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Subject: Re: [PATCH 00/11] Use global pages with PTI
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From: Dave Hansen <dave.hansen@linux.intel.com>
Message-ID: <2607b1b1-89a7-635c-0c5d-da9f558241f4@linux.intel.com>
Date: Sat, 31 Mar 2018 11:19:48 -0700
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To: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, Linus Torvalds <torvalds@linux-foundation.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>, Andrea Arcangeli <aarcange@redhat.com>, Andrew Lutomirski <luto@kernel.org>, Kees Cook <keescook@google.com>, Hugh Dickins <hughd@google.com>, =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= <jgross@suse.com>, the arch/x86 maintainers <x86@kernel.org>, namit@vmware.com

On 03/30/2018 10:39 PM, Ingo Molnar wrote:
> There were a couple of valid review comments which need to be addressed as well, 
> but other than that it all looks good to me and I plan to apply the next 
> iteration.

Testing on that non-PCID systems showed an oddity with parts of the
kernel image that are modified later in boot (when we set the kernel
image read-only).  We split a few of the PMD entries and the the old
(early boot) values were being used for userspace.

I don't think this is a big deal.  The most annoying thing is that it
makes it harder to quickly validate that all of the things we set to
global *should* be global.  I'll put some examples of how this looks in
the patch when I repost.