Re: [PATCH v3 8/8] cxl/mbox: Block inject and clear poison opcodes in raw mode

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

On Wed,  1 Mar 2023 13:36:33 -0800
alison.schofield@intel.com wrote:

> From: Alison Schofield <alison.schofield@intel.com>
> 
> Inject and clear poison are commands intended for debug environments,
> and can cause data corruption if issued without validation. They are
> kernel exclusive commands not available to userspace through ioctls,
> but could be submitted via the raw mode ioctl.
> 
> Add inject and clear poison to the cxl_disabled_raw_commands[] list.
> Attempts by userspace to issue either command via the RAW ioctl fail
> with -EPERM.
> 
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  drivers/cxl/core/mbox.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index 77fc811bdfed..4b5e65edbc71 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -89,6 +89,10 @@ static struct cxl_mem_command cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
>   *
>   * CXL_MBOX_OP_[GET_]SCAN_MEDIA: The kernel provides a native error list that
>   * is kept up to date with patrol notifications and error management.
> + *
> + * CXL_MBOX_OP_[INJECT|CLEAR]_POISON: The kernel provides a sysfs interface
> + * to these commands that ensures data protection of mapped resources.
> + * See: Documentation/ABI/testing/sysfs-bus-cxl
>   */
>  static u16 cxl_disabled_raw_commands[] = {
>  	CXL_MBOX_OP_ACTIVATE_FW,
> @@ -97,6 +101,8 @@ static u16 cxl_disabled_raw_commands[] = {
>  	CXL_MBOX_OP_SET_SHUTDOWN_STATE,
>  	CXL_MBOX_OP_SCAN_MEDIA,
>  	CXL_MBOX_OP_GET_SCAN_MEDIA,
> +	CXL_MBOX_OP_INJECT_POISON,
> +	CXL_MBOX_OP_CLEAR_POISON,
>  };
>  
>  /*