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 X-Spam-Level: X-Spam-Status: No, score=-12.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C439BC433DB for ; Mon, 25 Jan 2021 09:28:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7E45722472 for ; Mon, 25 Jan 2021 09:28:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726231AbhAYJ2R (ORCPT ); Mon, 25 Jan 2021 04:28:17 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:30942 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726459AbhAYJXg (ORCPT ); Mon, 25 Jan 2021 04:23:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611566512; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WPpcHHNYXgb8EJ4YJpldIC3hqvZPXfcymLwe5bxkhOk=; b=eisSbQEBq2NSNBffHb66yGAmPBlLDgoDKyhY7EhXx/b43mF4TH/bp9C4CsHa1wNv3xxQAQ VGUdWVktNgxhdfj73SekkrILwfIPD4E3iFX1zKQdqTNIwcMJQustmIx5eI05cU6ALNAcip m56qYUKU6IEXRxDUEPpGH5Zhc737nw0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-495-N__rCvLEMJCQr_IHHUDkCg-1; Mon, 25 Jan 2021 04:21:47 -0500 X-MC-Unique: N__rCvLEMJCQr_IHHUDkCg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1142FBBEE8; Mon, 25 Jan 2021 09:21:45 +0000 (UTC) Received: from [10.36.115.13] (ovpn-115-13.ams2.redhat.com [10.36.115.13]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7B5EC5D9D7; Mon, 25 Jan 2021 09:21:42 +0000 (UTC) Subject: Re: [PATCH V4 1/4] mm/memory_hotplug: Prevalidate the address range being added with platform To: Anshuman Khandual , linux-mm@kvack.org, akpm@linux-foundation.org, hca@linux.ibm.com, catalin.marinas@arm.com Cc: Oscar Salvador , Vasily Gorbik , Will Deacon , Ard Biesheuvel , Mark Rutland , linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org References: <1611543532-18698-1-git-send-email-anshuman.khandual@arm.com> <1611543532-18698-2-git-send-email-anshuman.khandual@arm.com> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: Date: Mon, 25 Jan 2021 10:21:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <1611543532-18698-2-git-send-email-anshuman.khandual@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25.01.21 03:58, Anshuman Khandual wrote: > This introduces mhp_range_allowed() which can be called in various memory > hotplug paths to prevalidate the address range which is being added, with > the platform. Then mhp_range_allowed() calls mhp_get_pluggable_range() > which provides applicable address range depending on whether linear mapping > is required or not. For ranges that require linear mapping, it calls a new > arch callback arch_get_mappable_range() which the platform can override. So > the new callback, in turn provides the platform an opportunity to configure > acceptable memory hotplug address ranges in case there are constraints. > > This mechanism will help prevent platform specific errors deep down during > hotplug calls. This drops now redundant check_hotplug_memory_addressable() > check in __add_pages() but instead adds a VM_BUG_ON() check which would > ensure that the range has been validated with mhp_range_allowed() earlier > in the call chain. Besides mhp_get_pluggable_range() also can be used by > potential memory hotplug callers to avail the allowed physical range which > would go through on a given platform. > > This does not really add any new range check in generic memory hotplug but > instead compensates for lost checks in arch_add_memory() where applicable > and check_hotplug_memory_addressable(), with unified mhp_range_allowed(). > > Cc: David Hildenbrand > Cc: Andrew Morton > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > Reviewed-by: Oscar Salvador > Suggested-by: David Hildenbrand > Signed-off-by: Anshuman Khandual [...] > + > +struct range mhp_get_pluggable_range(bool need_mapping) > +{ > + const u64 max_phys = (1ULL << MAX_PHYSMEM_BITS) - 1; > + struct range mhp_range; > + > + if (need_mapping) { > + mhp_range = arch_get_mappable_range(); > + if (mhp_range.start > max_phys) { > + mhp_range.start = 0; > + mhp_range.end = 0; > + } > + mhp_range.end = min_t(u64, mhp_range.end, max_phys); > + } else { > + mhp_range.start = 0; > + mhp_range.end = max_phys; > + } > + return mhp_range; > +} > +EXPORT_SYMBOL_GPL(mhp_get_pluggable_range); Some people might prefer the EXPORT_SYMBOL_GPL() going to the actual user (patch #4), I don't care :) Thanks! Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb