linux-kernel - Re: [RFC PATCH 3/9] cxl/mem: Add a driver for the type-3 mailbox

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 10 Nov 2020 22:17:08 -0800
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Ben Widawsky <ben.widawsky@...el.com>, linux-cxl@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
        linux-acpi@...r.kernel.org,
        Dan Williams <dan.j.williams@...el.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        "Kelley, Sean V" <sean.v.kelley@...el.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>
Subject: Re: [RFC PATCH 3/9] cxl/mem: Add a driver for the type-3 mailbox

Hi,

On 11/10/20 9:43 PM, Ben Widawsky wrote:
> ---
>  drivers/cxl/Kconfig  | 20 +++++++++++
>  drivers/cxl/Makefile |  2 ++
>  drivers/cxl/mem.c    | 82 ++++++++++++++++++++++++++++++++++++++++++++
>  drivers/cxl/pci.h    | 15 ++++++++
>  4 files changed, 119 insertions(+)

> diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
> index dd724bd364df..15548f5c77ff 100644
> --- a/drivers/cxl/Kconfig
> +++ b/drivers/cxl/Kconfig
> @@ -27,4 +27,24 @@ config CXL_ACPI
>  	  resources described by the CEDT (CXL Early Discovery Table)
>  
>  	  Say 'y' to enable CXL (Compute Express Link) drivers.
> +
> +config CXL_MEM
> +        tristate "CXL.mem Device Support"
> +        depends on PCI && CXL_BUS_PROVIDER != n
> +        default m if CXL_BUS_PROVIDER

The "if CXL_BUS_PROVIDER" should be redundant due to the "depends on" clause.
However, having any default or 'm' or 'y' needs to be justified.

> +        help
> +          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.
> +
> +          Say 'y/m' to enable a driver named "cxl_mem.ko" that will attach

The builtin driver will not be named cxl-mem.ko.

> +          to CXL.mem devices for configuration, provisioning, and health
> +          monitoring, the so called "type-3 mailbox". Note, this driver
> +          is required for dynamic provisioning of CXL.mem attached
> +          memory, a pre-requisite for persistent memory support, but

	               prerequisite

> +          devices that provide volatile memory may be fully described by
> +          existing platform firmware memory enumeration.
> +
> +          If unsure say 'n'.
>  endif


-- 
~Randy