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diff --git a/doc/guides/prog_guide/port_hotplug_framework.rst b/doc/guides/prog_guide/port_hotplug_framework.rst new file mode 100644 index 00000000..fe6d72a6 --- /dev/null +++ b/doc/guides/prog_guide/port_hotplug_framework.rst @@ -0,0 +1,110 @@ +.. BSD LICENSE + Copyright(c) 2015 IGEL Co.,Ltd. All rights reserved. + All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in + the documentation and/or other materials provided with the + distribution. + * Neither the name of IGEL Co.,Ltd. nor the names of its + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +Port Hotplug Framework +====================== + +The Port Hotplug Framework provides DPDK applications with the ability to +attach and detach ports at runtime. Because the framework depends on PMD +implementation, the ports that PMDs cannot handle are out of scope of this +framework. Furthermore, after detaching a port from a DPDK application, the +framework doesn't provide a way for removing the devices from the system. +For the ports backed by a physical NIC, the kernel will need to support PCI +Hotplug feature. + +Overview +-------- + +The basic requirements of the Port Hotplug Framework are: + +* DPDK applications that use the Port Hotplug Framework must manage their + own ports. + + The Port Hotplug Framework is implemented to allow DPDK applications to + manage ports. For example, when DPDK applications call the port attach + function, the attached port number is returned. DPDK applications can + also detach the port by port number. + +* Kernel support is needed for attaching or detaching physical device + ports. + + To attach new physical device ports, the device will be recognized by + userspace driver I/O framework in kernel at first. Then DPDK + applications can call the Port Hotplug functions to attach the ports. + For detaching, steps are vice versa. + +* Before detaching, they must be stopped and closed. + + DPDK applications must call "rte_eth_dev_stop()" and + "rte_eth_dev_close()" APIs before detaching ports. These functions will + start finalization sequence of the PMDs. + +* The framework doesn't affect legacy DPDK applications behavior. + + If the Port Hotplug functions aren't called, all legacy DPDK apps can + still work without modifications. + +Port Hotplug API overview +------------------------- + +* Attaching a port + + "rte_eth_dev_attach()" API attaches a port to DPDK application, and + returns the attached port number. Before calling the API, the device + should be recognized by an userspace driver I/O framework. The API + receives a pci address like "0000:01:00.0" or a virtual device name + like "eth_pcap0,iface=eth0". In the case of virtual device name, the + format is the same as the general "--vdev" option of DPDK. + +* Detaching a port + + "rte_eth_dev_detach()" API detaches a port from DPDK application, and + returns a pci address of the detached device or a virtual device name + of the device. + +Reference +--------- + + "testpmd" supports the Port Hotplug Framework. + +Limitations +----------- + +* The Port Hotplug APIs are not thread safe. + +* The framework can only be enabled with Linux. BSD is not supported. + +* To detach a port, the port should be backed by a device that igb_uio + manages. VFIO is not supported. + +* Not all PMDs support detaching feature. + To know whether a PMD can support detaching, search for the + "RTE_PCI_DRV_DETACHABLE" flag in PMD implementation. If the flag is + defined in the PMD, detaching is supported. |