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

[Janosch Frank]

On 2/25/20 10:50 AM, David Hildenbrand wrote:
> 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?

The sprinkled over PV lines annoyed me anyway, so I added a unprotect()
function yesterday and now also moved the migration blocker into
protect() and unprotect()

> 
>>  
>>          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();
>>
> 
>

signature.asc
Description: OpenPGP digital signature