Messages in this thread | | | Date | Mon, 24 Nov 2014 13:03:24 +0100 | Subject | Re: [PATCH v3 04/41] virtio: memory access APIs | From | Geert Uytterhoeven <> |
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On Mon, Nov 24, 2014 at 12:52 PM, Michael S. Tsirkin <mst@redhat.com> wrote: > virtio 1.0 makes all memory structures LE, so > we need APIs to conditionally do a byteswap on BE > architectures. > > To make it easier to check code statically, > add virtio specific types for multi-byte integers > in memory. > > Add low level wrappers that do a byteswap conditionally, these will be > useful e.g. for vhost. Add high level wrappers that > query device endian-ness and act accordingly.
> diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h > new file mode 100644 > index 0000000..824ed0b > --- /dev/null > +++ b/include/linux/virtio_byteorder.h
> +static inline u16 __virtio16_to_cpu(bool little_endian, __virtio16 val) > +{ > + if (little_endian) > + return le16_to_cpu((__force __le16)val); > + else > + return (__force u16)val; > +}
What's wrong with just using le16-to_cpu() ...
> --- a/include/uapi/linux/virtio_ring.h > +++ b/include/uapi/linux/virtio_ring.h
> /* Virtio ring descriptors: 16 bytes. These can chain together via "next". */ > struct vring_desc { > /* Address (guest-physical). */ > - __u64 addr; > + __virtio64 addr;
... and __le64?
There's already lots of precedence or this, even in include/uapi/.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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