Update the p2p_dma_distance() to determine virtual inter-switch P2P links
existing between two switches and use this to calculate the DMA distance
between two devices.
Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@xxxxxxxxxxxx>
---
drivers/pci/Kconfig | 1 +
drivers/pci/p2pdma.c | 18 +++++++++++++++++-
2 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index d35001589d88..3e6226ec91fd 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -174,6 +174,7 @@ config PCI_P2PDMA
depends on 64BIT
select GENERIC_ALLOCATOR
select NEED_SG_DMA_FLAGS
+ select PCI_SW_DISCOVERY
help
Enables drivers to do PCI peer-to-peer transactions to and from
BARs that are exposed in other devices that are the part of
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 4f47a13cb500..780e649b3a1d 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -21,6 +21,8 @@
#include <linux/seq_buf.h>
#include <linux/xarray.h>
+extern bool sw_disc_check_virtual_link(struct pci_dev *a, struct pci_dev *b);
+
struct pci_p2pdma {
struct gen_pool *pool;
bool p2pmem_published;
@@ -576,7 +578,7 @@ calc_map_type_and_dist(struct pci_dev *provider, struct pci_dev *client,
int *dist, bool verbose)
{
enum pci_p2pdma_map_type map_type = PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
- struct pci_dev *a = provider, *b = client, *bb;
+ struct pci_dev *a = provider, *b = client, *bb, *b_virtual_link = NULL;
bool acs_redirects = false;
struct pci_p2pdma *p2pdma;
struct seq_buf acs_list;
@@ -606,6 +608,17 @@ calc_map_type_and_dist(struct pci_dev *provider, struct pci_dev *client,
if (a == bb)
goto check_b_path_acs;
+ // Physical Broadcom PEX switches can be provisioned into
+ // multiple virtual switches.
+ // if both upstream bridges belong to the same physical
+ // switch, and the switch supports P2P,
+ // p2p_dma_distance() should take into account of such
+ // scenarios.
+ if (sw_disc_check_virtual_link(a, bb)) {
+ b_virtual_link = bb;
+ goto check_b_path_acs;
+ }
+
bb = pci_upstream_bridge(bb);
dist_b++;
}
@@ -629,6 +642,9 @@ calc_map_type_and_dist(struct pci_dev *provider, struct pci_dev *client,
acs_cnt++;
}
+ if (b_virtual_link && bb == b_virtual_link)
+ break;
+
bb = pci_upstream_bridge(bb);
}
--
2.43.0
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