On Tue, Feb 23, 2016 at 06:29:33PM +0300, Denis V. Lunev wrote: > On 02/23/2016 06:24 PM, Michael S. Tsirkin wrote: > >On Tue, Feb 23, 2016 at 05:59:44PM +0300, Denis V. Lunev wrote: > >>From: Igor Redko <red...@virtuozzo.com> > >> > >>We are making experiments with different autoballooning strategies > >>based on the guest behavior. Thus we need to experiment with different > >>guest statistics. For now every counter change requires QEMU recompilation > >>and dances with Libvirt. > >> > >>This patch introduces transport for unrecognized counters in virtio-balloon. > >>This transport can be used for measuring benefits from using new > >>balloon counters, before submitting any patches. Current alternative > >>is 'guest-exec' transport which isn't made for such delicate matters > >>and can influence test results. > >> > >>Originally all counters with tag >= VIRTIO_BALLOON_S_NR were ignored. > >>Instead of this we keep first (VIRTIO_BALLOON_S_NR + 32) counters from the > >>queue and pass unrecognized ones with the following names: 'x-stat-XXXX', > >>where XXXX is a tag number in hex. Defined counters are reported with their > >>regular names. > >> > >>Signed-off-by: Igor Redko <red...@virtuozzo.com> > >>Signed-off-by: Denis V. Lunev <d...@openvz.org> > >>CC: Michael S. Tsirkin <m...@redhat.com> > >This seems to open the ABI to abuse. > >Seems like a reasonable way to experiment though. > >How about adding this within #if 0 statements? > >You can uncomment them for debugging ... > I'd prefer to have this enabled. > > Why do you think that it opens "abuse" way?
Because people will use this to hack drivers and management tools bypassing qemu. > Actually the amount of host data is limited. If the guest > will send fake stats before real ones - this guest is > not cooperative and in this case the guest can > hust ignore any balloon change requests.
