If the PCI core set cfg_size isn't large enough for extended capabilities, then they're not there. Extended config space may be inaccessible due to a PCI bridge, in which case cfg_size may be cut short.
Signed-off-by: Alex Williamson <[email protected]> --- 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 83cd157..4a62a37 100644 --- a/drivers/vfio/pci/vfio_pci_config.c +++ b/drivers/vfio/pci/vfio_pci_config.c @@ -1027,8 +1027,11 @@ static int vfio_cap_len(struct vfio_pci_device *vdev, u8 cap, u8 pos) if (PCI_X_CMD_VERSION(word)) { /* Test for extended capabilities */ - pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE, &dword); - vdev->extended_caps = (dword != 0); + if (pdev->cfg_size > PCI_CFG_SPACE_SIZE) { + pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE, + &dword); + vdev->extended_caps = (dword != 0); + } return PCI_CAP_PCIX_SIZEOF_V2; } else return PCI_CAP_PCIX_SIZEOF_V0; @@ -1041,8 +1044,10 @@ static int vfio_cap_len(struct vfio_pci_device *vdev, u8 cap, u8 pos) return byte; case PCI_CAP_ID_EXP: /* Test for extended capabilities */ - pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE, &dword); - vdev->extended_caps = (dword != 0); + if (pdev->cfg_size > PCI_CFG_SPACE_SIZE) { + pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE, &dword); + vdev->extended_caps = (dword != 0); + } /* length based on version */ if ((pcie_caps_reg(pdev) & PCI_EXP_FLAGS_VERS) == 1) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
