Querying the CPU queue mapping of blk-mq device in general and nvme device in particular

[Vladislav Zolotarov <vladz@xxxxxxxxxxxx>]

Christoph, hi!
I'd like to ask you if there is a way to learn from the user space the 
current CPU queue mapping of a particular blk-mq device?
For instance, given a particular NVMe device queue (e.g. nvme0q8) how 
can I tell which CPU it is mapped to?

I need this in order to properly set the SMP affinity of the 
corresponding IRQ vectors in case when kernel doesn't auto-tune it.

Thanks in advance,
Vlad