Lx
> > Pages=0x%Lx, ReservedMemBitmap=0x%Lx\n",
> > > __FUNCTION__,
> > > MapInfo,
> > > MapInfo->PlainTextAddress,
> > > MapInfo->CryptedAddress,
> > > - (UINT64)MapInfo->NumberOfPages
> > > + (UINT64)MapInfo->NumberOfPages,
> > > + MapInfo->ReservedMemBitmap
> > > ));
> > >
> > > return EFI_SUCCESS;
> > > @@ -435,11 +411,13 @@ IoMmuUnmapWorker (
> > > // Restore the memory shared bit mask on the area we used to hold
> > the
> > > // plaintext.
> > > //
> > > - Status = MemEncryptTdxClearPageSharedBit (
> > > - 0,
> > > - MapInfo->PlainTextAddress,
> > > - MapInfo->NumberOfPages
> > > - );
> > > + if (MapInfo->ReservedMemBitmap == 0) {
> > > + Status = MemEncryptTdxClearPageSharedBit (
> > > + 0,
> > > + MapInfo->PlainTextAddress,
> > > + MapInfo->NumberOfPages
> > > + );
> > > + }
> > > } else {
> > > ASSERT (FALSE);
> > > }
> > > @@ -470,8 +448,9 @@ IoMmuUnmapWorker (
> > > (VOID *)(UINTN)MapInfo->PlainTextAddress,
> > > EFI_PAGES_TO_SIZE (MapInfo->NumberOfPages)
> > > );
> > > +
> > > if (!MemoryMapLocked) {
> > > - gBS->FreePages (MapInfo->PlainTextAddress, MapInfo-
> > >NumberOfPages);
> > > + IoMmuFreeBounceBuffer (MapInfo);
> > > }
> > > }
> > >
> > > @@ -551,6 +530,7 @@ IoMmuAllocateBuffer (
> > > VOID *StashBuffer;
> > > UINTN CommonBufferPages;
> > > COMMON_BUFFER_HEADER *CommonBufferHeader;
> > > + UINT32 ReservedMemBitmap;
> > >
> > > DEBUG ((
> > > DEBUG_VERBOSE,
> > > @@ -620,12 +600,13 @@ IoMmuAllocateBuffer (
> > > PhysicalAddress = SIZE_4GB - 1;
> > > }
> > >
> > > - Status = gBS->AllocatePages (
> > > - AllocateMaxAddress,
> > > - MemoryType,
> > > - CommonBufferPages,
> > > - &PhysicalAddress
> > > - );
> > > + Status = IoMmuAllocateCommonBuffer (
> > > + MemoryType,
> > > + CommonBufferPages,
> > > + &PhysicalAddress,
> > > + &ReservedMemBitmap
> > > + );
> > > +
> > > if (EFI_ERROR (Status)) {
> > > goto FreeStashBuffer;
> > > }
> > > @@ -633,8 +614,9 @@ IoMmuAllocateBuffer (
> > > CommonBufferHeader = (VOID *)(UINTN)PhysicalAddress;
> > > PhysicalAddress += EFI_PAGE_SIZE;
> > >
> > > - CommonBufferHeader->Signature = COMMON_BUFFER_SIG;
> > > - CommonBufferHeader->StashBuffer = StashBuffer;
> > > + CommonBufferHeader->Signature = COMMON_BUFFER_SIG;
> > > + CommonBufferHeader->StashBuffer = StashBuffer;
> > > + CommonBufferHeader->ReservedMemBitmap =
> ReservedMemBitmap;
> > >
> > > *HostAddress = (VOID *)(UINTN)PhysicalAddress;
> > >
> > > @@ -707,7 +689,7 @@ IoMmuFreeBuffer (
> > > // Release the common buffer itself. Unmap() has re-encrypted it in-
> > place, so
> > > // no need to zero it.
