RE: [PATCH v3 11/19] backends/iommufd: Implement HostIOMMUDeviceClass::check_cap() handler

[Duan, Zhenzhong]

>-----Original Message-----
>From: Cédric Le Goater <clg@redhat.com>
>Subject: Re: [PATCH v3 11/19] backends/iommufd: Implement
>HostIOMMUDeviceClass::check_cap() handler
>
>On 4/29/24 08:50, Zhenzhong Duan wrote:
>> Suggested-by: Cédric Le Goater <clg@redhat.com>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> ---
>>   backends/iommufd.c | 18 ++++++++++++++++++
>>   1 file changed, 18 insertions(+)
>>
>> diff --git a/backends/iommufd.c b/backends/iommufd.c
>> index d61209788a..28faec528e 100644
>> --- a/backends/iommufd.c
>> +++ b/backends/iommufd.c
>> @@ -233,6 +233,23 @@ int
>iommufd_backend_get_device_info(IOMMUFDBackend *be, uint32_t devid,
>>       return ret;
>>   }
>>
>> +static int hiod_iommufd_check_cap(HostIOMMUDevice *hiod, int cap,
>Error **errp)
>> +{
>> +    switch (cap) {
>> +    case HOST_IOMMU_DEVICE_CAP_IOMMUFD:
>> +        return 1;
>
>I don't understand this value.

1 means this host iommu device is attached to IOMMUFD backend,
or else 0 if attached to legacy backend.

Strictly speaking, HOST_IOMMU_DEVICE_CAP_IOMMUFD is not a
hardware capability, I'm trying to put all(sw/hw) in CAPs checking
framework just like KVM<->qemu CAPs does.

Thanks
Zhenzhong

>
>
>Thanks,
>
>C.
>
>
>> +    default:
>> +        return host_iommu_device_check_cap_common(hiod, cap, errp);
>> +    }
>> +}
>> +
>> +static void hiod_iommufd_class_init(ObjectClass *oc, void *data)
>> +{
>> +    HostIOMMUDeviceClass *hioc = HOST_IOMMU_DEVICE_CLASS(oc);
>> +
>> +    hioc->check_cap = hiod_iommufd_check_cap;
>> +};
>> +
>>   static const TypeInfo types[] = {
>>       {
>>           .name = TYPE_IOMMUFD_BACKEND,
>> @@ -251,6 +268,7 @@ static const TypeInfo types[] = {
>>           .parent = TYPE_HOST_IOMMU_DEVICE,
>>           .instance_size = sizeof(HostIOMMUDeviceIOMMUFD),
>>           .class_size = sizeof(HostIOMMUDeviceIOMMUFDClass),
>> +        .class_init = hiod_iommufd_class_init,
>>           .abstract = true,
>>       }
>>   };