Re: [RFC PATCH 0/4] Region Creation

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Thu, 10 Jun 2021 11:57:21 -0700
Ben Widawsky <ben.widawsky@intel.com> wrote:

> CXL interleave sets and non-interleave sets are described via regions. A region
> is specified in the CXL 2.0 specification and the purpose is to create a
> standardized way to preserve the region across reboots.

A specific section reference would be helpful.

> 
> Introduced here is the basic mechanism to create and configure and delete a CXL
> region. Configuring a region simply means giving it a size, offset within the
> CFMWS window, UUID, and a target list. Enabling/activating a region, which
> ultimately means programming the HDM decoders in the chain, is left for later
> work.
> 
> The patches are only minimally tested so far in QEMU emulation and so x1
> interleave is all that's supported.

I'm guessing this is why it's an RFC rather than a final submission?

If you can call out the RFC reasons in a cover letter it is helpful
as saves people wondering what specifically you want comments on.

> 
> Here is a sample topology (also in patch #4)
> 
>     decoder1.0
>     ├── create_region
>     ├── delete_region
>     ├── devtype
>     ├── locked
>     ├── region1.0:0
>     │   ├── offset
>     │   ├── size
>     │   ├── subsystem -> ../../../../../../../bus/cxl
>     │   ├── target0
>     │   ├── uevent
>     │   ├── uuid
>     │   └── verify
>     ├── size
>     ├── start
>     ├── subsystem -> ../../../../../../bus/cxl
>     ├── target_list
>     ├── target_type
>     └── uevent
> 
> Ben Widawsky (4):
>   cxl/region: Add region creation ABI
>   cxl/region: Create attribute structure / verify
>   cxl: Move cxl_memdev conversion helper to mem.h
>   cxl/region: Introduce concept of region configuration
> 
>  Documentation/ABI/testing/sysfs-bus-cxl       |  59 +++
>  .../driver-api/cxl/memory-devices.rst         |   8 +
>  drivers/cxl/Makefile                          |   2 +-
>  drivers/cxl/core.c                            |  71 ++++
>  drivers/cxl/cxl.h                             |  11 +
>  drivers/cxl/mem.h                             |  26 ++
>  drivers/cxl/pci.c                             |   5 -
>  drivers/cxl/region.c                          | 400 ++++++++++++++++++
>  8 files changed, 576 insertions(+), 6 deletions(-)
>  create mode 100644 drivers/cxl/region.c
>