From 15b49bee3a2b228370194f1b3ebc3db427cc9c94 Mon Sep 17 00:00:00 2001 From: Yu Zhao Date: Fri, 20 Mar 2009 11:25:18 +0800 Subject: PCI: manual for SR-IOV user and driver developer Reviewed-by: Randy Dunlap Reviewed-by: Matthew Wilcox Signed-off-by: Yu Zhao Signed-off-by: Jesse Barnes --- Documentation/PCI/pci-iov-howto.txt | 99 +++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 Documentation/PCI/pci-iov-howto.txt (limited to 'Documentation/PCI/pci-iov-howto.txt') diff --git a/Documentation/PCI/pci-iov-howto.txt b/Documentation/PCI/pci-iov-howto.txt new file mode 100644 index 000000000000..fc73ef5d65b8 --- /dev/null +++ b/Documentation/PCI/pci-iov-howto.txt @@ -0,0 +1,99 @@ + PCI Express I/O Virtualization Howto + Copyright (C) 2009 Intel Corporation + Yu Zhao + + +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 + +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. + +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: + int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn); + 'nr_virtfn' is number of VFs to be enabled. + +To disable SR-IOV capability: + void pci_disable_sriov(struct pci_dev *dev); + +To notify SR-IOV core of Virtual Function Migration: + irqreturn_t pci_sriov_migration(struct pci_dev *dev); + +3.2 Usage example + +Following piece of code illustrates the usage of the SR-IOV API. + +static int __devinit dev_probe(struct pci_dev *dev, const struct pci_device_id *id) +{ + pci_enable_sriov(dev, NR_VIRTFN); + + ... + + return 0; +} + +static void __devexit 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 struct pci_driver dev_driver = { + .name = "SR-IOV Physical Function driver", + .id_table = dev_id_table, + .probe = dev_probe, + .remove = __devexit_p(dev_remove), + .suspend = dev_suspend, + .resume = dev_resume, + .shutdown = dev_shutdown, +}; -- cgit v1.2.3