> > > //
> > > - return gBS->FreePages ((UINTN)CommonBufferHeader,
> > CommonBufferPages);
> > > + return IoMmuFreeCommonBuffer (CommonBufferHeader,
> > CommonBufferPages);
> > > }
> > >
> > > /**
> > > @@ -878,6 +860,11 @@ IoMmuUnmapAllMappings (
> > > TRUE // MemoryMapLocked
> > > );
> > > }
> > > +
> > > + //
> > > + // Release the reserved shared memory as well.
> > > + //
> > > + IoMmuReleaseReservedSharedMem (TRUE);
> > > }
> > >
> > > /**
> > > @@ -936,6 +923,19 @@ InstallIoMmuProtocol (
> > > goto CloseExitBootEvent;
> > > }
> > >
> > > + //
> > > + // Currently only Tdx guest support Reserved shared memory for
> DMA
> > operation.
> > > + //
> > > + if (CC_GUEST_IS_TDX (PcdGet64
> (PcdConfidentialComputingGuestAttr)))
> > {
> > > + mReservedSharedMemSupported = TRUE;
> > > + Status = IoMmuInitReservedSharedMem ();
> > > + if (EFI_ERROR (Status)) {
> > > + mReservedSharedMemSupported = FALSE;
> > > + } else {
> > > + DEBUG ((DEBUG_INFO, "%a: Feature of reserved memory for DMA
> is
> > supported.\n", __FUNCTION__));
> > > + }
> > > + }
> > > +
> > > return EFI_SUCCESS;
> > >
> > > CloseExitBootEvent:
> > > diff --git a/OvmfPkg/IoMmuDxe/IoMmuBuffer.c
> > b/OvmfPkg/IoMmuDxe/IoMmuBuffer.c
> > > new file mode 100644
> > > index 000000000000..5ada8e9d57bd
> > > --- /dev/null
> > > +++ b/OvmfPkg/IoMmuDxe/IoMmuBuffer.c
> > > @@ -0,0 +1,425 @@
> > > +/** @file
> > > +
> > > + Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
> > > +
> > > + SPDX-License-Identifier: BSD-2-Clause-Patent
> > > +
> > > +**/
> > > +#include <Library/BaseLib.h>
> > > +#include <Library/BaseMemoryLib.h>
> > > +#include <Library/DebugLib.h>
> > > +#include <Library/MemoryAllocationLib.h>
> > > +#include <Library/MemEncryptTdxLib.h>
> > > +#include <Library/UefiBootServicesTableLib.h>
> > > +#include "IoMmuInternal.h"
> > > +
> > > +extern BOOLEAN mReservedSharedMemSupported;
> > > +
> > > +#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
> > > +
> > > +STATIC IOMMU_RESERVED_MEM_RANGE mReservedMemRanges[] = {
> > > + { 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 },
> > > +};
> > > +
> > > +//
> > > +// Bitmap of the allocation of reserved memory.
> > > +//
> > > +STATIC UINT32 mReservedMemBitmap = 0;
> > > +
> > > +//
> > > +// Start address of the reserved memory region.
> > > +//
> > > +STATIC EFI_PHYSICAL_ADDRESS mReservedSharedMemAddress = 0;
> > > +
> > > +//
> > > +// Total size of the reserved memory region.
> > > +//
> > > +STATIC UINT32 mReservedSharedMemSize = 0;
> > > +
> > > +/**
> > > + * Calculate the size of reserved memory.
> > > + *
> > > + * @retval UINT32 Size of the reserved memory
> > > + */
> > > +STATIC
> > > +UINT32
> > > +CalcuateReservedMemSize (
> > > + VOID
> > > + )
> > > +{
> > > + UINT32 Index;
> > > + IOMMU_RESERVED_MEM_RANGE *MemRange;
> > > +
> > > + if (mReservedSharedMemSize != 0) {
> > > + return mReservedSharedMemSize;
> > > + }
> > > +
> > > + for (Index = 0; Index < ARRAY_SIZE (mReservedMemRanges); Index++)
> {
> > > + MemRange = &mReservedMemRanges[Index];
> > > + mReservedSharedMemSize += (SIZE_OF_MEM_RANGE (MemRange)
> *
> > MemRange->Slots);
> > > + }
> > > +
> > > + return mReservedSharedMemSize;
> > > +}
> > > +
> > > +/**
> > > + * 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 |
> > > + * |-----------------------------------------|
> > > + *
> > > + * @retval EFI_SUCCESS Successfully initialize the reserved memory.
