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

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

Ard,
The patch to MdeModulePkg/PciHostBridgeDxe is good.

Reviewed-by: Ruiyu Ni <Ruiyu.ni@intel.com>

Thanks/Ray

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Ard Biesheuvel
> Sent: Tuesday, September 6, 2016 3:48 PM
> To: edk2-devel-01 <edk2-devel@lists.01.org>; Tian, Feng
> <feng.tian@intel.com>; Zeng, Star <star.zeng@intel.com>; Gao, Liming
> <liming.gao@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>; Leif Lindholm
> <leif.lindholm@linaro.org>; Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Subject: Re: [edk2] [PATCH 0/7] MdeModulePkg ArmVirtPkg: fixes for 64-bit
> PCI DMA
> 
> 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/re
> > fs/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
> >
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