[PATCH v5 04/12] Documentation: PCI: convert pci-iov-howto.txt to reST

Changbin Du
2019-05-13T14:20:41Z

Documentation/PCI/index.rst | 1 +
.../{pci-iov-howto.txt => pci-iov-howto.rst} | 161 ++++++++++--------
2 files changed, 94 insertions(+), 68 deletions(-)
rename Documentation/PCI/{pci-iov-howto.txt => pci-iov-howto.rst} (63%)

diff --git a/Documentation/PCI/index.rst b/Documentation/PCI/index.rst
index 79d6d75bbf28..0d9390298c4a 100644
--- a/Documentation/PCI/index.rst
+++ b/Documentation/PCI/index.rst
@@ -10,3 +10,4 @@ Linux PCI Bus Subsystem

pci
picebus-howto
+ pci-iov-howto
diff --git a/Documentation/PCI/pci-iov-howto.txt b/Documentation/PCI/pci-iov-howto.rst
similarity index 63%
rename from Documentation/PCI/pci-iov-howto.txt
rename to Documentation/PCI/pci-iov-howto.rst
index d2a84151e99c..b9fd003206f1 100644
--- a/Documentation/PCI/pci-iov-howto.txt
+++ b/Documentation/PCI/pci-iov-howto.rst
@@ -1,14 +1,19 @@
- PCI Express I/O Virtualization Howto
- Copyright (C) 2009 Intel Corporation
- Yu Zhao <yu.zhao@intel.com>
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>

- Update: November 2012
- -- sysfs-based SRIOV enable-/disable-ment
- Donald Dutile <ddutile@redhat.com>
+====================================
+PCI Express I/O Virtualization Howto
+====================================

-1. Overview
+:Copyright: |copy| 2009 Intel Corporation
+:Authors: - Yu Zhao <yu.zhao@intel.com>
+ - Donald Dutile <ddutile@redhat.com>

-1.1 What is SR-IOV
+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
@@ -23,9 +28,11 @@ 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
+User Guide
+==========

-2.1 How can I enable SR-IOV capability
+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
@@ -43,105 +50,123 @@ 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
+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
+Developer Guide
+===============

-3.1 SR-IOV API
+SR-IOV API
+----------

To enable SR-IOV capability:
-(a) For the first method, in the driver:
+
+(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:
+
+'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:
+
+(a) For the first method, in the driver::
+
void pci_disable_sriov(struct pci_dev *dev);
-(b) For the second method, from sysfs:
+
+(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
+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);
+ 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);
+ 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_suspend(struct pci_dev *dev, pm_message_t state)
+ {
+ ...

-static int dev_resume(struct pci_dev *dev)
-{
- ...
+ return 0;
+ }

- return 0;
-}
+ static int dev_resume(struct pci_dev *dev)
+ {
+ ...

-static void dev_shutdown(struct pci_dev *dev)
-{
- ...
-}
+ return 0;
+ }

-static int dev_sriov_configure(struct pci_dev *dev, int numvfs)
-{
- if (numvfs > 0) {
- ...
- pci_enable_sriov(dev, numvfs);
+ static void dev_shutdown(struct pci_dev *dev)
+ {
...
- return numvfs;
}
- if (numvfs == 0) {
- ....
- pci_disable_sriov(dev);
- ...
- return 0;
+
+ 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,
-};
+
+ 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,
+ };
--
2.20.1