Re: [PATCH] target/ppc: Fix e6500 boot

[Cédric Le Goater]

Hello Mario,

> I have tried to launch a freshly compiled qemu from git master on a NXP 
> T2080RDB devkit that has a e6500 CPU in combination with a freshly compiled 
> kernel 5.16-rc6
> I have Debian SID ppc64 up and running using such a kernel, and when I launch 
> qemu to run a VM with the same debian sid for ppc64 and the same kernel using 
> --enable-kvm I end up with a kernel panic
>
> [....]
> Run /sbin/init as init process
> random: fast init done
> systemd[1]: illegal instruction (4) at 3fff96562ac8 nip 3fff96562ac8 lr 
> 3fff96562aa8 code 1 in libc-2.32.so[3fff96516000+1f7000]
> systemd[1]: code: 60000000 38600006 9122b7e8 4801bead 60000000 60000000 
> 8122b7e8 2c090004
> systemd[1]: code: 40820014 39200005 60000000 9122b7e8 <00000000> 60000000 
> 8122b7e8 2c090005
> Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004
> Rebooting in 180 seconds..

I spend sometime looking at the kernel and QEMU and I noticed that
TCG e6500 machines have an issue when the kernel has KVM support.
I have limited knowledge on that topic but e6500 has extra MMU
features that an hypervisor could use for the guest and the e6500
emulation clearly doesn't have support for it.

In the guest, could you try with to run the KVM guest with a kernel
without KVM support and let us know ?

Thanks,

C.