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

From	Ingo Molnar <mingo@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] x86/head: Refactor 32-bit pgtable setup
Date	2016-12-18 09:50 +0100
Message-ID	<sPFkl-5jX-1@gated-at.bofh.it> (permalink)
References	<sMa3n-8rP-17@gated-at.bofh.it> <sMl8t-792-3@gated-at.bofh.it> <sMuv7-4qd-15@gated-at.bofh.it>
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* Boris Ostrovsky <boris.ostrovsky@oracle.com> wrote:

> On 12/08/2016 11:33 PM, Ingo Molnar wrote:
> > * Boris Ostrovsky <boris.ostrovsky@oracle.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@oracle.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@kernel.org>

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

Thanks,

	Ingo

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Re: [PATCH] x86/head: Refactor 32-bit pgtable setup Ingo Molnar <mingo@kernel.org> - 2016-12-18 09:50 +0100
  Re: [PATCH] x86/head: Refactor 32-bit pgtable setup Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2016-12-19 15:10 +0100

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