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* [PATCH] virtio_config: add device ready status check
@ 2024-03-15 10:31 gavin.liu
  2024-03-15 11:07 ` Michael S. Tsirkin
  2024-03-18  4:21 ` Jason Wang
  0 siblings, 2 replies; 3+ messages in thread
From: gavin.liu @ 2024-03-15 10:31 UTC (permalink / raw)
  To: jasowang, mst, xuanzhuo, pbonzini
  Cc: stefanha, virtualization, angus.chen, yuxue.liu

From: Yuxue Liu <yuxue.liu@jaguarmicro.com>

Under the VDPA framework, when the VDPA driver of a device sets the status
to DRIVER OK,success is not guaranteed. The virtio driver should provide
some protection or notification.

Signed-off-by: Yuxue Liu <yuxue.liu@jaguarmicro.com>
---
 drivers/block/virtio_blk.c    |  4 +++-
 drivers/net/virtio_net.c      |  7 ++++++-
 include/linux/virtio_config.h | 14 ++++++++++++++
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 42dea7601d87..14cabf662705 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -1535,7 +1535,9 @@ static int virtblk_probe(struct virtio_device *vdev)
 		set_disk_ro(vblk->disk, 1);
 
 	virtblk_update_capacity(vblk, false);
-	virtio_device_ready(vdev);
+	err = virtio_device_ready_safe(vdev);
+	if (err)
+		goto out_cleanup_disk;
 
 	/*
 	 * All steps that follow use the VQs therefore they need to be
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d7ce4a1011ea..0431fc9095ae 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -4808,7 +4808,12 @@ static int virtnet_probe(struct virtio_device *vdev)
 		goto free_failover;
 	}
 
-	virtio_device_ready(vdev);
+	err = virtio_device_ready_safe(vdev);
+	if (err) {
+		pr_debug("virtio_net: setting device ready failed\n");
+		rtnl_unlock();
+		goto free_unregister_netdev;
+	}
 
 	_virtnet_set_queues(vi, vi->curr_queue_pairs);
 
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index da9b271b54db..de4e864952ef 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -301,6 +301,20 @@ void virtio_device_ready(struct virtio_device *dev)
 	dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
 }
 
+static inline
+int virtio_device_ready_safe(struct virtio_device *dev)
+{
+	u8 status;
+
+	virtio_device_ready(dev);
+	status = dev->config->get_status(dev);
+	if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
+		WARN_ON(1);
+		return -EINVAL;
+	}
+	return 0;
+}
+
 static inline
 const char *virtio_bus_name(struct virtio_device *vdev)
 {
-- 
2.43.0


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] virtio_config: add device ready status check
  2024-03-15 10:31 [PATCH] virtio_config: add device ready status check gavin.liu
@ 2024-03-15 11:07 ` Michael S. Tsirkin
  2024-03-18  4:21 ` Jason Wang
  1 sibling, 0 replies; 3+ messages in thread
From: Michael S. Tsirkin @ 2024-03-15 11:07 UTC (permalink / raw)
  To: gavin.liu
  Cc: jasowang, xuanzhuo, pbonzini, stefanha, virtualization,
	angus.chen, yuxue.liu

On Fri, Mar 15, 2024 at 06:31:25PM +0800, gavin.liu wrote:
> From: Yuxue Liu <yuxue.liu@jaguarmicro.com>
> 
> Under the VDPA framework, when the VDPA driver of a device sets the status
> to DRIVER OK,success is not guaranteed. The virtio driver should provide
> some protection or notification.
> 
> Signed-off-by: Yuxue Liu <yuxue.liu@jaguarmicro.com>
> ---
>  drivers/block/virtio_blk.c    |  4 +++-
>  drivers/net/virtio_net.c      |  7 ++++++-
>  include/linux/virtio_config.h | 14 ++++++++++++++
>  3 files changed, 23 insertions(+), 2 deletions(-)


And then what we are expected to change all drivers for this hack to
work? Suggest you instead have vdpa set broken flag and be done with it.

> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 42dea7601d87..14cabf662705 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -1535,7 +1535,9 @@ static int virtblk_probe(struct virtio_device *vdev)
>  		set_disk_ro(vblk->disk, 1);
>  
>  	virtblk_update_capacity(vblk, false);
> -	virtio_device_ready(vdev);
> +	err = virtio_device_ready_safe(vdev);
> +	if (err)
> +		goto out_cleanup_disk;
>  
>  	/*
>  	 * All steps that follow use the VQs therefore they need to be
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index d7ce4a1011ea..0431fc9095ae 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -4808,7 +4808,12 @@ static int virtnet_probe(struct virtio_device *vdev)
>  		goto free_failover;
>  	}
>  
> -	virtio_device_ready(vdev);
> +	err = virtio_device_ready_safe(vdev);
> +	if (err) {
> +		pr_debug("virtio_net: setting device ready failed\n");
> +		rtnl_unlock();
> +		goto free_unregister_netdev;
> +	}
>  
>  	_virtnet_set_queues(vi, vi->curr_queue_pairs);
>  
> diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> index da9b271b54db..de4e864952ef 100644
> --- a/include/linux/virtio_config.h
> +++ b/include/linux/virtio_config.h
> @@ -301,6 +301,20 @@ void virtio_device_ready(struct virtio_device *dev)
>  	dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
>  }
>  
> +static inline
> +int virtio_device_ready_safe(struct virtio_device *dev)
> +{
> +	u8 status;
> +
> +	virtio_device_ready(dev);
> +	status = dev->config->get_status(dev);
> +	if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
> +		WARN_ON(1);
> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +
>  static inline
>  const char *virtio_bus_name(struct virtio_device *vdev)
>  {
> -- 
> 2.43.0


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] virtio_config: add device ready status check
  2024-03-15 10:31 [PATCH] virtio_config: add device ready status check gavin.liu
  2024-03-15 11:07 ` Michael S. Tsirkin
@ 2024-03-18  4:21 ` Jason Wang
  1 sibling, 0 replies; 3+ messages in thread
From: Jason Wang @ 2024-03-18  4:21 UTC (permalink / raw)
  To: gavin.liu
  Cc: mst, xuanzhuo, pbonzini, stefanha, virtualization, angus.chen,
	yuxue.liu

On Fri, Mar 15, 2024 at 6:31 PM gavin.liu <gavin.liu@jaguarmicro.com> wrote:
>
> From: Yuxue Liu <yuxue.liu@jaguarmicro.com>
>
> Under the VDPA framework, when the VDPA driver of a device sets the status
> to DRIVER OK,success is not guaranteed. The virtio driver should provide
> some protection or notification.
>
> Signed-off-by: Yuxue Liu <yuxue.liu@jaguarmicro.com>
> ---
>  drivers/block/virtio_blk.c    |  4 +++-
>  drivers/net/virtio_net.c      |  7 ++++++-
>  include/linux/virtio_config.h | 14 ++++++++++++++
>  3 files changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 42dea7601d87..14cabf662705 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -1535,7 +1535,9 @@ static int virtblk_probe(struct virtio_device *vdev)
>                 set_disk_ro(vblk->disk, 1);
>
>         virtblk_update_capacity(vblk, false);
> -       virtio_device_ready(vdev);
> +       err = virtio_device_ready_safe(vdev);
> +       if (err)
> +               goto out_cleanup_disk;
>
>         /*
>          * All steps that follow use the VQs therefore they need to be
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index d7ce4a1011ea..0431fc9095ae 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -4808,7 +4808,12 @@ static int virtnet_probe(struct virtio_device *vdev)
>                 goto free_failover;
>         }
>
> -       virtio_device_ready(vdev);
> +       err = virtio_device_ready_safe(vdev);
> +       if (err) {
> +               pr_debug("virtio_net: setting device ready failed\n");
> +               rtnl_unlock();
> +               goto free_unregister_netdev;
> +       }
>
>         _virtnet_set_queues(vi, vi->curr_queue_pairs);
>
> diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> index da9b271b54db..de4e864952ef 100644
> --- a/include/linux/virtio_config.h
> +++ b/include/linux/virtio_config.h
> @@ -301,6 +301,20 @@ void virtio_device_ready(struct virtio_device *dev)
>         dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
>  }
>
> +static inline
> +int virtio_device_ready_safe(struct virtio_device *dev)
> +{
> +       u8 status;
> +
> +       virtio_device_ready(dev);
> +       status = dev->config->get_status(dev);
> +       if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
> +               WARN_ON(1);
> +               return -EINVAL;

The seems to be a violation of the virtio spec:

Section 3.1.1 Driver Requirements: Device Initialization said

"""
Set the DRIVER_OK status bit. At this point the device is “live”.
"""

Or why did you need to read the status back and check?

Thanks

> +       }
> +       return 0;
> +}
> +
>  static inline
>  const char *virtio_bus_name(struct virtio_device *vdev)
>  {
> --
> 2.43.0
>


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2024-03-18  4:21 UTC | newest]

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2024-03-15 10:31 [PATCH] virtio_config: add device ready status check gavin.liu
2024-03-15 11:07 ` Michael S. Tsirkin
2024-03-18  4:21 ` Jason Wang

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