Linux 5.9 Enables P2PDMA For All AMD CPUs Zen + Newer

Written by Michael Larabel in AMD on 9 August 2020 at 08:41 PM EDT. 7 Comments
The PCI subsystem updates have been sent in for the Linux 5.9 kernel. Peer-to-peer DMA support is now solid for all AMD CPUs of the Zen family or newer.

Support for peer-to-peer DMA (P2PDMA) on AMD Zen and newer CPUs is now set. This is for the whitelist being maintained around this feature. There previously was Zen bits in Linux 5.2 while now for Linux 5.9 appears ironed out.

This P2PDMA handling is now allowing all AMD CPU host bridges for AMD newer than Zen, to also cut-down on the maintenance burden moving forward with future generations. The kernel docs cover the support for PCI peer-to-peer DMA support for performing direct memory access transfers between two devices on the bus.

The PCI pull also has new drivers for Versal CPM Root Port and TI J721E PCIe host and endpoint. There are also various improvements to the likes of the Qualcomm, NVIDIA Tegra, Marvell, and Intel drivers.

The full list of PCI changes for Linux 5.9 via this pull request.
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