> > > + * @retval EFI_UNSUPPORTED This feature is not supported.
> > > + */
> > > +EFI_STATUS
> > > +IoMmuInitReservedSharedMem (
> > > + VOID
> > > + )
> > > +{
> > > + EFI_STATUS Status;
> > > + UINT32 Index1, Index2;
> > > + UINTN TotalPages;
> > > + IOMMU_RESERVED_MEM_RANGE *MemRange;
> > > + EFI_PHYSICAL_ADDRESS PhysicalAddress;
> > > +
> > > + if (!mReservedSharedMemSupported) {
> > > + return EFI_UNSUPPORTED;
> > > + }
> > > +
> > > + TotalPages = EFI_SIZE_TO_PAGES (CalcuateReservedMemSize ());
> > > +
> > > + PhysicalAddress = (EFI_PHYSICAL_ADDRESS)(UINTN)AllocatePages
> > (TotalPages);
> > > + DEBUG ((
> > > + DEBUG_VERBOSE,
> > > + "%a: ReservedMem (%d pages) address = 0x%llx\n",
> > > + __FUNCTION__,
> > > + TotalPages,
> > > + PhysicalAddress
> > > + ));
> > > +
> > > + mReservedMemBitmap = 0;
> > > + mReservedSharedMemAddress = PhysicalAddress;
> > > +
> > > + for (Index1 = 0; Index1 < ARRAY_SIZE (mReservedMemRanges);
> > Index1++) {
> > > + MemRange = &mReservedMemRanges[Index1];
> > > + MemRange->StartAddressOfMemRange = PhysicalAddress;
> > > +
> > > + for (Index2 = 0; Index2 < MemRange->Slots; Index2++) {
> > > + Status = MemEncryptTdxSetPageSharedBit (
> > > + 0,
> > > + (UINT64)(UINTN)(MemRange->StartAddressOfMemRange +
> > Index2 * SIZE_OF_MEM_RANGE (MemRange) + MemRange->HeaderSize),
> > > + EFI_SIZE_TO_PAGES (MemRange->DataSize)
> > > + );
> > > + ASSERT (!EFI_ERROR (Status));
> > > + }
> > > +
> > > + PhysicalAddress += (MemRange->Slots * SIZE_OF_MEM_RANGE
> > (MemRange));
> > > + }
> > > +
> > > + return EFI_SUCCESS;
> > > +}
> > > +
> > > +/**
> > > + * Release the pre-alloc shared memory.
> > > + *
> > > + * @retval EFI_SUCCESS Successfully release the shared memory
> > > + */
> > > +EFI_STATUS
> > > +IoMmuReleaseReservedSharedMem (
> > > + BOOLEAN MemoryMapLocked
> > > + )
> > > +{
> > > + EFI_STATUS Status;
> > > + UINT32 Index1, Index2;
> > > + IOMMU_RESERVED_MEM_RANGE *MemRange;
> > > +
> > > + for (Index1 = 0; Index1 < ARRAY_SIZE (mReservedMemRanges);
> > Index1++) {
> > > + MemRange = &mReservedMemRanges[Index1];
> > > + for (Index2 = 0; Index2 < MemRange->Slots; Index2++) {
> > > + Status = MemEncryptTdxClearPageSharedBit (
> > > + 0,
> > > + (UINT64)(UINTN)(MemRange->StartAddressOfMemRange +
> > Index2 * SIZE_OF_MEM_RANGE (MemRange) + MemRange->HeaderSize),
> > > + EFI_SIZE_TO_PAGES (MemRange->DataSize)
> > > + );
> > > + ASSERT (!EFI_ERROR (Status));
> > > + }
> > > + }
> > > +
> > > + if (!MemoryMapLocked) {
> > > + FreePages ((VOID *)(UINTN)mReservedSharedMemAddress,
> > EFI_SIZE_TO_PAGES (CalcuateReservedMemSize ()));
> > > + mReservedSharedMemAddress = 0;
> > > + mReservedMemBitmap = 0;
> > > + }
> > > +
> > > + return EFI_SUCCESS;
> > > +}
> > > +
> > > +/**
> > > + * Allocate from the reserved memory pool.
