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Subject: RE: [PATCH v2 5/8] cxl/mem: Add a "RAW" send command
Thread-Topic: [PATCH v2 5/8] cxl/mem: Add a "RAW" send command
Thread-Index: AQHW/0AqZCOVul459UanKz+acVTCvapRfUwQ
Date:   Wed, 10 Feb 2021 15:26:27 +0000
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> diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
> index c4ba3aa0a05d..08eaa8e52083 100644
> --- a/drivers/cxl/Kconfig
> +++ b/drivers/cxl/Kconfig
> @@ -33,6 +33,24 @@ config CXL_MEM
>=20
>           If unsure say 'm'.
>=20
> +config CXL_MEM_RAW_COMMANDS
> +       bool "RAW Command Interface for Memory Devices"
> +       depends on CXL_MEM
> +       help
> +         Enable CXL RAW command interface.
> +
> +         The CXL driver ioctl interface may assign a kernel ioctl comman=
d
> +         number for each specification defined opcode. At any given poin=
t in
> +         time the number of opcodes that the specification defines and a=
 device
> +         may implement may exceed the kernel's set of associated ioctl f=
unction
> +         numbers. The mismatch is either by omission, specification is t=
oo new,
> +         or by design. When prototyping new hardware, or developing /
> debugging
> +         the driver it is useful to be able to submit any possible comma=
nd to
> +         the hardware, even commands that may crash the kernel due to th=
eir
> +         potential impact to memory currently in use by the kernel.
> +
> +         If developing CXL hardware or the driver say Y, otherwise say N=
.

Blocking RAW commands by default will prevent vendors from developing user =
space tools that utilize vendor specific commands. Vendors of CXL.mem devic=
es should take ownership of ensuring any vendor defined commands that could=
 cause user data to be exposed or corrupted are disabled at the device leve=
l for shipping configurations.