On Fri, Feb 08, 2013 at 11:46:34AM +0100, Paolo Bonzini wrote: > Il 08/02/2013 11:20, Luigi Rizzo ha scritto: ... > > I am happy to make this default to off. But it would be good if you could > > actually give it a try. Note that linux and FreeBSD (and presumably windows) > > do use moderation by default so enabling the emulation of the > > registers makes the guest OS behave differently (and closer to bare metal). > > > > To test that the patch itself does not cause regression in the emulator > > one should also turn off moderation in the guest (one of the tests i > > have run). > > I think making the default on is fine, but you need to add compatibility > options to leave it off in older machine types (pc-1.4 and earlier).
I am unclear on what you mean by "older machine types" ? The hardware (E1000_DEV_ID_82540EM) does have these registers, and it is entirely up to the guest OS to use them or not. cheers luigi
