diff options
| -rw-r--r-- | drivers/pci/probe.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index a3a3c6b28343..439244ff8f09 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1561,6 +1561,21 @@ int pci_cfg_space_size(struct pci_dev *dev) u32 status; u16 class; +#ifdef CONFIG_PCI_IOV + /* + * Per the SR-IOV specification (rev 1.1, sec 3.5), VFs are required to + * implement a PCIe capability and therefore must implement extended + * config space. We can skip the NO_EXTCFG test below and the + * reachability/aliasing test in pci_cfg_space_size_ext() by virtue of + * the fact that the SR-IOV capability on the PF resides in extended + * config space and must be accessible and non-aliased to have enabled + * support for this VF. This is a micro performance optimization for + * systems supporting many VFs. + */ + if (dev->is_virtfn) + return PCI_CFG_SPACE_EXP_SIZE; +#endif + if (dev->bus->bus_flags & PCI_BUS_FLAGS_NO_EXTCFG) return PCI_CFG_SPACE_SIZE; |