Hello, On Mon, 26 Oct 2026 at 09:55, Raghavendra Ningoji <[email protected]> wrote: > > This series adds support for the Non-Transparent Bridge (NTB) endpoints > integrated in AMD EPYC Embedded "Turin", "Genoa" and "Siena" processors > to the raw/ntb driver. > > The common NTB code validates the vendor ops once at probe time, and the > vendor abstraction is built around a small set of mandatory ops instead > of optional hooks with built-in fallbacks: > > - Patch 1 is a preparation commit that enforces the vendor ops once, at > probe time, and removes the per-call NULL checks that are scattered > throughout the common code. > > - Patch 2 generalizes the framework for multiple vendors. The link > bring-up/tear-down is now expressed through mandatory ops > (dev_handshake, peer_mw_validate, read_peer_config, link_cleanup); the > former built-in scratchpad logic moved into the Intel driver. The > mw_set_trans op is gone (it is now a vendor-internal concern of the > handshake), and there is a single common interrupt handler with just > one optional op (handle_hw_event) for vendor-specific hardware events. > > - Patch 3 adds the AMD hardware driver, its documentation, release note > and MAINTAINERS entry. > > A few AMD-specific hardware details worth noting for reviewers: > > - Primary/secondary topology. One endpoint enumerates as the primary > (device ID 0x14c0) and the other as the secondary (0x14c3), rather > than the Intel back-to-back model. > > - Packed scratchpad handshake. The hardware exposes a single shared > 16-register scratchpad bank split into two disjoint 8-register sets > (one per side), so the driver uses a packed handshake layout that > fits in 8 registers, plugged in through the dev_handshake, > peer_mw_validate and read_peer_config ops. > > - Outbound translation window. AMD NTB uses an outbound translation > window: a write to a BARxx memory-window offset is forwarded to > (xlat_base | offset) in the peer's memory rather than > (xlat_base + offset). The translation base must therefore be aligned > to a power of two >= the window length so that no offset bit collides > with a set bit in the base. This is reported to applications through > the rte_pmd_ntb_get_mem_align() API and honoured by the ntb example > when reserving the memory window memzone. > > - Secondary-side link status. On the secondary side the device's own > PCIe link status does not reflect the true inter-host link, so the > speed and width are read from the upstream switch port via sysfs. > > Tested on a two-node setup (primary + secondary EPYC Embedded hosts) > with the dpdk-ntb example: the link comes up at the expected speed and > width on both sides, and file transfers are byte-correct end to end for > both small and large files. > > Changes since v3: > > - Simplified the probe-time vendor ops check (patch 1) to a plain > per-member macro instead of an offsetof() table. > > - Removed the mw_size_align field from struct ntb_dev_info entirely > (patch 2): applications must now use rte_pmd_ntb_get_mem_align(). This > is documented in the API changes section of the release notes. > > - Removed the unused pmd_private field from struct ntb_hw and the whole > struct amd_ntb_hw (patch 3): self_mmio is just ntb->hw_addr, peer_mmio > becomes AMD_PEER_MMIO(ntb), the scratchpad offsets become an > AMD_SPAD_BASE(ntb, peer) macro, and int_mask/peer_status/ctl_status > were unused. > > - Sorted AMD alphabetically before Intel in meson.build, the ntb_hw > header include, the PCI id mapping table and usertools/dpdk-devbind.py. > > - Moved the primary/secondary topology definitions (NTB_TOPO_PRI/SEC) > from patch 2 to patch 3 where they are first used. > > - Updated the Limitation section of doc/guides/rawdevs/ntb.rst to list > the supported AMD processors.
- "external" build was broken for the example as spotted by the CI. https://github.com/ovsrobot/dpdk/actions/runs/40296962846/job/121485246438 This is a known limitation of the .pc provided by DPDK (which Robin recently tried to fix). I tested and squashed a simple fix: https://github.com/david-marchand/dpdk/commit/16b0d741ebf39b22ebb696c07f2ed44ad383bfc9 - Some commitlogs were not updated after the v4 changes, fixed. - Some strange indentation issues were still there, fixed. With all those fixes applied, I pushed this driver update. Thanks. -- David Marchand
