Pawel Moll <pawel.moll@xxxxxxx> writes: > On Tue, 2013-03-05 at 00:11 +0000, Rusty Russell wrote: >> Pawel Moll <pawel.moll@xxxxxxx> writes: >> > On Fri, 2013-03-01 at 11:21 +0000, Marc Zyngier wrote: >> >> > Having said that, Rusty was contemplating enforcing LE config space in >> >> > the new PCI layout... >> >> >> >> I wouldn't complain about that, and would like to see a similar thing on >> >> MMIO. >> > >> > Wherever PCI goes, MMIO follows :-) >> >> Yes, but if you switch from 'guest-endian' to 'little-endian' how will >> you tell? For PCI, we'd detect it by using the new layout. > > The version register/value. At some point of time there will be a > new(ish) MMIO layout anyway to deal with 64-bit addresses, replacing the > ring page number with two 32-bit hi/lo physical address registers. This > was discussed not long after the driver got merged... As long as you have a plan for older guests... >> I'd rather you specify MMIO as little endian, and we fix the kernel >> config accessors to be endian aware (ie. 8, 16, 32, 64-bit accessors). >> Since noone BE is using MMIO right now, it's safe... > > That's absolutely fine with me, however I don't see anything I could do > in the virtio_mmio driver and spec - the virtio_config_ops specifies > get/set as void * operations and I simply do byte-by-byte copy. Have I > missed some config/endianess/PCI related discussion? Yes, that's exactly what I mean, they'd have to be split into 8/16/32/64 accessors. Which would do byte-by-byte for PCI. The spec can simply be updated. Cheers, Rusty. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
