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Writing Device Drivers     Oracle Solaris 11.1 Information Library
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Document Information

Preface

Part I Designing Device Drivers for the Oracle Solaris Platform

1.  Overview of Oracle Solaris Device Drivers

2.  Oracle Solaris Kernel and Device Tree

3.  Multithreading

4.  Properties

5.  Managing Events and Queueing Tasks

6.  Driver Autoconfiguration

7.  Device Access: Programmed I/O

8.  Interrupt Handlers

9.  Direct Memory Access (DMA)

10.  Mapping Device and Kernel Memory

11.  Device Context Management

12.  Power Management

13.  Hardening Oracle Solaris Drivers

14.  Layered Driver Interface (LDI)

Part II Designing Specific Kinds of Device Drivers

15.  Drivers for Character Devices

16.  Drivers for Block Devices

17.  SCSI Target Drivers

18.  SCSI Host Bus Adapter Drivers

19.  Drivers for Network Devices

20.  USB Drivers

21.  SR-IOV Drivers

Introduction to SR-IOV

Benefits of SR-IOV

Supported Platforms

Glossary

Overview of SR-IOV Device Driver

Physical Function (PF) Driver

Virtual Function (VF) Driver

Device Configuration Parameters

pci.conf File

Setting Device Configuration Parameters

SR-IOV Configuration on Sparc OVM Platform

SR-IOV Configuration on Bare Metal Platforms

Boot Configuration Sequence

SR-IOV Interfaces Summary

Driver Ioctls

Interfaces for SR-IOV Drivers

pci_param_get() Interface

pci_param_get_ioctl() Interface

pci_plist_get() Interface

pci_plist_getvf() Interface

pciv_vf_config() Interface

pci_plist_lookup() Interface

pci_param_free() Interface

pciv_send() Interface

SR-IOV Driver Ioctls

Data Structures

iov_param_ver_info Structure

iov_param_validate Structure

iov_param_desc Structure

IOV_GET_VER_INFO Ioctl

IOV_GET_PARAM_INFO Ioctl

IOV_VALIDATE_PARAM Ioctl

Driver Callbacks

Sample Code for Driver Ioctls

Part III Building a Device Driver

22.  Compiling, Loading, Packaging, and Testing Drivers

23.  Debugging, Testing, and Tuning Device Drivers

24.  Recommended Coding Practices

Part IV Appendixes

A.  Hardware Overview

B.  Summary of Oracle Solaris DDI/DKI Services

C.  Making a Device Driver 64-Bit Ready

D.  Console Frame Buffer Drivers

E.  pci.conf File

Index

Introduction to SR-IOV

The SR-IOV technology is a hardware based virtualization solution that improves both performance and scalability. The SR-IOV standard enables efficient sharing of PCIe (Peripheral Component Interconnect) Express devices among virtual machines and is implemented in the hardware to achieve I/O performance which is comparable to native performance. The SR-IOV specification defines a new standard wherein the new devices that are created will enable the virtual machine to be directly connected to the I/O device.

The SR-IOV specification is defined and maintained by PCI-SIG at http://www.pcisig.com

A single I/O resource can be shared by many virtual machines. The shared devices will provide dedicated resources and also utilize shared common resources. In this way, each virtual machine will have access to unique resources. Therefore, a PCIe device, such as an Ethernet Port, that is SR-IOV enabled with appropriate hardware and OS support can appear as multiple, separate physical devices, each with its own configuration space.

The following figure illustrates the SR-IOV technology for PCIe hardware.

Figure 21-1 SR-IOV Technology

image:This figures illustrated the SR-IOV technology

Two new function types in SR-IOV are:

Physical Function (PF)

A PCI Function that supports the SR-IOV capabilities as defined in SR-IOV specification. A PF contains the SR-IOV capability structure and is used to manage the SR-IOV functionality. PFs are fully featured PCIe functions that can be discovered, managed, and manipulated like any other PCIe device. PFs have full configuration resources, and can be used to configure or control the PCIe device.

Virtual Function (VF)

A function that is associated with a Physical Function. A VF is a lightweight PCIe function that shares one or more physical resources with the Physical Function and with other VFs that are associated with the same PF. VFs are only allowed to have configuration resources for its own behavior.

Each SR-IOV device can have a Physical Function (PF) and each PF can have upto 64K Virtual Functions (VFs) associated with the PF. The VFs can be created by the PF through registers designed with properties specifically for this purpose.

Once SR-IOV is enabled in the PF, the PCI configuration space of each VF can be accessed by the bus, device, and function number (Routing ID) of the PF. Each VF also has a PCI Memory Space, which is used to map its register set. The device drivers of the VFs operate on the register set to enable its functionality and appear as a real existing PCI device. Once VFs are created, they can be directly assigned to IO guest domains or individual applications such as Oracle Solaris Zones on bare-metal platforms. This capability enables them to share the physical device and perform I/O without CPU and Hypervisor software overhead.

Benefits of SR-IOV

The SR-IOV standard allows efficient sharing of PCIe devices among IO Guest Domains. An SR-IOV device can have hundreds of Virtual Functions (VFs) associating with a Physical Function (PF). The creation of VFs can be dynamically controlled by the PF through registers designed to turn on the SR-IOV capability. By default, the SR-IOV capability is turned off, and the PF behaves as traditional PCIe device.

Devices that have SR-IOV capability can take advantage of the following benefits: