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diff --git a/Documentation/PCI/pci-iov-howto.txt b/Documentation/PCI/pci-iov-howto.txt deleted file mode 100644 index d2a84151e99c..000000000000 --- a/Documentation/PCI/pci-iov-howto.txt +++ /dev/null @@ -1,147 +0,0 @@ - PCI Express I/O Virtualization Howto - Copyright (C) 2009 Intel Corporation - Yu Zhao <yu.zhao@intel.com> - - Update: November 2012 - -- sysfs-based SRIOV enable-/disable-ment - Donald Dutile <ddutile@redhat.com> - -1. Overview - -1.1 What is SR-IOV - -Single Root I/O Virtualization (SR-IOV) is a PCI Express Extended -capability which makes one physical device appear as multiple virtual -devices. The physical device is referred to as Physical Function (PF) -while the virtual devices are referred to as Virtual Functions (VF). -Allocation of the VF can be dynamically controlled by the PF via -registers encapsulated in the capability. By default, this feature is -not enabled and the PF behaves as traditional PCIe device. Once it's -turned on, each VF's PCI configuration space can be accessed by its own -Bus, Device and Function Number (Routing ID). And each VF also has PCI -Memory Space, which is used to map its register set. VF device driver -operates on the register set so it can be functional and appear as a -real existing PCI device. - -2. User Guide - -2.1 How can I enable SR-IOV capability - -Multiple methods are available for SR-IOV enablement. -In the first method, the device driver (PF driver) will control the -enabling and disabling of the capability via API provided by SR-IOV core. -If the hardware has SR-IOV capability, loading its PF driver would -enable it and all VFs associated with the PF. Some PF drivers require -a module parameter to be set to determine the number of VFs to enable. -In the second method, a write to the sysfs file sriov_numvfs will -enable and disable the VFs associated with a PCIe PF. This method -enables per-PF, VF enable/disable values versus the first method, -which applies to all PFs of the same device. Additionally, the -PCI SRIOV core support ensures that enable/disable operations are -valid to reduce duplication in multiple drivers for the same -checks, e.g., check numvfs == 0 if enabling VFs, ensure -numvfs <= totalvfs. -The second method is the recommended method for new/future VF devices. - -2.2 How can I use the Virtual Functions - -The VF is treated as hot-plugged PCI devices in the kernel, so they -should be able to work in the same way as real PCI devices. The VF -requires device driver that is same as a normal PCI device's. - -3. Developer Guide - -3.1 SR-IOV API - -To enable SR-IOV capability: -(a) For the first method, in the driver: - int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn); - 'nr_virtfn' is number of VFs to be enabled. -(b) For the second method, from sysfs: - echo 'nr_virtfn' > \ - /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_numvfs - -To disable SR-IOV capability: -(a) For the first method, in the driver: - void pci_disable_sriov(struct pci_dev *dev); -(b) For the second method, from sysfs: - echo 0 > \ - /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_numvfs - -To enable auto probing VFs by a compatible driver on the host, run -command below before enabling SR-IOV capabilities. This is the -default behavior. - echo 1 > \ - /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_drivers_autoprobe - -To disable auto probing VFs by a compatible driver on the host, run -command below before enabling SR-IOV capabilities. Updating this -entry will not affect VFs which are already probed. - echo 0 > \ - /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_drivers_autoprobe - -3.2 Usage example - -Following piece of code illustrates the usage of the SR-IOV API. - -static int dev_probe(struct pci_dev *dev, const struct pci_device_id *id) -{ - pci_enable_sriov(dev, NR_VIRTFN); - - ... - - return 0; -} - -static void dev_remove(struct pci_dev *dev) -{ - pci_disable_sriov(dev); - - ... -} - -static int dev_suspend(struct pci_dev *dev, pm_message_t state) -{ - ... - - return 0; -} - -static int dev_resume(struct pci_dev *dev) -{ - ... - - return 0; -} - -static void dev_shutdown(struct pci_dev *dev) -{ - ... -} - -static int dev_sriov_configure(struct pci_dev *dev, int numvfs) -{ - if (numvfs > 0) { - ... - pci_enable_sriov(dev, numvfs); - ... - return numvfs; - } - if (numvfs == 0) { - .... - pci_disable_sriov(dev); - ... - return 0; - } -} - -static struct pci_driver dev_driver = { - .name = "SR-IOV Physical Function driver", - .id_table = dev_id_table, - .probe = dev_probe, - .remove = dev_remove, - .suspend = dev_suspend, - .resume = dev_resume, - .shutdown = dev_shutdown, - .sriov_configure = dev_sriov_configure, -}; |