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

From: Alex Williamson
Date: Thu Jul 27 2017 - 12:52:42 EST


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@xxxxxxxxxx>
---
drivers/vfio/pci/vfio_pci_config.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index 330a57024cbc..5628fe114347 100644
--- 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)