Re: [RFC] [PATCH 2/3] MdeModulePkg/PciHostBridge: Add IOMMU support.

["Yao, Jiewen" <jiewen.yao@intel.com>]

Answer below:

From: Ni, Ruiyu
Sent: Monday, March 27, 2017 1:32 PM
To: Yao, Jiewen <jiewen.yao@intel.com>; edk2-devel@lists.01.org
Cc: Leo Duran <leo.duran@amd.com>; Brijesh Singh <brijesh.singh@amd.com>
Subject: RE: [RFC] [PATCH 2/3] MdeModulePkg/PciHostBridge: Add IOMMU support.

Jiewen,
#1. In RootBridgeIoMap(), NeedMap is TRUE when:
 1). Host or device doesn't support above 4GB DMA access
Or
 2). The memory size is not multiple of IO MMU page size

For case 2), we only need to call BS.AllocatePages with AllocateAnyAddress allocation type,
but I saw you still use AllocateMaxAddress allocation type.
Can we guarantee that (AllocateMaxAddress plus MaxAddress = MAX_UINT64) equals to
(AllocateAnyAddress)?
[Jiewen] Yes.

 I thought the first combination requires to allocate from very top
physical memory, but the second (AllocateAnyAddress) doesn't have such requirement.
[Jiewen] That is not true.
UEFI spec: "Allocation requests of Type AllocateMaxAddress allocate any available range of pages whose uppermost address is less than or equal to the address pointed to by Memory on input."
It means "any available range".




#2. In InternalAllocateAlignedPagesWithAllocateType ():
      #a). AlignedMemory  = ((UINTN) Memory + AlignmentMask) & ~AlignmentMask;
      Can we use ALIGNED_POINTER() macro?
      #b). I think we do not need to free last unaligned pages. Because we only over-allocate
      several pages in the beginning. Please correct me if I am wrong.
      #c). The function name is too long. Can we rename it to IAllocatePages()? The parameter
      Type and Alignment indicate the allocation honors Type and Alignment.
[Jiewen] I copied the code from MemoryAllocationLib.





