From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35551) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fG3FU-0001pk-V1 for qemu-devel@nongnu.org; Tue, 08 May 2018 10:05:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fG3FS-00054O-6i for qemu-devel@nongnu.org; Tue, 08 May 2018 10:05:48 -0400 Received: from indium.canonical.com ([91.189.90.7]:37370) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fG3FR-00054A-Uw for qemu-devel@nongnu.org; Tue, 08 May 2018 10:05:46 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.86_2 #2 (Debian)) id 1fG3FQ-0000C4-QC for ; Tue, 08 May 2018 14:05:44 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id BDA6A2E80CB for ; Tue, 8 May 2018 14:05:44 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Tue, 08 May 2018 14:00:19 -0000 From: "Dr. David Alan Gilbert" Reply-To: Bug 1769053 <1769053@bugs.launchpad.net> Sender: bounces@canonical.com References: <152541524728.557.4600864098110042577.malonedeb@gac.canonical.com> <152577650854.21921.3043264133804855985.malone@soybean.canonical.com> <20180508112338.GI2500@work-vm> <20180508132234.yegmw442swuofykh@sirius.home.kraxel.org> Message-Id: <20180508140019.GM2500@work-vm> Errors-To: bounces@canonical.com Subject: Re: [Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org * Gerd Hoffmann (1769053@bugs.launchpad.net) wrote: > Hi, > = > > d) For smaller amount of RAM it might still fail if > > RAM+rounding+pci+hotplug space goes over the limit. > > Figuring that limit out is tricky (and I thought it > > might be BIOS/EFI dependent as well depending where they > > decide to put their PCI devices) > = > Both seabios and ovmf try to not go too high in address space. Reason > is exactly the phys-bits issue. Using 40 here by default does not only > limit the memory to 1TB. It also has the problem that the guest thinks > it has 1TB of address space but in reality it might be less. Even > recent skylake machines have phys-bits=3D39 (512G) only, and trying to use > the physical address space above 512G in the guest just doesn't work > because the phys-bits=3D39 limit applies to EPT too. > = > So checking phys-bits in the firmware, for example to place pci bars as > high as possible in physical address space, is not going to work. > = > IIRC ovmf uses a 32G sized region with 32G alignment by default, which > will land below 64G (aka phys-bits=3D36 address space) unless the guest > has more than 30 (q35) or 31 (piix4) GB of memory. > = > seabios will not map pci bars above 4G unless it runs out of space below > 4G. If needed 64bit PCI bars will be placed right above ram, with > gigabyte alignment. Yep, I was tempted to set host-phys-bits=3Dtrue on upstream, but TCG has a fixed 40 bits last time I looked. Dave > cheers, > Gerd > = > -- = > You received this bug notification because you are subscribed to the bug > report. > https://bugs.launchpad.net/bugs/1769053 > = > Title: > Cannot start a guest with more than 1TB of RAM > = > Status in QEMU: > Incomplete > Status in qemu package in Ubuntu: > Incomplete > = > Bug description: > Attempting to start a KVM guest with more than 1TB of RAM fails. > = > It looks like we might need some extra patches: > https://lists.gnu.org/archive/html/qemu-discuss/2017-12/msg00005.html > = > ProblemType: Bug > DistroRelease: Ubuntu 18.04 > Package: qemu-system-x86 1:2.11+dfsg-1ubuntu7 > ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17 > Uname: Linux 4.15.0-20-generic x86_64 > ApportVersion: 2.20.9-0ubuntu7 > Architecture: amd64 > CurrentDesktop: Unity:Unity7:ubuntu > Date: Fri May 4 16:21:14 2018 > InstallationDate: Installed on 2017-04-05 (393 days ago) > InstallationMedia: Ubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012= .2) > MachineType: Dell Inc. XPS 13 9360 > ProcKernelCmdLine: BOOT_IMAGE=3D/vmlinuz-4.15.0-20-generic root=3D/dev/= mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=3Dmadvise vt.ha= ndoff=3D1 > SourcePackage: qemu > UpgradeStatus: Upgraded to bionic on 2018-04-30 (3 days ago) > dmi.bios.date: 02/26/2018 > dmi.bios.vendor: Dell Inc. > dmi.bios.version: 2.6.2 > dmi.board.name: 0PF86Y > dmi.board.vendor: Dell Inc. > dmi.board.version: A00 > dmi.chassis.type: 9 > dmi.chassis.vendor: Dell Inc. > dmi.modalias: dmi:bvnDellInc.:bvr2.6.2:bd02/26/2018:svnDellInc.:pnXPS13= 9360:pvr:rvnDellInc.:rn0PF86Y:rvrA00:cvnDellInc.:ct9:cvr: > dmi.product.family: XPS > dmi.product.name: XPS 13 9360 > dmi.sys.vendor: Dell Inc. > = > To manage notifications about this bug go to: > https://bugs.launchpad.net/qemu/+bug/1769053/+subscriptions -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1769053 Title: Cannot start a guest with more than 1TB of RAM Status in QEMU: Incomplete Status in qemu package in Ubuntu: Incomplete Bug description: Attempting to start a KVM guest with more than 1TB of RAM fails. It looks like we might need some extra patches: https://lists.gnu.org/archive/html/qemu-discuss/2017-12/msg00005.html ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: qemu-system-x86 1:2.11+dfsg-1ubuntu7 ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17 Uname: Linux 4.15.0-20-generic x86_64 ApportVersion: 2.20.9-0ubuntu7 Architecture: amd64 CurrentDesktop: Unity:Unity7:ubuntu Date: Fri May 4 16:21:14 2018 InstallationDate: Installed on 2017-04-05 (393 days ago) InstallationMedia: Ubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012.2) MachineType: Dell Inc. XPS 13 9360 ProcKernelCmdLine: BOOT_IMAGE=3D/vmlinuz-4.15.0-20-generic root=3D/dev/ma= pper/ubuntu--vg-root ro quiet splash transparent_hugepage=3Dmadvise vt.hand= off=3D1 SourcePackage: qemu UpgradeStatus: Upgraded to bionic on 2018-04-30 (3 days ago) dmi.bios.date: 02/26/2018 dmi.bios.vendor: Dell Inc. dmi.bios.version: 2.6.2 dmi.board.name: 0PF86Y dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 9 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvr2.6.2:bd02/26/2018:svnDellInc.:pnXPS1393= 60:pvr:rvnDellInc.:rn0PF86Y:rvrA00:cvnDellInc.:ct9:cvr: dmi.product.family: XPS dmi.product.name: XPS 13 9360 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1769053/+subscriptions