DMA to/from PCIe BAR region memory

Hi vidyas!

According to DMA to PCIe BARs, you said that it is not allowed to use DMA for PCIe BAR region on Xavier NX.

Recently I connected 2 Orin through a PCIe switch, both Orin are regarded as RC(host) and the data will be transferred by NTB.

Now I have achieved to exchange data between 2 Orin by doing memcpy to/from the PCIe BAR region on each side. Then I’m curious about how to improve the performance by using DMA to move the data into/out from the BAR region memory.

So I want to confirm if there are some upgrading kernel facilities for performing DMA to/from PCIe BAR regions on Jetson AGX Orin?

I’m using the latest version JetPack 5.1.1.

If it is still impossible, please explain more in detail about the root cause of this issue. Thanks a lot!

@vidyas