[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Daniel Axtens]

** Also affects: qemu
   Importance: Undecided
       Status: New

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Title:
  Cannot start a guest with more than 1TB of RAM

Status in QEMU:
  New
Status in qemu package in Ubuntu:
  New

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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:
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[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[ChristianEhrhardt]

Hi Daniel,
might I ask what you expect now?

The changes to seabios are not even upstream yet in git://git.seabios.org/seabios.git
The changes to qemu are neither upstream in git://git.qemu.org/qemu.git

The changes linked also are for a qemu way++ back in time (like pre trusty), so they just don't apply. Some of these changes are handled already, but different like the second qemu change of above mail is in qemu since "6c7c3c21 x86: implement la57 paging mode" which is qemu >=2.9.
That said - this one I could track, maybe the other changes are also upstream but in a way different form.

At least for myself I currently have no >1TB system to even try this -
well I have done this on s390x and there it works fine already but you
need x86 here.

Even when all of the above would be resolved, the mail above states that
even if those are applied they still have issues when going >1TB.

I think you'd need a clear this is what I tried and this is what fails
with a setup as simple as possible. If it fails in Ubuntu we can build a
latest upstream build for you and if failing there we can work with
upstream to resolve properly. From there we can think about the
backportability of those changes. But the suggested "hey there are these
patches, won't work.

Please don't get me wrong (I want to help), but so far this appears to me so far as a suggestion of a set of non-upstreamed, non-applicable, non-testable, non-working changes.
We need to better sort out how to handle this which is why I ask what you expect to happen now.

-- 
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:
  New
Status in qemu package in Ubuntu:
  New

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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:
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Re: [Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Daniel Axtens]

Hi Christian,

Sorry, I should have been a *lot* more clear.

I wanted to file the bug so that we have somewhere to figure out what needs
to be done and track the progress - trying to avoid it becoming something
we vaguely know about but don't ever do anything about.

Thanks so much for your analysis of the patches. I will dig in to the
upstream status and see where they're at with large memory guests.

I know we're missing test hardware. I will make some enquiries within the
team and see what can dig up, otherwise we have a customer that might be
able to run some tests.

So for now, the action items are:
 - I will hunt down a >1TB machine.
 - I will check what the progress of 1TB guests in upstream Qemu is.

Apologies again, and thanks for the pointers.

Regards,
Daniel

On Fri, May 4, 2018 at 5:44 PM, ChristianEhrhardt <
1769053@bugs.launchpad.net> wrote:

> Hi Daniel,
> might I ask what you expect now?
>
> The changes to seabios are not even upstream yet in git://
> git.seabios.org/seabios.git
> The changes to qemu are neither upstream in git://git.qemu.org/qemu.git
>
> The changes linked also are for a qemu way++ back in time (like pre
> trusty), so they just don't apply. Some of these changes are handled
> already, but different like the second qemu change of above mail is in qemu
> since "6c7c3c21 x86: implement la57 paging mode" which is qemu >=2.9.
> That said - this one I could track, maybe the other changes are also
> upstream but in a way different form.
>
> At least for myself I currently have no >1TB system to even try this -
> well I have done this on s390x and there it works fine already but you
> need x86 here.
>
> Even when all of the above would be resolved, the mail above states that
> even if those are applied they still have issues when going >1TB.
>
> I think you'd need a clear this is what I tried and this is what fails
> with a setup as simple as possible. If it fails in Ubuntu we can build a
> latest upstream build for you and if failing there we can work with
> upstream to resolve properly. From there we can think about the
> backportability of those changes. But the suggested "hey there are these
> patches, won't work.
>
> Please don't get me wrong (I want to help), but so far this appears to me
> so far as a suggestion of a set of non-upstreamed, non-applicable,
> non-testable, non-working changes.
> We need to better sort out how to handle this which is why I ask what you
> expect to happen now.
>
> --
> 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:
>   New
> Status in qemu package in Ubuntu:
>   New
>
> 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=/vmlinuz-4.15.0-20-generic
> root=/dev/mapper/ubuntu--vg-root ro quiet splash
> transparent_hugepage=madvise vt.handoff=1
>   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.:
> pnXPS139360: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
>

-- 
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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[ChristianEhrhardt]

Thanks for your clarification Daniel, I'll mark both tasks incomplete
then until you come back with that data.

** Changed in: qemu (Ubuntu)
       Status: New => Incomplete

** Changed in: qemu
       Status: New => Incomplete

-- 
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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Dr. David Alan Gilbert]

Interesting; I thought this was supposed to work.
I know we (RH) have some downstream patches for >1TB RAM, but the last I'd heard they weren't supposed to be necessary any more, except for compatibility with old versions.

It's probably worth checking the guest view fo the CPUs physical address bits and making sure it's no bigger than the host (phys-bits=n or host-phys-bits=true on the -cpu)
QEMU often defaults to 40 bits and things get confusing.

Note also you can do some 1TB+ tests on smaller machines as long as they
have a large enough address size on the host CPUs.  Tricks like adding
empty hot-plug DIMM slots leaving a 1TB hole can tickle some bugs.
Even adding 1TB of swap to your host and being careful with your guest
can work :-)

-- 
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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Dan Streetman]

You don't need a >1TB host to spin up a >1TB guest.  Unless you're using
pci passthru (and/or SRIOV), or something else that requires qemu to
alloc and pin all guest mem, you can simply overcommit; normal guests
don't require mem pre-allocation or pinning.

On your host do this to allow overcommitting such a large amount (this
allows 16T but can be adjusted as needed):

$ echo $[ 16 * 1024 * 1024 * 1024 ] | sudo tee /proc/sys/vm/overcommit_kbytes 
17179869184
$ echo 1 | sudo tee /proc/sys/vm/overcommit_memory 
1


Then just virsh edit your guest to use >1TB, e.g.:

  <memory unit='GiB'>1500</memory>


And of course, stop and restart the guest to pick up the xml change.

-- 
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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Dan Streetman]

BTW this is the stacktrace I get from a Xenial guest on Xenial host:

[    0.000000] BUG: unable to handle kernel paging request at ffffc90000000004
[    0.000000] IP: [<ffffffff81f7dc60>] hpet_enable.part.13+0x23/0x2a5
[    0.000000] PGD 171629ab067 PUD 171629ac067 PMD 171629ad067 PTE 80000000fed00073
[    0.000000] Oops: 0009 [#1] SMP 
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-122-generic #146-Ubuntu
[    0.000000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[    0.000000] task: ffffffff81e13500 ti: ffffffff81e00000 task.ti: ffffffff81e00000
[    0.000000] RIP: 0010:[<ffffffff81f7dc60>]  [<ffffffff81f7dc60>] hpet_enable.part.13+0x23/0x2a5
[    0.000000] RSP: 0000:ffffffff81e03ef0  EFLAGS: 00010282
[    0.000000] RAX: ffffc90000000000 RBX: ffffffffffffffff RCX: 0000000000000000
[    0.000000] RDX: 0000000000000000 RSI: 0000000000000100 RDI: 0000000000000000
[    0.000000] RBP: ffffffff81e03f10 R08: 000000000001ad50 R09: 00000000000001f0
[    0.000000] R10: ffff89773fa20000 R11: 0000000000000001 R12: ffff89773f99f6c0
[    0.000000] R13: ffffffff8200e920 R14: ffffffff8201c2e0 R15: ffffffff81e03fa8
[    0.000000] FS:  0000000000000000(0000) GS:ffff897162c00000(0000) knlGS:0000000000000000
[    0.000000] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[    0.000000] CR2: ffffc90000000004 CR3: 0000000001e0a000 CR4: 0000000000000630
[    0.000000] Stack:
[    0.000000]  ffffffffffffffff ffff89773f99f6c0 ffffffff8200e920 ffffffff8201c2e0
[    0.000000]  ffffffff81e03f20 ffffffff81f7df00 ffffffff81e03f30 ffffffff81f6ee7a
[    0.000000]  ffffffff81e03f40 ffffffff81f6ee4a ffffffff81e03f80 ffffffff81f63f71
[    0.000000] Call Trace:
[    0.000000]  [<ffffffff81f7df00>] hpet_enable+0x1e/0x20
[    0.000000]  [<ffffffff81f6ee7a>] hpet_time_init+0x9/0x19
[    0.000000]  [<ffffffff81f6ee4a>] x86_late_time_init+0x10/0x17
[    0.000000]  [<ffffffff81f63f71>] start_kernel+0x3d8/0x4aa
[    0.000000]  [<ffffffff81f63120>] ? early_idt_handler_array+0x120/0x120
[    0.000000]  [<ffffffff81f63339>] x86_64_start_reservations+0x2a/0x2c
[    0.000000]  [<ffffffff81f63485>] x86_64_start_kernel+0x14a/0x16d
[    0.000000] Code: 01 00 00 00 41 5c 5d c3 55 48 8b 3d 63 f4 18 00 be 00 04 00 00 48 89 e5 41 56 41 55 41 54 53 e8 f7 f2 0e ff 48 89 05 d8 f4 18 00 <8b> 48 04 b8 e9 03 00 00 48 8b 15 c9 f4 18 00 8b 52 10 ff c2 75 
[    0.000000] RIP  [<ffffffff81f7dc60>] hpet_enable.part.13+0x23/0x2a5
[    0.000000]  RSP <ffffffff81e03ef0>
[    0.000000] CR2: ffffc90000000004
[    0.000000] ---[ end trace 404be15fe05aa681 ]---
[    0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
[    0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task!

-- 
You received this bug notification because you are a member of qemu-
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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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Dan Streetman]

And with non-massive mem (so the guest actually boots up), the guest
does show only 40 bits of phys mem addressing, so qemu will definitely
have to increase that to be able to provide >1TB of phys mem to the
guest (assuming qemu doesn't adjust that dynamically based on the total
mem provided to the guest)

ubuntu@largemem:~$ grep -m 1 'address sizes' /proc/cpuinfo 
address sizes	: 40 bits physical, 48 bits virtual

-- 
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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Dr. David Alan Gilbert]

Ah right Dan, if you're seeing the 40 bits physical in the guest you
definitely need to try the flags I suggest in comment 6; host-phys-
bits=true  should work for you.

-- 
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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[ChristianEhrhardt]

> Interesting; I thought this was supposed to work.

Exactly that was my thought when triaging it initially
Furthermore I assume people working la57 (https://lwn.net/Articles/730925/) and such ran tests on much bigger sizes.

> Ah right Dan, if you're seeing the 40 bits physical in the guest you
definitely need to try the flags I suggest in comment 6; host-phys-
bits=true should work for you.

I tested Bionic to be at least on libvirt 4.0 / qemu 2.11.1 when we want
to check things under the "supposed to work now" flag.

Defaults:
Host:  address sizes   : 46 bits physical, 48 bits virtual
Guest: address sizes   : 40 bits physical, 48 bits virtual

I ensured that with option -cpu host,host-phys-bits=true set I successfully get what my host can provide in the guest:
Guest: address sizes   : 46 bits physical, 48 bits virtual

Starting a guest with that >1TB (that would be mostly on swap if needed) works just fine as expected. Here ~1063 GB from /proc/meminfo
MemTotal:       1114676492 kB

I also checked a more compatible approach like -cpu qemu64,phys-bits=42
and that works as well.

IMHO - if anything - one could argue that libvirt/qemu could be smarter
about e.g. auto adding those arguments (or print a warning) when
crossing a certain memory size.

So for now I'd stick to the "actually works" summary and keep the status
to incomplete.

-- 
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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

Re: [Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Dr. David Alan Gilbert]

* ChristianEhrhardt (1769053@bugs.launchpad.net) wrote:
> > Interesting; I thought this was supposed to work.
> 
> Exactly that was my thought when triaging it initially
> Furthermore I assume people working la57 (https://lwn.net/Articles/730925/) and such ran tests on much bigger sizes.

I assume so, but I've not looked at the detail of that.

> > Ah right Dan, if you're seeing the 40 bits physical in the guest you
> definitely need to try the flags I suggest in comment 6; host-phys-
> bits=true should work for you.
> 
> I tested Bionic to be at least on libvirt 4.0 / qemu 2.11.1 when we want
> to check things under the "supposed to work now" flag.
> 
> Defaults:
> Host:  address sizes   : 46 bits physical, 48 bits virtual
> Guest: address sizes   : 40 bits physical, 48 bits virtual
> 
> I ensured that with option -cpu host,host-phys-bits=true set I successfully get what my host can provide in the guest:
> Guest: address sizes   : 46 bits physical, 48 bits virtual
> 
> Starting a guest with that >1TB (that would be mostly on swap if needed) works just fine as expected. Here ~1063 GB from /proc/meminfo
> MemTotal:       1114676492 kB

OK, good - that suggests there's nothing missing.
We enable host-phys-bits=true by default I think (in our machine type?)

