Re: [PATCH RFC v3 07/13] vhost: add support for negotiating extended features

[Paolo Abeni <pabeni@redhat.com>]

On 7/18/25 4:36 PM, Stefano Garzarella wrote:
> On Fri, Jul 18, 2025 at 10:52:33AM +0200, Paolo Abeni wrote:
>> @@ -1871,6 +1900,20 @@ uint64_t vhost_get_features(struct vhost_dev *hdev, const int *feature_bits,
>>     return features;
>> }
>>
>> +void vhost_get_features_ex(struct vhost_dev *hdev,
>> +                           const int *feature_bits,
>> +                           uint64_t *features)
>> +{
>> +    const int *bit = feature_bits;
>> +
>> +    while (*bit != VHOST_INVALID_FEATURE_BIT) {
>> +        if (!virtio_has_feature_ex(hdev->features_ex, *bit)) {
>> +            virtio_clear_feature_ex(features, *bit);
>> +        }
>> +        bit++;
>> +    }
>> +}
>> +
> 
> Can we do something similar of what we do in hw/virtio/virtio.c where
> the old virtio_set_features() use the new virtio_set_features_ex()?
> 
>> void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits,
>>                         uint64_t features)
>> {
>> @@ -1884,6 +1927,18 @@ void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits,
>>     }
>> }
>>
>> +void vhost_ack_features_ex(struct vhost_dev *hdev, const int *feature_bits,
>> +                           const uint64_t *features)
>> +{
>> +    const int *bit = feature_bits;
>> +    while (*bit != VHOST_INVALID_FEATURE_BIT) {
>> +        if (virtio_has_feature_ex(features, *bit)) {
>> +            virtio_add_feature_ex(hdev->acked_features_ex, *bit);
>> +        }
>> +        bit++;
>> +    }
>> +}
>> +
> 
> Ditto.
> 
> Not a strong opinion, but just to reduce code duplication.

The incremental diffstat with such cleanup looks good, so I'll include
that in the next revision, thanks!

Paolo