vfio/pci: Fix handling of RC integrated endpoint PCIe capability size

Root complex integrated endpoints do not have a link and therefore may
use a smaller PCIe capability in config space than we expect when
building our config map.  Add a case for these to avoid reporting an
erroneous overlap.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index 330a57024cbc5414b381b26e6ef80cf129cd7f9b..5628fe114347a9d710860022182a26893a87d5ab 100644 (file)
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -839,7 +839,7 @@ static int vfio_exp_config_write(struct vfio_pci_device *vdev, int pos,
 /* Permissions for PCI Express capability */
 static int __init init_pci_cap_exp_perm(struct perm_bits *perm)
 {
-       /* Alloc larger of two possible sizes */
+       /* Alloc largest of possible sizes */
        if (alloc_perm_bits(perm, PCI_CAP_EXP_ENDPOINT_SIZEOF_V2))
                return -ENOMEM;
 
@@ -1243,11 +1243,16 @@ static int vfio_cap_len(struct vfio_pci_device *vdev, u8 cap, u8 pos)
                        vdev->extended_caps = (dword != 0);
                }
 
-               /* length based on version */
-               if ((pcie_caps_reg(pdev) & PCI_EXP_FLAGS_VERS) == 1)
+               /* length based on version and type */
+               if ((pcie_caps_reg(pdev) & PCI_EXP_FLAGS_VERS) == 1) {
+                       if (pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END)
+                               return 0xc; /* "All Devices" only, no link */
                        return PCI_CAP_EXP_ENDPOINT_SIZEOF_V1;
-               else
+               } else {
+                       if (pci_pcie_type(pdev) == PCI_EXP_TYPE_RC_END)
+                               return 0x2c; /* No link */
                        return PCI_CAP_EXP_ENDPOINT_SIZEOF_V2;
+               }
        case PCI_CAP_ID_HT:
                ret = pci_read_config_byte(pdev, pos + 3, &byte);
                if (ret)