From patchwork Mon Sep 27 15:05:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 12520129 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3375BC433F5 for ; Mon, 27 Sep 2021 15:05:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DBB6A610A2 for ; Mon, 27 Sep 2021 15:05:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org DBB6A610A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 827F56B0074; Mon, 27 Sep 2021 11:05:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7D7386B0075; Mon, 27 Sep 2021 11:05:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 629C5900002; Mon, 27 Sep 2021 11:05:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0223.hostedemail.com [216.40.44.223]) by kanga.kvack.org (Postfix) with ESMTP id 552896B0074 for ; Mon, 27 Sep 2021 11:05:56 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0D20918026102 for ; Mon, 27 Sep 2021 15:05:56 +0000 (UTC) X-FDA: 78633678312.10.483614D Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by imf22.hostedemail.com (Postfix) with ESMTP id B08681905 for ; Mon, 27 Sep 2021 15:05:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632755155; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IXtVRZZ4VG4VKdaLmU64Y/xSRw+uB9sGtv3RuAELTns=; b=Twt5GQuCOjknXBEJ2CGl8UtE9rt16nF1FaCxkrpHuZWFdKcpkaeX9L9Yajox+Vsh2XWGyo jHFTTT9DbuGI1nbZ/ABu8p78YDxTljBcXDDLBzSZCzaYEb2gcbjA2+6Hu36XeQjq5JuiMZ t4U7Q84gXM/6aEPinUW4InfbUUMgejk= 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-155-3Qz6qLwMMqC7uaL1kAt7pg-1; Mon, 27 Sep 2021 11:05:53 -0400 X-MC-Unique: 3Qz6qLwMMqC7uaL1kAt7pg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DE18A1926DB4; Mon, 27 Sep 2021 15:05:50 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.193.71]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9015060C17; Mon, 27 Sep 2021 15:05:46 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: David Hildenbrand , Andrew Morton , Mike Rapoport , Michal Hocko , Oscar Salvador , Jianyong Wu , "Aneesh Kumar K . V" , Vineet Gupta , Geert Uytterhoeven , Huacai Chen , Jiaxun Yang , Thomas Bogendoerfer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Eric Biederman , Arnd Bergmann , linux-snps-arc@lists.infradead.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-s390@vger.kernel.org, linux-mm@kvack.org, kexec@lists.infradead.org Subject: [PATCH v1 3/4] memblock: add MEMBLOCK_DRIVER_MANAGED to mimic IORESOURCE_SYSRAM_DRIVER_MANAGED Date: Mon, 27 Sep 2021 17:05:17 +0200 Message-Id: <20210927150518.8607-4-david@redhat.com> In-Reply-To: <20210927150518.8607-1-david@redhat.com> References: <20210927150518.8607-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: B08681905 X-Stat-Signature: rsac86xuo414zse7j78pts7fjpiaotyz Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Twt5GQuC; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf22.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 216.205.24.124) smtp.mailfrom=david@redhat.com X-HE-Tag: 1632755155-981159 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: Let's add a flag that corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED. Similar to MEMBLOCK_HOTPLUG, most infrastructure has to treat such memory like ordinary MEMBLOCK_NONE memory -- for example, when selecting memory regions to add to the vmcore for dumping in the crashkernel via for_each_mem_range(). However, especially kexec_file is not supposed to select such memblocks via for_each_free_mem_range() / for_each_free_mem_range_reverse() to place kexec images, similar to how we handle IORESOURCE_SYSRAM_DRIVER_MANAGED without CONFIG_ARCH_KEEP_MEMBLOCK. Let's document why kexec_walk_memblock() won't try placing images on areas marked MEMBLOCK_DRIVER_MANAGED -- similar to