From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mgwym01.jp.fujitsu.com (mgwym01.jp.fujitsu.com [211.128.242.40]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 46201207E36C1 for ; Tue, 22 May 2018 22:08:53 -0700 (PDT) Received: from m3050.s.css.fujitsu.com (msm.b.css.fujitsu.com [10.134.21.208]) by yt-mxauth.gw.nic.fujitsu.com (Postfix) with ESMTP id 4ECA9AC00FF for ; Wed, 23 May 2018 14:08:45 +0900 (JST) Date: Wed, 23 May 2018 14:08:12 +0900 From: Yasunori Goto Subject: Questions about vNVDIMM on qemu/KVM Message-Id: <20180523140809.622F.E1E9C6FF@jp.fujitsu.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: qemu-devel@nongnu.org Cc: NVDIMM-ML List-ID: Hello, I'm investigating status of vNVDIMM on qemu/KVM, and I have some questions about it. I'm glad if anyone answer them. In my understanding, qemu/KVM has a feature to show NFIT for guest, and it will be still updated about platform capability with this patch set. https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg04756.html And libvirt also supports this feature with https://libvirt.org/formatdomain.html#elementsMemory However, virtio-pmem is developing now, and it is better for archtectures to detect regions of NVDIMM without ACPI (like s390x) In addition, It is also necessary to flush guest contents on vNVDIMM who has a backend-file. Q1) Does ACPI.NFIT bus of qemu/kvm remain with virtio-pmem? How do each roles become it if both NFIT and virtio-pmem will be available? If my understanding is correct, both NFIT and virtio-pmem is used to detect vNVDIMM regions, but only one seems to be necessary.... Otherwize, is the NFIT bus just for keeping compatibility, and virtio-pmem is promising way? Q2) What bus is(will be?) created for virtio-pmem? I could confirm the bus of NFIT is created with , and I heard other bus will be created for virtio-pmem, but I could not find what bus is created concretely. --- # ndctl list -B { "provider":"ACPI.NFIT", "dev":"ndbus0" } --- I think it affects what operations user will be able to, and what notification is necessary for vNVDIMM. ACPI defines some operations like namespace controll, and notification for NVDIMM health status or others. (I suppose that other status notification might be necessary for vNVDIMM, but I'm not sure yet...) If my understanding is wrong, please correct me. Thanks, --- Yasunori Goto _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm