Re: [RFC PATCH v2 03/15] khwasan: add CONFIG_KASAN_CLASSIC and CONFIG_KASAN_TAGS

From: Ingo Molnar <mingo@kernel.org>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Julien Thierry <julien.thierry@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Christopher Li <sparse@chrisli.org>,
	Tyler Baicar <tbaicar@codeaurora.org>,
	Will Deacon <will.deacon@arm.com>,
	Paul Lawrence <paullawrence@google.com>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Yury Norov <ynorov@caviumnetworks.com>,
	Alexander Potapenko <glider@google.com>,
	Christoph Lameter <cl@linux.com>,
	Michael Weiser <michael.weiser@gmx.de>,
	kvmarm@lists.cs.columbia.edu, Kees Cook <keescook@google.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Jonathan Corbet <corbet@lwn.net>,
	linux-doc@vger.kernel.org, Mark Brand <markbrand@google.com>,
	kasan-dev <kasan-dev@googlegroups.com>,
	linux-sparse@vger.kernel.org,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	David Rientjes <rientjes@google.com>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>
Subject: Re: [RFC PATCH v2 03/15] khwasan: add CONFIG_KASAN_CLASSIC and CONFIG_KASAN_TAGS
Date: Tue, 27 Mar 2018 22:02:23 +0200	[thread overview]
Message-ID: <20180327200223.5ku2eqkppi7z3sd2@gmail.com> (raw)
In-Reply-To: <CAAeHK+za1Zg2+1_CFrQbdn_Hwa9o_nZkHuMLaekV18W380jAoQ@mail.gmail.com>

* Andrey Konovalov <andreyknvl@google.com> wrote:

> On Sat, Mar 24, 2018 at 9:43 AM, Ingo Molnar <mingo@kernel.org> wrote:
> >
> > * Andrey Konovalov <andreyknvl@google.com> wrote:
> >
> >> This commit splits the current CONFIG_KASAN config option into two:
> >> 1. CONFIG_KASAN_CLASSIC, that enables the classic KASAN version (the one
> >>    that exists now);
> >> 2. CONFIG_KASAN_TAGS, that enables KHWASAN.
> >
> > Sorry, but this is pretty obscure naming scheme that doesn't explain the primary
> > difference between these KASAN models to users: that the first one is a pure
> > software implementation and the other is hardware-assisted.
> >
> > Reminds me of the transparency of galactic buerocracy in "The Hitchhiker's Guide
> > to the Galaxy":
> >
> >   “But look, you found the notice, didn’t you?”
> >   “Yes,” said Arthur, “yes I did. It was on display in the bottom of a locked filing
> >    cabinet stuck in a disused lavatory with a sign on the door saying ‘Beware of the
> >    Leopard.”
> >
> > I'd suggest something more expressive, such as:
> >
> >         CONFIG_KASAN
> >           CONFIG_KASAN_GENERIC
> >           CONFIG_KASAN_HW_ASSIST
> >
> > or so?
> >
> > The 'generic' variant will basically run on any CPU. The 'hardware assisted' one
> > needs support from the CPU.
> >
> > The following ones might also work:
> >
> >    CONFIG_KASAN_HWASSIST
> >    CONFIG_KASAN_HW_TAGS
> >    CONFIG_KASAN_HWTAGS
> >
> > ... or simply CONFIG_KASAN_SW/CONFIG_KASAN_HW.
> >
> > If other types of KASAN hardware acceleration are implemented in the future then
> > the CONFIG_KASAN_HW namespace can be extended:
> >
> >         CONFIG_KASAN_HW_TAGS
> >         CONFIG_KASAN_HW_KEYS
> >         etc.
> 
> How about these two:
> 
> CONFIG_KASAN_GENERIC
> CONFIG_KASAN_HW
> 
> ?
> 
> Shorter config name looks better to me and I think it makes sense to
> name the new config just HW, as there's only one HW implementation
> right now. When (and if) there are more, we can expand the config name
> as you suggested (CONFIG_KASAN_HW_TAGS, CONFIG_KASAN_HW_KEYS, etc).

Sure, sounds good to me!

Thanks,

	Ingo
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