From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58973) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zo7mL-0004vV-Br for qemu-devel@nongnu.org; Mon, 19 Oct 2015 06:35:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zo7mF-00056T-3I for qemu-devel@nongnu.org; Mon, 19 Oct 2015 06:34:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51343) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zo7mE-00056B-VY for qemu-devel@nongnu.org; Mon, 19 Oct 2015 06:34:51 -0400 Date: Mon, 19 Oct 2015 13:34:46 +0300 From: "Michael S. Tsirkin" Message-ID: <20151019133311-mutt-send-email-mst@redhat.com> References: <1444535584-18220-1-git-send-email-guangrong.xiao@linux.intel.com> <1444535584-18220-23-git-send-email-guangrong.xiao@linux.intel.com> <20151019095612-mutt-send-email-mst@redhat.com> <56249B59.1040103@linux.intel.com> <20151019103754-mutt-send-email-mst@redhat.com> <56249F4D.10709@linux.intel.com> <20151019121707-mutt-send-email-mst@redhat.com> <20151019114635.510b031c@igors-macbook-pro.local> <5624BF6D.8060509@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5624BF6D.8060509@linux.intel.com> Subject: Re: [Qemu-devel] [PATCH v3 22/32] nvdimm: init the address region used by NVDIMM ACPI List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Xiao Guangrong Cc: ehabkost@redhat.com, kvm@vger.kernel.org, gleb@kernel.org, mtosatti@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, pbonzini@redhat.com, Igor Mammedov , dan.j.williams@intel.com, rth@twiddle.net On Mon, Oct 19, 2015 at 06:01:17PM +0800, Xiao Guangrong wrote: > > > On 10/19/2015 05:46 PM, Igor Mammedov wrote: > >On Mon, 19 Oct 2015 12:17:22 +0300 > >"Michael S. Tsirkin" wrote: > > > >>On Mon, Oct 19, 2015 at 03:44:13PM +0800, Xiao Guangrong wrote: > >>> > >>> > >>>On 10/19/2015 03:39 PM, Michael S. Tsirkin wrote: > >>>>On Mon, Oct 19, 2015 at 03:27:21PM +0800, Xiao Guangrong wrote: > >>>>>>>+ nvdimm_init_memory_state(&pcms->nvdimm_memory, > >>>>>>>system_memory, machine, > >>>>>>>+ TARGET_PAGE_SIZE); > >>>>>>>+ > >>>>>> > >>>>>>Shouldn't this be conditional on presence of the nvdimm device? > >>>>>> > >>>>> > >>>>>We will enable hotplug on nvdimm devices in the near future once > >>>>>Linux driver is ready. I'd keep it here for future development. > >>>> > >>>>No, I don't think we should add stuff unconditionally. If not > >>>>nvdimm, some other flag should indicate user intends to hotplug > >>>>things. > >>>> > >>> > >>>Actually, it is not unconditionally which is called if parameter > >>>"-m aaa, maxmem=bbb" (aaa < bbb) is used. It is on the some path of > >>>memoy-hotplug initiation. > >>> > >> > >>Right, but that's not the same as nvdimm. > >> > > > >it could be pc-machine property, then it could be turned on like this: > > -machine nvdimm_support=on > > Er, I do not understand why this separate switch is needed and why nvdimm > and pc-dimm is different. :( > > NVDIMM reuses memory-hotplug's framework, such as maxmem, slot, and dimm > device, even some of ACPI logic to do hotplug things, etc. Both nvdimm > and pc-dimm are built on the same infrastructure. > > > > It does seem to add a bunch of devices in ACPI and memory regions in memory space. Whatever your device is, it's generally safe to assume that most people don't need it. -- MST