[Linaro-uefi] [RFC][edk2] MdeModulePkg/NonDiscoverablePciDeviceDxe: NonCoherentPciIoAllocateBuffer issue with AArch64

Hi folks,

In NonDiscoverablePciDeviceDxe driver, NonCoherentPciIoAllocateBuffer may allocate EFI_MEMORY_UC buffer depending on input Attributes and GCD capabilities. If it does, it actually allocates memory of "device" type in AArch64, but not "normal uncacheable" memory. For "device" memory type, it requires restrict access alignment and it may trigger alignment fault exception with BaseMemoryLibOptDxe in which read/write alignment is not guaranteed.

Is EFI_MOMORY_WC enough for AArch64 platforms? How about other platforms, like X86?

Thanks and regards,

Heyi Guo