> I also checked a more compatible approach like -cpu qemu64,phys-bits=42
> and that works as well.
> 
> IMHO - if anything - one could argue that libvirt/qemu could be smarter
> about e.g. auto adding those arguments (or print a warning) when
> crossing a certain memory size.

The problem is there are a whole bunch of things that are hard to deal
with:
  a) Cheaper CPUs tend to have smaller phys-bits even in the same
generation; e.g. my laptop is still 36 bits, a lot are 39 bits.  I think
the same is true of the Xeon E3-.... family.   It makes it hard to know
what to pick when you're going to allow migration.

  b) Reasoning about the total address size range is difficult; you've
got to take into account PCI address space and hot plug space etc
to know where the upper edge is.

Dave

> So for now I'd stick to the "actually works" summary and keep the status
> to incomplete.
> 
> -- 
> 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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
>   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.:pnXPS139360: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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

Re: [Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[ChristianEhrhardt]

On Tue, May 8, 2018 at 10:37 AM, Dr. David Alan Gilbert <dgilbert@redhat.com
> wrote:

> * ChristianEhrhardt (1769053@bugs.launchpad.net) wrote:
> > > Interesting; I thought this was supposed to work.
> >
> > Exactly that was my thought when triaging it initially
> > Furthermore I assume people working la57 (https://lwn.net/Articles/
> 730925/) and such ran tests on much bigger sizes.
>
> I assume so, but I've not looked at the detail of that.
>
> > > Ah right Dan, if you're seeing the 40 bits physical in the guest you
> > definitely need to try the flags I suggest in comment 6; host-phys-
> > bits=true should work for you.
> >
> > I tested Bionic to be at least on libvirt 4.0 / qemu 2.11.1 when we want
> > to check things under the "supposed to work now" flag.
> >
> > Defaults:
> > Host:  address sizes   : 46 bits physical, 48 bits virtual
> > Guest: address sizes   : 40 bits physical, 48 bits virtual
> >
> > I ensured that with option -cpu host,host-phys-bits=true set I
> successfully get what my host can provide in the guest:
> > Guest: address sizes   : 46 bits physical, 48 bits virtual
> >
> > Starting a guest with that >1TB (that would be mostly on swap if needed)
> works just fine as expected. Here ~1063 GB from /proc/meminfo
> > MemTotal:       1114676492 kB
>
> OK, good - that suggests there's nothing missing.
> We enable host-phys-bits=true by default I think (in our machine type?)
>

Interesting approach, I see your comment about that already in [1] when it
was added.
I didn't realize some machine types were setting this already - I assume it
isn't the general default for migratebility to other hosts (like our 36/39
bit laptops).

I assume "we" in this context are RedHat downstream changes to the (some)
machine type(s)?
I see the benefit for huge guests to work without setting those properties,
but I wonder if that caused you trouble in regard to migrations?

[1]: https://patchwork.kernel.org/patch/9223999/


> > I also checked a more compatible approach like -cpu qemu64,phys-bits=42
> > and that works as well.
> >
> > IMHO - if anything - one could argue that libvirt/qemu could be smarter
> > about e.g. auto adding those arguments (or print a warning) when
> > crossing a certain memory size.
>
> The problem is there are a whole bunch of things that are hard to deal
> with:
>   a) Cheaper CPUs tend to have smaller phys-bits even in the same
> generation; e.g. my laptop is still 36 bits, a lot are 39 bits.  I think
> the same is true of the Xeon E3-.... family.   It makes it hard to know
> what to pick when you're going to allow migration.
>
>   b) Reasoning about the total address size range is difficult; you've
> got to take into account PCI address space and hot plug space etc
> to know where the upper edge is.
>

I agree that checking the total address size might have too much false
positives for all the complexities around "estimating" that size.
/me is giving up this idea :-)


> Dave
>
> > So for now I'd stick to the "actually works" summary and keep the status
> > to incomplete.
> >
> > --
> > 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=/vmlinuz-4.15.0-20-generic
> root=/dev/mapper/ubuntu--vg-root ro quiet splash
> transparent_hugepage=madvise vt.handoff=1
> >   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.:
> pnXPS139360: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 Ubuntu
> Virtualisation team, which is subscribed to qemu in Ubuntu.
> 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=/vmlinuz-4.15.0-20-generic
> root=/dev/mapper/ubuntu--vg-root ro quiet splash
> transparent_hugepage=madvise vt.handoff=1
>   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.:
> pnXPS139360: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
>


