Re: [RFC PATCH v1 3/6] KVM: s390: Simplify SIGP Restart

[Thomas Huth <thuth@redhat.com>]

On 11/10/2021 09.45, Christian Borntraeger wrote:
> 
> 
> Am 08.10.21 um 22:31 schrieb Eric Farman:
>> Now that we check for the STOP IRQ injection at the top of the SIGP
>> handler (before the userspace/kernelspace check), we don't need to do
>> it down here for the Restart order.
>>
>> Signed-off-by: Eric Farman <farman@linux.ibm.com>
>> ---
>>   arch/s390/kvm/sigp.c | 11 +----------
>>   1 file changed, 1 insertion(+), 10 deletions(-)
>>
>> diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c
>> index 6ca01bbc72cf..0c08927ca7c9 100644
>> --- a/arch/s390/kvm/sigp.c
>> +++ b/arch/s390/kvm/sigp.c
>> @@ -240,17 +240,8 @@ static int __sigp_sense_running(struct kvm_vcpu *vcpu,
>>   static int __prepare_sigp_re_start(struct kvm_vcpu *vcpu,
>>                      struct kvm_vcpu *dst_vcpu, u8 order_code)
>>   {
>> -    struct kvm_s390_local_interrupt *li = &dst_vcpu->arch.local_int;
>>       /* handle (RE)START in user space */
>> -    int rc = -EOPNOTSUPP;
>> -
>> -    /* make sure we don't race with STOP irq injection */
>> -    spin_lock(&li->lock);
>> -    if (kvm_s390_is_stop_irq_pending(dst_vcpu))
>> -        rc = SIGP_CC_BUSY;
>> -    spin_unlock(&li->lock);
>> -
>> -    return rc;
>> +    return -EOPNOTSUPP;
>>   }
>>   static int __prepare_sigp_cpu_reset(struct kvm_vcpu *vcpu,
>>
> 
> @thuth?
> Question is, does it make sense to merge patch 2 and 3 to make things more 
> obvious?

Maybe.

Anyway: Would it make sense to remove __prepare_sigp_re_start() completely 
now and let __prepare_sigp_unknown() set the return code in the "default:" case?

  Thomas