Question about migrate the vm with host-passthrough cpu

Guoyi Tu
Wed, 24 Feb 2021 13:42:37 -0000

Hi there,

Sorry to bother you, but could I ask you a question about the live
migration of virtual machine configured with host-passthough cpu, it
confuse me a lot.

Here i have two hosts with different cpu, and the cpu feature set of old
host is subset of the new one (by virsh cpu-compare). If the vm was
first started on the old host,is it safe to migrate the vm between the
two hosts back and forth with the vm always keep running?

I've test the case in my environment, and the migration succeeds, the
cpu family/model/stepping and features of lscpu in Guest OS is the same.


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Best Regards,
Guoyi Tu