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

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

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

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

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

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)

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

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

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

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

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

* Gerd Hoffmann (1769...@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

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

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

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

* Daniel Berrange (1769...@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

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

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

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

* ChristianEhrhardt (1769...@bugs.launchpad.net) wrote: > On Tue, May 8, 2018 at 10:37 AM, Dr. David Alan Gilbert > wrote: > > > * ChristianEhrhardt (1769...@bugs.launchpad.net) wrote: > > > > Interesting; I thought this was supposed to work. > > > > > > Exactly that was my

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

On Tue, May 8, 2018 at 10:37 AM, Dr. David Alan Gilbert wrote: > * ChristianEhrhardt (1769...@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

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

* ChristianEhrhardt (1769...@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

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

> 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

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

BTW this is the stacktrace I get from a Xenial guest on Xenial host: [0.00] BUG: unable to handle kernel paging request at c904 [0.00] IP: [] hpet_enable.part.13+0x23/0x2a5 [0.00] PGD 171629ab067 PUD 171629ac067 PMD 171629ad067 PTE 8000fed00073 [

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

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