On 09/05/16 11:17, Ard Biesheuvel wrote:
> Currently, the EFI_PCI_ATTRIBUTE_DUAL_ADDRESS_CYCLE attribute is completely
> ignored by the PCI host bridge driver, which means that, on an implementation
> that supports DMA above 4 GB, allocations above 4 GB may be provided to
> devices that have not expressed support for it.
>
> So in addition to checking 'RootBridge->DmaAbove4G' to establish whether the
> root bridge itself supports DMA above 4 GB, we must also take into account
> the operation type (EfiPciOperationBusMaster{Read|Write|CommBuffer}64),
> and the EFI_PCI_ATTRIBUTE_DUAL_ADDRESS_CYCLE attribute, when mapping and
> allocating DMA memory, respectively.
>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <[email protected]>
> ---
> MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> index b2d76d67afa2..8af131b0af37 100644
> --- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> +++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciRootBridgeIo.c
> @@ -1073,10 +1073,15 @@ RootBridgeIoMap (
> RootBridge = ROOT_BRIDGE_FROM_THIS (This);
>
> PhysicalAddress = (EFI_PHYSICAL_ADDRESS) (UINTN) HostAddress;
> - if (!RootBridge->DmaAbove4G && ((PhysicalAddress + *NumberOfBytes) >
> SIZE_4GB)) {
> + if ((!RootBridge->DmaAbove4G ||
> + (Operation != EfiPciOperationBusMasterRead64 &&
> + Operation != EfiPciOperationBusMasterWrite64 &&
> + Operation != EfiPciOperationBusMasterCommonBuffer64)) &&
> + ((PhysicalAddress + *NumberOfBytes) > SIZE_4GB)) {
> +
> //
> - // If the root bridge can not handle performing DMA above 4GB but
> - // any part of the DMA transfer being mapped is above 4GB, then
> + // If the root bridge or the device cannot handle performing DMA above
> + // 4GB but any part of the DMA transfer being mapped is above 4GB, then
> // map the DMA transfer to a buffer below 4GB.
> //
>
> @@ -1308,7 +1313,8 @@ RootBridgeIoAllocateBuffer (
> RootBridge = ROOT_BRIDGE_FROM_THIS (This);
>
> AllocateType = AllocateAnyPages;
> - if (!RootBridge->DmaAbove4G) {
> + if (!RootBridge->DmaAbove4G ||
> + (Attributes & EFI_PCI_ATTRIBUTE_DUAL_ADDRESS_CYCLE) == 0) {
> //
> // Limit allocations to memory below 4GB
> //
>
Reviewed-by: Laszlo Ersek <[email protected]>
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