From cf0921bea66c55600a48009597caa5fcb1419748 Mon Sep 17 00:00:00 2001 From: KarimAllah Ahmed Date: Mon, 19 Mar 2018 21:06:00 +0100 Subject: [PATCH] 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 +++++++++++++++++++++++++++++++++------- drivers/pci/pci.h | 4 ++++ drivers/pci/probe.c | 47 ++++++++++++++++++++++++++++++++++++++++----- 3 files changed, 81 insertions(+), 12 deletions(-) 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: diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index fcd81911b127..bdb4ba2d5f95 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -271,6 +271,10 @@ struct pci_sriov { u16 driver_max_VFs; /* Max num VFs driver supports */ struct pci_dev *dev; /* Lowest numbered PF */ struct pci_dev *self; /* This PF */ + u32 class; /* VF device */ + u8 hdr_type; /* VF header type */ + u16 subsystem_vendor; /* VF subsystem vendor */ + u16 subsystem_device; /* VF subsystem device */ resource_size_t barsz[PCI_SRIOV_NUM_BARS]; /* VF BAR size */ bool drivers_autoprobe; /* Auto probing of VFs by driver */ }; diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 9f80b904bf76..708094f720fd 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1400,6 +1400,43 @@ int pci_cfg_space_size(struct pci_dev *dev) return PCI_CFG_SPACE_SIZE; } +static u32 pci_class(struct pci_dev *dev) +{ + u32 class; + +#ifdef CONFIG_PCI_IOV + if (dev->is_virtfn) + return dev->physfn->sriov->class; +#endif + pci_read_config_dword(dev, PCI_CLASS_REVISION, &class); + return class; +} + +static void pci_subsystem_ids(struct pci_dev *dev, u16 *vendor, u16 *device) +{ +#ifdef CONFIG_PCI_IOV + if (dev->is_virtfn) { + *vendor = dev->physfn->sriov->subsystem_vendor; + *device = dev->physfn->sriov->subsystem_device; + return; + } +#endif + pci_read_config_word(dev, PCI_SUBSYSTEM_VENDOR_ID, vendor); + pci_read_config_word(dev, PCI_SUBSYSTEM_ID, device); +} + +static u8 pci_hdr_type(struct pci_dev *dev) +{ + u8 hdr_type; + +#ifdef CONFIG_PCI_IOV + if (dev->is_virtfn) + return dev->physfn->sriov->hdr_type; +#endif + pci_read_config_byte(dev, PCI_HEADER_TYPE, &hdr_type); + return hdr_type; +} + #define LEGACY_IO_RESOURCE (IORESOURCE_IO | IORESOURCE_PCI_FIXED) static void pci_msi_setup_pci_dev(struct pci_dev *dev) @@ -1465,8 +1502,7 @@ int pci_setup_device(struct pci_dev *dev) struct pci_bus_region region; struct resource *res; - if (pci_read_config_byte(dev, PCI_HEADER_TYPE, &hdr_type)) - return -EIO; + hdr_type = pci_hdr_type(dev); dev->sysdata = dev->bus->sysdata; dev->dev.parent = dev->bus->bridge; @@ -1488,7 +1524,8 @@ int pci_setup_device(struct pci_dev *dev) dev->bus->number, PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn)); - pci_read_config_dword(dev, PCI_CLASS_REVISION, &class); + class = pci_class(dev); + dev->revision = class & 0xff; dev->class = class >> 8; /* upper 3 bytes */ @@ -1528,8 +1565,8 @@ int pci_setup_device(struct pci_dev *dev) goto bad; pci_read_irq(dev); pci_read_bases(dev, 6, PCI_ROM_ADDRESS); - pci_read_config_word(dev, PCI_SUBSYSTEM_VENDOR_ID, &dev->subsystem_vendor); - pci_read_config_word(dev, PCI_SUBSYSTEM_ID, &dev->subsystem_device); + + pci_subsystem_ids(dev, &dev->subsystem_vendor, &dev->subsystem_device); /* * Do the ugly legacy mode stuff here rather than broken chip -- GitLab