-- 
Christian Ehrhardt
Software Engineer, Ubuntu Server
Canonical Ltd

-- 
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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

Re: [Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Dr. David Alan Gilbert]

* ChristianEhrhardt (1769053@bugs.launchpad.net) wrote:
> On Tue, May 8, 2018 at 10:37 AM, Dr. David Alan Gilbert <dgilbert@redhat.com
> > wrote:
> 
> > * ChristianEhrhardt (1769053@bugs.launchpad.net) wrote:
> > > > Interesting; I thought this was supposed to work.
> > >
> > > Exactly that was my thought when triaging it initially
> > > Furthermore I assume people working la57 (https://lwn.net/Articles/
> > 730925/) and such ran tests on much bigger sizes.
> >
> > I assume so, but I've not looked at the detail of that.
> >
> > > > Ah right Dan, if you're seeing the 40 bits physical in the guest you
> > > definitely need to try the flags I suggest in comment 6; host-phys-
> > > bits=true should work for you.
> > >
> > > I tested Bionic to be at least on libvirt 4.0 / qemu 2.11.1 when we want
> > > to check things under the "supposed to work now" flag.
> > >
> > > Defaults:
> > > Host:  address sizes   : 46 bits physical, 48 bits virtual
> > > Guest: address sizes   : 40 bits physical, 48 bits virtual
> > >
> > > I ensured that with option -cpu host,host-phys-bits=true set I
> > successfully get what my host can provide in the guest:
> > > Guest: address sizes   : 46 bits physical, 48 bits virtual
> > >
> > > Starting a guest with that >1TB (that would be mostly on swap if needed)
> > works just fine as expected. Here ~1063 GB from /proc/meminfo
> > > MemTotal:       1114676492 kB
> >
> > OK, good - that suggests there's nothing missing.
> > We enable host-phys-bits=true by default I think (in our machine type?)
> >
> 
> Interesting approach, I see your comment about that already in [1] when it
> was added.
> I didn't realize some machine types were setting this already - I assume it
> isn't the general default for migratebility to other hosts (like our 36/39
> bit laptops).
> 
> I assume "we" in this context are RedHat downstream changes to the (some)
> machine type(s)?

That's right; you sohuld be able to find them if you dig around CentOS's
set.

> I see the benefit for huge guests to work without setting those properties,
> but I wonder if that caused you trouble in regard to migrations?

It could, although I don't remember any reports of people hitting it.
The problem is finding a better solution;  that's why I added both the
host-phys-bits and the ability to set phys-bits=   so that you can make
a smarter choice based on what hardware you actually have.  Who or what
should make that smarter choice hasn't really ever been answered.

> [1]: https://patchwork.kernel.org/patch/9223999/

Prior to that patch set, QEMU had always been a fixed 40 bits, so I
didn't change the default behaviour with that set; I just let you change
it by adding the flags.
(As I remember TCG was hard coded as 40 bits in some places so didn't
want to break that either).

Dave

> 
> 
> > > I also checked a more compatible approach like -cpu qemu64,phys-bits=42
> > > and that works as well.
> > >
> > > IMHO - if anything - one could argue that libvirt/qemu could be smarter
> > > about e.g. auto adding those arguments (or print a warning) when
> > > crossing a certain memory size.
> >
> > The problem is there are a whole bunch of things that are hard to deal
> > with:
> >   a) Cheaper CPUs tend to have smaller phys-bits even in the same
> > generation; e.g. my laptop is still 36 bits, a lot are 39 bits.  I think
> > the same is true of the Xeon E3-.... family.   It makes it hard to know
> > what to pick when you're going to allow migration.
> >
> >   b) Reasoning about the total address size range is difficult; you've
> > got to take into account PCI address space and hot plug space etc
> > to know where the upper edge is.
> >
> 
> I agree that checking the total address size might have too much false
> positives for all the complexities around "estimating" that size.
> /me is giving up this idea :-)
> 
> 
> > Dave
> >
> > > So for now I'd stick to the "actually works" summary and keep the status
> > > to incomplete.
> > >
> > > --
> > > 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=/vmlinuz-4.15.0-20-generic
> > root=/dev/mapper/ubuntu--vg-root ro quiet splash
> > transparent_hugepage=madvise vt.handoff=1
> > >   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.:
> > pnXPS139360: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 Ubuntu
> > Virtualisation team, which is subscribed to qemu in Ubuntu.
> > 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=/vmlinuz-4.15.0-20-generic
> > root=/dev/mapper/ubuntu--vg-root ro quiet splash
> > transparent_hugepage=madvise vt.handoff=1
> >   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.:
> > pnXPS139360: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
> >
> 
> 
> -- 
> Christian Ehrhardt
> Software Engineer, Ubuntu Server
> Canonical Ltd
> 
> -- 
> 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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
>   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.:pnXPS139360: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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Daniel Berrange]

