Re: [PATCH v4 4/5] [FUTURE] xen/arm: enable vPCI for domUs

[Julien Grall <julien@xen.org>]

Hi,

On 31/10/2023 11:03, Jan Beulich wrote:
> On 31.10.2023 00:52, Stewart Hildebrand wrote:
>> --- a/xen/drivers/passthrough/pci.c
>> +++ b/xen/drivers/passthrough/pci.c
>> @@ -1618,6 +1618,16 @@ int iommu_do_pci_domctl(
>>           bus = PCI_BUS(machine_sbdf);
>>           devfn = PCI_DEVFN(machine_sbdf);
>>   
>> +        if ( IS_ENABLED(CONFIG_ARM) &&
>> +             !is_hardware_domain(d) &&
>> +             !is_system_domain(d) &&
>> +             (!IS_ENABLED(CONFIG_HAS_VPCI_GUEST_SUPPORT) || !has_vpci(d)) )
> 
> I don't think you need the explicit ARM check; that's redundant with
> checking !HAS_VPCI_GUEST_SUPPORT. It's also not really clear why you
> need to check for the system domain here.

I might be missing but I wouldn't expect the domain to have vPCI enabled 
if CONFIG_HAVE_VPCI_GUEST_SUPPORT=n. So why can't this simply be:

if ( !has_vcpi(d) )
{
    ...
}

Cheers,

-- 
Julien Grall