Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 25 Jan 2018 17:09:25 +0000
From:   Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To:     Joerg Roedel <joro@8bytes.org>
Cc:     Nadav Amit <nadav.amit@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>,
        "H . Peter Anvin" <hpa@zytor.com>,
        the arch/x86 maintainers <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Juergen Gross <jgross@suse.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Borislav Petkov <bp@alien8.de>, Jiri Kosina <jkosina@suse.cz>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Brian Gerst <brgerst@gmail.com>,
        David Laight <David.Laight@aculab.com>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        Eduardo Valentin <eduval@amazon.com>,
        Greg KH <gregkh@linuxfoundation.org>,
        Will Deacon <will.deacon@arm.com>, aliguori@amazon.com,
        daniel.gruss@iaik.tugraz.at, hughd@google.com, keescook@google.com,
        Andrea Arcangeli <aarcange@redhat.com>,
        Waiman Long <llong@redhat.com>, jroedel@suse.de
Subject: Re: [RFC PATCH 00/16] PTI support for x86-32
Message-ID: <20180125170925.1d72d587@alans-desktop>
In-Reply-To: <20180122085625.GE28161@8bytes.org>
References: <1516120619-1159-1-git-send-email-joro@8bytes.org>
        <5D89F55C-902A-4464-A64E-7157FF55FAD0@gmail.com>
        <886C924D-668F-4007-98CA-555DB6279E4F@gmail.com>
        <9CF1DD34-7C66-4F11-856D-B5E896988E16@gmail.com>
        <20180122085625.GE28161@8bytes.org>
Organization: Intel Corporation
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, 22 Jan 2018 09:56:25 +0100
Joerg Roedel <joro@8bytes.org> wrote:

> Hey Nadav,
> 
> On Sun, Jan 21, 2018 at 03:46:24PM -0800, Nadav Amit wrote:
> > It does seem that segmentation provides sufficient protection from Meltdown.  
> 
> Thanks for testing this, if this turns out to be true for all affected
> uarchs it would be a great and better way of protection than enabling
> PTI.
> 
> But I'd like an official statement from Intel on that one, as their
> recommended fix is still to use PTI.

It is: we don't think segmentation works on all processors as a defence.

Alan