Re: [PATCH v2 07/18] nitro_enclaves: Init misc device providing the ioctl interface

[Greg KH]

On Mon, May 25, 2020 at 11:49:50PM +0300, Paraschiv, Andra-Irina wrote:
> 
> 
> On 22/05/2020 10:07, Greg KH wrote:
> > On Fri, May 22, 2020 at 09:29:35AM +0300, Andra Paraschiv wrote:
> > > +static char *ne_cpus;
> > > +module_param(ne_cpus, charp, 0644);
> > > +MODULE_PARM_DESC(ne_cpus, "<cpu-list> - CPU pool used for Nitro Enclaves");
> > This is not the 1990's, don't use module parameters if you can help it.
> > Why is this needed, and where is it documented?
> 
> This is a CPU pool that can be set by the root user and that includes CPUs
> set aside to be used for the enclave(s) setup; these CPUs are offlined. From
> this CPU pool, the kernel logic chooses the CPUs that are set for the
> created enclave(s).
> 
> The cpu-list format is matching the same that is documented here:
> 
> https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html
> 
> I've also thought of having a sysfs entry for the setup of this enclave CPU
> pool.

Ok, but again, do not use a module parameter, they are hard to use,
tough to document, and global.  All things we moved away from a long
time ago.  Please use something else for this (sysfs, configfs, etc.)
instead.

thanks,

greg k-h