2021-06-04 05:05:36

by Jason Wang

Subject: [PATCH] vdpa: mandate 1.0 device

This patch mandates 1.0 for vDPA devices. The plan is never to support
transitional devices for vDPA devices in the future.

The reasons are:

- To have the semantic of normative statement in the virtio spec and
eliminate the burden of transitional device for both vDPA bus and
vDPA parent
- Eliminate the efforts for dealing with endian conversion in the
management tool
- Mandate vDPA vendor to ship modern device instead of transitional
device which is easily broken and unsafe
- Transitional device never work since the first day of vDPA

Signed-off-by: Jason Wang <[email protected]>
---
include/linux/vdpa.h | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index f311d227aa1b..11dd05b805a7 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -6,6 +6,7 @@
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/vhost_iotlb.h>
+#include <uapi/linux/virtio_config.h>

/**
* struct vdpa_calllback - vDPA callback definition.
@@ -328,6 +329,11 @@ static inline int vdpa_set_features(struct vdpa_device *vdev, u64 features)
{
const struct vdpa_config_ops *ops = vdev->config;

+ /* Mandating 1.0 to have semantics of normative statements in
+ * the spec. */
+ if (!(features & BIT_ULL(VIRTIO_F_VERSION_1)))
+ return -EINVAL;
+
vdev->features_valid = true;
return ops->set_features(vdev, features);
}
--
2.25.1

2021-06-04 08:01:24

by Stefano Garzarella

Subject: Re: [PATCH] vdpa: mandate 1.0 device

On Fri, Jun 04, 2021 at 01:02:51PM +0800, Jason Wang wrote:
>This patch mandates 1.0 for vDPA devices. The plan is never to support
>transitional devices for vDPA devices in the future.
>
>The reasons are:
>
>- To have the semantic of normative statement in the virtio spec and
> eliminate the burden of transitional device for both vDPA bus and
> vDPA parent
>- Eliminate the efforts for dealing with endian conversion in the
> management tool
>- Mandate vDPA vendor to ship modern device instead of transitional
> device which is easily broken and unsafe
>- Transitional device never work since the first day of vDPA
>
>Signed-off-by: Jason Wang <[email protected]>
>---
> include/linux/vdpa.h | 6 ++++++
> 1 file changed, 6 insertions(+)

Reviewed-by: Stefano Garzarella <[email protected]>

2021-06-06 06:38:18

by Eli Cohen

Subject: Re: [PATCH] vdpa: mandate 1.0 device

On Fri, Jun 04, 2021 at 01:02:51PM +0800, Jason Wang wrote:
> This patch mandates 1.0 for vDPA devices. The plan is never to support
> transitional devices for vDPA devices in the future.
>
> The reasons are:
>
> - To have the semantic of normative statement in the virtio spec and
> eliminate the burden of transitional device for both vDPA bus and
> vDPA parent
> - Eliminate the efforts for dealing with endian conversion in the
> management tool
> - Mandate vDPA vendor to ship modern device instead of transitional
> device which is easily broken and unsafe
> - Transitional device never work since the first day of vDPA
Transitional devices never worked...

Reviewed-by: Eli Cohen <[email protected]>

>
> Signed-off-by: Jason Wang <[email protected]>
> ---
> include/linux/vdpa.h | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index f311d227aa1b..11dd05b805a7 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -6,6 +6,7 @@
> #include <linux/device.h>
> #include <linux/interrupt.h>
> #include <linux/vhost_iotlb.h>
> +#include <uapi/linux/virtio_config.h>
>
> /**
> * struct vdpa_calllback - vDPA callback definition.
> @@ -328,6 +329,11 @@ static inline int vdpa_set_features(struct vdpa_device *vdev, u64 features)
> {
> const struct vdpa_config_ops *ops = vdev->config;
>
> + /* Mandating 1.0 to have semantics of normative statements in
> + * the spec. */
> + if (!(features & BIT_ULL(VIRTIO_F_VERSION_1)))
> + return -EINVAL;
> +
> vdev->features_valid = true;
> return ops->set_features(vdev, features);
> }
> --
> 2.25.1
>