Skip to content

RFC Inter-guest virtio I/O example with lguest

Rusty Russell kvm virtualization 1 version In review

Get series with b4
b4 am [email protected]

Versions newest first

  1. v1 RFC Latest0 of 4 patches 22 repliesIn review

Patches in v1 No applies recorded yet

None of the 4 patches the cover letter announces are in this archive.

Reviews trailers per patch

No Reviewed-by, Acked-by or Tested-by trailers for v1 yet.

Read the v1 thread

Cover letter [RFC PATCH 0/4] Inter-guest virtio I/O example with lguest

Hi all,

Just finished my prototype of inter-guest virtio, using networking as an
example. Each guest mmaps the other's address space and uses a FIFO for notifications.

There are two issues with this approach. The first is that neither guest
can change its mappings. See patch 1. The second is that our feature configuration is "host presents, guest chooses" which breaks down when we don't know the capabilities of each guest. In particular, TSO capability for networking.

There are three possible solutions:
1) Just offer the lowest common denominator to both sides (ie. no features). This is what I do with lguest in these patches.
2) Offer something and handle the case where one Guest accepts and another doesn't by emulating it. ie. de-TSO the packets manually.
3) "Hot unplug" the device from the guest which asks for the greater features, then re-add it offering less features. Requires hotplug in the guest OS.

I haven't tuned or even benchmarked these patches, but it pings! Rusty.