An issue was discovered in the Linux kernel for powerpc before 5.14.15. It allows a malicious KVM guest to crash the host, when the host is running on Power8, due to an arch/powerpc/kvm/book3s_hv_rmhandlers.S implementation bug in the handling of the SRR1 register values.
https://lore.kernel.org/linuxppc-dev/87pmrtbbdt.fsf%40mpe.ellerman.id.au/T/#u
https://git.kernel.org/linus/cdeb5d7d890e14f3b70e8087e745c4a6a7d9f337
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.14.15