> > > + * If the reserved shared memory is exausted or there is no suitalbe
> size,
> > it turns
> > > + * to the LegacyAllocateBuffer.
> > > + *
> > > + * @param Type Allocate type
> > > + * @param MemoryType The memory type to be allocated
> > > + * @param Pages Pages to be allocated.
> > > + * @param ReservedMemBitmap Bitmap of the allocated memory
> > region
> > > + * @param PhysicalAddress Pointer to the data part of allocated
> > memory region
> > > + *
> > > + * @retval EFI_SUCCESS Successfully allocate the buffer
> > > + * @retval Other As the error code indicates
> > > + */
> > > +STATIC
> > > +EFI_STATUS
> > > +InternalAllocateBuffer (
> > > + IN EFI_ALLOCATE_TYPE Type,
> > > + IN EFI_MEMORY_TYPE MemoryType,
> > > + IN UINTN Pages,
> > > + IN OUT UINT32 *ReservedMemBitmap,
> > > + IN OUT EFI_PHYSICAL_ADDRESS *PhysicalAddress
> > > + )
> > > +{
> > > + UINT32 MemBitmap;
> > > + UINT8 Index;
> > > + IOMMU_RESERVED_MEM_RANGE *MemRange;
> > > + UINTN PagesOfLastMemRange;
> > > +
> > > + *ReservedMemBitmap = 0;
> > > +
> > > + if (Pages == 0) {
> > > + ASSERT (FALSE);
> > > + return EFI_INVALID_PARAMETER;
> > > + }
> > > +
> > > + if (!mReservedSharedMemSupported) {
> > > + goto LegacyAllocateBuffer;
> > > + }
> > > +
> > > + if (mReservedSharedMemAddress == 0) {
> > > + goto LegacyAllocateBuffer;
> > > + }
> > > +
> > > + PagesOfLastMemRange = 0;
> > > +
> > > + for (Index = 0; Index < ARRAY_SIZE (mReservedMemRanges); Index++)
> {
> > > + if ((Pages > PagesOfLastMemRange) && (Pages <=
> EFI_SIZE_TO_PAGES
> > (mReservedMemRanges[Index].DataSize))) {
> > > + break;
> > > + }
> > > +
> > > + PagesOfLastMemRange = EFI_SIZE_TO_PAGES
> > (mReservedMemRanges[Index].DataSize);
> > > + }
> > > +
> > > + if (Index == ARRAY_SIZE (mReservedMemRanges)) {
> > > + // There is no suitable size of reserved memory. Turn to legacy
> > allocate.
> > > + goto LegacyAllocateBuffer;
> > > + }
> > > +
> > > + MemRange = &mReservedMemRanges[Index];
> > > +
> > > + if ((mReservedMemBitmap & MemRange->BitmapMask) ==
> > MemRange->BitmapMask) {
> > > + // The reserved memory is exausted. Turn to legacy allocate.
