From cf0921bea66c55600a48009597caa5fcb1419748 Mon Sep 17 00:00:00 2001 From: KarimAllah Ahmed Date: Mon, 19 Mar 2018 21:06:00 +0100 Subject: PCI/IOV: Use VF0 cached config registers for other VFs Cache some config data from VF0 and use it for all other VFs instead of reading it from the config space of each VF. We assume these items are the same across all associated VFs: Revision ID Class Code Subsystem Vendor ID Subsystem ID This is an optimization when enabling SR-IOV on a device with many VFs. Signed-off-by: KarimAllah Ahmed [bhelgaas: changelog, simplify comments, remove unused "device", test CONFIG_PCI_IOV instead of CONFIG_PCI_ATS, rename functions] Signed-off-by: Bjorn Helgaas --- drivers/pci/iov.c | 42 +++++++++++++++++++++++++++++++++++------- 1 file changed, 35 insertions(+), 7 deletions(-) (limited to 'drivers/pci/iov.c') diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index 677924ae0350..30bf8f706ed9 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -114,6 +114,29 @@ resource_size_t pci_iov_resource_size(struct pci_dev *dev, int resno) return dev->sriov->barsz[resno - PCI_IOV_RESOURCES]; } +static void pci_read_vf_config_common(struct pci_dev *virtfn) +{ + struct pci_dev *physfn = virtfn->physfn; + + /* + * Some config registers are the same across all associated VFs. + * Read them once from VF0 so we can skip reading them from the + * other VFs. + * + * PCIe r4.0, sec 9.3.4.1, technically doesn't require all VFs to + * have the same Revision ID and Subsystem ID, but we assume they + * do. + */ + pci_read_config_dword(virtfn, PCI_CLASS_REVISION, + &physfn->sriov->class); + pci_read_config_byte(virtfn, PCI_HEADER_TYPE, + &physfn->sriov->hdr_type); + pci_read_config_word(virtfn, PCI_SUBSYSTEM_VENDOR_ID, + &physfn->sriov->subsystem_vendor); + pci_read_config_word(virtfn, PCI_SUBSYSTEM_ID, + &physfn->sriov->subsystem_device); +} + int pci_iov_add_virtfn(struct pci_dev *dev, int id) { int i; @@ -136,13 +159,17 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id) virtfn->devfn = pci_iov_virtfn_devfn(dev, id); virtfn->vendor = dev->vendor; virtfn->device = iov->vf_device; + virtfn->is_virtfn = 1; + virtfn->physfn = pci_dev_get(dev); + + if (id == 0) + pci_read_vf_config_common(virtfn); + rc = pci_setup_device(virtfn); if (rc) - goto failed0; + goto failed1; virtfn->dev.parent = dev->dev.parent; - virtfn->physfn = pci_dev_get(dev); - virtfn->is_virtfn = 1; virtfn->multifunction = 0; for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) { @@ -163,10 +190,10 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id) sprintf(buf, "virtfn%u", id); rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf); if (rc) - goto failed1; + goto failed2; rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn"); if (rc) - goto failed2; + goto failed3; kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE); @@ -174,11 +201,12 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id) return 0; -failed2: +failed3: sysfs_remove_link(&dev->dev.kobj, buf); +failed2: + pci_stop_and_remove_bus_device(virtfn); failed1: pci_dev_put(dev); - pci_stop_and_remove_bus_device(virtfn); failed0: virtfn_remove_bus(dev->bus, bus); failed: -- cgit v1.2.3