user-level: 0.583
graphic: 0.526
peripherals: 0.507
PID: 0.500
device: 0.495
arm: 0.493
permissions: 0.484
network: 0.481
virtual: 0.460
mistranslation: 0.447
performance: 0.442
semantic: 0.442
vnc: 0.442
KVM: 0.435
ppc: 0.433
hypervisor: 0.429
files: 0.418
risc-v: 0.414
kernel: 0.402
architecture: 0.398
VMM: 0.398
x86: 0.383
socket: 0.380
register: 0.378
boot: 0.366
assembly: 0.353
i386: 0.323
debug: 0.318
TCG: 0.307

savevm with hax saves wrong register state

I use qemu-i386 with IntelHaxm on Windows 10 x64 host with Windows 7 x86 guest. I run the guest till OS loads and create a snapshot with savevm, then close qemu, run it again and try to load the snapshot with loadvm. The guest crashes or freezes. I dumped registers on snapshot creation and loading (in Haxm) and found that they are different.
When returning from Haxm in hax_vcpu_hax_exec, there is no regular register read. I found hax_arch_get_registers function which reads registers from Haxm and is called from a synchronization procedure. I placed a breakpoint on it, ran qemu and found that it is hit one time during guest OS boot. Exactly these registers where saved in the snapshot.

cc'ing Colin and Yu for Hax info:

* Alex (<email address hidden>) wrote:
> Public bug reported:
> 
> I use qemu-i386 with IntelHaxm on Windows 10 x64 host with Windows 7 x86 guest. I run the guest till OS loads and create a snapshot with savevm, then close qemu, run it again and try to load the snapshot with loadvm. The guest crashes or freezes. I dumped registers on snapshot creation and loading (in Haxm) and found that they are different.
> When returning from Haxm in hax_vcpu_hax_exec, there is no regular register read. I found hax_arch_get_registers function which reads registers from Haxm and is called from a synchronization procedure. I placed a breakpoint on it, ran qemu and found that it is hit one time during guest OS boot. Exactly these registers where saved in the snapshot.
> 
> ** Affects: qemu
>      Importance: Undecided
>          Status: New
> 
> -- 
> You received this bug notification because you are a member of qemu-
> devel-ml, which is subscribed to QEMU.
> https://bugs.launchpad.net/bugs/1855617
> 
> Title:
>   savevm with hax saves wrong register state
> 
> Status in QEMU:
>   New
> 
> Bug description:
>   I use qemu-i386 with IntelHaxm on Windows 10 x64 host with Windows 7 x86 guest. I run the guest till OS loads and create a snapshot with savevm, then close qemu, run it again and try to load the snapshot with loadvm. The guest crashes or freezes. I dumped registers on snapshot creation and loading (in Haxm) and found that they are different.
>   When returning from Haxm in hax_vcpu_hax_exec, there is no regular register read. I found hax_arch_get_registers function which reads registers from Haxm and is called from a synchronization procedure. I placed a breakpoint on it, ran qemu and found that it is hit one time during guest OS boot. Exactly these registers where saved in the snapshot.
> 
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/qemu/+bug/1855617/+subscriptions
> 
--
Dr. David Alan Gilbert / <email address hidden> / Manchester, UK



The QEMU project is currently considering to move its bug tracking to
another system. For this we need to know which bugs are still valid
and which could be closed already. Thus we are setting older bugs to
"Incomplete" now.

If you still think this bug report here is valid, then please switch
the state back to "New" within the next 60 days, otherwise this report
will be marked as "Expired". Or please mark it as "Fix Released" if
the problem has been solved with a newer version of QEMU already.

Thank you and sorry for the inconvenience.



This is an automated cleanup. This bug report has been moved to QEMU's
new bug tracker on gitlab.com and thus gets marked as 'expired' now.
Please continue with the discussion here:

 https://gitlab.com/qemu-project/qemu/-/issues/188