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 <[email protected]>
---
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
On Fri, May 04, 2018 at 12:59:15PM +0800, Tiwei Bie wrote:
> 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
Have you updated "2.2 Feature Bits" in the VIRTIO spec?
In 1.0 it says:
24 to 32
Feature bits reserved for extensions to the queue and feature negotiation mechanisms
This information is out-of-date.
Stefan
On Thu, May 10, 2018 at 10:53:17AM +0100, Stefan Hajnoczi wrote:
> On Fri, May 04, 2018 at 12:59:15PM +0800, Tiwei Bie wrote:
> > 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
>
> Have you updated "2.2 Feature Bits" in the VIRTIO spec?
>
> In 1.0 it says:
>
> 24 to 32
> Feature bits reserved for extensions to the queue and feature negotiation mechanisms
>
> This information is out-of-date.
>
No. In the latest spec draft, it's 24 to 33. And it
becomes out-of-date since VIRTIO_F_RING_PACKED(34)
and VIRTIO_F_IN_ORDER(35) were introduced. Do you
want me to update it in the IO_BARRIER patch or do
you want me to update it in a new patch?
Best regards,
Tiwei Bie
On Thu, May 10, 2018 at 06:39:41PM +0800, Tiwei Bie wrote:
> On Thu, May 10, 2018 at 10:53:17AM +0100, Stefan Hajnoczi wrote:
> > On Fri, May 04, 2018 at 12:59:15PM +0800, Tiwei Bie wrote:
> > > 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
> >
> > Have you updated "2.2 Feature Bits" in the VIRTIO spec?
> >
> > In 1.0 it says:
> >
> > 24 to 32
> > Feature bits reserved for extensions to the queue and feature negotiation mechanisms
> >
> > This information is out-of-date.
> >
>
> No. In the latest spec draft, it's 24 to 33. And it
> becomes out-of-date since VIRTIO_F_RING_PACKED(34)
> and VIRTIO_F_IN_ORDER(35) were introduced. Do you
> want me to update it in the IO_BARRIER patch or do
> you want me to update it in a new patch?
Please update it to 37 in the IO_BARRIER patch.
Stefan
On Thu, May 10, 2018 at 04:02:58PM +0100, Stefan Hajnoczi wrote:
> On Thu, May 10, 2018 at 06:39:41PM +0800, Tiwei Bie wrote:
> > On Thu, May 10, 2018 at 10:53:17AM +0100, Stefan Hajnoczi wrote:
> > > On Fri, May 04, 2018 at 12:59:15PM +0800, Tiwei Bie wrote:
> > > > 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
> > >
> > > Have you updated "2.2 Feature Bits" in the VIRTIO spec?
> > >
> > > In 1.0 it says:
> > >
> > > 24 to 32
> > > Feature bits reserved for extensions to the queue and feature negotiation mechanisms
> > >
> > > This information is out-of-date.
> > >
> >
> > No. In the latest spec draft, it's 24 to 33. And it
> > becomes out-of-date since VIRTIO_F_RING_PACKED(34)
> > and VIRTIO_F_IN_ORDER(35) were introduced. Do you
> > want me to update it in the IO_BARRIER patch or do
> > you want me to update it in a new patch?
>
> Please update it to 37 in the IO_BARRIER patch.
Will do it! Thanks!
Best regards,
Tiwei Bie