vmm: clear restore snapshot after device creation#157
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tpressure merged 1 commit intoMay 19, 2026
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A restore snapshot is only construction input. The restore path should use it while rebuilding the VM from saved state, then discard it before later VM lifecycle operations run. Keeping it around is observable after a restored VM changes its device set. For example, a VM can be restored from a snapshot, live-migrated, and then hot-remove a device on the destination. The restored device tree no longer contains that device, but DeviceManager still carries the original device snapshot. That stale snapshot can affect later hotplug. Every added device eventually reaches a constructor that calls state_from_id(self.snapshot.as_ref(), id) or an equivalent snapshot lookup. If the stale snapshot still contains an entry with the newly added device name, the new device is created with old saved state even though the matching device was already removed from the live device tree. Clear the DeviceManager snapshot after hypervisor-specific initialization has rebuilt the interrupt controller and devices. From that point onward, device operations should behave as normal runtime operations, not as restore operations. Co-developed-by: Thomas Prescher <thomas.prescher@cyberus-technology.de> Co-developed-by: Leander Kohler <leander.kohler@cyberus-technology.de> On-behalf-of: SAP philipp.schuster@sap.com Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
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Coffeeri
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Great work @tpressure and @phip1611!
Please run the libvirt test pipeline before merging this.
amphi
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tpressure
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We both ran the test locally :) a new pipeline is running now including the CH bump: https://gitlab.cyberus-technology.de/cyberus/cloud/libvirt/-/merge_requests/209 |
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Upstream PR: cloud-hypervisor#8251 |
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Different solution to #156. Please see the commit message for more details.
Fixes: https://github.com/cobaltcore-dev/cobaltcore/issues/567