Thanks/Ray

> -----Original Message-----
> From: Yao, Jiewen
> Sent: Saturday, March 25, 2017 5:29 PM
> To: edk2-devel@lists.01.org<mailto:edk2-devel@lists.01.org>
> Cc: Ni, Ruiyu <ruiyu.ni@intel.com<mailto:ruiyu.ni@intel.com>>; Leo Duran <leo.duran@amd.com<mailto:leo.duran@amd.com>>;
> Brijesh Singh <brijesh.singh@amd.com<mailto:brijesh.singh@amd.com>>
> Subject: [RFC] [PATCH 2/3] MdeModulePkg/PciHostBridge: Add IOMMU
> support.
>
> The responsibility of PciHostBridge is to allocate IOMMU page aligned
> memory for Map and AllocateBuffer, because PciHostBridge driver already
> handles Map() request to allocate another buffer for DMA read/write.
>
> PciHostBridge does not set IOMMU attribute because it does not know
> which device request the DMA. This work is done by PciBus driver.
>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com<mailto:ruiyu.ni@intel.com>>
> Cc: Leo Duran <leo.duran@amd.com<mailto:leo.duran@amd.com>>
> Cc: Brijesh Singh <brijesh.singh@amd.com<mailto:brijesh.singh@amd.com>>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Jiewen Yao <jiewen.yao@intel.com<mailto:jiewen.yao@intel.com>>
> ---
>  MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c      |   3 +
>  MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf |   1 +
>  MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridge.h      |   7 +
>  MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c    | 172
> +++++++++++++++++++-
>  4 files changed, 178 insertions(+), 5 deletions(-)
>
> diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c
> b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c
> index 9005dee..35233a7 100644
> --- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c
> +++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c
> @@ -28,6 +28,9 @@ GLOBAL_REMOVE_IF_UNREFERENCED CHAR16
> *mPciResourceTypeStr[] = {
>    L"I/O", L"Mem", L"PMem", L"Mem64", L"PMem64", L"Bus"
>  };
>
> +EDKII_IOMMU_PROTOCOL        *gIoMmuProtocol;
> +UINTN                       mIoMmuPageSize = 1;
> +
>  /**
>    Ensure the compatibility of an IO space descriptor with the IO aperture.
>
> diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf
> b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf
> index d8b0439..2d3c8c9 100644
> --- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf
> +++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf
> @@ -49,6 +49,7 @@
>    gEfiDevicePathProtocolGuid                      ## BY_START
>    gEfiPciRootBridgeIoProtocolGuid                 ## BY_START
>    gEfiPciHostBridgeResourceAllocationProtocolGuid ## BY_START
> +  gEdkiiIoMmuProtocolGuid                         ## CONSUMES
>
>  [Depex]
>    gEfiCpuIo2ProtocolGuid AND
> diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridge.h
> b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridge.h
> index 13185b4..4d21d10 100644
> --- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridge.h
> +++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridge.h
> @@ -27,6 +27,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY
> KIND, EITHER EXPRESS OR IMPLIED.
>  #include <Protocol/CpuIo2.h>
>  #include <Protocol/DevicePath.h>
>  #include <Protocol/PciRootBridgeIo.h>
> +#include <Protocol/IoMmu.h>
>  #include <Library/DebugLib.h>
>  #include <Library/DevicePathLib.h>
>  #include <Library/BaseMemoryLib.h>
> @@ -50,6 +51,8 @@ typedef struct {
>    EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL_OPERATION Operation;
>    UINTN                                     NumberOfBytes;
>    UINTN                                     NumberOfPages;
> +  UINTN                                     MappedNumberOfBytes;
> +  UINTN                                     MappedNumberOfPages;
>    EFI_PHYSICAL_ADDRESS                      HostAddress;
>    EFI_PHYSICAL_ADDRESS                      MappedHostAddress;
>  } MAP_INFO;
> @@ -575,4 +578,8 @@ RootBridgeIoConfiguration (
>
>  extern EFI_METRONOME_ARCH_PROTOCOL *mMetronome;
>  extern EFI_CPU_IO2_PROTOCOL         *mCpuIo;
> +
> +extern EDKII_IOMMU_PROTOCOL        *gIoMmuProtocol;
> +extern UINTN                       mIoMmuPageSize;
> +
>  #endif
> diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> index 8af131b..47ea697 100644
> --- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> +++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> @@ -1022,6 +1022,121 @@ RootBridgeIoPciWrite (  }
