QEMU 11.0 available on pve-test and pve-no-subscription as of now

fiona

Proxmox Staff Member
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Aug 1, 2019
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There is a new QEMU 11.0 package available in the pve-test and pve-no-subscription repositories for Proxmox VE 9.

After internally testing QEMU 11.0 for over two weeks and having this version available on the pve-test repository for over a week, we now (2026-05-13) made our QEMU 11.0 package available in the pve-no-subscription repository.

Version 11.0.0-2 of our QEMU package pve-qemu-kvm includes some important stable fixes that have been developed since the original QEMU 11.0 release.

Note: While some of our production workloads already use this version and run stable, we cannot test every possible hardware and configuration combination, so we recommend testing the upgrade before applying it to mission-critical setups.

To upgrade, make sure you have configured either the Proxmox VE No-Subscription repository or the Proxmox VE Test repository.

Either use the web-interface to refresh and then upgrade using the Node -> Updates panel, or use a console with the following standard apt commands:
Bash:
apt update
apt full-upgrade

The output of the pveversion -v CLI command (or the web-interface's Node Summary -> Packages versions) should then include something like pve-qemu-kvm: 11.0.0-2.

Note, as with all QEMU updates: To run with the new QEMU version, a VM must either be completely restarted (shut it down and then start it again, or use the restart command via the CLI or web-interface) or, to avoid downtime, consider live-migrating to a host that has already been upgraded to the new QEMU package version.

While we have been successfully running our production and many test loads on this version for some time now, no software is bug-free, and often such issues are related to the specific setup. So if you encounter regressions that are definitely caused by installing the new QEMU version (and not some other change), please always include the affected VM configuration and some basic HW (e.g. CPU model) and memory details.

We welcome your feedback!

Known issues:
None at the time of publishing.
 
Code:
[  285.467448] ------------[ cut here ]------------
[  285.467451] WARNING: ./arch/x86/kvm/mmu.h:227 at paging64_walk_addr_generic+0x7fc/0xa00 [kvm], CPU#20: CPU 11/KVM/9733
....

I am hitting this WARN_ON_ONCE that was committed here:

https://lkml.org/lkml/2025/9/19/1479

I believe it's because of the shadow stack (PFERR_SS_MASK) that my newer EPYC processor supports. We did not see it on another server that did not have shadow stack support.

Only started seeing this on the QEMU 11 upgrade. Coincidentally, CET virtualization was added with this release:

https://www.phoronix.com/news/QEMU-11.0-Released

Which corresponds to that warning and flag.

CET is an umbrella term coined by Intel for Shadow Stack and Indirect Branch Tracking. My processor only supports Shadow Stack and not IBT since it's AMD. To be clear, that particular code path is agnostic to whether its an Intel or AMD processor.
 
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Thanks Proxmox team.
Just upgraded - will report back if anything unforeseen happens - hopefully not!
 
 
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@fw1976 I should probably continue this discussion in the thread you started, but there are still some issues with Qemu11.

Boot loops and startup failures are still occurring on virtual machines with HVCI and RDS roles added.

*This also happens with Hyper-V roles, but since nested virtual environments aren’t meant for production use, I understand that reconfiguration is necessary in this case…


However, we should not cause issues with HVCI or RDS, which are not experimental features. It would be counterproductive for the addition of MBEC/GMET used by HVCI to cause problems in environments where HVCI is enabled.

In addition, there are other issues, such as those listed below. These issues remain unresolved.


Known issues:
None at the time of publishing.

???

 
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