...
How to use:
1. enable background snapshot capability
virsh qemu-monitor-command vm --hmp migrate_set_capability
background-snapshot on
2. stop the vm
virsh qemu-monitor-command vm --hmp stop
3. Start the external migration to a file
virsh qemu-monitor-command cent78-bs --hmp migrate exec:'cat > ./vm_state'
4. Wait for the migration finish and check that the migration has completed
state.
Thanks for continued working on this project! I have two high level questions
before dig into the patches.
Firstly, is step 2 required? Can we use a single QMP command to take snapshots
(which can still be a "migrate" command)?
Meanwhile, we might also want to check around the type of backend RAM. E.g.,
shmem and hugetlbfs are still not supported for uffd-wp (which I'm still
working on). I didn't check explicitly whether we'll simply fail the migration
for those cases since the uffd ioctls will fail for those kinds of RAM. It
would be okay if we handle all the ioctl failures gracefully,