Messages in this thread | | | Subject | Re: [RFC] virtio: support VIRTIO_F_IO_BARRIER | From | Jason Wang <> | Date | Thu, 3 May 2018 15:30:03 +0800 |
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On 2018年05月03日 10:59, Tiwei Bie wrote: > 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@intel.com> > --- > 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..6ca8d24bf468 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 38 > > #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 37 > #endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */
Hi:
I believe this depends on Michael's patch of
"[PATCH] virtio_ring: switch to dma_XX barriers for rpmsg"
?
Thanks
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