Re: [PATCH v2 00/10] Copy Offload in NVMe Fabrics with P2P PCI Memory

Logan Gunthorpe
2018-03-01T21:22:56Z

On 01/03/18 02:18 PM, Jerome Glisse wrote:
> This is pretty easy to do with HMM:
>
> unsigned long hmm_page_to_phys_pfn(struct page *page)
This is not useful unless you want to go through all the kernel paths we
are using and replace page_to_phys() and friends with something else
that calls an HMM function when appropriate...

The problem isn't getting the physical address from a page, it's that we
are passing these pages through various kernel interfaces which expect
pages that work in the usual manner. (Look at the code: we quite simply
provide a way to get the PCI bus address from a page when necessary).

Logan