Re: [edk2-devel] [PATCH v2] MdeModulePkg: Correct high-memory use in NvmExpressDxe

["Ard Biesheuvel" <ardb@kernel.org>]

On Thu, 24 Feb 2022 at 13:58, Tomas Pilar (tpilar)
<quic_tpilar@quicinc.com> wrote:
>
> Move the logic that sets EFI_PCI_IO_ATTRIBUTE_DUAL_ADDRESS_CYCLE Pci
>
> attribute to DriverBindingStart() before the memory that backs the
>
> DMA engine is allocated.
>
>
>
> This ensures that the DMA-backing memory is not forcibly allocated
>
> below 4G in system address map. Otherwise the allocation fails on
>
> platforms that do not have any memory below the 4G mark and the drive
>
> initialisation fails.
>
>
>
> Cc: Ray Ni <ray.ni@intel.com>
>
> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
>
> Cc: Leif Lindholm <leif@nuviainc.com>
>
> Signed-off-by: Tomas Pilar <quic_tpilar@quicinc.com>

Ehm, nope, that is not exactly what I meant.

The existing code stores the original PCI attributes in the controller
private data, enables MMIO/IO decoding and bus mastering, and only
then sets the dual address cycle attribute.

All of that needs to move, so that the captured attributes are accurate.


>
> ---
>
>  MdeModulePkg/Bus/Pci/NvmExpressDxe/NvmExpress.c    | 13 +++++++++++++
>
>  MdeModulePkg/Bus/Pci/NvmExpressDxe/NvmExpressHci.c | 13 -------------
>
>  2 files changed, 13 insertions(+), 13 deletions(-)
>
>
>
> diff --git a/MdeModulePkg/Bus/Pci/NvmExpressDxe/NvmExpress.c b/MdeModulePkg/Bus/Pci/NvmExpressDxe/NvmExpress.c
>
> index 9d40f67e8e..1f0fc5bb68 100644
>
> --- a/MdeModulePkg/Bus/Pci/NvmExpressDxe/NvmExpress.c
>
> +++ b/MdeModulePkg/Bus/Pci/NvmExpressDxe/NvmExpress.c
>
> @@ -959,6 +959,19 @@ NvmExpressDriverBindingStart (
>
>        goto Exit;
>
>      }
>
>
>
> +    //
>
> +    // Enable 64-bit DMA support in the PCI layer.
>
> +    //
>
> +    Status = PciIo->Attributes (
>
> +                      PciIo,
>
> +                      EfiPciIoAttributeOperationEnable,
>
> +                      EFI_PCI_IO_ATTRIBUTE_DUAL_ADDRESS_CYCLE,
>
> +                      NULL
>
> +                      );
>
> +    if (EFI_ERROR (Status)) {
>
> +      DEBUG ((DEBUG_WARN, "NvmeControllerInit: failed to enable 64-bit DMA (%r)\n", Status));
>
> +    }
>
> +
>
>      //
>
>      // 6 x 4kB aligned buffers will be carved out of this buffer.
>
>      // 1st 4kB boundary is the start of the admin submission queue.
>
> diff --git a/MdeModulePkg/Bus/Pci/NvmExpressDxe/NvmExpressHci.c b/MdeModulePkg/Bus/Pci/NvmExpressDxe/NvmExpressHci.c
>
> index ac77afe113..748cb0ba24 100644
>
> --- a/MdeModulePkg/Bus/Pci/NvmExpressDxe/NvmExpressHci.c
>
> +++ b/MdeModulePkg/Bus/Pci/NvmExpressDxe/NvmExpressHci.c
>
> @@ -764,19 +764,6 @@ NvmeControllerInit (
>
>      return Status;
>
>    }
>
>
>
> -  //
>
> -  // Enable 64-bit DMA support in the PCI layer.
>
> -  //
>
> -  Status = PciIo->Attributes (
>
> -                    PciIo,
>
> -                    EfiPciIoAttributeOperationEnable,
>
> -                    EFI_PCI_IO_ATTRIBUTE_DUAL_ADDRESS_CYCLE,
>
> -                    NULL
>
> -                    );
>
> -  if (EFI_ERROR (Status)) {
>
> -    DEBUG ((DEBUG_WARN, "NvmeControllerInit: failed to enable 64-bit DMA (%r)\n", Status));
>
> -  }
>
> -
>
>    //
>
>    // Read the Controller Capabilities register and verify that the NVM command set is supported
>
>    //
>
> --
>
> 2.30.2
>
>
>
> 
>
>