> > > + goto LegacyAllocateBuffer;
> > > + }
> > > +
> > > + MemBitmap = (mReservedMemBitmap & MemRange-
> >BitmapMask) >>
> > MemRange->Shift;
> > > +
> > > + for (Index = 0; Index < MemRange->Slots; Index++) {
> > > + if ((MemBitmap & (UINT8)(1<<Index)) == 0) {
> > > + break;
> > > + }
> > > + }
> > > +
> > > + ASSERT (Index != MemRange->Slots);
> > > +
> > > + *PhysicalAddress = MemRange->StartAddressOfMemRange + Index
> *
> > SIZE_OF_MEM_RANGE (MemRange) + MemRange->HeaderSize;
> > > + *ReservedMemBitmap = (UINT32)(1 << (Index + MemRange->Shift));
> > > +
> > > + DEBUG ((
> > > + DEBUG_VERBOSE,
> > > + "%a: range-size: %lx, start-address=0x%llx, pages=0x%llx, bits=0x%lx,
> > bitmap: %lx => %lx\n",
> > > + __FUNCTION__,
> > > + MemRange->DataSize,
> > > + *PhysicalAddress,
> > > + Pages,
> > > + *ReservedMemBitmap,
> > > + mReservedMemBitmap,
> > > + mReservedMemBitmap | *ReservedMemBitmap
> > > + ));
> > > +
> > > + return EFI_SUCCESS;
> > > +
> > > +LegacyAllocateBuffer:
> > > +
> > > + *ReservedMemBitmap = 0;
> > > + return gBS->AllocatePages (Type, MemoryType, Pages,
> PhysicalAddress);
> > > +}
> > > +
> > > +/**
> > > + * Allocate reserved shared memory for bounce buffer.
> > > + *
> > > + * @param Type Allocate type
> > > + * @param MemoryType The memory type to be allocated
> > > + * @param MapInfo Pointer to the MAP_INFO
> > > + *
> > > + * @retval EFI_SUCCESS Successfully allocate the bounce buffer
> > > + * @retval Other As the error code indicates
> > > +
> > > + */
> > > +EFI_STATUS
> > > +IoMmuAllocateBounceBuffer (
> > > + IN EFI_ALLOCATE_TYPE Type,
> > > + IN EFI_MEMORY_TYPE MemoryType,
> > > + IN OUT MAP_INFO *MapInfo
> > > + )
> > > +{
> > > + EFI_STATUS Status;
> > > + UINT32 ReservedMemBitmap;
> > > +
> > > + ReservedMemBitmap = 0;
> > > + Status = InternalAllocateBuffer (
> > > + Type,
> > > + MemoryType,
> > > + MapInfo->NumberOfPages,
> > > + &ReservedMemBitmap,
> > > + &MapInfo->PlainTextAddress
> > > + );
> > > + MapInfo->ReservedMemBitmap = ReservedMemBitmap;
> > > + mReservedMemBitmap |= ReservedMemBitmap;
> > > +
> > > + ASSERT (Status == EFI_SUCCESS);
> > > +
> > > + return Status;
> > > +}
> > > +
> > > +/**
> > > + * Free the bounce buffer allocated in IoMmuAllocateBounceBuffer.
> > > + *
> > > + * @param MapInfo Pointer to the MAP_INFO
> > > + * @return EFI_SUCCESS Successfully free the bounce buffer.
> > > + */
> > > +EFI_STATUS
> > > +IoMmuFreeBounceBuffer (
> > > + IN OUT MAP_INFO *MapInfo
> > > + )
> > > +{
> > > + if (MapInfo->ReservedMemBitmap == 0) {
> > > + gBS->FreePages (MapInfo->PlainTextAddress, MapInfo-
> > >NumberOfPages);
> > > + } else {
> > > + DEBUG ((
> > > + DEBUG_VERBOSE,
> > > + "%a: PlainTextAddress=0x%Lx, bits=0x%Lx, bitmap: %Lx => %Lx\n",
> > > + __FUNCTION__,
> > > + MapInfo->PlainTextAddress,
> > > + MapInfo->ReservedMemBitmap,
> > > + mReservedMemBitmap,
> > > + mReservedMemBitmap & ((UINT32)(~MapInfo-
> > >ReservedMemBitmap))
> > > + ));
> > > + MapInfo->PlainTextAddress = 0;
> > > + mReservedMemBitmap &= (UINT32)(~MapInfo-
> > >ReservedMemBitmap);
> > > + MapInfo->ReservedMemBitmap = 0;
> > > + }
> > > +
> > > + return EFI_SUCCESS;
> > > +}
> > > +
> > > +/**
> > > + * Allocate CommonBuffer from pre-allocated shared memory.
