[PATCH v9 10/18] PCI/P2PDMA: Route Translated Requests under Direct Translated P2P

[Leon Romanovsky]

From: Leon Romanovsky <leonro@xxxxxxxxxx>

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.

Reviewed-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Tested-by: Tushar Dave <tdave@xxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
---
 drivers/pci/p2pdma.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 569a74de3b3a..3fd2cb8d16f0 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -548,6 +548,15 @@ 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) ?

-- 
2.55.0