virtio: optimize virtio_access_is_big_endian() for little-endian targets
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. Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: NLaurent Vivier <lvivier@redhat.com> Signed-off-by: NGreg Kurz <gkurz@linux.vnet.ibm.com> Reviewed-by: NMichael S. Tsirkin <mst@redhat.com> Signed-off-by: NMichael S. Tsirkin <mst@redhat.com> Reviewed-by: NLaurent Vivier <lvivier@redhat.com>
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