Hmm, if we know that QEMU guests will crash & burn when > 1 TB mem, when
host-phys-bits/phys-bits are unset, then perhaps libvirt should do the
right thing by default here. eg we can't use host-phys-bits=true due to
migration compat issues, but if we see > 1TB mem, libvirt could
reasonably set phys-bits=NNN for some suitable value of NNN.  We should
expose this in the XML config for the CPU explicitly too.

-- 
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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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

Re: [Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Dr. David Alan Gilbert]

* Daniel Berrange (1769053@bugs.launchpad.net) wrote:
> Hmm, if we know that QEMU guests will crash & burn when > 1 TB mem, when
> host-phys-bits/phys-bits are unset, then perhaps libvirt should do the
> right thing by default here. eg we can't use host-phys-bits=true due to
> migration compat issues, but if we see > 1TB mem, libvirt could
> reasonably set phys-bits=NNN for some suitable value of NNN.  We should
> expose this in the XML config for the CPU explicitly too.

Yep:
  a) It should be possible to add a setting to the XML to specify the
     phys-bits
  b) It should be possible for libvirt to check the host it's on can
     satisfy that requirement
  c) libvirt can check that if RAM > 2^phys-bits it can complain

but

  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)

Dave

> -- 
> 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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
>   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.:pnXPS139360: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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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:
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Re: [Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Gerd Hoffmann]

  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=39 (512G) only, and trying to use
the physical address space above 512G in the guest just doesn't work
because the phys-bits=39 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=36 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.

cheers,
  Gerd

Re: [Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[Dr. David Alan Gilbert]

* 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=39 (512G) only, and trying to use
> the physical address space above 512G in the guest just doesn't work
> because the phys-bits=39 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=36 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=true 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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
>   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.:pnXPS139360: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

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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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360:pvr:rvnDellInc.:rn0PF86Y:rvrA00:cvnDellInc.:ct9:cvr:
  dmi.product.family: XPS
  dmi.product.name: XPS 13 9360
  dmi.sys.vendor: Dell Inc.

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[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[David Coronel]

** Changed in: qemu (Ubuntu)
   Importance: Undecided => Critical

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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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360:pvr:rvnDellInc.:rn0PF86Y:rvrA00:cvnDellInc.:ct9:cvr:
  dmi.product.family: XPS
  dmi.product.name: XPS 13 9360
  dmi.sys.vendor: Dell Inc.

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[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[ Christian Ehrhardt ]

Crit prio on Qemu which was explained to work just fine is not correct IMHO.
After checking with David he meant to want to raise the prio on the suggested libvirt extensions instead. I'm re-triaging this bug for that and will ping David Berrange if work on this is already tracked on a libvirt-BZ or worked on in general.

** Also affects: libvirt (Ubuntu)
   Importance: Undecided
       Status: New

** Changed in: libvirt (Ubuntu)
       Status: New => Triaged

** Changed in: libvirt (Ubuntu)
   Importance: Undecided => High

** Changed in: qemu (Ubuntu)
   Importance: Critical => Undecided

-- 
You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1769053

Title:
  Cannot start a guest with more than 1TB of RAM

Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360:pvr:rvnDellInc.:rn0PF86Y:rvrA00:cvnDellInc.:ct9:cvr:
  dmi.product.family: XPS
  dmi.product.name: XPS 13 9360
  dmi.sys.vendor: Dell Inc.

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[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[ Christian Ehrhardt ]

Actually the qemu tasks are "invalid" not "incomplete" as they currently
are - after our discussions here it seems we agreed that qemu is doing
what is intended (and the reasons why larger bits are not the default).
Therefore set the status to that for the qemu tasks.

** Changed in: qemu (Ubuntu)
       Status: Incomplete => Invalid

** Changed in: qemu
       Status: Incomplete => Invalid

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You received this bug notification because you are a member of qemu-
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Title:
  Cannot start a guest with more than 1TB of RAM

Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360:pvr:rvnDellInc.:rn0PF86Y:rvrA00:cvnDellInc.:ct9:cvr:
  dmi.product.family: XPS
  dmi.product.name: XPS 13 9360
  dmi.sys.vendor: Dell Inc.

