[PATCH v1 4/5] PCI/ATS: For PF/VF skip ATS initalization if spec check failed

[sathyanarayanan . kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>

Don't initialize ATS for VF/PF devices if the ATS Capability
implementaion is not aligned with PCIe spec r4.0 sec 9.3.7.8.

Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
Cc: Keith Busch <keith.busch@xxxxxxxxx>
Suggested-by: Ashok Raj <ashok.raj@xxxxxxxxx>
Reviewed-by: Keith Busch <keith.busch@xxxxxxxxx>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
---
 drivers/pci/ats.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index 28bbf7dad425..11299d93a59a 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -23,6 +23,12 @@ void pci_ats_init(struct pci_dev *dev)
 	if (pci_ats_disabled())
 		return;
 
+	/* If ATS Cap is invalid then return */
+	if (dev->is_virtfn || dev->is_physfn) {
+		if (dev->invalid_cap & PCI_IOV_INVALID_ATS)
+			return;
+	}
+
 	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
 	if (!pos)
 		return;
-- 
2.20.1