> > > + *
> > > + * @param MemoryType Memory type
> > > + * @param CommonBufferPages Pages of CommonBuffer
> > > + * @param PhysicalAddress Allocated physical address
> > > + * @param ReservedMemBitmap Bitmap which indicates the
> allocation
> > of reserved memory
> > > + *
> > > + * @retval EFI_SUCCESS Successfully allocate the common buffer
> > > + * @retval Other As the error code indicates
> > > + */
> > > +EFI_STATUS
> > > +IoMmuAllocateCommonBuffer (
> > > + IN EFI_MEMORY_TYPE MemoryType,
> > > + IN UINTN CommonBufferPages,
> > > + OUT EFI_PHYSICAL_ADDRESS *PhysicalAddress,
> > > + OUT UINT32 *ReservedMemBitmap
> > > + )
> > > +{
> > > + EFI_STATUS Status;
> > > +
> > > + Status = InternalAllocateBuffer (
> > > + AllocateMaxAddress,
> > > + MemoryType,
> > > + CommonBufferPages,
> > > + ReservedMemBitmap,
> > > + PhysicalAddress
> > > + );
> > > + ASSERT (Status == EFI_SUCCESS);
> > > +
> > > + mReservedMemBitmap |= *ReservedMemBitmap;
> > > +
> > > + if (*ReservedMemBitmap != 0) {
> > > + *PhysicalAddress -= SIZE_4KB;
> > > + }
> > > +
> > > + return Status;
> > > +}
> > > +
> > > +/**
> > > + * Free CommonBuffer which is allocated by
> > IoMmuAllocateCommonBuffer().
> > > + *
> > > + * @param CommonBufferHeader Pointer to the
> CommonBufferHeader
> > > + * @param CommonBufferPages Pages of CommonBuffer
> > > + *
> > > + * @retval EFI_SUCCESS Successfully free the common buffer
> > > + * @retval Other As the error code indicates
> > > + */
> > > +EFI_STATUS
> > > +IoMmuFreeCommonBuffer (
> > > + IN COMMON_BUFFER_HEADER *CommonBufferHeader,
> > > + IN UINTN CommonBufferPages
> > > + )
> > > +{
> > > + if (!mReservedSharedMemSupported) {
> > > + goto LegacyFreeCommonBuffer;
> > > + }
> > > +
> > > + if (CommonBufferHeader->ReservedMemBitmap == 0) {
> > > + goto LegacyFreeCommonBuffer;
> > > + }
> > > +
> > > + DEBUG ((
> > > + DEBUG_VERBOSE,
> > > + "%a: CommonBuffer=0x%Lx, bits=0x%Lx, bitmap: %Lx => %Lx\n",
> > > + __FUNCTION__,
> > > + (UINT64)(UINTN)CommonBufferHeader + SIZE_4KB,
> > > + CommonBufferHeader->ReservedMemBitmap,
> > > + mReservedMemBitmap,
> > > + mReservedMemBitmap & ((UINT32)(~CommonBufferHeader-
> > >ReservedMemBitmap))
> > > + ));
> > > +
> > > + mReservedMemBitmap &= (UINT32)(~CommonBufferHeader-
> > >ReservedMemBitmap);
> > > + return EFI_SUCCESS;
> > > +
> > > +LegacyFreeCommonBuffer:
> > > + return gBS->FreePages ((UINTN)CommonBufferHeader,
> > CommonBufferPages);
> > > +}
> > > diff --git a/OvmfPkg/IoMmuDxe/IoMmuDxe.inf
> > b/OvmfPkg/IoMmuDxe/IoMmuDxe.inf
