Messages in this thread | | | Date | Fri, 01 Mar 2013 11:21:06 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH] virtio-spec: Define virtio-mmio registers as LE |
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On 01/03/13 10:50, Pawel Moll wrote: > On Fri, 2013-03-01 at 10:41 +0000, Marc Zyngier wrote: >> On 14/02/13 10:54, Pawel Moll wrote: >>> To solve the never-ending confusions between hosts and guests >>> of different endianess, define all virtio-mmio registers as LE. >>> >>> This change should be safe at this stage, because no known >>> working mixed-endian system exists so there is virtually no >>> risk of breaking compatibility. >>> >>> Signed-off-by: Pawel Moll <pawel.moll@arm.com> >> >> Shouldn't we exclude the config space? PCI defines it as guest-endian, >> and the above tends to indicate that it should be LE with MMIO. > > The spec says: "Device-specific configuration space starts at an offset > 0x100 and is accessed with byte alignment. Its meaning and size depends > on the device and the driver." > > I would hope that "accessed with byte alignment" is enough of a clue in > this subject, but if you think otherwise I can add a sentence stating > this explicitly.
Well, it was unclear enough for me to get confused... ;-) It would make sense to have a wording similar to the one in the PCI section.
> 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.
M. -- Jazz is not dead. It just smells funny...
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