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[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[ Christian Ehrhardt ]

Reported to upstream libvirt's BZ with the suggestions of Daniel Berrage
and David Alan Glibert; now available at [1] I linked that up in the LP
bug status so that we auto-track this.

As eventually this has to go upstream using the bug tracker should
better ensure that there is no concurrent conflicting work (or opinion)
on it.

[1]: https://bugzilla.redhat.com/show_bug.cgi?id=1578278

** Bug watch added: Red Hat Bugzilla #1578278
   https://bugzilla.redhat.com/show_bug.cgi?id=1578278

** Also affects: libvirt via
   https://bugzilla.redhat.com/show_bug.cgi?id=1578278
   Importance: Unknown
       Status: Unknown

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Title:
  Cannot start a guest with more than 1TB of RAM

Status in libvirt:
  Unknown
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360:pvr:rvnDellInc.:rn0PF86Y:rvrA00:cvnDellInc.:ct9:cvr:
  dmi.product.family: XPS
  dmi.product.name: XPS 13 9360
  dmi.sys.vendor: Dell Inc.

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[Qemu-devel] [Bug 1769053] Re: Cannot start a guest with more than 1TB of RAM

[ Christian Ehrhardt ]

Since all but the libvirt task to expose these are set to invalid in
regard to the issue here I'm changing the title accordingly.

As a short term solution for Ubuntu users I forked bug 1776189 to
provide a machine type based solution until this here is implemented and
widely available and exploited.

** Summary changed:

- Cannot start a guest with more than 1TB of RAM
+ Ability to control phys-bits through libvirt

-- 
You received this bug notification because you are a member of qemu-
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Title:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Unknown
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360:pvr:rvnDellInc.:rn0PF86Y:rvrA00:cvnDellInc.:ct9:cvr:
  dmi.product.family: XPS
  dmi.product.name: XPS 13 9360
  dmi.sys.vendor: Dell Inc.

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[Qemu-devel] [Bug 1769053] Re: Ability to control phys-bits through libvirt

[Launchpad Bug Tracker]

** Merge proposal linked:
   https://code.launchpad.net/~paelzer/ubuntu/+source/qemu/+git/qemu/+merge/347796

-- 
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Title:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Unknown
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360:pvr:rvnDellInc.:rn0PF86Y:rvrA00:cvnDellInc.:ct9:cvr:
  dmi.product.family: XPS
  dmi.product.name: XPS 13 9360
  dmi.sys.vendor: Dell Inc.

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[Qemu-devel] [Bug 1769053] Re: Ability to control phys-bits through libvirt

[ Christian Ehrhardt ]

** Merge proposal unlinked:
   https://code.launchpad.net/~paelzer/ubuntu/+source/qemu/+git/qemu/+merge/347796

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Title:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Unknown
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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/libvirt/+bug/1769053/+subscriptions

[Qemu-devel] [Bug 1769053] Re: Ability to control phys-bits through libvirt

[Launchpad Bug Tracker]

** Merge proposal linked:
   https://code.launchpad.net/~paelzer/ubuntu/+source/qemu/+git/qemu/+merge/347801

-- 
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:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Unknown
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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/libvirt/+bug/1769053/+subscriptions

[Qemu-devel] [Bug 1769053] Re: Ability to control phys-bits through libvirt

[ Christian Ehrhardt ]

** Merge proposal unlinked:
   https://code.launchpad.net/~paelzer/ubuntu/+source/qemu/+git/qemu/+merge/347801

-- 
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:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Unknown
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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/libvirt/+bug/1769053/+subscriptions

[Qemu-devel] [Bug 1769053] Re: Ability to control phys-bits through libvirt

[Launchpad Bug Tracker]

** Merge proposal linked:
   https://code.launchpad.net/~paelzer/ubuntu/+source/qemu/+git/qemu/+merge/347801

-- 
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:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Unknown
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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:
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[Qemu-devel] [Bug 1769053] Re: Ability to control phys-bits through libvirt

[ Christian Ehrhardt ]

** Merge proposal unlinked:
   https://code.launchpad.net/~paelzer/ubuntu/+source/qemu/+git/qemu/+merge/347801

-- 
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:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Unknown
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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/libvirt/+bug/1769053/+subscriptions

[Qemu-devel] [Bug 1769053] Re: Ability to control phys-bits through libvirt

[Launchpad Bug Tracker]

** Merge proposal linked:
   https://code.launchpad.net/~paelzer/ubuntu/+source/qemu/+git/qemu/+merge/347801

-- 
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:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Unknown
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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/libvirt/+bug/1769053/+subscriptions

[Bug 1769053]

[sirswa]

Hi

We are hitting this bug. We have specialist hardwares including hi-
memory hypervisors to run HPC workload on virtualised environment. This
bug is affecting us at the machines which has more than 1TB of memory.

