Re: [PATCH v3 04/41] virtio: memory access APIs
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2014-11-24 12:03:29
Also in:
linux-api, lkml
Possibly related (same subject, not in this thread)
- 2014-11-24 · Re: [PATCH v3 04/41] virtio: memory access APIs · "Michael S. Tsirkin" <mst@redhat.com>
On Mon, Nov 24, 2014 at 12:52 PM, Michael S. Tsirkin [off-list ref] 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.
quoted hunk ↗ jump to hunk
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() ...
quoted hunk ↗ jump to hunk
--- 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