From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f70.google.com (mail-pg0-f70.google.com [74.125.83.70]) by kanga.kvack.org (Postfix) with ESMTP id EF4C96B026F for ; Wed, 22 Nov 2017 17:54:33 -0500 (EST) Received: by mail-pg0-f70.google.com with SMTP id i123so17502969pgd.2 for ; Wed, 22 Nov 2017 14:54:33 -0800 (PST) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTPS id a12si14533633pls.398.2017.11.22.14.54.32 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 Nov 2017 14:54:32 -0800 (PST) Subject: Re: [PATCH 08/30] x86, kaiser: unmap kernel from userspace page tables (core patch) References: <20171110193058.BECA7D88@viggo.jf.intel.com> <20171110193112.6A962D6A@viggo.jf.intel.com> From: Dave Hansen Message-ID: <63daa6c0-76de-ee67-6a77-fef601a22943@linux.intel.com> Date: Wed, 22 Nov 2017 14:54:29 -0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Thomas Gleixner Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, richard.fellner@student.tugraz.at, 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 11/20/2017 09:21 AM, Thomas Gleixner wrote: >> +page tables are switched to the full "kernel" copy. When the >> +system switches back to user mode, the user/shadow copy is used. >> + >> +The minimalistic kernel portion of the user page tables try to >> +map only what is needed to enter/exit the kernel such as the >> +entry/exit functions themselves and the interrupt descriptor >> +table (IDT). > s/try to// Actually, they do _aspire_ "to map only what is needed". But, there *is* some non-necessary cruft (like the first C function in an interrupt). So, removing this language actually makes the description less precise. -- 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