--- /dev/null
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+====================================
+PCI Express I/O Virtualization Howto
+====================================
+
+:Copyright: |copy| 2009 Intel Corporation
+:Authors: - Yu Zhao <yu.zhao@intel.com>
+ - Donald Dutile <ddutile@redhat.com>
+
+Overview
+========
+
+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.
+
+User Guide
+==========
+
+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.
+
+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.
+
+Developer Guide
+===============
+
+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
+
+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,
+ };
+++ /dev/null
- 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,
-};
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