Commit 3c185597 authored by Cornelia Huck's avatar Cornelia Huck Committed by Michael S. Tsirkin
Browse files

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: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 24bfa207

hw/virtio/virtio.c

+5 −1
Original line number Diff line number Diff line
@@ -903,8 +903,12 @@ static bool virtio_device_endian_needed(void *opaque) 
    VirtIODevice *vdev = opaque;



    assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);

    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)

{

include/hw/virtio/virtio-access.h

+4 −0
Original line number Diff line number Diff line
@@ -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)

include/hw/virtio/virtio.h

+6 −2
Original line number Diff line number Diff line
@@ -252,7 +252,11 @@ static inline bool virtio_has_feature(VirtIODevice *vdev, unsigned int fbit) 


static inline bool virtio_is_big_endian(VirtIODevice *vdev)

{

    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