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authorCornelia Huck <cornelia.huck@de.ibm.com>2015-06-04 12:34:11 +0200
committerMichael S. Tsirkin <mst@redhat.com>2015-06-10 18:15:04 +0200
commit3c185597c86b8cd0a07c46e7a5bd5aac28bb7200 (patch)
tree5a72cf952a60188058c1e195da2a13fd67e31553
parent24bfa207efb9b9d591552eefc1f414ff33ef0eac (diff)
virtio: endianness checks for virtio 1.0 devices
Add code that checks for the VERSION_1 feature bit in order to make decisions about the device's endianness. This allows us to support transitional devices. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
-rw-r--r--hw/virtio/virtio.c6
-rw-r--r--include/hw/virtio/virtio-access.h4
-rw-r--r--include/hw/virtio/virtio.h8
3 files changed, 15 insertions, 3 deletions
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 8ac6156861..d37d27b4ea 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -903,7 +903,11 @@ static bool virtio_device_endian_needed(void *opaque)
VirtIODevice *vdev = opaque;
assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
- return vdev->device_endian != virtio_default_endian();
+ if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
+ return vdev->device_endian != virtio_default_endian();
+ }
+ /* Devices conforming to VIRTIO 1.0 or later are always LE. */
+ return vdev->device_endian != VIRTIO_DEVICE_ENDIAN_LITTLE;
}
static bool virtio_64bit_features_needed(void *opaque)
diff --git a/include/hw/virtio/virtio-access.h b/include/hw/virtio/virtio-access.h
index 46456fd9da..ee28c21fef 100644
--- a/include/hw/virtio/virtio-access.h
+++ b/include/hw/virtio/virtio-access.h
@@ -19,6 +19,10 @@
static inline bool virtio_access_is_big_endian(VirtIODevice *vdev)
{
+ if (virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
+ /* Devices conforming to VIRTIO 1.0 or later are always LE. */
+ return false;
+ }
#if defined(TARGET_IS_BIENDIAN)
return virtio_is_big_endian(vdev);
#elif defined(TARGET_WORDS_BIGENDIAN)
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 2bb7c1ad1a..13e8549dcf 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -252,7 +252,11 @@ static inline bool virtio_has_feature(VirtIODevice *vdev, unsigned int fbit)
static inline bool virtio_is_big_endian(VirtIODevice *vdev)
{
- assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
- return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_BIG;
+ if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
+ assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
+ return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_BIG;
+ }
+ /* Devices conforming to VIRTIO 1.0 or later are always LE. */
+ return false;
}
#endif