Linux Plumbers Conf 2014

One Line Summary

Abstract

This discussion focuses on approaches to managing errors triggered by devices bound to vfio. In-band device errors are fairly straightforward and in most cases would be sent to user space by the standard eventfd mechnaism.

Out-of-band errors would include things like IOMMU faults (e.g. an access violation) are more difficult. The IOMMU layer in Linux supports a fault handler, but VFIO does not use this currently. How should an access violation by a vfio-bound device be handled? SIGSEGV to the app? Do KVM virtual machines have any different requirements than other user space apps?

How would IOMMU faults work in an architecture supporting two stage IOMMU address translations where a fault was caused by a vfio-assigned device in guest user space?

This discussion focuses on these types of questions.

Tags

VFIO, IOMMU

Speakers

• Bharat Bhushan

  Biography

  Bharat Bhushan is a Senior software developer at Freescale Semiconductor. He worked on low level software development, RTOS, secure boot, Linux drivers, Linux Kernel, KVM virtualization, performance optimization and debugging for 13 years. Prior to this he worked with Centre for Development for Telematics (C-DOT) for 4 years. Bharat earned a Bachelor of Technology degree in Electronics and Communication Engineering from National Institute of Technology Kurukshetra.

  Sessions

  • * VFIO and the Freescale Management Complex
    • Title: VFIO and the Freescale Management Complex
    • Microconference: BoF Track
    • Room: Room 28
    • Time: 4:30 – 5:30pm
    • One Line Summary:

      The Freescale Management Complex (fsl-mc) is a new type of bus that requires VFIO support, and has some substantial differences from PCI and platform buses. This discussion presents an overview of the new bus and a proposal for how to integrate it with VFIO.

    • Speakers: Stuart Yoder, Bharat Bhushan
  • * VFIO and Management of Errors
    • Title: VFIO and Management of Errors
    • Microconference: BoF Track
    • Room: Room 28
    • Time: 5:30 – 6:30pm
    • One Line Summary:

      Devices assigned to user space through vfio can trigger a number of error conditions. This discussion looks at approaches to managing errors.

    • Speakers: Stuart Yoder, Bharat Bhushan
  • * VFIO and non-DMA devices
    • Title: VFIO and non-DMA devices
    • Microconference: IOMMU and VFIO
    • Time: 2:30 – 5:00pm
    • One Line Summary:

      This session proposes changes to vfio to remove a current limitation— allowing the passthrough of non-DMA devices to user space.

    • Speakers: Stuart Yoder, Bharat Bhushan
• 

  Stuart Yoder

  Freescale Semiconductor
  Biography

  Stuart is a software architect with Freescale Semiconductor working on Linux and virtualization technologies for networking SoCs based on the Power and ARM architectures.

  Sessions

  • * VFIO and the Freescale Management Complex
    • Title: VFIO and the Freescale Management Complex
    • Microconference: BoF Track
    • Room: Room 28
    • Time: 4:30 – 5:30pm
    • One Line Summary:

      The Freescale Management Complex (fsl-mc) is a new type of bus that requires VFIO support, and has some substantial differences from PCI and platform buses. This discussion presents an overview of the new bus and a proposal for how to integrate it with VFIO.

    • Speakers: Stuart Yoder, Bharat Bhushan
  • * VFIO and Management of Errors
    • Title: VFIO and Management of Errors
    • Microconference: BoF Track
    • Room: Room 28
    • Time: 5:30 – 6:30pm
    • One Line Summary:

      Devices assigned to user space through vfio can trigger a number of error conditions. This discussion looks at approaches to managing errors.

    • Speakers: Stuart Yoder, Bharat Bhushan
  • * VFIO and non-DMA devices
    • Title: VFIO and non-DMA devices
    • Microconference: IOMMU and VFIO
    • Time: 2:30 – 5:00pm
    • One Line Summary:

      This session proposes changes to vfio to remove a current limitation— allowing the passthrough of non-DMA devices to user space.

    • Speakers: Stuart Yoder, Bharat Bhushan