Re: [Qemu-devel] [PATCH v1 for-2.12 2/2] s390x: load_psw() should only exchange the PSW for KVM

[David Hildenbrand <david@redhat.com>]

On 09.04.2018 13:35, Christian Borntraeger wrote:
> 
> 
> On 04/09/2018 01:30 PM, David Hildenbrand wrote:
>> Let's simplify it a bit. On some weird circumstances we would have tried
>> to recompute watchpoints when running under KVM.
>>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
>> ---
>>  target/s390x/helper.c | 10 ++++++----
>>  1 file changed, 6 insertions(+), 4 deletions(-)
>>
>> diff --git a/target/s390x/helper.c b/target/s390x/helper.c
>> index 615fa24ab9..e8548f340a 100644
>> --- a/target/s390x/helper.c
>> +++ b/target/s390x/helper.c
>> @@ -103,16 +103,18 @@ void load_psw(CPUS390XState *env, uint64_t mask, uint64_t addr)
>>
>>      env->psw.addr = addr;
>>      env->psw.mask = mask;
>> -    if (tcg_enabled()) {
>> -        env->cc_op = (mask >> 44) & 3;
>> +
>> +    /* KVM will handle all WAITs and trigger a WAIT exit on disabled_wait */
>> +    if (!tcg_enabled()) {
>> +        return;
>>      }
>> +    env->cc_op = (mask >> 44) & 3;
> 
> Do we have any call path were KVM could call load_psw?

do_restart_interrupt()

SIGP while the target CPU is stopped.

> 
>>
>>      if ((old_mask ^ mask) & PSW_MASK_PER) {
>>          s390_cpu_recompute_watchpoints(CPU(s390_env_get_cpu(env)));
>>      }
>>
>> -    /* KVM will handle all WAITs and trigger a WAIT exit on disabled_wait */
>> -    if (tcg_enabled() && (mask & PSW_MASK_WAIT)) {
>> +    if (mask & PSW_MASK_WAIT) {
>>          s390_handle_wait(s390_env_get_cpu(env));
>>      }
>>  }
>>
> 


-- 

Thanks,

David / dhildenb