Re: Linux 4.15-rc7

From: Pavel Machek <pavel@ucw.cz>
To: Olivier Galibert <galibert@pobox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	jikos@suse.cz
Subject: Re: Linux 4.15-rc7
Date: Fri, 12 Jan 2018 12:06:24 +0100	[thread overview]
Message-ID: <20180112110624.GA13254@amd> (raw)
In-Reply-To: <CAMFK0guEASKq1zS3S3u=e7TAAYTvmfWfWe5k+X+hKV6RTpyw_Q@mail.gmail.com>

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Hi!

> Wasn't/Isn't the 4G/4G  memory layout for 32 bits essentially KPTI?

Good point. Is that still supported? Was it ever?

Umm. I seem to recall that 4G/4G layout was out of tree but never
merged.

High Memory Support
  1. off (NOHIGHMEM)
    2. 4GB (HIGHMEM4G)
    > 3. 64GB (HIGHMEM64G)
    choice[1-3]: 3
    Memory split
    > 1. 3G/1G user/kernel split (VMSPLIT_3G) (NEW)
      2. 2G/2G user/kernel split (VMSPLIT_2G)
      3. 1G/3G user/kernel split (VMSPLIT_1G)
choice[1-3?]:

Does anyone have recent patches?

Best regards,
								Pavel

> On Thu, Jan 11, 2018 at 12:32 AM, Pavel Machek <pavel@ucw.cz> wrote:
> > Hi!
> >
> >> The one thing I want to do now that Meltdown and Spectre are public,
> >> is to give a *big* shout-out to the x86 people, and Thomas Gleixner in
> >> particular for really being on top of this.  It's been one huge
> >> annoyance, and honestly, Thomas really went over and beyond in this
> >> whole mess.  A lot of other people have obviously been involved too,
> >
> > As I understand it: KPTI prevents Meltdown attack on x86-64, but
> > Spectre means even x86-64 is not expected to be safe?
> >
> > Ok, so Meltdown is public... And I still have some nice 32-bit
> > machines I'd like to keep working.
> >
> > Proof of concept is out, https://github.com/IAIK/meltdown/ .
> >
> > Is anyone working on KPTI for x86-32? SLES11 should still be
> > supported, and that should have x86-32 version; any chance SUSE can
> > share some patches?
> >
> > Thanks,
> >                                                                         Pavel
> > --
> > (english) http://www.livejournal.com/~pavelmachek
> > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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