linux-kernel - Re: [RFC PATCH] Use feature bit names in clearcpuid=

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Message-ID: <20200920183527.GA3970023@rani.riverdale.lan>
Date:   Sun, 20 Sep 2020 14:35:27 -0400
From:   Arvind Sankar <nivedita@...m.mit.edu>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Arvind Sankar <nivedita@...m.mit.edu>, x86-ml <x86@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH] Use feature bit names in clearcpuid=

On Sun, Sep 20, 2020 at 07:29:54PM +0200, Borislav Petkov wrote:
> On Sun, Sep 20, 2020 at 12:16:28PM -0400, Arvind Sankar wrote:
> > Allowing 13:24 as input would be icing on the cake :)
> 
> Well, I'm kinda "meh" on that. Why, you ask?
> 
> Well, whether the user multiplies two integers or the kernel does it for
> her/him, I'd prefer the user.
> 
> But that's not even the problem - whether the product of the word number
> and the bit within that word, or the two supplied as a pair - either is
> the wrong interface. It is ugly and not even close to even beginning to
> be user-friendly.
> 
> However, we can't make it fully user-friendly yet because not all bits
> have names. :-\
> 
> But you know what, that doesn't matter too because that clearcpuid=
> thing is mainly for poking at sh*t and testing, not meant for users.
> Thus the tainting...
> 
> So I guess the one who needs it, can go the minute distance and do the
> multiplication. According to that argument, adding the string parsing is
> not really needed too, but it is simple enough so WTH.
> 
> I've incorporated all your other comments, see below.
> 
> Thx!
> 

Thanks. Maybe also mention in the documentation that names can now be
used.