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virtio.h: add some user-friendly apis #622

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virtio.h: add some user-friendly apis #622

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9a215d0
virtio.h: add new feature bit VIRTIO_F_ANY_LAYOUT
CV-Bowen Oct 8, 2024
d4c0152
virtio.h: add new api virtio_has_feature()
CV-Bowen Oct 8, 2024
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26 changes: 26 additions & 0 deletions lib/include/openamp/virtio.h
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Original file line number Diff line number Diff line change
Expand Up @@ -118,6 +118,12 @@ struct virtio_device_id {
*/
#define VIRTIO_F_NOTIFY_ON_EMPTY (1 << 24)

/*
* This feature indicates that the device accepts arbitrary
* descriptor layouts.
*/
#define VIRTIO_F_ANY_LAYOUT (1 << 27)

/*
* The guest should never negotiate this feature; it
* is used to detect faulty drivers.
Expand Down Expand Up @@ -431,6 +437,9 @@ static inline int virtio_get_features(struct virtio_device *vdev,
return -ENXIO;

*features = vdev->func->get_features(vdev);
if (VIRTIO_ROLE_IS_DEVICE(vdev))
vdev->features = *features;

return 0;
}

Expand Down Expand Up @@ -499,6 +508,23 @@ static inline int virtio_reset_device(struct virtio_device *vdev)
return 0;
}

/**
* @brief Check if the virtio device support a specific feature.
*
* @param vdev Pointer to device structure.
* @param feature_bit Feature bit to check.
*
* @return true if the feature is supported, otherwise false.
*/
static inline bool virtio_has_feature(struct virtio_device *vdev,
unsigned int feature_bit)
{
if (!vdev)
return false;

return (vdev->features & (1UL << feature_bit)) != 0;
}
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This function return valid value only if virtio_negotiate_features has been called first . That also means that it does not work for virtio device role.

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Yes, I consider assign back the final features to vdev->features when call virtio_get_feature() for VIRTIO_DEVICE side, so VIRTIO_DEVICE can use this virtio_has_feature() after called virtio_get_feature(). What do you think?

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Done, @arnopo Could you review again?


#if defined __cplusplus
}
#endif
Expand Down