linux-kernel - Re: Yet another KPTI regression with 4.14.x series in a VM

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: <20180113135140.nloztfyel3szt4h2@pd.tnic>
Date:   Sat, 13 Jan 2018 14:51:40 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Laura Abbott <labbott@...hat.com>, X86 ML <x86@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        stable <stable@...r.kernel.org>
Subject: Re: Yet another KPTI regression with 4.14.x series in a VM

On Sat, Jan 13, 2018 at 01:50:55PM +0100, Thomas Gleixner wrote:
>  2:0 Ignored
>    3 PWT
>    4 PCD

Btw, those last two are "(implies PCD=PWT=0)" according to
http://www.sandpile.org/x86/crx.htm with PCID. I was wondering recently
what happens with those bits when PCID is enabled and CR3[11:0] is the
ASID. I couldn't find it in the SDM.

And it kinda makes sense, PCD=1b is probably only for testing some
hardware crud and not really sensible for normal production.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.