There is no PCI spec defined capability with ID 0, therefore we don't
expect to find it in a capability chain and we use this index in an
internal array for tracking the sizes of various capabilities to handle
standard config space. Therefore if a device does present us with a
capability ID 0, we mark our capability map with nonsense that can
trigger conflicts with other capabilities in the chain. Ignore ID 0
when walking the capability chain, handling it as a hidden capability.
Seen on an NVIDIA Tesla T4.
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
drivers/vfio/pci/vfio_pci_config.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index 87d0cc8c86ad..5935a804cb88 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -1487,7 +1487,7 @@ static int vfio_cap_init(struct vfio_pci_device *vdev)
if (ret)
return ret;
- if (cap <= PCI_CAP_ID_MAX) {
+ if (cap && cap <= PCI_CAP_ID_MAX) {
len = pci_cap_length[cap];
if (len == 0xFF) { /* Variable length */
len = vfio_cap_len(vdev, cap, pos);
