From 46f70ff148ae01e2dc96e64c393e295a0092555d Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Fri, 5 Feb 2016 11:46:04 +0100 Subject: [PATCH] vhost: simplify vhost_needs_vring_endian() After the call to virtio_vdev_has_feature(), we only care for legacy devices, so we don't need the extra check in virtio_is_big_endian(). Also the device_endian field is always set (VIRTIO_DEVICE_ENDIAN_UNKNOWN may only happen on a virtio_load() path that cannot lead here), so we don't need the assert() either. This open codes the device_endian checking in vhost_needs_vring_endian(). It also adds a comment to explain the logic, as recent reviews showed the cross-endian tweaks aren't that obvious. Signed-off-by: Greg Kurz Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Laurent Vivier Reviewed-by: Cornelia Huck --- hw/virtio/vhost.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index bb17177f5e..9f8ac38ccf 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -749,6 +749,11 @@ static void vhost_log_stop(MemoryListener *listener, /* FIXME: implement */ } +/* The vhost driver natively knows how to handle the vrings of non + * cross-endian legacy devices and modern devices. Only legacy devices + * exposed to a bi-endian guest may require the vhost driver to use a + * specific endianness. + */ static inline bool vhost_needs_vring_endian(VirtIODevice *vdev) { if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { @@ -756,9 +761,9 @@ static inline bool vhost_needs_vring_endian(VirtIODevice *vdev) } #ifdef TARGET_IS_BIENDIAN #ifdef HOST_WORDS_BIGENDIAN - return !virtio_is_big_endian(vdev); + return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_LITTLE; #else - return virtio_is_big_endian(vdev); + return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_BIG; #endif #else return false; -- GitLab