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authorAlex Williamson <alex.williamson@redhat.com>2020-04-08 20:45:28 +0300
committerAlex Williamson <alex.williamson@redhat.com>2020-05-18 18:55:35 +0300
commitbc138db1b96264b9c1779cf18d5a3b186aa90066 (patch)
treec7b6a789a66931a2ed9bb6324de08f76df769935 /drivers/vfio
parentb9bbe6ed63b2b9f2c9ee5cbd0f2c946a2723f4ce (diff)
downloadlinux-bc138db1b96264b9c1779cf18d5a3b186aa90066.tar.xz
vfio-pci: Mask cap zero
The PCI Code and ID Assignment Specification changed capability ID 0 from reserved to a NULL capability in the v1.1 revision. The NULL capability is defined to include only the 16-bit capability header, ie. only the ID and next pointer. Unfortunately vfio-pci creates a map of config space, where ID 0 is used to reserve the standard type 0 header. Finding an actual capability with this ID therefore results in a bogus range marked in that map and conflicts with subsequent capabilities. As this seems to be a dummy capability anyway and we already support dropping capabilities, let's hide this one rather than delving into the potentially subtle dependencies within our map. Seen on an NVIDIA Tesla T4. Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/pci/vfio_pci_config.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index 90c0b80f8acf..8fc27393bf7a 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -1462,7 +1462,12 @@ static int vfio_cap_init(struct vfio_pci_device *vdev)
if (ret)
return ret;
- if (cap <= PCI_CAP_ID_MAX) {
+ /*
+ * ID 0 is a NULL capability, conflicting with our fake
+ * PCI_CAP_ID_BASIC. As it has no content, consider it
+ * hidden for now.
+ */
+ if (cap && cap <= PCI_CAP_ID_MAX) {
len = pci_cap_length[cap];
if (len == 0xFF) { /* Variable length */
len = vfio_cap_len(vdev, cap, pos);