Re: [PATCH v4 04/16] s390x: protvirt: Add migration blocker

[David Hildenbrand]

On 20.02.20 13:56, Janosch Frank wrote:
> Migration is not yet supported.
> 
> Signed-off-by: Janosch Frank <address@hidden>
> ---
>  hw/s390x/s390-virtio-ccw.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index aa974d294e..6fba8d9331 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -42,6 +42,9 @@
>  #include "hw/s390x/tod.h"
>  #include "sysemu/sysemu.h"
>  #include "hw/s390x/pv.h"
> +#include "migration/blocker.h"
> +
> +static Error *pv_mig_blocker;
>  
>  S390CPU *s390_cpu_addr2state(uint16_t cpu_addr)
>  {
> @@ -387,6 +390,7 @@ static void s390_machine_reset(MachineState *machine)
>      CPUState *cs, *t;
>      S390CPU *cpu;
>      S390CcwMachineState *ms = S390_CCW_MACHINE(machine);
> +    static Error *local_err;
>  
>      /* get the reset parameters, reset them once done */
>      s390_ipl_get_reset_request(&cs, &reset_type);
> @@ -436,13 +440,20 @@ static void s390_machine_reset(MachineState *machine)
>          }
>          run_on_cpu(cs, s390_do_cpu_reset, RUN_ON_CPU_NULL);
>  
> -        if (s390_machine_protect(ms)) {
> +        if (!pv_mig_blocker) {
> +            error_setg(&pv_mig_blocker,
> +                       "protected VMs are currently not migrateable.");
> +        }
> +        migrate_add_blocker(pv_mig_blocker, &local_err);
> +        if (!local_err && s390_machine_protect(ms)) {
>              s390_machine_inject_pv_error(cs);
> -            s390_cpu_set_state(S390_CPU_STATE_OPERATING, cpu);
> -            return;
> +            migrate_del_blocker(pv_mig_blocker);
> +            goto pv_err;
>          }

I'm sorry, but that looks ... a little to interesting to me. Why can't
you register/unregister the blocker where you actually perform the
switch to/from PV?

>  
>          run_on_cpu(cs, s390_do_cpu_load_normal, RUN_ON_CPU_NULL);
> +pv_err:
> +        s390_cpu_set_state(S390_CPU_STATE_OPERATING, cpu);
>          break;
>      default:
>          g_assert_not_reached();
> 


-- 
Thanks,

David / dhildenb