Enabling peer to peer device transactions for PCIe devices

[Logan Gunthorpe]

On 05/12/16 12:46 PM, Jason Gunthorpe wrote:
> NVMe might have to deal with pci-e hot-unplug, which is a similar
> problem-class to the GPU case..

Sure, but if the NVMe device gets hot-unplugged it means that all the 
CMB mappings are useless and need to be torn down. This probably means 
killing any process that has mappings open.

> In any event the allocator still needs to track which regions are in
> use and be able to hook 'free' from userspace. That does suggest it
> should be integrated into the nvme driver and not a bolt on driver..

Yup, that's correct. And yes, I've never suggested this to be a bolt on 
driver -- I always expected for it to get integrated into the nvme 
driver. (iopmem was not meant for this.)

Logan