From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id 19D016B025F for ; Wed, 1 Nov 2017 16:42:49 -0400 (EDT) Received: by mail-wm0-f71.google.com with SMTP id y83so1829484wmc.8 for ; Wed, 01 Nov 2017 13:42:49 -0700 (PDT) Received: from mail.skyhub.de (mail.skyhub.de. [2a01:4f8:190:11c2::b:1457]) by mx.google.com with ESMTP id v5si1381158wme.189.2017.11.01.13.42.47 for ; Wed, 01 Nov 2017 13:42:48 -0700 (PDT) Date: Wed, 1 Nov 2017 21:42:42 +0100 From: Borislav Petkov Subject: Re: [PATCH 01/23] x86, kaiser: prepare assembly for entry/exit CR3 switching Message-ID: <20171101204242.whvunv2yvgj2uw22@pd.tnic> References: <20171031223146.6B47C861@viggo.jf.intel.com> <20171031223148.5334003A@viggo.jf.intel.com> <20171101181805.3jjzfe6vhmgorjtp@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, moritz.lipp@iaik.tugraz.at, daniel.gruss@iaik.tugraz.at, michael.schwarz@iaik.tugraz.at, luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, x86@kernel.org On Wed, Nov 01, 2017 at 11:27:48AM -0700, Dave Hansen wrote: > This allows for a tiny optimization of Andy's that I realize I must have > blown away at some point. It lets us do a 32-bit-register instruction > (and using %eXX) when checking KAISER_SWITCH_MASK instead of a 64-bit > register via %rXX. > > I don't feel strongly about maintaining that optimization it looks weird > and surely doesn't actually do much. Yeah, and consistent syntax would probably bring more. > Thanks for catching that. We can kill one of these. I'm inclined to > kill the first one. Looking at the second one since we've just saved > off ptregs, that should make %rdi safe to clobber without the push/pop > at all. > > Does that seem like it would work? Yap, sounds about right. Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org