This patch introduces the support for VIRTIO_F_IO_BARRIER. When this feature is negotiated, driver will use the barriers suitable for hardware devices. Signed-off-by: Tiwei Bie <tiwei.bie@xxxxxxxxx> --- This patch depends on below proposal for virtio-spec: https://lists.oasis-open.org/archives/virtio-dev/201805/msg00019.html This patch also depends on below patch: https://lkml.org/lkml/2018/4/19/789 RFC -> v1: - Address the changes in the proposal; drivers/virtio/virtio_ring.c | 5 +++++ include/uapi/linux/virtio_config.h | 8 +++++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 21d464a29cf8..edb565643bf4 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -996,6 +996,9 @@ 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_IO_BARRIER)) + vq->weak_barriers = false; + /* No callback? Tell other side not to bother us. */ if (!callback) { vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT; @@ -1164,6 +1167,8 @@ void vring_transport_features(struct virtio_device *vdev) break; case VIRTIO_F_IOMMU_PLATFORM: break; + case VIRTIO_F_IO_BARRIER: + 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 308e2096291f..9fb519a9df28 100644 --- a/include/uapi/linux/virtio_config.h +++ b/include/uapi/linux/virtio_config.h @@ -49,7 +49,7 @@ * transport being used (eg. virtio_ring), the rest are per-device feature * bits. */ #define VIRTIO_TRANSPORT_F_START 28 -#define VIRTIO_TRANSPORT_F_END 34 +#define VIRTIO_TRANSPORT_F_END 37 #ifndef VIRTIO_CONFIG_NO_LEGACY /* Do we get callbacks when the ring is completely used, even if we've @@ -71,4 +71,10 @@ * this is for compatibility with legacy systems. */ #define VIRTIO_F_IOMMU_PLATFORM 33 + +/* + * If clear - driver may use barriers suitable for CPU cores. + * If set - driver must use barriers suitable for hardware devices. + */ +#define VIRTIO_F_IO_BARRIER 36 #endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */ -- 2.11.0 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
