On Mon, Apr 07, 2025 at 10:54:00AM +0200, David Hildenbrand wrote: > On 07.04.25 10:49, Michael S. Tsirkin wrote: > > On Mon, Apr 07, 2025 at 10:44:21AM +0200, David Hildenbrand wrote: > > > > > > > > > > > > > > > > > Whoever adds new feat_X *must be aware* about all previous features, > > > > > otherwise we'd be reusing feature bits and everything falls to pieces. > > > > > > > > > > > > The knowledge is supposed be limited to which feature bit to use. > > > > > > I think we also have to know which virtqueue bits can be used, right? > > > > > > > what are virtqueue bits? vq number? > > Yes, sorry. I got confused myself, it's vq index actually now, we made the spec consistent with that terminology. used to be number/index interchangeably. > Assume cross-vm as an example. It would make use of virtqueue indexes 5+6 > with their VIRTIO_BALLOON_F_WS_REPORTING. crossvm guys really should have reserved the feature bit even if they did not bother specifying it. Let's reserve it now at least? > So whatever feature another device implements couldn't use this feature bit > or these virtqueue indexes. > > (as long the other device never intends to implement > VIRTIO_BALLOON_F_WS_REPORTING, the virtqueue indexes could be reused. But > the spec will also be a mess, because virtqueue indexes could also have > duplicate meanings ... ugh) what do they do with vq indices btw? > -- > Cheers, > > David / dhildenb
