Re: [PATCH 1/1] Add virtio-input driver.

From: Michael S. Tsirkin
Date: Mon Mar 23 2015 - 10:54:18 EST


On Mon, Mar 23, 2015 at 03:27:35PM +0100, Gerd Hoffmann wrote:
> Hi,
>
> > > > > You are doing leXXX everywhere, that's VERSION_1 dependency.
> > > > > virtio_cread will do byteswaps differently without VERSION_1.
> > > > > Just don't go there.
>
> > So to clarify, you dislike using __virtio32 in virtio input header?
>
> Well, as I understand things __virtio32 implies byteorder depends on
> whenever we are using VERSION_1 or not. And non-transitional drivers
> should not need it as everything is by definition little endian.
>
> So, yes, your suggestion to just require VERSION_1 in the driver implies
> in my eyes that there should be no reason to use __virtio32 instead of
> __le32.
>
> Or do I miss something here?
>
> cheers,
> Gerd
>

You are right but then if you do require VERSION_1 then
__virtio32 becomes identical to __le32.
There's some runtime overhead as we check on each access,
but it shouldn't matter here, right?
I guess we could add virtio_cread_le - is this what
you'd like?


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