Re: [RFC] [PATCH 0/3] Add IOMMU support.

["Duran, Leo" <leo.duran@amd.com>]

Hi Yao,

This patch-set, in its current form, does not address all of the required SEV functionality for PcIHostBridgeIo.
Basically, we need to intercept all 4 I/O Operations:
- IoMap()
- IoUnmap()
- IoAllocateBuffer()
- IoFreeBuffer()

SEV I/O intercepts would do this:
1) IoMap()
- Allocate an accessible bounce buffer (AllocateType depends on consumer's capabilities).
- Clear SEV mask on retuned mapped DMA buffer
- On DMA Read: CopyMem() from consumer buffer to mapped buffer (bounce operation)

2) IoUnmap()
- On DMA Write: CopyMem() from mapped buffer to consumer buffer (bounce operation)
- Restore SEV mask on mapped DMA buffer

3) IoAllocateBuffer()
- Allocate an accessible buffer (AllocateType depends on consumer's capabilities).
- Clear SEV mask on allocated buffer
- return allocated buffer

4) IoFreeBuffer()
- Restore SEV mask on allocated buffer
- Free allocated buffer

For an sample on how we've intercepted BmDmaLib operations, please refer to the patch-sets posted by Brijesh:
https://lists.01.org/pipermail/edk2-devel/2017-March/008838.html
https://lists.01.org/pipermail/edk2-devel/2017-March/008840.html

Thanks,
Leo

> -----Original Message-----
> From: Jiewen Yao [mailto:jiewen.yao@intel.com]
> Sent: Saturday, March 25, 2017 4:29 AM
> To: edk2-devel@lists.01.org
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>; Duran, Leo <leo.duran@amd.com>;
> Singh, Brijesh <brijesh.singh@amd.com>
> Subject: [RFC] [PATCH 0/3] Add IOMMU support.
> 
> This patch series adds IOMMU protocol and updates the consumer to
> support IOMMU based DMA access in UEFI.
> 
> This patch series can support the BmDmaLib request for AMD SEV.
> submitted by Duran, Leo <leo.duran@amd.com> and Brijesh Singh
> <brijesh.ksingh@gmail.com>.
> https://lists.01.org/pipermail/edk2-devel/2017-March/008109.html, and
> https://lists.01.org/pipermail/edk2-devel/2017-March/008820.html.
> We can have an AMD SEV specific IOMMU driver to produce IOMMU
> protocol, and clear SEV in IOMMU->SetAttribute().
> 
> This patch series can also support Intel VTd based DMA protection,
> requested by Jiewen Yao <jiewen.yao@intel.com>, discussed in
> https://lists.01.org/pipermail/edk2-devel/2017-March/008157.html.
> We can have an Intel VTd specific IOMMU driver to produce IOMMU
> protocol, and update VTd engine to grant or deny access in IOMMU-
> >SetAttribute().
> 
> This patch series does not provide a full Intel VTd driver, which will be
> provide in other patch in the future.
> 
> The purpose of this patch series to review if this IOMMU protocol design can
> meet all DMA access and management requirement.
> 
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Cc: Leo Duran <leo.duran@amd.com>
> Cc: Brijesh Singh <brijesh.singh@amd.com>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Jiewen Yao <jiewen.yao@intel.com>
> 
> 
> Jiewen Yao (3):
>   MdeModulePkg/Include: Add IOMMU protocol definition.
>   MdeModulePkg/PciHostBridge: Add IOMMU support.
>   MdeModulePkg/PciBus: Add IOMMU support.
> 
>  MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c                    |  12 ++
>  MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h                    |  10 ++
>  MdeModulePkg/Bus/Pci/PciBusDxe/PciBusDxe.inf               |   1 +
>  MdeModulePkg/Bus/Pci/PciBusDxe/PciIo.c                     | 100 ++++++++++++
>  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
> +++++++++++++++++++-
>  MdeModulePkg/Include/Protocol/IoMmu.h                      | 132
> +++++++++++++++
>  MdeModulePkg/MdeModulePkg.dec                              |   3 +
>  10 files changed, 436 insertions(+), 5 deletions(-)  create mode 100644
> MdeModulePkg/Include/Protocol/IoMmu.h
> 
> --
> 2.7.4.windows.1