Il 02/07/2012 02:29, Rusty Russell ha scritto: > VIRTIO_BALLOON_F_MUST_TELL_HOST > implies you should tell the host (eventually). I don't know if any > implementations actually care though. This is indeed broken, because it is a "negative" feature: it tells you that "implicit deflate" is _not_ supported. Right now, QEMU refuses migration if the target does not support all the features that were negotiated. But then: - a migration from non-MUST_TELL_HOST to MUST_TELL_HOST will succeed, which is wrong; - a migration from MUST_TELL_HOST to non-MUST_TELL_HOST will fail, which is useless. > We could add a VIRTIO_BALLOON_F_NEVER_TELL_DEFLATE which would mean the > deflate vq need not be used at all. That would work. At the same time we could deprecate MUST_TELL_HOST. Certainly the guest implementations don't care, or we would have experienced problems such as the one above. The QEMU implementation also does not care but, for example, a Xen implementation would care. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
