From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-fw-9101.amazon.com ([207.171.184.25]:29436 "EHLO smtp-fw-9101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750775AbeCCEd2 (ORCPT ); Fri, 2 Mar 2018 23:33:28 -0500 From: KarimAllah Ahmed To: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Cc: KarimAllah Ahmed , Bjorn Helgaas Subject: [PATCH] PCI/IOV: Skip initializing the base addresses from the VF config space Date: Sat, 3 Mar 2018 05:33:10 +0100 Message-Id: <1520051590-11750-1-git-send-email-karahmed@amazon.de> Sender: linux-pci-owner@vger.kernel.org List-ID: Per PCIe r4.0, sec 9.3.4.1.11, the BARs registers from the VF config space are all RO Zero for PCI VFs. So just skip reading them for VFs. This is an optimization when enabling SR-IOV on a device with many VFs. Cc: Bjorn Helgaas Cc: linux-pci@vger.kernel.org Cc: linux-kernel@vger.kernel.org Suggested-by: Bjorn Helgaas Signed-off-by: KarimAllah Ahmed --- drivers/pci/probe.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index a96837e..7204d46 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