linux-kernel - Re: [PATCH] x86/head: Refactor 32-bit pgtable setup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20161218084457.GA19538@gmail.com>
Date:   Sun, 18 Dec 2016 09:44:57 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, linux-kernel@...r.kernel.org,
        xen-devel@...ts.xenproject.org, matt@...eblueprint.co.uk,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andy Lutomirski <luto@...nel.org>,
        Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Denys Vlasenko <dvlasenk@...hat.com>,
        Brian Gerst <brgerst@...il.com>
Subject: Re: [PATCH] x86/head: Refactor 32-bit pgtable setup


* Boris Ostrovsky <boris.ostrovsky@...cle.com> wrote:

> On 12/08/2016 11:33 PM, Ingo Molnar wrote:
> > * Boris Ostrovsky <boris.ostrovsky@...cle.com> wrote:
> >
> >> The new Xen PVH entry point requires page tables to be setup by the
> >> kernel since it is entered with paging disabled.
> >>
> >> Pull the common code out of head_32.S so that mk_early_pgtbl_32 can be
> >> invoked from both the new Xen entry point and the existing startup_32
> >> code.
> >>
> >> Convert resulting common code to C.
> >>
> >> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@...cle.com>
> >> ---
> >> This is replacement for https://lkml.org/lkml/2016/10/14/434, with
> >> assembly code re-written in C as requested by Ingo.
> >>
> >>
> >>  arch/x86/include/asm/pgtable_32.h |  32 ++++++++++
> >>  arch/x86/kernel/head32.c          |  62 +++++++++++++++++++
> >>  arch/x86/kernel/head_32.S         | 122 +++-----------------------------------
> >>  3 files changed, 101 insertions(+), 115 deletions(-)
> > Whee, I love it! And the code is so much more readable!
> >
> > Did you have any particular robustness problems (difficult to resolve crashes) 
> > while developing it, or was it reasonably straightforward to do?
> 
> There was nothing particularly difficult beyond understanding current
> code. That, of course, is not to say that there were no crashes but
> developing this on a guest gives you pretty good insight into why/where
> you crashed.
> 
> This was tested on bare-metal (in case you are wondering), but obviously
> more testing is always good.

Ok, cool!

Would you like to carry this with your other Xen dependencies? If yes:

   Acked-by: Ingo Molnar <mingo@...nel.org>

If not then I can pick it up and get it to Linus in v4.10.

Thanks,

	Ingo