Re: [PATCH v5 1/9] cxl/mem: Introduce a driver for CXL-2.0-Type-3 endpoints
From: Konrad Rzeszutek Wilk
Date: Fri Feb 19 2021 - 19:57:46 EST
On Tue, Feb 16, 2021 at 08:09:50PM -0800, Ben Widawsky wrote:
> From: Dan Williams <dan.j.williams@xxxxxxxxx>
>
> The CXL.mem protocol allows a device to act as a provider of "System
> RAM" and/or "Persistent Memory" that is fully coherent as if the memory
> was attached to the typical CPU memory controller.
>
> With the CXL-2.0 specification a PCI endpoint can implement a "Type-3"
> device interface and give the operating system control over "Host
> Managed Device Memory". See section 2.3 Type 3 CXL Device.
>
> The memory range exported by the device may optionally be described by
> the platform firmware memory map, or by infrastructure like LIBNVDIMM to
> provision persistent memory capacity from one, or more, CXL.mem devices.
>
> A pre-requisite for Linux-managed memory-capacity provisioning is this
> cxl_mem driver that can speak the mailbox protocol defined in section
> 8.2.8.4 Mailbox Registers.
>
> For now just land the initial driver boiler-plate and Documentation/
> infrastructure.
>
> Link: https://www.computeexpresslink.org/download-the-specification
> Cc: Jonathan Corbet <corbet@xxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> (v1)
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Albeit you may want to modify 2020 to 2021 in the Copyright sections.