[Qemu-discuss] QEMU is looping when I load a VM snapshot

[Arnabjyoti Kalita]

Hello,

I am repeatedly facing an issue while loading a saved snapshot into QEMU.

I will detail the steps which I follow when I take a snapshot:

1. I start QEMU with *-enable-kvm* option. I then run a workload(a program
from Spec2006) on QEMU.
2. Immediately after I start running the workload, I open the QEMU monitor
and using "SAVEVM" command I save the QEMU state when the program just
started to execute.
3. Once the QEMU state is saved, I allow the program to complete. I will
then quit QEMU.
4. Finally, I will load this snapshot back while starting QEMU - using the
same CPU and machine configurations. This time I do not apply the *-enable-kvm
*option, when loading the snapshot back.
5. I have added print statements to see the value of "PC" in the function --
      cpu_get_tb_cpu_state()
6. I see that the PC value does not change and keeps looping around two or
three values every time.
7. Hence the program which was paused(upon saving) does not complete
execution upon loading.

Why would this happen ? Any inputs on where I can seemingly identify the
root cause of this problem would help me a lot.

If you require any other information, I would be excited to help you out.

Thanks and Regards,
Arnab
Masters Student,
Stony Brook University