This patch introduces the support for VIRTIO_F_ORDER_PLATFORM. When this feature is negotiated, driver will use the barriers suitable for hardware devices. Signed-off-by: Tiwei Bie <tiwei.bie@xxxxxxxxx> --- drivers/virtio/virtio_ring.c | 8 ++++++++ include/uapi/linux/virtio_config.h | 6 ++++++ 2 files changed, 14 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index cd7e755484e3..27d3f057493e 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -1609,6 +1609,9 @@ static struct virtqueue *vring_create_virtqueue_packed( !context; vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); + if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM)) + vq->weak_barriers = false; + vq->packed.ring_dma_addr = ring_dma_addr; vq->packed.driver_event_dma_addr = driver_event_dma_addr; vq->packed.device_event_dma_addr = device_event_dma_addr; @@ -2079,6 +2082,9 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, !context; vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); + if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM)) + vq->weak_barriers = false; + vq->split.queue_dma_addr = 0; vq->split.queue_size_in_bytes = 0; @@ -2213,6 +2219,8 @@ void vring_transport_features(struct virtio_device *vdev) break; case VIRTIO_F_RING_PACKED: break; + case VIRTIO_F_ORDER_PLATFORM: + break; default: /* We don't understand this bit. */ __virtio_clear_bit(vdev, i); diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h index 1196e1c1d4f6..ff8e7dc9d4dd 100644 --- a/include/uapi/linux/virtio_config.h +++ b/include/uapi/linux/virtio_config.h @@ -78,6 +78,12 @@ /* This feature indicates support for the packed virtqueue layout. */ #define VIRTIO_F_RING_PACKED 34 +/* + * This feature indicates that memory accesses by the driver and the + * device are ordered in a way described by the platform. + */ +#define VIRTIO_F_ORDER_PLATFORM 36 + /* * Does the device support Single Root I/O Virtualization? */ -- 2.17.1 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