> > > index e10be1dcff49..2192145ea661 100644
> > > --- a/OvmfPkg/IoMmuDxe/IoMmuDxe.inf
> > > +++ b/OvmfPkg/IoMmuDxe/IoMmuDxe.inf
> > > @@ -21,6 +21,7 @@
> > > AmdSevIoMmu.c
> > > AmdSevIoMmu.h
> > > IoMmuDxe.c
> > > + IoMmuBuffer.c
> > >
> > > [Packages]
> > > MdePkg/MdePkg.dec
> > > diff --git a/OvmfPkg/IoMmuDxe/IoMmuInternal.h
> > b/OvmfPkg/IoMmuDxe/IoMmuInternal.h
> > > new file mode 100644
> > > index 000000000000..936c35aa536c
> > > --- /dev/null
> > > +++ b/OvmfPkg/IoMmuDxe/IoMmuInternal.h
> > > @@ -0,0 +1,179 @@
> > > +/** @file
> > > +
> > > + Copyright (c) 2022, Intel Corporation. All rights reserved.<BR>
> > > +
> > > + SPDX-License-Identifier: BSD-2-Clause-Patent
> > > +
> > > +**/
> > > +
> > > +#ifndef IOMMU_INTERNAL_H_
> > > +#define IOMMU_INTERNAL_H_
> > > +
> > > +#include <Base.h>
> > > +#include <Protocol/IoMmu.h>
> > > +#include <Uefi/UefiBaseType.h>
> > > +#include <Uefi/UefiSpec.h>
> > > +
> > > +#define MAP_INFO_SIG SIGNATURE_64 ('M', 'A', 'P', '_', 'I', 'N', 'F', 'O')
> > > +
> > > +typedef struct {
> > > + UINT64 Signature;
> > > + LIST_ENTRY Link;
> > > + EDKII_IOMMU_OPERATION Operation;
> > > + UINTN NumberOfBytes;
> > > + UINTN NumberOfPages;
> > > + EFI_PHYSICAL_ADDRESS CryptedAddress;
> > > + EFI_PHYSICAL_ADDRESS PlainTextAddress;
> > > + UINT32 ReservedMemBitmap;
> > > +} MAP_INFO;
> > > +
> > > +#define COMMON_BUFFER_SIG SIGNATURE_64 ('C', 'M', 'N', 'B', 'U',
> 'F',
> > 'F', 'R')
> > > +
> > > +#pragma pack (1)
> > > +//
> > > +// The following structure enables Map() and Unmap() to perform in-
> > place
> > > +// decryption and encryption, respectively, for
> > BusMasterCommonBuffer[64]
> > > +// operations, without dynamic memory allocation or release.
> > > +//
> > > +// Both COMMON_BUFFER_HEADER and
> > COMMON_BUFFER_HEADER.StashBuffer are allocated
> > > +// by AllocateBuffer() and released by FreeBuffer().
> > > +//
> > > +typedef struct {
> > > + UINT64 Signature;
> > > +
> > > + //
> > > + // Always allocated from EfiBootServicesData type memory, and
> always
> > > + // encrypted.
> > > + //
> > > + VOID *StashBuffer;
> > > +
> > > + //
> > > + // Bitmap of reserved memory
> > > + //
> > > + UINT32 ReservedMemBitmap;
> > > +
> > > + //
> > > + // Followed by the actual common buffer, starting at the next page.
> > > + //
> > > +} COMMON_BUFFER_HEADER;
> > > +
> > > +//
> > > +// This data structure defines a memory range in the reserved memory
> > region.
> > > +// Please refer to IoMmuInitReservedSharedMem() for detailed
> > information.
