From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1874C7EE25 for ; Thu, 8 Jun 2023 15:56:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237100AbjFHP44 (ORCPT ); Thu, 8 Jun 2023 11:56:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237141AbjFHP4w (ORCPT ); Thu, 8 Jun 2023 11:56:52 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87A8330FD for ; Thu, 8 Jun 2023 08:56:29 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1686239780; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Pi/Ml/HjFhIPKGpG6a2XNyaJJkM+1hcuNsAqSb+ysvI=; b=AkNvho9aGbIFH9ExnaqkQ/NHoYh+PBS6TgybX4r4rzp2TM5xx+SuurGlPACjtvO7eFoUWp ARckTvITbSMyNRiKLb9F3PD94+HdxZFjCU7qWUfD5D1pO3v/WRhn/RfKvwT4vj1NNbKd1M y2a/oA0RnrgUqg2KY9ttJQRsVHyzEGQksyD/EILAIKZZplGMYRnYsOJNgyjwxeZ+LUu2BM nPsU3wPTGl5B+O79mJ+yqtMgFF7FWGfu+kyoC3laX4nk2npAu5102UA3y73mCzOEziiAyk fOkRX0ewY+sYY6apF9bRn4rqxWVPEuv1HF2c/oruTZEvIACshmckgu4T42uoBg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1686239780; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Pi/Ml/HjFhIPKGpG6a2XNyaJJkM+1hcuNsAqSb+ysvI=; b=IT85OYZI3Il+mINfOwHin88cOxJUAmW4X7Lik/zQnXJHVE2uw1JxX5V49kC8Be23tHDaGk JjoVSkB1DrcNnnDg== To: Andrew Cooper , Nikolay Borisov , x86@kernel.org Cc: linux-kernel@vger.kernel.org, mhocko@suse.com, jslaby@suse.cz Subject: Re: [PATCH 3/3] x86: Disable running 32bit processes if ia32_disabled is passed In-Reply-To: <455418fb-8050-3985-5c6c-8b2068702286@citrix.com> References: <20230607072936.3766231-1-nik.borisov@suse.com> <20230607072936.3766231-4-nik.borisov@suse.com> <87legvjxat.ffs@tglx> <80f2045b-f276-e127-8e46-87fb6994fb41@suse.com> <87fs73juwa.ffs@tglx> <87a5xbjpk2.ffs@tglx> <875d0ab7-4470-25e2-6c01-72e231aae515@citrix.com> <874jnjj5z2.ffs@tglx> <278d7231-ee27-602f-4ba7-45d45d6772b3@citrix.com> <871qimkdft.ffs@tglx> <455418fb-8050-3985-5c6c-8b2068702286@citrix.com> Date: Thu, 08 Jun 2023 17:56:19 +0200 Message-ID: <87v8fyhrrw.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 08 2023 at 12:25, Andrew Cooper wrote: > On 08/06/2023 1:25 am, Thomas Gleixner wrote: >> I really wish that we could disable syscall32 reliably on AMD and make >> it raise #UD as it does on Intal. > > You know that's changing in FRED, and will follow the AMD model? > > The SYSCALL instruction is lower latency if it doesn't need to check %cs > to conditionally #UD. Yes, but with FRED the CPL0 context is fully consistent. There are no CPL3 leftovers. >> Didn't we assume that there are no CPU bugs? :) > > Tell me, is such a CPU delivered with or without a complimentary unicorn? :) It's deliverd by a fairytale princess :) Thanks, tglx