>
>  /**
> +  Allocates one or more 4KB pages of a certain memory type at a specified
> alignment.
> +
> +  Allocates the number of 4KB pages specified by Pages of a certain
> + memory type with an alignment  specified by Alignment.  The allocated
> buffer is returned.  If Pages is 0, then NULL is returned.
> +  If there is not enough memory at the specified alignment remaining to
> + satisfy the request, then  NULL is returned.
> +  If Alignment is not a power of two and Alignment is not zero, then
> ASSERT().
> +  If Pages plus EFI_SIZE_TO_PAGES (Alignment) overflows, then ASSERT().
> +
> +  @param  Type                  The type of allocation to perform.
> +  @param  MemoryType            The type of memory to allocate.
> +  @param  Pages                 The number of 4 KB pages to allocate.
> +  @param  Alignment             The requested alignment of the allocation.
> Must be a power of two.
> +                                If Alignment is zero, then byte alignment is used.
> +  @param  Address               Pointer to a physical address.
> +
> +  @return Memory Allocation Status.
> +
> +**/
> +EFI_STATUS
> +InternalAllocateAlignedPagesWithAllocateType (
> +  IN EFI_ALLOCATE_TYPE         Type,
> +  IN EFI_MEMORY_TYPE           MemoryType,
> +  IN UINTN                     Pages,
> +  IN UINTN                     Alignment,
> +  IN OUT EFI_PHYSICAL_ADDRESS  *Address
> +  )
> +{
> +  EFI_STATUS            Status;
> +  EFI_PHYSICAL_ADDRESS  Memory;
> +  UINTN                 AlignedMemory;
> +  UINTN                 AlignmentMask;
> +  UINTN                 UnalignedPages;
> +  UINTN                 RealPages;
> +
> +  //
> +  // Alignment must be a power of two or zero.
> +  //
> +  ASSERT ((Alignment & (Alignment - 1)) == 0);
> +
> +  if (Pages == 0) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +  if (Alignment > EFI_PAGE_SIZE) {
> +    //
> +    // Calculate the total number of pages since alignment is larger than page
> size.
> +    //
> +    AlignmentMask  = Alignment - 1;
> +    RealPages      = Pages + EFI_SIZE_TO_PAGES (Alignment);
> +    //
> +    // Make sure that Pages plus EFI_SIZE_TO_PAGES (Alignment) does not
> overflow.
> +    //
> +    ASSERT (RealPages > Pages);
> +
> +    Memory         = *Address;
> +    Status         = gBS->AllocatePages (Type, MemoryType, RealPages,
> &Memory);
> +    if (EFI_ERROR (Status)) {
> +      return Status;
> +    }
> +    AlignedMemory  = ((UINTN) Memory + AlignmentMask) &
> ~AlignmentMask;
> +    UnalignedPages = EFI_SIZE_TO_PAGES (AlignedMemory - (UINTN)
> Memory);
> +    if (UnalignedPages > 0) {
> +      //
> +      // Free first unaligned page(s).
> +      //
> +      Status = gBS->FreePages (Memory, UnalignedPages);
> +      ASSERT_EFI_ERROR (Status);
> +    }
> +    Memory         = (EFI_PHYSICAL_ADDRESS) (AlignedMemory +
> EFI_PAGES_TO_SIZE (Pages));
> +    UnalignedPages = RealPages - Pages - UnalignedPages;
> +    if (UnalignedPages > 0) {
> +      //
> +      // Free last unaligned page(s).
> +      //
> +      Status = gBS->FreePages (Memory, UnalignedPages);
> +      ASSERT_EFI_ERROR (Status);
> +    }
> +  } else {
> +    //
> +    // Do not over-allocate pages in this case.
> +    //
> +    Memory = *Address;
> +    Status = gBS->AllocatePages (Type, MemoryType, Pages, &Memory);
> +    if (EFI_ERROR (Status)) {
> +      return Status;
> +    }
> +    AlignedMemory  = (UINTN) Memory;
> +  }
> +  *Address = AlignedMemory;
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  Return if a value is aligned.
> +
> +  @param Value the value to be checked
> +  @param Alignment the alignment to be checked with.
> +
> +  @retval TRUE  The value is aligned
> +  @retval FALSE The value is not aligned.
> +**/
> +BOOLEAN
> +InternalIsAlgined (
> +  IN UINTN  Value,
> +  IN UINTN  Alignment
> +  )
> +{
> +  if (Value != ALIGN_VALUE(Value, Alignment)) {
> +    return FALSE;
> +  } else {
> +    return FALSE;
> +  }
> +}
> +
> +/**
>    Provides the PCI controller-specific address needed to access
>    system memory for DMA.
>
> @@ -1057,6 +1172,8 @@ RootBridgeIoMap (
>    PCI_ROOT_BRIDGE_INSTANCE                          *RootBridge;
>    EFI_PHYSICAL_ADDRESS                              PhysicalAddress;
