Re: [Qemu-devel] [PATCH v3 8/9] s390x/kvm: msi route fixup for non-pci

[David Hildenbrand]

On 26.07.2017 10:25, Thomas Huth wrote:
> On 26.07.2017 10:20, Cornelia Huck wrote:
>> On Wed, 26 Jul 2017 09:09:06 +0200
>> Thomas Huth <address@hidden> wrote:
>>
>>> On 25.07.2017 17:33, Cornelia Huck wrote:
>>>> If we don't provide pci, we cannot have a pci device for which we
>>>> have to translate to adapter routes: just return -ENODEV.
>>>>
>>>> Signed-off-by: Cornelia Huck <address@hidden>
>>>> ---
>>>>  target/s390x/kvm.c | 5 +++++
>>>>  1 file changed, 5 insertions(+)
>>>>
>>>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
>>>> index dc3f940b95..fb3e21a3a4 100644
>>>> --- a/target/s390x/kvm.c
>>>> +++ b/target/s390x/kvm.c
>>>> @@ -2424,6 +2424,11 @@ int kvm_arch_fixup_msi_route(struct 
>>>> kvm_irq_routing_entry *route,
>>>>      uint32_t idx = data >> ZPCI_MSI_VEC_BITS;
>>>>      uint32_t vec = data & ZPCI_MSI_VEC_MASK;
>>>>  
>>>> +    if (!s390_has_feat(S390_FEAT_ZPCI)) {
>>>> +        DPRINTF("fixup_msi_route on non-pci machine?!\n");
>>>> +        return -ENODEV;
>>>> +    }
>>>> +
>>>>      pbdev = s390_pci_find_dev_by_idx(s390_get_phb(), idx);
>>>>      if (!pbdev) {
>>>>          DPRINTF("add_msi_route no dev\n");
>>>>   
>>>
>>> Is this additional check really needed here? I'd rather expect
>>> s390_pci_find_dev_by_idx() to return NULL here already, so we should
>>> already be fine, shouldn't we?
>>
>> Yes, the end result is the same, but (1) better safe than sorry and (2)
>> I can add a debug print here.
>>
>> I had actually considered throwing an error here, as this function
>> really should not be called for !pci. Opinions?
> 
> At least the current DPRINTF will go unnoticed in 99% of all cases since
> it is not compiled in by default. So I'd say either do a proper
> error_report() or even g_assert() here, or simply drop the patch.
> 
>  Thomas
> 

I'd vote for g_assert() or simply dropping it.

-- 

Thanks,

David