Cloud Hypervisor now refuses a live migrate if the destination lacks the guest's matrix CPU features
Brief
Anyone still on v53.0 does not have this check.
Notes
Three Oliver Anderson commits landed on main (2026-08-13): f2d5f82293088cb6b105dbcdbda075428f0f97bf (TMUL / AMX feature bits), bfbcbd2a3927549d50615d29315965d5790e4b77 (how many AMX sub-leaves), cf5d9e6d8a218b933fd3fc42a7c78517d25c5727 (AMX max palette). No new release tag. Latest release remains v53.0.
The destination must support any AMX feature the source already exposed. A dest with fewer sub-leaves is not a sound migrate even if KVM would accept the write. AMD is assumed unused for these leaves.
This is live-migrate compatibility. Not virtio overflow, not a jailer miss, not a snapshot host-file leak. No GHSA or CVE in the messages. One story, not three.
Commit f2d5f82293088cb6b105dbcdbda075428f0f97bf