>    MAP_INFO                                          *MapInfo;
> +  BOOLEAN                                           NeedMap;
> +  EFI_PHYSICAL_ADDRESS                              MaxAddress;
>
>    if (HostAddress == NULL || NumberOfBytes == NULL || DeviceAddress ==
> NULL ||
>        Mapping == NULL) {
> @@ -1072,12 +1189,40 @@ RootBridgeIoMap (
>
>    RootBridge = ROOT_BRIDGE_FROM_THIS (This);
>
> +  if (gIoMmuProtocol == NULL) {
> +    gBS->LocateProtocol (
> +          &gEdkiiIoMmuProtocolGuid,
> +          NULL,
> +          (VOID **) &gIoMmuProtocol
> +          );
> +    if (gIoMmuProtocol != NULL) {
> +      gIoMmuProtocol->GetPageSize (gIoMmuProtocol, &mIoMmuPageSize);
> +      ASSERT ((mIoMmuPageSize & (mIoMmuPageSize - 1)) == 0);
> +    }
> +  }
> +
>    PhysicalAddress = (EFI_PHYSICAL_ADDRESS) (UINTN) HostAddress;
> +
> +  NeedMap = FALSE;
> +  MaxAddress = (UINT64)-1;
> +
>    if ((!RootBridge->DmaAbove4G ||
>         (Operation != EfiPciOperationBusMasterRead64 &&
>          Operation != EfiPciOperationBusMasterWrite64 &&
>          Operation != EfiPciOperationBusMasterCommonBuffer64)) &&
>        ((PhysicalAddress + *NumberOfBytes) > SIZE_4GB)) {
> +    NeedMap = TRUE;
> +    MaxAddress = SIZE_4GB - 1;
> +  }
> +
> +  if (gIoMmuProtocol != NULL) {
> +    if ((!InternalIsAlgined (*NumberOfBytes, mIoMmuPageSize)) ||
> +        (!InternalIsAlgined ((UINTN)HostAddress, mIoMmuPageSize))) {
> +      NeedMap = TRUE;
> +    }
> +  }
> +
> +  if (NeedMap) {
>
>      //
>      // If the root bridge or the device cannot handle performing DMA above
> @@ -1113,15 +1258,18 @@ RootBridgeIoMap (
>      MapInfo->NumberOfBytes     = *NumberOfBytes;
>      MapInfo->NumberOfPages     = EFI_SIZE_TO_PAGES (MapInfo-
> >NumberOfBytes);
>      MapInfo->HostAddress       = PhysicalAddress;
> -    MapInfo->MappedHostAddress = SIZE_4GB - 1;
> +    MapInfo->MappedHostAddress = MaxAddress;
> +    MapInfo->MappedNumberOfBytes = ALIGN_VALUE (MapInfo-
> >NumberOfBytes, mIoMmuPageSize);
> +    MapInfo->MappedNumberOfPages = EFI_SIZE_TO_PAGES
> + (MapInfo->MappedNumberOfBytes);
>
>      //
>      // Allocate a buffer below 4GB to map the transfer to.
>      //
> -    Status = gBS->AllocatePages (
> +    Status = InternalAllocateAlignedPagesWithAllocateType (
>                      AllocateMaxAddress,
>                      EfiBootServicesData,
> -                    MapInfo->NumberOfPages,
> +                    MapInfo->MappedNumberOfPages,
> +                    mIoMmuPageSize,
>                      &MapInfo->MappedHostAddress
>                      );
>      if (EFI_ERROR (Status)) {
> @@ -1240,7 +1388,7 @@ RootBridgeIoUnmap (
>    //
>    // Free the mapped buffer and the MAP_INFO structure.
>    //
> -  gBS->FreePages (MapInfo->MappedHostAddress, MapInfo-
> >NumberOfPages);
> +  gBS->FreePages (MapInfo->MappedHostAddress,
> + MapInfo->MappedNumberOfPages);
>    FreePool (Mapping);
>    return EFI_SUCCESS;
>  }
> @@ -1286,6 +1434,7 @@ RootBridgeIoAllocateBuffer (
>    EFI_PHYSICAL_ADDRESS      PhysicalAddress;
>    PCI_ROOT_BRIDGE_INSTANCE  *RootBridge;
>    EFI_ALLOCATE_TYPE         AllocateType;
> +  UINTN                     Size;
>
>    //
>    // Validate Attributes
> @@ -1321,10 +1470,16 @@ RootBridgeIoAllocateBuffer (
>      AllocateType    = AllocateMaxAddress;
>      PhysicalAddress = (EFI_PHYSICAL_ADDRESS) (SIZE_4GB - 1);
>    }
> -  Status = gBS->AllocatePages (
> +  if (gIoMmuProtocol != NULL) {
> +    Size = EFI_PAGES_TO_SIZE(Pages);
> +    Size = ALIGN_VALUE(EFI_PAGES_TO_SIZE(Pages), mIoMmuPageSize);
> +    Pages = EFI_SIZE_TO_PAGES (Size);
> +  }
> +  Status = InternalAllocateAlignedPagesWithAllocateType (
>                    AllocateType,
>                    MemoryType,
>                    Pages,
> +                  mIoMmuPageSize,
>                    &PhysicalAddress
>                    );
>    if (!EFI_ERROR (Status)) {
> @@ -1356,6 +1511,13 @@ RootBridgeIoFreeBuffer (
>    OUT VOID                             *HostAddress
>    )
>  {
> +  UINTN                     Size;
> +
> +  if (gIoMmuProtocol != NULL) {
> +    Size = EFI_PAGES_TO_SIZE(Pages);
> +    Size = ALIGN_VALUE(EFI_PAGES_TO_SIZE(Pages), mIoMmuPageSize);
> +    Pages = EFI_SIZE_TO_PAGES (Size);
> +  }
>    return gBS->FreePages ((EFI_PHYSICAL_ADDRESS) (UINTN) HostAddress,
> Pages);  }
>
> --
> 2.7.4.windows.1