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bh=z6Q72O726VvpueMtyVLYMyFL2oyboTiE5pP86t/3D3U=; b=gBNJCOFad4SQ6c9REnC0zRa/fGiLFuUeA/if/D+l4KplpZzQpbl+u1DMZM7kRkacJlcSyV DIu3XGZ3YJ28yUCct4geNgpLmAUaapUs77PtfjZCIgQsZZgPPUQxbmnnVnPIfJvTnQOKNY GBBFItLqGz8X9I+2NM4g8OI6iprPJCA= 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-493-UVW6FRJSMT6h7GZGg_IOUw-1; Wed, 02 Jun 2021 22:47:10 -0400 X-MC-Unique: UVW6FRJSMT6h7GZGg_IOUw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3AB4F80DE00; Thu, 3 Jun 2021 02:47:09 +0000 (UTC) Received: from [10.64.54.205] (vpn2-54-205.bne.redhat.com [10.64.54.205]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 93A4F1037EBF; Thu, 3 Jun 2021 02:47:00 +0000 (UTC) Subject: Re: [PATCH] hw/arm/boot: Use NUMA node ID in memory node name To: Andrew Jones References: <20210601073004.106490-1-gshan@redhat.com> <20210601075045.ppmceogd5hp5rqcf@gator.home> <20210602113642.axaxxgnw2haghas4@gator.home> From: Gavin Shan Message-ID: <493194a5-bf72-de17-8de9-4b3556a011be@redhat.com> Date: Thu, 3 Jun 2021 14:48:03 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: <20210602113642.axaxxgnw2haghas4@gator.home> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 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 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit 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: -37 X-Spam_score: -3.8 X-Spam_bar: --- X-Spam_report: (-3.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.371, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.613, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: , Reply-To: Gavin Shan Cc: peter.maydell@linaro.org, qemu-arm@nongnu.org, qemu-devel@nongnu.org, shan.gavin@gmail.com, eric.auger@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Drew, On 6/2/21 9:36 PM, Andrew Jones wrote: > On Wed, Jun 02, 2021 at 11:09:32AM +1000, Gavin Shan wrote: >> On 6/1/21 5:50 PM, Andrew Jones wrote: >>> On Tue, Jun 01, 2021 at 03:30:04PM +0800, Gavin Shan wrote: >>>> We possibly populate empty nodes where memory isn't included and might >>>> be hot added at late time. The FDT memory nodes can't be created due >>>> to conflicts on their names if multiple empty nodes are specified. >>>> For example, the VM fails to start with the following error messages. >>>> >>>> /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,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 \ >>>> : >>>> -device virtio-balloon-pci,id=balloon0,free-page-reporting=yes >>>> >>>> qemu-system-aarch64: FDT: Failed to create subnode /memory@80000000: \ >>>> FDT_ERR_EXISTS >>>> >>>> This fixes the issue by using NUMA node ID or zero in the memory node >>>> name to avoid the conflicting memory node names. With this applied, the >>>> VM can boot successfully with above command lines. >>>> >>>> Signed-off-by: Gavin Shan >>>> --- >>>> hw/arm/boot.c | 7 ++++++- >>>> 1 file changed, 6 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/hw/arm/boot.c b/hw/arm/boot.c >>>> index d7b059225e..3169bdf595 100644 >>>> --- a/hw/arm/boot.c >>>> +++ b/hw/arm/boot.c >>>> @@ -432,7 +432,12 @@ static int fdt_add_memory_node(void *fdt, uint32_t acells, hwaddr mem_base, >>>> char *nodename; >>>> int ret; >>>> - nodename = g_strdup_printf("/memory@%" PRIx64, mem_base); >>>> + if (numa_node_id >= 0) { >>>> + nodename = g_strdup_printf("/memory@%d", numa_node_id); >>>> + } else { >>>> + nodename = g_strdup("/memory@0"); >>>> + } >>>> + >>>> qemu_fdt_add_subnode(fdt, nodename); >>>> qemu_fdt_setprop_string(fdt, nodename, "device_type", "memory"); >>>> ret = qemu_fdt_setprop_sized_cells(fdt, nodename, "reg", acells, mem_base, >> >> [...] >> >>> >>> Is it conventional to use the unit-address like this? If so, can you point >>> out where that's documented? If it's not conventional, then we shouldn't >>> do it. And then I'm not sure what we should do in this case. Here's a >>> couple links I found, but they don't really help... >>> >>> https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#sect-node-names >>> https://devicetree-specification.readthedocs.io/en/latest/chapter3-devicenodes.html#memory-node >>> >> >> As stated in the document (section 2.2.1.1). It's conventional to take the first >> address of 'reg' property as unit-address, but it's not mandatory as I understand: >> >> (1) In section 2.2.1.1, the bus can specify additional format to unit-address. > > The bus type we're using is the physical memory map. Does it allow this > use of the unit-address? I still haven't seen that documented anywhere. > >> (2) The device node name isn't used to identify the device node in Linux kernel. >> They are actually identified by 'device_type' property. >> (drivers/of/fdt.c::early_init_dt_scan_memory()) > > This doesn't matter. We can't change DT node name formats just because > they may not impact Linux. We need to follow the DT standard and the Linux > convention. > >> >> I think it's still nice to include the unit-address in meory node's name. For the >> conflicting nodes, we add more suffix like below. I can update the code in v2 if >> it's preferred way to go. > > I don't think we should change the semantics of the unit address at all, > not without either a) finding a document that says our use is OK or b) > getting it documented in the Linux kernel first. > [...] I've sent one separate mail to check with Rob Herring. Hopefully he have ideas as he is maintaining linux FDT subsystem. You have been included to that thread. I didn't find something meaningful to this thread after doing some google search either. Yes, I agree with you we need to follow the specification strictly. It seems it's uncertain about the 'physical memory map' bus binding requirements. Thanks, Gavin