Re: [RFC 0/6] DxeBmDmaLib

["Ni, Ruiyu" <ruiyu.ni@intel.com>]

Leo,
1. What does "Bm" stand for in "BmDmaLib"?
2. Include/Library/BmDmaLib.h says
    " DMA abstraction library APIs. Based on PCI IO protocol DMA abstractions."
    I think that means the BmDmaLib library class knows the PCI IO concept.
    If so, why not directly use the EFI_PCI_ROT_BRIDGE_IO_PROTOCOL_OPERATION
    enum in this library class API, but invent a new BM_DMA_OPERATION enum type?
3. Can you explain more about AMD's SEV? What will a new instance of this library
    class look like for AMD's SEV? And what will ... for Andrew's usage model?
    I am asking this question because I try to understand the needs of the additional
    layer of abstraction. I want to make sure the additional layer is generic enough
    not just to meet one silicon feature, but can meet a more wide range of silicon
    features.


Thanks/Ray

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Leo Duran
> Sent: Tuesday, January 10, 2017 8:17 AM
> To: edk2-devel@lists.01.org
> Cc: Tian, Feng <feng.tian@intel.com>; brijesh.singh@amd.com;
> ard.biesheuvel@linaro.org; Justen, Jordan L <jordan.l.justen@intel.com>;
> Leo Duran <leo.duran@amd.com>; Agyeman, Prince
> <prince.agyeman@intel.com>; lersek@redhat.com; Zeng, Star
> <star.zeng@intel.com>
> Subject: [edk2] [RFC 0/6] DxeBmDmaLib
> 
> This patch-set provides an abstraction layer for DMA operations
> implemented by the PciHostBridgeDxe driver. The intent is to then allow
> override of this library as may be required by specific hardware
> implementations, such as AMD's Secure Encrypted Virtualization (SEV).
> 
> This new (BmDmaLib class) library is modeled after the existing DmaLib plus
> an extra DmaAbove4GB (BOOLEAN) parameter in the Map and Allocate
> interfaces, so that decisions can be made about the need to allocate DMA
> buffers below the 4GB boundary.
> 
> Leo Duran (6):
>   MdeModulePkg: Add DxeBmDmaLib library
>   ArmVirtPkg: Modify .DSC files that include PciHostBridgeDxe driver
>   CorebootPayloadPkg: Modify .DSC files that include PciHostBridgeDxe
>     driver
>   MdeModulePkg: Modify .DSC files that include PciHostBridgeDxe driver
>   OvmfPkg: Modify .DSC files that include PciHostBridgeDxe driver
>   MdeModulePkg: Modify PciHostBridgeDxe to use new BmDmaLib library.
> 
>  ArmVirtPkg/ArmVirtQemu.dsc                         |   1 +
>  ArmVirtPkg/ArmVirtQemuKernel.dsc                   |   1 +
>  CorebootPayloadPkg/CorebootPayloadPkgIa32.dsc      |   1 +
>  CorebootPayloadPkg/CorebootPayloadPkgIa32X64.dsc   |   1 +
>  .../Bus/Pci/PciHostBridgeDxe/PciHostBridgeDxe.inf  |   1 +
>  .../Bus/Pci/PciHostBridgeDxe/PciRootBridge.h       |  13 +-
>  .../Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c     | 272 ++++------------
>  MdeModulePkg/Include/Library/BmDmaLib.h            | 161 ++++++++++
>  MdeModulePkg/Library/DxeBmDmaLib/DxeBmDmaLib.c     | 351
> +++++++++++++++++++++
>  MdeModulePkg/Library/DxeBmDmaLib/DxeBmDmaLib.inf   |  41 +++
>  MdeModulePkg/MdeModulePkg.dsc                      |   3 +
>  OvmfPkg/OvmfPkgIa32.dsc                            |   1 +
>  OvmfPkg/OvmfPkgIa32X64.dsc                         |   1 +
>  OvmfPkg/OvmfPkgX64.dsc                             |   1 +
>  14 files changed, 629 insertions(+), 220 deletions(-)  create mode 100644
> MdeModulePkg/Include/Library/BmDmaLib.h
>  create mode 100644
> MdeModulePkg/Library/DxeBmDmaLib/DxeBmDmaLib.c
>  create mode 100644
> MdeModulePkg/Library/DxeBmDmaLib/DxeBmDmaLib.inf
> 
> --
> 1.9.1
> 
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