linux-kernel - Re: [PATCH 3/4] x86/umip: Identify the str and sldt instructions

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Message-ID: <20171113081203.qi54w55vwrmic4mw@gmail.com>
Date:   Mon, 13 Nov 2017 09:12:03 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...e.de>,
        Andy Lutomirski <luto@...nel.org>,
        Tony Luck <tony.luck@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>, x86@...nel.org,
        ricardo.neri@...el.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] x86/umip: Identify the str and sldt instructions


* Ricardo Neri <ricardo.neri-calderon@...ux.intel.com> wrote:

> The instructions str and sldt are not emulated in any case. Thus, it made
> sense to not implement functionality to identify them. However, a
> subsequent commit will introduce functionality to warn about the use of
> all the instructions that UMIP protect, not only those that are emulated.
> A first step for that is the ability to identify them.
> 
> Plus, now that str and sldt are identified, we need to explicitly avoid
> their emulation (i.e., not rely on unsuccessful identification). Group
> togehter all the cases that we do not want to emulate: str, sldt and user
> long mode processes.

Did you notice how in all your previous patches (both in the code and in the 
changelogs) I have manually fixed up the capitalization of these instruction 
mnenonics?

The capitalized form is much more readable, especially with seriously overloaded 
acronyms such as 'str' ...

You now repeat the same bad pattern, in fact you regress existing code:

> -	/* SLDT AND STR are not emulated */

> +	/* Do not emulate sldt, str or user long mode processes. */

Please be more careful with such details, and please fix & resend this series.

Thanks,

	Ingo