From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41335) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VktuJ-0006mx-3G for qemu-devel@nongnu.org; Mon, 25 Nov 2013 06:00:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VktuC-0002EO-Ik for qemu-devel@nongnu.org; Mon, 25 Nov 2013 06:00:46 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42780) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VktuB-0002EB-Rf for qemu-devel@nongnu.org; Mon, 25 Nov 2013 06:00:40 -0500 Date: Mon, 25 Nov 2013 12:00:19 +0100 From: Igor Mammedov Message-ID: <20131125120019.7b6d4140@nial.usersys.redhat.com> In-Reply-To: <1385130236.3681.94.camel@nilsson.home.kraxel.org> References: <1385001528-12003-1-git-send-email-imammedo@redhat.com> <1385001528-12003-22-git-send-email-imammedo@redhat.com> <1385130236.3681.94.camel@nilsson.home.kraxel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 21/27] pc: add memory hotplug 440fx machine List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: peter.maydell@linaro.org, aliguori@amazon.com, stefanb@linux.vnet.ibm.com, qemu-devel@nongnu.org, hutao@cn.fujitsu.com, mst@redhat.com, mjt@tls.msk.ru, mdroth@linux.vnet.ibm.com, armbru@redhat.com, vasilis.liaskovitis@profitbricks.com, quintela@redhat.com, stefanha@redhat.com, pbonzini@redhat.com, marcel.a@redhat.com, lcapitulino@redhat.com, chegu_vinod@hp.com, afaerber@suse.de On Fri, 22 Nov 2013 15:23:56 +0100 Gerd Hoffmann wrote: > On Do, 2013-11-21 at 03:38 +0100, Igor Mammedov wrote: > > Add DimmBus for memory hotplug below 4Gb or above 4Gb depending > > on initial memory size and hotplug memory size. > > > > * if ram_size is less than 32-bit PCI hole start, reserve > > hotplug memory region as [ram_size,32bit-PCIhole-start) > > if hotplug memory region fits there, > > otherwise reserve hotplug memory region after "0x100000000ULL > > + above_4g_mem_size" > > Hmm, 32-bit pci hole start depends on ram size ... > > Does it make sense to hotplug memory above 4g unconditionally to > simplify things? It does and it was so in v6 RFC, But it would rule out hotplug for 32-bit guests that doesn't support more then 4Gb. As use case 32-bit guest could start whit small initial memory and hotplug additional memory if needed up to point where 32-bit PCI hole starts. That would allow guests to launch with small amount but baloon up upto 2-3.5 Gb depending on machine type. I could drop 32-bit guest support and do only high mem hotplug if this case it not interesting to the comunity, any suggestions? I'm now experimenting with removing pci-info and allowing BIOS to do placement of 32-bit PCI bars akin it was done with 64-bit BARs, (I'm looking to using E820 reservations for it but I'm not sure it will work with every guest OS, so it needs more testing). > cheers, > Gerd > > >