From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40149) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1db9d8-0002SR-LT for qemu-devel@nongnu.org; Fri, 28 Jul 2017 14:04:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1db9d3-00050y-Ri for qemu-devel@nongnu.org; Fri, 28 Jul 2017 14:04:54 -0400 Received: from mga06.intel.com ([134.134.136.31]:19129) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1db9d3-0004zl-Jk for qemu-devel@nongnu.org; Fri, 28 Jul 2017 14:04:49 -0400 Date: Fri, 28 Jul 2017 12:04:46 -0600 From: Ross Zwisler Message-ID: <20170728180446.GA31104@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: [Qemu-devel] QEMU NVDIMM as type 7 in e820 table List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, linux-nvdimm@lists.01.org Cc: Haozhong Zhang , "Michael S. Tsirkin" , Stefan Hajnoczi , Xiao Guangrong , Igor Mammedov , Dan Williams I've been using the virtualized NVDIMM support in QEMU for testing, and I noticed that the physical addresses used by the virtual NVDIMMs aren't present in the guest's e820 table. Here is the e820 table on my QEMU instance where I have one 32 GiB virtual NVDIMM: [ 0.000000] e820: BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable [ 0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000bffdefff] usable [ 0.000000] BIOS-e820: [mem 0x00000000bffdf000-0x00000000bfffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000023fffffff] usable The physical addresses used by the virtual NVDIMM are 0x240000000-0xA40000000. You can see this by looking at ndctl and the values we get from the NFIT: # ndctl list -R { "dev":"region0", "size":34359738368, "available_size":0, "type":"pmem" } # grep . /sys/bus/nd/devices/region0/{resource,size} region0/resource:0x240000000 region0/size:34359738368 Or you can see the same info by using iasl to dump /sys/firmware/acpi/tables/NFIT: [028h 0040 2] Subtable Type : 0000 [System Physical Address Range] [02Ah 0042 2] Length : 0038 [02Ch 0044 2] Range Index : 0002 [02Eh 0046 2] Flags (decoded below) : 0003 Add/Online Operation Only : 1 Proximity Domain Valid : 1 [030h 0048 4] Reserved : 00000000 [034h 0052 4] Proximity Domain : 00000000 [038h 0056 16] Address Range GUID : 66F0D379-B4F3-4074-AC43-0D3318B78CDB [048h 0072 8] Address Range Base : 0000000240000000 [050h 0080 8] Address Range Length : 0000000800000000 [058h 0088 8] Memory Map Attribute : 0000000000008008 I expected to see a type 7 region for the NVDIMM physical address range in the e820 table, so something like: [ 0.000000] e820: BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable [ 0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000bffdefff] usable [ 0.000000] BIOS-e820: [mem 0x00000000bffdf000-0x00000000bfffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000023fffffff] usable [ 0.000000] BIOS-e820: [mem 0x0000000240000000-0x0000000A40000000] persistent (type 7) Thanks, - Ross