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 <[email protected]> --- 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);
