From 3c185597c86b8cd0a07c46e7a5bd5aac28bb7200 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Thu, 4 Jun 2015 12:34:11 +0200 Subject: [PATCH] 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 Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Michael S. Tsirkin --- hw/virtio/virtio.c | 6 +++++- include/hw/virtio/virtio-access.h | 4 ++++ include/hw/virtio/virtio.h | 8 ++++++-- 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 -- GitLab