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 D83FDC433FE for ; Mon, 21 Nov 2022 19:45:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231483AbiKUTpR (ORCPT ); Mon, 21 Nov 2022 14:45:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229501AbiKUTpQ (ORCPT ); Mon, 21 Nov 2022 14:45:16 -0500 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9D03C76A0; Mon, 21 Nov 2022 11:45:15 -0800 (PST) Received: from zn.tnic (p200300ea9733e725329c23fffea6a903.dip0.t-ipconnect.de [IPv6:2003:ea:9733:e725:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 1D7071EC03EA; Mon, 21 Nov 2022 20:45:14 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1669059914; 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: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=P5b4SWEpwjdHbs/SaEnye+cahlzdG2kmJ0e9jMb+r2g=; b=Hz5c9OWHGhKRkyTmVzuAfPJFyiaBTj+VZZ3OGJhdc9XkaxCu4vpc31EVCIYsCPfNZfVrYd SFHZv45DG4dfpvL57diwCak69jxSyHAuAk0AaX0/cl+i/fym7Dc0ipCRSFWzl3qMwi/fY5 tnAdZjL9Js8BPlHA3bg7m21jURO6bQ0= Date: Mon, 21 Nov 2022 20:45:10 +0100 From: Borislav Petkov To: "Michael Kelley (LINUX)" Cc: "hpa@zytor.com" , KY Srinivasan , Haiyang Zhang , "wei.liu@kernel.org" , Dexuan Cui , "luto@kernel.org" , "peterz@infradead.org" , "davem@davemloft.net" , "edumazet@google.com" , "kuba@kernel.org" , "pabeni@redhat.com" , "lpieralisi@kernel.org" , "robh@kernel.org" , "kw@linux.com" , "bhelgaas@google.com" , "arnd@arndb.de" , "hch@infradead.org" , "m.szyprowski@samsung.com" , "robin.murphy@arm.com" , "thomas.lendacky@amd.com" , "brijesh.singh@amd.com" , "tglx@linutronix.de" , "mingo@redhat.com" , "dave.hansen@linux.intel.com" , Tianyu Lan , "kirill.shutemov@linux.intel.com" , "sathyanarayanan.kuppuswamy@linux.intel.com" , "ak@linux.intel.com" , "isaku.yamahata@intel.com" , "Williams, Dan J" , "jane.chu@oracle.com" , "seanjc@google.com" , "tony.luck@intel.com" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "linux-hyperv@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-pci@vger.kernel.org" , "linux-arch@vger.kernel.org" , "iommu@lists.linux.dev" Subject: Re: [Patch v3 01/14] x86/ioremap: Fix page aligned size calculation in __ioremap_caller() Message-ID: References: <1668624097-14884-1-git-send-email-mikelley@microsoft.com> <1668624097-14884-2-git-send-email-mikelley@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Mon, Nov 21, 2022 at 04:40:16PM +0000, Michael Kelley (LINUX) wrote: > As discussed in a parallel thread [1], the incorrect code here doesn't have > any real impact in already released Linux kernels. It only affects the > transition that my patch series implements to change the way vTOM > is handled. Are you sure? PHYSICAL_PAGE_MASK is controlled by __PHYSICAL_MASK which is determined by CONFIG_DYNAMIC_PHYSICAL_MASK and __PHYSICAL_MASK_SHIFT which all differ depending on configurations and also dynamic. It is probably still ok, in probably all possible cases even though I wouldn't bet on it. And this fix is simple and all clear so lemme ask it differently: what would be any downsides in backporting it to stable, just in case? > I don't know what the tradeoffs are for backporting a fix that doesn't solve > a real problem vs. just letting it be. Every backport carries some overhead > in the process Have you seen the deluge of stable fixes? :-) > and there's always a non-zero risk of breaking something. I don't see how this one would cause any breakage... > I've leaned away from adding the "Fixes:" tag in such cases. But if > it's better to go ahead and add the "Fixes:" tag for what's only a > theoretical problem, I'm OK with doing so. I think this is a good to have fix anyway as it is Obviously Correct(tm). Unless you have any reservations you haven't shared yet... > [1] https://lkml.org/lkml/2022/11/11/1348 Btw, the proper way to reference to a mail message now is simply to do: https://lore.kernel.org/r/ as long as it has been posted on some ML which lore archives. And I think it archives all. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette