From bf4447fd1cb6158b60bd60a79998e1d029d31e68 Mon Sep 17 00:00:00 2001 From: KarimAllah Ahmed Date: Sat, 3 Mar 2018 05:33:10 +0100 Subject: [PATCH] PCI/IOV: Skip BAR sizing for VFs Per PCIe r4.0, sec 9.3.4.1.11, the BAR registers in VF config space are all RO Zero, so skip sizing them. This is an optimization when enabling SR-IOV on a device with many VFs. Suggested-by: Bjorn Helgaas Signed-off-by: KarimAllah Ahmed Signed-off-by: Bjorn Helgaas --- drivers/pci/probe.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index a1cddca..9f80b90 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -329,6 +329,10 @@ static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom) if (dev->non_compliant_bars) return; + /* Per PCIe r4.0, sec 9.3.4.1.11, the VF BARs are all RO Zero */ + if (dev->is_virtfn) + return; + for (pos = 0; pos < howmany; pos++) { struct resource *res = &dev->resource[pos]; reg = PCI_BASE_ADDRESS_0 + (pos << 2); -- 2.7.4