When looking at a PCIe switch we want to see that the USP/DSP MMIO have
request redirect enabled. Detect the case where the USP is expressly not
isolated from the DSP and ensure the USP is included in the group.
The DSP Memory Target also applies to the Root Port, check it there
too. If upstream directed transactions can reach the root port MMIO then
it is not isolated.
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
drivers/pci/search.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index 2be6881087b335..7425680fe92d60 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -127,6 +127,8 @@ static enum pci_bus_isolation pcie_switch_isolated(struct pci_bus *bus)
* traffic flowing upstream back downstream through another DSP.
*
* Thus any non-permissive DSP spoils the whole bus.
+ * PCI_ACS_UNCLAIMED_RR is not required since rejecting requests with
+ * error is still isolation.
*/
guard(rwsem_read)(&pci_bus_sem);
list_for_each_entry(pdev, &bus->devices, bus_list) {
@@ -136,8 +138,14 @@ static enum pci_bus_isolation pcie_switch_isolated(struct pci_bus *bus)
pdev->dma_alias_mask)
return PCIE_NON_ISOLATED;
- if (!pci_acs_enabled(pdev, PCI_ACS_ISOLATED))
+ if (!pci_acs_enabled(pdev, PCI_ACS_ISOLATED |
+ PCI_ACS_DSP_MT_RR |
+ PCI_ACS_USP_MT_RR)) {
+ /* The USP is isolated from the DSP */
+ if (!pci_acs_enabled(pdev, PCI_ACS_USP_MT_RR))
+ return PCIE_NON_ISOLATED;
return PCIE_SWITCH_DSP_NON_ISOLATED;
+ }
}
return PCIE_ISOLATED;
}
@@ -231,11 +239,13 @@ enum pci_bus_isolation pci_bus_isolated(struct pci_bus *bus)
switch (type) {
/*
* Since PCIe links are point to point root and downstream ports are
- * isolated if their own MMIO cannot be reached.
+ * isolated if their own MMIO cannot be reached. The root port
+ * uses DSP_MT_RR for its own MMIO.
*/
case PCI_EXP_TYPE_ROOT_PORT:
case PCI_EXP_TYPE_DOWNSTREAM:
- if (!pci_acs_enabled(bridge, PCI_ACS_ISOLATED))
+ if (!pci_acs_enabled(bridge,
+ PCI_ACS_ISOLATED | PCI_ACS_DSP_MT_RR))
return PCIE_NON_ISOLATED;
return PCIE_ISOLATED;
--
2.43.0
