>-----Original Message-----
>From: Cédric Le Goater <c...@redhat.com>
>Subject: Re: [PATCH v3 11/19] backends/iommufd: Implement
>HostIOMMUDeviceClass::check_cap() handler
>
>On 4/30/24 12:06, Duan, Zhenzhong wrote:
>>
>>
>>> -----Original Message-----
>>> From: Cédric Le Goater <c...@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 <c...@redhat.com>
>>>> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@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.
>
>Hmm, this looks hacky to me and it is not used anywhere in the patchset.
>Let's reconsider when there is actually a use for it. Until then, please
>drop. My feeling is that a new HostIOMMUDeviceClass handler/attributed
>should be introduced instead.
Got it, will drop it in this series.
Is "return 1" directly the concern on your side? If yes, what about adding a new
element be_type which can be initialized in realize(), like below:
--- a/include/sysemu/host_iommu_device.h
+++ b/include/sysemu/host_iommu_device.h
@@ -28,6 +28,9 @@
* @fs1gp: first stage(a.k.a, Stage-1) 1GB huge page support.
*/
typedef struct HostIOMMUDeviceCaps {
+#define HOST_IOMMU_DEVICE_CAP_BACKEND_LEGACY 0
+#define HOST_IOMMU_DEVICE_CAP_BACKEND_IOMMUFD 1
+ uint32_t be_type;
enum iommu_hw_info_type type;
uint8_t aw_bits;
bool nesting;
@@ -91,7 +94,7 @@ struct HostIOMMUDeviceClass {
/*
* Host IOMMU device capability list.
*/
-#define HOST_IOMMU_DEVICE_CAP_IOMMUFD 0
+#define HOST_IOMMU_DEVICE_CAP_BACKEND_TYPE 0
#define HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE 1
#define HOST_IOMMU_DEVICE_CAP_AW_BITS 2
#define HOST_IOMMU_DEVICE_CAP_NESTING 3
This looks a bit simpler than adding another handler.
Or you have other concern?
Thanks
Zhenzhong
>
>
>Thanks,
>
>C.
>
>
>
>> 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,
>>>> }
>>>> };
>>
