Description
Please vote Yes if you agree with all of the following. If you disagree, please vote No. If you don't have an opinion, please vote Abstain. I move that: The TC agrees to resolve the following specification issue: VIRTIO-143: balloon: allow transitional devices -------------------------------------- Virtio 1.0 cs02 doesn't include a modern balloon device. At some point we'll likely define an incompatible interface with a different ID and different semantics. But for now, it's not a big effort to support a transitional balloon device: this has the advantage of supporting existing drivers, transparently, as well as transports that don't allow mixing virtio 0 and virtio 1 devices. And balloon is an easy device to test, so it's also useful for people to test virtio core handling of transitional devices. -------------------------------------- The TC accepts the following proposed changes to the specification: -------------------------------------- mid.gmane.org/1430235439-3812-1-git-send-email-mst@redhat.com [PATCH v3] balloon: transitional device support Support a transitional balloon device: this has the advantage of supporting existing drivers, transparently, as well as transports that don't allow mixing virtio 0 and virtio 1 devices. And balloon is an easy device to test, so it's also useful for people to test virtio core handling of transitional devices. Three issues with legacy hypervisors have been identified: 1. Actual value is actually used, and is necessary for management to work. Luckily 4 byte config space writes are now atomic. When using old guests, hypervisors can detect access to the last byte. When using old hypervisors, drivers can use atomic 4-byte accesses. 2. Hypervisors actually didn't ignore the stats from the first buffer supplied. This means the values there would be incorrect until hypervisor resends the request. Add a note suggesting hypervisors ignore the 1st buffer. 3. QEMU simply over-writes stats from each buffer it gets. Thus if driver supplies a different subset of stats on each request, stale values will be there. Require drivers to supply the same subset on each request. This also gives us a simple way to figure out which stats are supported. Additionally, this fixes a typo: - the driver SHOULD omit unsupported statistics. should be: + devices omit unsupported statistics. Note that we have a normative statement with this requirement already, this is just general high-level description. -------------------------------------- The TC agrees to include the above change(s) in specification version(s) "virtio 1.0 cs03", and future versions of the specification. -------------------------------------- Reminder: A Voting Member must be active in a TC to maintain voting rights. As the Virtio TC has adopted a standing rule to conduct business only by electronic ballot, without Meetings, a Voting Member who fails to cast a ballot in two consecutive Work Product Ballots loses his or her voting rights at the close of the second ballot missed. --------------------------------------