-- 
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:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Confirmed
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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/libvirt/+bug/1769053/+subscriptions

[Bug 1769053]

[ehabkost]

(In reply to sirswa@gmail.com from comment #1)
> Hi
> 
> We are hitting this bug. We have specialist hardwares including hi-memory
> hypervisors to run HPC workload on virtualised environment. This bug is
> affecting us at the machines which has more than 1TB of memory.

This bz# is not a bug, but a feature planned to make live migration
ability more flexible.  The option might be useful to work around bugs
or other limitations, though.

If you are seeing a bug related to large guests or large hosts, please
send more details so we can investigate it.

-- 
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:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Confirmed
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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:
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[Bug 1769053]

[raistlin]

Hello.

Recently I had to deal with a VM with ~2.7 TB of RAM. The [open]SUSE
QEMU package carries a patch for bumping the default maximum virtual
address bits to 42 (from 40). Now, the last entry of the VM's e820 was
this one:

    BIOS-e820: [mem 0x0000000100000000-0x000002b57fffffff] usable

Which, if I have computed correctly, is representable on 42 bits, so
things should be fine. However, during boot, the VM shows this:

    L1TF: System has more than MAX_PA/2 memory. L1TF mitigation not
effective

And if I look in /sys/devices/system/cpu/vulnerabilities/l1tf, I see
this:

    l1tf: Vulnerable

This is because, while the RAM fits in MAX_PA=42, as soon as we take 1
bit off for PTE inversion, it does not fit any longer (in MAX_PA/2).

I understand that this is not critical per-se, but I think it's rather
annoying for a user to see messages like the ones above, especially
considering they're about vulnerabilities and security. And it's not
necessarily easy for everyone to realize that L1TF is reported as
vulnerable because QEMU is making the VM think that physical addresses
are on 42 (or 40) bits.

So, I also think we need to be able to tweak this part of the VM
configuration more easily, from libvirt. It's doable either by using
specially modified CPU-models, or doing things like this, which are
rather inconvenient:

    <qemu:commandline>
      <qemu:arg value='-cpu'/>
      <qemu:arg value='host,host-phys-bits=on'/>
    </qemu:commandline>

I also believe that host-phys-bits=on should be QEMU's default when the
user chooses host as CPU model, but that's for another bugzilla. :-)

-- 
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:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Confirmed
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Triaged
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360: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/libvirt/+bug/1769053/+subscriptions

[Bug 1769053] Re: Ability to control phys-bits through libvirt

[Christian Ehrhardt ]

While the bugzilla case wasn't updated this landed in v8.7.0 via a series around
https://gitlab.com/libvirt/libvirt/-/commit/e6c29f09e5b75d7a8d79ae670407060446282c78

v9.0.0 of libvirt is in Ubuntu Lunar, due to that - from now on - one
can control the physical bit settings in a defined way through libvirt.

See maxphysaddr in [1] for how to use that.

Mid term Ubuntu will consider no more adding further variants of the
workaround, that was providing machine types with the -hpb suffix to
allow larger guests.

[1]: https://libvirt.org/formatdomain.html#cpu-model-and-topology

** Changed in: libvirt (Ubuntu)
       Status: Triaged => Fix Released

-- 
You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1769053

Title:
  Ability to control phys-bits through libvirt

Status in libvirt:
  Confirmed
Status in QEMU:
  Invalid
Status in libvirt package in Ubuntu:
  Fix Released
Status in qemu package in Ubuntu:
  Invalid

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=/vmlinuz-4.15.0-20-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash transparent_hugepage=madvise vt.handoff=1
  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.:pnXPS139360:pvr:rvnDellInc.:rn0PF86Y:rvrA00:cvnDellInc.:ct9:cvr:
  dmi.product.family: XPS
  dmi.product.name: XPS 13 9360
  dmi.sys.vendor: Dell Inc.

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