Re: [PATCH v1] vdpa/mlx5: Restore the hardware used index after change map

On 2/19/2021 6:38 PM, Jason Wang wrote:

quoted

quoted

Right now the value is exposed to userspace via GET_VRING_BASE, so 
only last_avail_idx is synced. If we need sync last_used_idx, we 
should also sync pending indices which requires more thoughts.

Technically it doesn't sound right - crossing the boundary a bit even 
with simplified form of assumption. But depending on how userspace 
could make use of this API, it doesn't seem it breaks existing 
functionality for the moment.

I don't get here, maybe you can explain a little bit more? 

Please refer to the email I just sent.

https://lore.kernel.org/lkml/033b0806-4037-5755-a1fa-91dbb58bab2e@oracle.com/ (local)

-Siwei