diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 30b1df3c9d2f..187047be83a0 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -327,15 +327,19 @@ static const struct pci_p2pdma_whitelist_entry {
/*
* This lookup function tries to find the PCI device corresponding to a given
- * host bridge.
+ * host bridge or a root port.
*
* It assumes the host bridge device is the first PCI device in the
- * bus->devices list and that the devfn is 00.0. These assumptions should hold
- * for all the devices in the whitelist above.
+ * bus->devices list and that the devfn is 00.0. The first assumption should
+ * hold for all the devices in the whitelist above, however the second
+ * assumption doesn't always hold for root ports.
+ * For example for Intel Skylake devices 2030, 2031, 2032 and 2033,
+ * which are root ports (A, B, C and D respectively).
+ * So the function checks explicitly that the device is a root port.
*
- * This function is equivalent to pci_get_slot(host->bus, 0), however it does
- * not take the pci_bus_sem lock seeing __host_bridge_whitelist() must not
- * sleep.
+ * This function is equivalent to pci_get_slot(host->bus, 0) (except for
+ * the root port test), however it does not take the pci_bus_sem lock seeing
+ * __host_bridge_whitelist() must not sleep.
*
* For this to be safe, the caller should hold a reference to a device on the
* bridge, which should ensure the host_bridge device will not be freed
@@ -350,10 +354,19 @@ static struct pci_dev *pci_host_bridge_dev(struct pci_host_bridge *host)
if (!root)
return NULL;
- if (root->devfn != PCI_DEVFN(0, 0))
- return NULL;
- return root;
+ /* Verify that the device is a host bridge or a root port
+ * It is assumed that host bridges have a 0 devfn, (common practice)
+ * but some of the entries in the whitelist are root ports that can
+ * have any devfn
+ */
+ if (root->devfn == PCI_DEVFN(0, 0))
+ return root;
+
+ if (pci_pcie_type(root) == PCI_EXP_TYPE_ROOT_PORT)
+ return root;
+
+ return NULL;
}
static bool __host_bridge_whitelist(struct pci_host_bridge *host,
Thanks, it also helped our system.
Tested-by: Maor Gottlieb <maorg@xxxxxxxxxx>
