[pve-devel] [PATCH v2 00/11] live-restore for PBS snapshots

Thomas Lamprecht t.lamprecht at proxmox.com
Thu Apr 15 20:35:46 CEST 2021

On 03.03.21 10:56, Stefan Reiter wrote:
> "live-restore" allows starting a VM immediately from a backup snapshot, no
> waiting for a long restore process. This is made possible with QEMU backing
> images, i.e. data is read from the backup which is attached to the VM as a
> drive, but new data is written to the destination, while a background process
> ('block-stream') copies over data in a linear fashion as well.

as mentioned off-list, it works good in general, but live-migration afterwards
seem to be broken, as resume on target fails:

kvm: ../target/i386/kvm.c:2538: kvm_put_msr_feature_control: Assertion `ret == 1' failed.

Stack trace of thread 1240139:
#0  0x00007f96834617bb __GI_raise (libc.so.6)
#1  0x00007f968344c535 __GI_abort (libc.so.6)
#2  0x00007f968344c40f __assert_fail_base (libc.so.6)
#3  0x00007f968345a102 __GI___assert_fail (libc.so.6)
#4  0x000055e795c18b82 kvm_put_msr_feature_control (qemu-system-x86_64)
#5  0x000055e795c9be7e do_kvm_cpu_synchronize_post_init (qemu-system-x86_64)
#6  0x000055e795acc5a6 process_queued_cpu_work (qemu-system-x86_64)
#7  0x000055e795d355b8 kvm_vcpu_thread_fn (qemu-system-x86_64)
#8  0x000055e795ece91a qemu_thread_start (qemu-system-x86_64)
#9  0x00007f96835f4fa3 start_thread (libpthread.so.0)
#10 0x00007f96835234cf __clone (libc.so.6)

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