From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54473) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eqF2U-0007I9-Rh for qemu-devel@nongnu.org; Mon, 26 Feb 2018 04:25:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eqF2Q-00082X-Su for qemu-devel@nongnu.org; Mon, 26 Feb 2018 04:25:42 -0500 References: <20180223173657.29125-1-david@redhat.com> From: David Hildenbrand Message-ID: <19e19b72-ac67-8210-345b-41431f7d2075@redhat.com> Date: Mon, 26 Feb 2018 10:25:19 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v1] numa: s390x has no NUMA List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Christian Borntraeger , qemu-s390x@nongnu.org Cc: qemu-devel@nongnu.org, Eduardo Habkost , Cornelia Huck On 26.02.2018 10:20, Christian Borntraeger wrote: > > > On 02/23/2018 06:36 PM, David Hildenbrand wrote: >> Right now it is possible to crash QEMU for s390x by providing e.g. >> -numa node,nodeid=0,cpus=0-1 >> >> Problem is, that numa.c uses mc->cpu_index_to_instance_props as an >> indicator whether NUMA is supported by a machine type. We don't >> implement NUMA on s390x (and that concept also doesn't really exist). >> We need mc->cpu_index_to_instance_props for query-cpus. > > Looks like we assert because of > machine->possible_cpus == 0. > > Later during boot this is created in s390_possible_cpu_arch_ids. (via > s390_init_cpus). What we (in the future) actually could provide is a > cpu topology. > > So something like this also fixes the bug Yes, but I decided to not go this way because we don't support NUMA as of now. -numa has to bail out (just as it did before I implemented proper query-cpus support). What you propose is something for future support - one we have cpu topology information exposed. -- Thanks, David / dhildenb