IORESOURCE_SYSRAM_DRIVER_MANAGED handling in locate_mem_hole_callback() via kexec_walk_resources(). We'll make sure that memory hotplug code sets the flag where applicable (IORESOURCE_SYSRAM_DRIVER_MANAGED) next. This prepares architectures that need CONFIG_ARCH_KEEP_MEMBLOCK, such as arm64, for virtio-mem support. Signed-off-by: David Hildenbrand --- include/linux/memblock.h | 16 ++++++++++++++-- kernel/kexec_file.c | 5 +++++ mm/memblock.c | 4 ++++ 3 files changed, 23 insertions(+), 2 deletions(-) diff --git a/include/linux/memblock.h b/include/linux/memblock.h index b49a58f621bc..7d8d656d5082 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -33,12 +33,17 @@ extern unsigned long long max_possible_pfn; * @MEMBLOCK_NOMAP: don't add to kernel direct mapping and treat as * reserved in the memory map; refer to memblock_mark_nomap() description * for further details + * @MEMBLOCK_DRIVER_MANAGED: memory region that is always detected via a driver, + * corresponding to IORESOURCE_SYSRAM_DRIVER_MANAGED in the kernel resource + * tree. Especially kexec should never use this memory for placing images and + * shouldn't expose this memory to the second kernel. */ enum memblock_flags { MEMBLOCK_NONE = 0x0, /* No special request */ MEMBLOCK_HOTPLUG = 0x1, /* hotpluggable region */ MEMBLOCK_MIRROR = 0x2, /* mirrored region */ MEMBLOCK_NOMAP = 0x4, /* don't add to kernel direct mapping */ + MEMBLOCK_DRIVER_MANAGED = 0x8, /* always detected via a driver */ }; /** @@ -209,7 +214,8 @@ static inline void __next_physmem_range(u64 *idx, struct memblock_type *type, */ #define for_each_mem_range(i, p_start, p_end) \ __for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, \ - MEMBLOCK_HOTPLUG, p_start, p_end, NULL) + MEMBLOCK_HOTPLUG | MEMBLOCK_DRIVER_MANAGED, \ + p_start, p_end, NULL) /** * for_each_mem_range_rev - reverse iterate through memblock areas from @@ -220,7 +226,8 @@ static inline void __next_physmem_range(u64 *idx, struct memblock_type *type, */ #define for_each_mem_range_rev(i, p_start, p_end) \ __for_each_mem_range_rev(i, &memblock.memory, NULL, NUMA_NO_NODE, \ - MEMBLOCK_HOTPLUG, p_start, p_end, NULL) + MEMBLOCK_HOTPLUG | MEMBLOCK_DRIVER_MANAGED,\ + p_start, p_end, NULL) /** * for_each_reserved_mem_range - iterate over all reserved memblock areas @@ -250,6 +257,11 @@ static inline bool memblock_is_nomap(struct memblock_region *m) return m->flags & MEMBLOCK_NOMAP; } +static inline bool memblock_is_driver_managed(struct memblock_region *m) +{ + return m->flags & MEMBLOCK_DRIVER_MANAGED; +} + int memblock_search_pfn_nid(unsigned long pfn, unsigned long *start_pfn, unsigned long *end_pfn); void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn, diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 33400ff051a8..8347fc158d2b 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -556,6 +556,11 @@ static int kexec_walk_memblock(struct kexec_buf *kbuf, if (kbuf->image->type == KEXEC_TYPE_CRASH) return func(&crashk_res, kbuf); + /* + * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See + * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in + * locate_mem_hole_callback(). + */ if (kbuf->top_down) { for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE, &mstart, &mend, NULL) { diff --git a/mm/memblock.c b/mm/memblock.c index 47a56b223141..540a35317fb0 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -979,6 +979,10 @@ static bool should_skip_region(struct memblock_type *type, if (!(flags & MEMBLOCK_NOMAP) && memblock_is_nomap(m)) return true; + /* skip driver-managed memory unless we were asked for it explicitly */ + if (!(flags & MEMBLOCK_DRIVER_MANAGED) && memblock_is_driver_managed(m)) + return true; + return false; }