On Wed, 2013-02-13 at 15:28 +0000, Marc Zyngier wrote: > Well, the spec clearly says that the registers reflect the endianess of > the guest, and it makes sense: when performing the MMIO access, KVM > needs to convert between host and guest endianess. It's actually a horrible idea :-) What does "guest endianness" means from a qemu perspective if your emulated CPU can operate in either mode ? It's actually been causing endless problems, besides linux doesn't have "Sane" MMIO accessors that say "current endianness". ioreadN/writeN are LE, realN/writeN are LE, ioreadNbe/iowriteNbe are BE always, the only "whatever my endianness is" are the __raw ones which also don't have barriers etc... > > Having said that, does the change make everything else work with a BE > > guest? (I assume we're talking about the guest being BE, right? ;-) If > > so it means that the host is not following the current spec and it > > treats all the registers as LE. > > Yes, I only care about a BE guest. And no, not much is actually working > (kvmtool is not happy about the guest addresses it finds in the > virtio-ring). Need to dive into it and understand what needs to be fixed... > > >> - Reading the MAGIC register byte by byte. Is that allowed? The spec > >> only says it is 32bit wide. > > > > And the spirit of the spec was: _exactly 32bit wide_. It's just simpler > > to implement one access width on the host side. > > I guessed as much... Cheers, Ben. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
