RE: [PATCH 1/2] virtio: introduce selective queue enabling

[Parav Pandit <parav@nvidia.com>]

> From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> Sent: Thursday, June 8, 2023 8:12 AM


> Although there is no "all queues" here, if the queue is not ready, the device may
> use all the queues after "Device OK". So I also think it might be dangerous.
>
Device can only used enabled queues at any stage before/after DRIVER_OK.
If the queue is not enabled, there is simply no rx packet or anything on that queue.
 
> But I also ran into this problem. We want the device to support 100 queues, but
> we also want to use only 16 queues by default. The user can then manually
> scale up to 100, if the user has a large memory.
> 
So, one config sequence :
a. driver can enable 16 queues before  driver ok 
b. driver does driver ok
c. few hours later driver enables remaining 84 queues

in second config sequence:
a. driver can enable 0 queues before  driver ok 
b. driver does driver ok
c. few hours later driver enables remaining 16+84 queues