From patchwork Fri Oct 15 12:42:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 12561397 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 12552C433F5 for ; Fri, 15 Oct 2021 12:47:47 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 B5E8260ED4 for ; Fri, 15 Oct 2021 12:47:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org B5E8260ED4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:51164 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mbMcj-0007Rw-Qj for qemu-devel@archiver.kernel.org; Fri, 15 Oct 2021 08:47:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56146) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mbMYl-0004K0-9B for qemu-devel@nongnu.org; Fri, 15 Oct 2021 08:43:43 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:59002) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mbMYe-0007NN-38 for qemu-devel@nongnu.org; Fri, 15 Oct 2021 08:43:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634301810; 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; bh=Y3CQLFRSmnzmNpDgdTSL8MqMr3tL+HLcQJ58HgW7YXA=; b=Oo96yPICKI5kqH/tNds20VfAreJ6ZfIMjkpgkDuPUHmXtD9QNM9gpIGqrA+jYDZfqfsOfn H2b44R21zETfKU+UiaEjhzZlybSNrQI44sVBXay6XNnlJN1+EQc1VCYd/ImaGoM4gzqDyt bQeR7cgdUwTac9s8zQA0If2n/AhLHso= 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-469-PKjm2rPxOsWDrCTjFhyR-A-1; Fri, 15 Oct 2021 08:43:27 -0400 X-MC-Unique: PKjm2rPxOsWDrCTjFhyR-A-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 59FEC10A8E00; Fri, 15 Oct 2021 12:43:26 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-38.bne.redhat.com [10.64.54.38]) by smtp.corp.redhat.com (Postfix) with ESMTP id D297A196E5; Fri, 15 Oct 2021 12:42:50 +0000 (UTC) From: Gavin Shan To: qemu-arm@nongnu.org Subject: [PATCH v5] hw/arm/virt: Don't create device-tree node for empty NUMA node Date: Fri, 15 Oct 2021 20:42:46 +0800 Message-Id: <20211015124246.23073-1-gshan@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=gshan@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=216.205.24.124; envelope-from=gshan@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.049, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: robh@kernel.org, drjones@redhat.com, qemu-riscv@nongnu.org, ehabkost@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org, shan.gavin@gmail.com, imammedo@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The empty NUMA node, where no memory resides, are allowed. For example, the following command line specifies two empty NUMA nodes. With this, QEMU fails to boot because of the conflicting device-tree node names, as the following error message indicates. /home/gavin/sandbox/qemu.main/build/qemu-system-aarch64 \ -accel kvm -machine virt,gic-version=host \ -cpu host -smp 4,sockets=2,cores=2,threads=1 \ -m 1024M,slots=16,maxmem=64G \ -object memory-backend-ram,id=mem0,size=512M \ -object memory-backend-ram,id=mem1,size=512M \ -numa node,nodeid=0,cpus=0-1,memdev=mem0 \ -numa node,nodeid=1,cpus=2-3,memdev=mem1 \ -numa node,nodeid=2 \ -numa node,nodeid=3 : qemu-system-aarch64: FDT: Failed to create subnode /memory@80000000: FDT_ERR_EXISTS As specified by linux device-tree binding document, the device-tree nodes for these empty NUMA nodes shouldn't be generated. However, the corresponding NUMA node IDs should be included in the distance map. The memory hotplug through device-tree on ARM64 isn't existing so far and it's not necessary to require the user to provide a distance map. Furthermore, the default distance map Linux generates may even be sufficient. So this simply skips populating the device-tree nodes for these empty NUMA nodes to avoid the error, so that QEMU can be started successfully. Signed-off-by: Gavin Shan Reviewed-by: Andrew Jones --- v5: Improved commit log and comments as Drew suggested. --- hw/arm/boot.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/hw/arm/boot.c b/hw/arm/boot.c index 57efb61ee4..74ad397b1f 100644 --- a/hw/arm/boot.c +++ b/hw/arm/boot.c @@ -599,10 +599,23 @@ int arm_load_dtb(hwaddr addr, const struct arm_boot_info *binfo, } g_strfreev(node_path); + /* + * We drop all the memory nodes which correspond to empty NUMA nodes + * from the device tree, because the Linux NUMA binding document + * states they should not be generated. Linux will get the NUMA node + * IDs of the empty NUMA nodes from the distance map if they are needed. + * This means QEMU users may be obliged to provide command lines which + * configure distance maps when the empty NUMA node IDs are needed and + * Linux's default distance map isn't sufficient. + */ if (ms->numa_state != NULL && ms->numa_state->num_nodes > 0) { mem_base = binfo->loader_start; for (i = 0; i < ms->numa_state->num_nodes; i++) { mem_len = ms->numa_state->nodes[i].node_mem; + if (!mem_len) { + continue; + } + rc = fdt_add_memory_node(fdt, acells, mem_base, scells, mem_len, i); if (rc < 0) {