Bug 1531076 - Support 'host-model' on aarch64
Summary: Support 'host-model' on aarch64
Keywords:
Status: CLOSED DEFERRED
Alias: None
Product: Virtualization Tools
Classification: Community
Component: libvirt
Version: unspecified
Hardware: aarch64
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Libvirt Maintainers
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2018-01-04 14:30 UTC by Marcin Juszkiewicz
Modified: 2024-12-17 12:24 UTC (History)
3 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2024-12-17 12:24:41 UTC
Embargoed:


Attachments (Terms of Use)
nova log with domain xml (4.76 KB, text/plain)
2018-01-04 14:30 UTC, Marcin Juszkiewicz
no flags Details


Links
System ID Private Priority Status Summary Last Updated
Launchpad 1741230 0 None None None 2018-01-04 14:30:14 UTC
Red Hat Bugzilla 1430987 1 None None None 2021-01-20 06:05:38 UTC

Internal Links: 1430987

Description Marcin Juszkiewicz 2018-01-04 14:30:14 UTC
Created attachment 1376987 [details]
nova log with domain xml

Description of problem:

Nova (OpenStack component) defaults to cpu_mode = host-model on all architectures. And then all VM instances fail:

"Failed to start libvirt guest: libvirtError: unsupported configuration: CPU mode 'host-model' for aarch64 kvm domain on aarch64 host is not supported by hypervisor."

Popular workaround is to use 'host-passthrough' but that breaks live migration on cloud setups with different ARMv8a cpu cores.

Version-Release number of selected component (if applicable):

3.10.0

How reproducible:

always

Steps to Reproduce:
1. Deploy Nova compute component
2. Run VM instance

Actual results:

"Failed to start libvirt guest: libvirtError: unsupported configuration: CPU mode 'host-model' for aarch64 kvm domain on aarch64 host is not supported by hypervisor."

Expected results:

Instance runs.
Additional info:

Comment 1 Marcin Juszkiewicz 2018-01-04 14:34:33 UTC
After some reading I tried 'cpu_mode=custom' + 'cpu_model=cortex-a53' but such setup broke Nova.

CPU snippet from domain definition was:

<cpu mode='custom' match='exact' check='partial'>
  <model fallback='allow'>cortex-a53</model>
  <topology sockets='1' cores='1' threads='1'/>
</cpu>

Comment 2 Daniel Berrangé 2024-12-17 12:24:41 UTC
Thank you for reporting this issue to the libvirt project. Unfortunately we have been unable to resolve this issue due to insufficient maintainer capacity and it will now be closed. This is not a reflection on the possible validity of the issue, merely the lack of resources to investigate and address it, for which we apologise. If you none the less feel the issue is still important, you may choose to report it again at the new project issue tracker https://gitlab.com/libvirt/libvirt/-/issues The project also welcomes contribution from anyone who believes they can provide a solution.


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