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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50A04C433EF for ; Sat, 14 May 2022 08:37:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B699A8D0001; Sat, 14 May 2022 04:37:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B17196B0078; Sat, 14 May 2022 04:37:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A06408D0001; Sat, 14 May 2022 04:37:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 937946B0075 for ; Sat, 14 May 2022 04:37:57 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 6F66FBB5 for ; Sat, 14 May 2022 08:37:57 +0000 (UTC) X-FDA: 79463695794.04.0438F6D Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by imf14.hostedemail.com (Postfix) with ESMTP id 8F3C61000BB for ; Sat, 14 May 2022 08:37:54 +0000 (UTC) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1652517475; 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=l6e1jTkAbidYEYkvtAlwySzul8HD/CSNOuCA4PYjeMA=; b=GqntqGTEYbeXboqHBKQtbKbNZor6WVvmvezaJ9tHWBUr5KzMyrNdMMDfnYFs7ydZeqfBqF uz5jOfOiRiRTXQu6xWsgm9xqxxsDFJLPfJD4Bsd5fX4jhAWXpZvHLelYrQ56Q9oL5NA4j2 4mR+2vREQALY3cLjbEjXWFX8XMmDyP1xcaIGPqgtXn+wIPa12xFxccGe/JNaXtsD+IX2zI UoahGfHQFN1A9YgqYQw56u4/Z+1KBRdVax0hRuwfXzKaXm+rt1AzJMBVui+P3gDsW9DqnW 49JEkXxKPdQmoER1Tif0JRzez4tefe16yvFnjttzRw3bZrRDoe5agsIVraEzzA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1652517475; 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=l6e1jTkAbidYEYkvtAlwySzul8HD/CSNOuCA4PYjeMA=; b=7S01T5JIx2GvRHvdFB0JVC0zNy9JSJDffIBBolmfNTszaX9PlAuHsIiStajOqQTkImV4VY Mj/sry6jcYL77ZAw== To: "Kirill A. Shutemov" Cc: Dave Hansen , Andy Lutomirski , Peter Zijlstra , x86@kernel.org, Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , "H . J . Lu" , Andi Kleen , Rick Edgecombe , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFCv2 08/10] x86/mm: Make LAM_U48 and mappings above 47-bits mutually exclusive In-Reply-To: <20220513232242.7ac7herw7iyfkd2h@black.fi.intel.com> References: <20220511022751.65540-1-kirill.shutemov@linux.intel.com> <20220511022751.65540-10-kirill.shutemov@linux.intel.com> <875ymax480.ffs@tglx> <20220513232242.7ac7herw7iyfkd2h@black.fi.intel.com> Date: Sat, 14 May 2022 10:37:55 +0200 Message-ID: <87h75sse58.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: 8F3C61000BB X-Stat-Signature: jcr4ojtnczj48bs4qi8pcu7zaxy4kx8r X-Rspam-User: Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=linutronix.de header.s=2020 header.b=GqntqGTE; dkim=pass header.d=linutronix.de header.s=2020e header.b=7S01T5JI; spf=pass (imf14.hostedemail.com: domain of tglx@linutronix.de designates 193.142.43.55 as permitted sender) smtp.mailfrom=tglx@linutronix.de; dmarc=pass (policy=none) header.from=linutronix.de X-Rspamd-Server: rspam09 X-HE-Tag: 1652517474-72745 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, May 14 2022 at 02:22, Kirill A. Shutemov wrote: > On Thu, May 12, 2022 at 03:36:31PM +0200, Thomas Gleixner wrote: >> On Wed, May 11 2022 at 05:27, Kirill A. Shutemov wrote: >> > LAM_U48 steals bits above 47-bit for tags and makes it impossible for >> > userspace to use full address space on 5-level paging machine. >> >> > Make these features mutually exclusive: whichever gets enabled first >> > blocks the othe one. >> >> So this patch prevents a mapping above 47bit when LAM48 is enabled, but >> I fail to spot how an already existing mapping above 47bit would prevent >> LAM48 from being enabled. >> >> Maybe I'm missing something which makes this magically mutually >> exclusive. > > It is in 09/10. See lam_u48_allowed() Sure, but that makes this changelog not any more correct.