> > > +//
> > > +// The memory region looks like:
> > > +// |------------|----------------------------|
> > > +// | Header | Data |
> > > +// | 4k, private| 4k/32k/128k/etc, shared |
> > > +// |-----------------------------------------|
> > > +//
> > > +typedef struct {
> > > + UINT32 BitmapMask;
> > > + UINT32 Shift;
> > > + UINT32 Slots;
> > > + UINT32 DataSize;
> > > + UINT32 HeaderSize;
> > > + EFI_PHYSICAL_ADDRESS StartAddressOfMemRange;
> > > +} IOMMU_RESERVED_MEM_RANGE;
> > > +#pragma pack()
> > > +
> > > +/**
> > > + * 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 |
> > > + * |-----------------------------------------|
> > > + *
> > > + * @retval EFI_SUCCESS Successfully initialize the reserved memory.
> > > + * @retval EFI_UNSUPPORTED This feature is not supported.
> > > + */
> > > +EFI_STATUS
> > > +IoMmuInitReservedSharedMem (
> > > + VOID
> > > + );
> > > +
> > > +/**
> > > + * Release the pre-alloc shared memory.
> > > + *
> > > + * @retval EFI_SUCCESS Successfully release the shared memory
> > > + */
> > > +EFI_STATUS
> > > +IoMmuReleaseReservedSharedMem (
> > > + BOOLEAN MemoryMapLocked
> > > + );
> > > +
> > > +/**
> > > + * Allocate reserved shared memory for bounce buffer.
> > > + *
> > > + * @param Type Allocate type
> > > + * @param MemoryType The memory type to be allocated
> > > + * @param MapInfo Pointer to the MAP_INFO
> > > + *
> > > + * @retval EFI_SUCCESS Successfully allocate the bounce buffer
> > > + * @retval Other As the error code indicates
> > > + */
> > > +EFI_STATUS
> > > +IoMmuAllocateBounceBuffer (
> > > + IN EFI_ALLOCATE_TYPE Type,
> > > + IN EFI_MEMORY_TYPE MemoryType,
> > > + IN OUT MAP_INFO *MapInfo
> > > + );
> > > +
> > > +/**
> > > + * Free the bounce buffer allocated in IoMmuAllocateBounceBuffer.
> > > + *
> > > + * @param MapInfo Pointer to the MAP_INFO
> > > + * @return EFI_SUCCESS Successfully free the bounce buffer.
> > > + */
> > > +EFI_STATUS
> > > +IoMmuFreeBounceBuffer (
> > > + IN OUT MAP_INFO *MapInfo
> > > + );
> > > +
> > > +/**
> > > + * Allocate CommonBuffer from pre-allocated shared memory.
> > > + *
> > > + * @param MemoryType Memory type
> > > + * @param CommonBufferPages Pages of CommonBuffer
> > > + * @param PhysicalAddress Allocated physical address
> > > + * @param ReservedMemBitmap Bitmap which indicates the
> allocation
> > of reserved memory
> > > + *
> > > + * @retval EFI_SUCCESS Successfully allocate the common buffer
> > > + * @retval Other As the error code indicates
> > > + */
> > > +EFI_STATUS
> > > +IoMmuAllocateCommonBuffer (
> > > + IN EFI_MEMORY_TYPE MemoryType,
> > > + IN UINTN CommonBufferPages,
> > > + OUT EFI_PHYSICAL_ADDRESS *PhysicalAddress,
> > > + OUT UINT32 *ReservedMemBitmap
> > > + );
> > > +
> > > +/**
> > > + * Free CommonBuffer which is allocated by
> > IoMmuAllocateCommonBuffer().
> > > + *
> > > + * @param CommonBufferHeader Pointer to the
> CommonBufferHeader
> > > + * @param CommonBufferPages Pages of CommonBuffer
> > > + *
> > > + * @retval EFI_SUCCESS Successfully free the common buffer
> > > + * @retval Other As the error code indicates
> > > + */
> > > +EFI_STATUS
> > > +IoMmuFreeCommonBuffer (
> > > + IN COMMON_BUFFER_HEADER *CommonBufferHeader,
> > > + IN UINTN CommonBufferPages
> > > + );
> > > +
> > > +#endif
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