From: Leon Romanovsky leonro@nvidia.com
A Downstream Port with ACS Direct Translated P2P enabled routes a Request whose Address Type is Translated "to the peer Egress Port without redirection, regardless of ACS P2P Request Redirect and ACS P2P Egress Control", per PCIe r7.0 sec 6.12.3. P2PDMA assumes every Request carries an Untranslated address, so it sends an ATS client through the host bridge even where the fabric would route it straight to the peer.
Add PCI_P2PDMA_TLP_TRANSLATED and consult Direct Translated P2P for the Requests it describes.
Tested-by: Tushar Dave tdave@nvidia.com Signed-off-by: Leon Romanovsky leonro@nvidia.com --- drivers/pci/p2pdma.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 839285b77b62..13fe83142c71 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -521,6 +521,15 @@ pci_acs_p2pdma_request(u16 ctrl, unsigned int tlp_flags) */ if (ctrl & PCI_ACS_TB) return PCI_ACS_P2PDMA_BLOCKED; + + /* + * PCIe r7.0 sec 6.12.3: ACS Direct Translated P2P routes a + * Request carrying a Translated address to the peer "without + * redirection, regardless of ACS P2P Request Redirect and ACS + * P2P Egress Control settings". + */ + if (ctrl & PCI_ACS_DT) + return PCI_ACS_P2PDMA_DIRECT; }
return ctrl & (PCI_ACS_RR | PCI_ACS_EC) ?