Re: [PATCH v3 2/2] powerpc/pseries: Add driver for PAPR SCM regions

On Mon, Oct 15, 2018 at 10:44 AM Dan Williams [off-list ref] wrote:

On Sun, Oct 14, 2018 at 4:19 PM Oliver O'Halloran [off-list ref] wrote:

quoted

Adds a driver that implements support for enabling and accessing PAPR
SCM regions. Unfortunately due to how the PAPR interface works we can't
use the existing of_pmem driver (yet) because:

 a) The guest is required to use the H_SCM_BIND_MEM h-call to add
    add the SCM region to it's physical address space, and
 b) There is currently no mechanism for relating a bare of_pmem region
    to the backing DIMM (or not-a-DIMM for our case).

Both of these are easily handled by rolling the functionality into a
seperate driver so here we are...

Acked-by: Dan Williams <redacted>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
---
The alternative implementation here is that we have the pseries code
do the h-calls and craft a pmem-region@<addr> node based on that.
However, that doesn't solve b) and mpe has expressed his dislike of
adding new stuff to the DT at runtime so i'd say that's a non-starter.
---
v2: no change
v3: Corrected the mapping to use a DPA start address of zero
    Added cond_resched() calls in the bind/unbind loops

Looks good, could I trouble you for an ack on the build / merge fix?

https://patchwork.kernel.org/patch/10640385/

Sure thing. I checked that it built when rebased on top of your
pending branch before posting.