On 08/07/2015 06:49 PM, Cornelia Huck wrote: > On Fri, 07 Aug 2015 13:07:35 +0800 > Jason Wang <jasow...@redhat.com> wrote: > >>> 2. ring resizing is broken - it actually has a comment: >>> /* TODO: need a way to put num back on reset. */ >>> guest that runs out of memory might down-size the ring. >>> Afterwards, ring size won't come back up after reset - not nice. >>> >> Then we need a new field to keep track the original queue size and >> migrate this. > virtio-ccw neatly sidesteps it by not implementing ring size changes at > all :) > > But it isn't really all good, see > > /* TODO: Add interface to handle vring.num changing */ > > We either need to implement this or fence off changing the ring size, I > guess.
Yes. >>> Given that the modern layout is disabled by default, >>> I don't think these are release blockers. >>> >> Yes and looks like we need a new subsection and transport specific >> callbacks to fix above? > Agreed, it's not urgent as virtio-1 is not yet the default (and not > even enabled for ccw). > > I'm not sure we need transport-specific callbacks. Shouldn't the core > be able to track initial and actual size (and migrate in an optional > subsection), as long as the transports use defined interfaces to > interact with it? > For size, I agree it should be tracked by core. But we need also track transport specific data like dfselect/gfselect for pci.
