Features/Virtio RNG

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== Current status ==
 
== Current status ==
 
* Targeted release: [[Releases/19 | Fedora 19]]
 
* Targeted release: [[Releases/19 | Fedora 19]]
* Last updated:  
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* Last updated: January 26 2013
 
* Percentage of completion: 50%
 
* Percentage of completion: 50%
  
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== How To Test ==
 
== How To Test ==
See http://wiki.qemu.org/Features/VirtIORNG#Testing
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TBD
 
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XXX: Manual qemu bits at http://wiki.qemu.org/Features/VirtIORNG#Testing
XXX: copy bits here, proposed libvirt bits
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XXX: Libvirt instructions based on posted patches
  
 
== User Experience ==
 
== User Experience ==
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== Dependencies ==
 
== Dependencies ==
None
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None.
  
 
== Contingency Plan ==
 
== Contingency Plan ==
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== Documentation ==
 
== Documentation ==
<!-- Is there upstream documentation on this feature, or notes you have written yourself?  Link to that material here so other interested developers can get involved. -->
 
 
 
* [http://wiki.qemu-project.org/Features/VirtIORNG QEMU VirtIO RNG feature page]
 
* [http://wiki.qemu-project.org/Features/VirtIORNG QEMU VirtIO RNG feature page]
 
* [https://lists.gnu.org/archive/html/qemu-devel/2012-05/msg02235.html QEMU patch email from May 2012]
 
* [https://lists.gnu.org/archive/html/qemu-devel/2012-05/msg02235.html QEMU patch email from May 2012]
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None yet.
 
None yet.
  
[[Category:FeaturePageIncomplete]]
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[[Category:FeatureReadyForWrangler]]
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<!-- remove Category:FeaturePageIncomplete and change it to Category:FeatureReadyForWrangler -->
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<!-- After review, the feature wrangler will move your page to Category:FeatureReadyForFesco... if it still needs more work it will move back to Category:FeaturePageIncomplete-->
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Revision as of 01:04, 27 January 2013

Contents

Virtio RNG

Summary

Provide a paravirtual random number generator to virtual machines, to prevent entropy starvation in guests.

Owner

Current status

  • Targeted release: Fedora 19
  • Last updated: January 26 2013
  • Percentage of completion: 50%

Detailed Description

The linux kernel collects entropy from various non-deterministic hardware events, like mouse and keyboard input, and network traffic. This entropy is then exposed through /dev/random, commonly used by cryptographic applications that need true randomness to maintain security. However if more entropy is being consumed than is being produced, we have entropy starvation: reading from /dev/random will block, which can cause a denial of service. A common example here is use of /dev/random by SSL in various services.

VirtIO RNG (random number generator) is a paravirtualized device that is exposed as a hardware RNG device to the guest. Virtio RNG just appears as a regular hardware RNG to the guest, which the kernel reads from to fill its entropy pool. This effectively allows a host to entropy into a guest via several means: The default mode uses the host's /dev/random, but a physical HW RNG device or EGD (Entropy Gathering Daemon) can also be used.

Benefit to Fedora

Guests will have access to better and faster entropy.

Scope

  • Virtio RNG driver in kernel (DONE, since 2.6.26)
  • QEMU Device (DONE, since qemu 1.3)
  • Libvirt support (patch posted, not commited yet)
  • Apps (all optional but would be nice if they are done)
    • virt-install (Not done)
    • virt-manager (Not done)

How To Test

TBD XXX: Manual qemu bits at http://wiki.qemu.org/Features/VirtIORNG#Testing XXX: Libvirt instructions based on posted patches

User Experience

Guests will have access to better and faster entropy.

Dependencies

None.

Contingency Plan

Since this is brand new functionality, if it isn't ready in time, nothing has changed. We just drop this feature page.

Documentation

Release Notes

KVM and libvirt now support a paravirtual random number generator device. This can be used to prevent entropy starvation in virtual machines.

Comments and Discussion

None yet.