Re: [PATCH 0/7] MdeModulePkg ArmVirtPkg: fixes for 64-bit PCI DMA

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

Feng, Star: do you have any feedback on these patches? Thanks.

On 5 September 2016 at 10:17, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> After moving ArmVirtQemu to the generic PciHostBridgeDxe, we noticed that
> setting DmaAbove4G resulted in problems with the emulated EHCI USB host
> controller, which were caused by the fact that the PCI layer was providing
> DMA buffers allocated above 4 GB while the emulated EHCI controller in QEMU
> does not indicate support for 64-bit addressing.
>
> As it turns out, the PCI drivers in MdeModulePkg *completely* ignore the
> EFI_PCI_ATTRIBUTE_DUAL_ADDRESS_CYCLE attribute, and simply assume that no
> PCI root bridge driver will produce mappings above 4 GB. On ARM, this is
> problematic, since not all platforms have memory below 4 GB, and so having
> full support for DMA above 4 GB is indispensable.
>
> So first, make the various drivers under MdeModulePkg/Pci/Bus set the
> EFI_PCI_IO_ATTRIBUTE_DUAL_ADDRESS_CYCLE attributes for devices that can
> support 64-bit DMA addressing (patches #1 - #5). Then, we can update the
> host bridge driver to actually take these attributes into account, and only
> create mappings above 4 GB for devices that have indicated support for it.
>
> Finally, in patch #7 we can remove the 4 GB DMA limit from ArmVirtPkg.
>
> Branch can be found here:
> https://git.linaro.org/people/ard.biesheuvel/uefi-next.git/shortlog/refs/heads/pci-64bit-dma-fixes
>
> Ard Biesheuvel (7):
>   MdeModulePkg/AtaAtapiPassThru: enable 64-bit PCI DMA
>   MdeModulePkg/EhciDxe: enable 64-bit PCI DMA
>   MdeModulePkg/NvmExpressDxe: enable 64-bit PCI DMA
>   MdeModulePkg/SdMmcPciHcDxe: enable 64-bit PCI DMA
>   MdeModulePkg/XhciDxe: enable 64-bit PCI DMA
>   MdeModulePkg/PciHostBridgeDxe: restrict 64-bit DMA to devices that
>     support it
>   ArmVirtPkg/FdtPciHostBridgeLib: enable 64-bit PCI DMA
>
>  ArmVirtPkg/Library/FdtPciHostBridgeLib/FdtPciHostBridgeLib.c |  2 +-
>  MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c             | 20 +++++++++++++++++-
>  MdeModulePkg/Bus/Pci/EhciDxe/Ehci.c                          | 22 +++++++++++++++++++-
>  MdeModulePkg/Bus/Pci/EhciDxe/Ehci.h                          |  2 ++
>  MdeModulePkg/Bus/Pci/EhciDxe/EhciSched.c                     |  2 +-
>  MdeModulePkg/Bus/Pci/NvmExpressDxe/NvmExpressHci.c           | 13 ++++++++++++
>  MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c      | 14 +++++++++----
>  MdeModulePkg/Bus/Pci/SdMmcPciHcDxe/SdMmcPciHcDxe.c           | 20 ++++++++++++++++++
>  MdeModulePkg/Bus/Pci/XhciDxe/Xhci.c                          | 22 +++++++++++++++++++-
>  MdeModulePkg/Bus/Pci/XhciDxe/Xhci.h                          |  2 ++
>  10 files changed, 110 insertions(+), 9 deletions(-)
>
> --
> 2.7.4
>