From patchwork Thu Apr 30 10:29:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 11519817 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B9F431392 for ; Thu, 30 Apr 2020 10:31:14 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9700B20838 for ; Thu, 30 Apr 2020 10:31:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JgnBcs7K" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9700B20838 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jU6S7-0006F8-0t; Thu, 30 Apr 2020 10:29:59 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jU6S6-0006Ex-Ax for xen-devel@lists.xenproject.org; Thu, 30 Apr 2020 10:29:58 +0000 X-Inumbo-ID: 882ef636-8acd-11ea-b07b-bc764e2007e4 Received: from us-smtp-delivery-1.mimecast.com (unknown [207.211.31.81]) by us1-rack-iad1.inumbo.com (Halon) with ESMTP id 882ef636-8acd-11ea-b07b-bc764e2007e4; Thu, 30 Apr 2020 10:29:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588242594; 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=cBxdneYzv1oFt6rUtmxHP8L8tmn6FMG5Rn0MO+hCbf0=; b=JgnBcs7KbVtrO7Y5XfXBFfSQ+NrjRi8mdy5Cr5AYJ+OR4F9XWVZhy+DVTG3KrWbLdA9f/W AE5Ax6d9xrMiHXyk++HbDJzk88SljTr7qQpELHA22vggLAR1Z5u6neaCXRulDFOFU0OktS bNjc7fOsnXDTZ/hgIM25m0vmQuSgup8= 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-323-ZkDsTUQ-OxW7sjqOoV_anw-1; Thu, 30 Apr 2020 06:29:51 -0400 X-MC-Unique: ZkDsTUQ-OxW7sjqOoV_anw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 920BB45F; Thu, 30 Apr 2020 10:29:49 +0000 (UTC) Received: from t480s.redhat.com (ovpn-113-172.ams2.redhat.com [10.36.113.172]) by smtp.corp.redhat.com (Postfix) with ESMTP id B43035EDEB; Thu, 30 Apr 2020 10:29:40 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Subject: [PATCH v2 2/3] mm/memory_hotplug: Introduce MHP_NO_FIRMWARE_MEMMAP Date: Thu, 30 Apr 2020 12:29:07 +0200 Message-Id: <20200430102908.10107-3-david@redhat.com> In-Reply-To: <20200430102908.10107-1-david@redhat.com> References: <20200430102908.10107-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: virtio-dev@lists.oasis-open.org, linux-hyperv@vger.kernel.org, Michal Hocko , linux-acpi@vger.kernel.org, Baoquan He , linux-nvdimm@lists.01.org, linux-s390@vger.kernel.org, "Michael S . Tsirkin" , David Hildenbrand , virtualization@lists.linux-foundation.org, linux-mm@kvack.org, Wei Yang , Eric Biederman , Pankaj Gupta , xen-devel@lists.xenproject.org, Andrew Morton , Michal Hocko , linuxppc-dev@lists.ozlabs.org Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Some devices/drivers that add memory via add_memory() and friends (e.g., dax/kmem, but also virtio-mem in the future) don't want to create entries in /sys/firmware/memmap/ - primarily to hinder kexec from adding this memory to the boot memmap of the kexec kernel. In fact, such memory is never exposed via the firmware memmap as System RAM (e.g., e820), so exposing this memory via /sys/firmware/memmap/ is wrong: "kexec needs the raw firmware-provided memory map to setup the parameter segment of the kernel that should be booted with kexec. Also, the raw memory map is useful for debugging. For that reason, /sys/firmware/memmap is an interface that provides the raw memory map to userspace." [1] We don't have to worry about firmware_map_remove() on the removal path. If there is no entry, it will simply return with -EINVAL. [1] https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-firmware-memmap Cc: Andrew Morton Cc: Michal Hocko Cc: Pankaj Gupta Cc: Wei Yang Cc: Baoquan He Cc: Eric Biederman Signed-off-by: David Hildenbrand Nacked-by: "Eric W. Biederman" --- include/linux/memory_hotplug.h | 8 ++++++++ mm/memory_hotplug.c | 3 ++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 0151fb935c09..4ca418a731eb 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -68,6 +68,14 @@ struct mhp_params { pgprot_t pgprot; }; +/* Flags used for add_memory() and friends. */ + +/* + * Don't create entries in /sys/firmware/memmap/. The memory is detected and + * added via a device driver, not via the initial (firmware) memmap. + */ +#define MHP_NO_FIRMWARE_MEMMAP 1 + /* * Zone resizing functions * diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index c01be92693e3..e94ede9cad00 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1062,7 +1062,8 @@ int __ref add_memory_resource(int nid, struct resource *res, BUG_ON(ret); /* create new memmap entry */ - firmware_map_add_hotplug(start, start + size, "System RAM"); + if (!(flags & MHP_NO_FIRMWARE_MEMMAP)) + firmware_map_add_hotplug(start, start + size, "System RAM"); /* device_online() will take the lock when calling online_pages() */ mem_hotplug_done();