> Peer-to-Peer DMA (P2PDMA) between two devices requires either a shared > upstream bridge or a host bridge matching pci_p2pdma_whitelist[]. In > Hyper-V guests, each passthrough device appears in a PCI domain of its > own without a host bridge device. Consequently, P2PDMA checks evaluate > endpoint Device IDs against the host bridge whitelist, causing P2PDMA > requests to fail regardless of host support. > > This affects discrete devices such as GPUs, NICs and NVMe drives. > > The P2PDMA host bridge check does not work in a Hyper-V guest. Apply > the same bypass as for VMware, on the same Intel Xeon generations. > > Tested with the Intel Level Zero P2P benchmark (ze_peer) on Arc Pro B60 > cards in a Linux guest on Windows Server 2025 (Emerald Rapids host). > > Signed-off-by: Pavel Popov <[email protected]>
Sashiko has reviewed this patch and found no issues. -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=2
