Re: qemu aarch64 info registers PC register not changing

[Peter Maydell]

On Mon, 10 Jul 2023 at 09:12, Jiatong Shen <yshxxsjt715@gmail.com> wrote:
>
> Hello community experts,
>
>     I am trying to learn some arm64 basics using qemu. I would like to 
> retrieve a register value
> through hmp command info register. The output is
>
> virsh # qemu-monitor-command --hmp eefcdf53-2fd5-40ee-91a8-858b3e621fc5 info 
> registers -a

> every time I issue the command, PC register is always the value. My question 
> is should PC value be changed every time an instruction completes? Thank you 
> very much.
>
> The qemu version is 4.2.1. And the virtual machine is accelerated by KVM.

It's worth looking at what that PC is in the guest,
and what the guest is doing. If the guest is not particularly
doing much, then it's very likely that almost all of the time
when you look at it you'll find that the guest PC is pointing
to the WFI in the guest kernel's idle loop.

Other than that, QEMU 4.2.1 is pretty old, especially in
Arm terms (where KVM support has not been so mature for
as long as x86); so you could check whether a newer QEMU
also behaves the same way.

thanks
-- PMM