[PATCH v3 05/14] PCI/P2PDMA: Apply host bridge whitelist for ACS

Logan Gunthorpe
2019-08-12T17:31:23Z

When a P2PDMA transfer is rejected due to ACS being set, we can also check
the whitelist and allow the transactions.

Do this by pushing the whitelist check into the upstream_bridge_distance()
function.

Link: https://lore.kernel.org/r/20190730163545.4915-6-logang@deltatee.com
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
---
drivers/pci/p2pdma.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 600ba6a7aa11..f7f7e5862bab 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -339,15 +339,7 @@ __upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,
if (dist)
*dist = dist_a + dist_b;

- /*
- * Allow the connection if both devices are on a whitelisted root
- * complex, but add an arbitrary large value to the distance.
- */
- if (root_complex_whitelist(provider) &&
- root_complex_whitelist(client))
- return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
-
- return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+ return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;

check_b_path_acs:
bb = b;
@@ -371,7 +363,7 @@ __upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,
if (acs_redirects)
*acs_redirects = true;

- return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+ return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
}

return PCI_P2PDMA_MAP_BUS_ADDR;
@@ -420,8 +412,18 @@ static enum pci_p2pdma_map_type
upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client,
int *dist, bool *acs_redirects, struct seq_buf *acs_list)
{
- return __upstream_bridge_distance(provider, client, dist,
- acs_redirects, acs_list);
+ enum pci_p2pdma_map_type map_type;
+
+ map_type = __upstream_bridge_distance(provider, client, dist,
+ acs_redirects, acs_list);
+
+ if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) {
+ if (!root_complex_whitelist(provider) ||
+ !root_complex_whitelist(client))
+ return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+ }
+
+ return map_type;
}

static enum pci_p2pdma_map_type
--
2.20.1