On Wed, 2013-12-18 at 23:07 +0100, Alexander Graf wrote: > On 18.12.2013, at 23:04, Benjamin Herrenschmidt <b...@kernel.crashing.org> > wrote: > > > On Wed, 2013-12-18 at 22:24 +0100, Alexander Graf wrote: > >> Then I don't understand why we break when we limit the data region to > >> 4 bytes. > > > > This is old uninorth, not U3 HT right ? The latter is memory mapped. > > Depends, we use the same code to cover both. With 32bit guests we expose an > old UniNorth. > With 64bit guests we have to expose a U3 as the guest doesn't know what old > UniNorth is anymore. > > So yeah, maybe that's biting us.
Well, it's different. Old uninorth uses some form of indirect address/data registers, as does U3 AGP... but U3 HT uses memory mapped. So U3 has a bit of both :) I think U4 PCIe is yet another beast as well. Cheers, Ben.