[PATCH 05/44] KVM: s390: Unwind kvm_arch_init() piece-by-piece() if a step fails

[Eric Farman]

On Wed, 2022-11-02 at 23:18 +0000, Sean Christopherson wrote:
> In preparation for folding kvm_arch_hardware_setup() into
> kvm_arch_init(),
> unwind initialization one step at a time instead of simply calling
> kvm_arch_exit().  Using kvm_arch_exit() regardless of which
> initialization
> step failed relies on all affected state playing nice with being
> undone
> even if said state wasn't first setup.  That holds true for state
> that is
> currently configured by kvm_arch_init(), but not for state that's
> handled
> by kvm_arch_hardware_setup(), e.g. calling
> gmap_unregister_pte_notifier()
> without first registering a notifier would result in list corruption
> due
> to attempting to delete an entry that was never added to the list.
> 
> Signed-off-by: Sean Christopherson <seanjc at google.com>
> ---
>  arch/s390/kvm/kvm-s390.c | 21 ++++++++++++++-------
>  1 file changed, 14 insertions(+), 7 deletions(-)

Reviewed-by: Eric Farman <farman at linux.ibm.com>