When adding cross-endian support, we introduced the TARGET_IS_BIENDIAN macro
and the virtio_access_is_big_endian() helper to have a branchless fast path
in the virtio memory accessors for targets that don't switch endian.
This was considered as a strong requirement at the time.
Now we have added a runtime check for virtio 1.0, which ruins the benefit
of the virtio_access_is_big_endian() helper for always little-endian targets.
With this patch, always little-endian targets stop checking for virtio 1.0,
since the result is little-endian in all cases.
Signed-off-by: Greg Kurz <gk...@linux.vnet.ibm.com>
---
v2: - don't rename helper to virtio_is_big_endian_fast()
---
include/hw/virtio/virtio-access.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/hw/virtio/virtio-access.h
b/include/hw/virtio/virtio-access.h
index f1f12afe9089..fba4b4a4e1b2 100644
--- a/include/hw/virtio/virtio-access.h
+++ b/include/hw/virtio/virtio-access.h
@@ -19,10 +19,13 @@
static inline bool virtio_access_is_big_endian(VirtIODevice *vdev)
{
+#if defined(TARGET_IS_BIENDIAN) || defined(TARGET_WORDS_BIGENDIAN)
if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
/* Devices conforming to VIRTIO 1.0 or later are always LE. */
return false;
}
+#endif
+
#if defined(TARGET_IS_BIENDIAN)
return virtio_is_big_endian(vdev);
#elif defined(TARGET_WORDS_BIGENDIAN)
