Re: [PATCH v5 5/9] cxl/mem: Add a "RAW" send command

[Konrad Rzeszutek Wilk]

On Tue, Feb 16, 2021 at 08:09:54PM -0800, Ben Widawsky wrote:
> The CXL memory device send interface will have a number of supported
> commands. The raw command is not such a command. Raw commands allow
> userspace to send a specified opcode to the underlying hardware and
> bypass all driver checks on the command. The primary use for this
> command is to [begrudgingly] allow undocumented vendor specific hardware
> commands.
> 
> While not the main motivation, it also allows prototyping new hardware
> commands without a driver patch and rebuild.
> 
> While this all sounds very powerful it comes with a couple of caveats:
> 1. Bug reports using raw commands will not get the same level of
>    attention as bug reports using supported commands (via taint).
> 2. Supported commands will be rejected by the RAW command.
> 
> With this comes new debugfs knob to allow full access to your toes with
> your weapon of choice.
> 
> Cc: Ariel Sibley <Ariel.Sibley@xxxxxxxxxxxxx>
> Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
> Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx> (v2)
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>