>-----Original Message-----
>From: Cédric Le Goater <c...@redhat.com>
>Subject: Re: [PATCH 1/5] vfio/iommufd: Save host iommu capabilities in
>VFIODevice.caps
>
>On 4/11/25 12:17, Zhenzhong Duan wrote:
>> The saved caps copy can be used to check dirty tracking capability.
>>
>> The capabilities is gotten through IOMMUFD interface, so define a
>> new structure HostIOMMUDeviceIOMMUFDCaps which contains vendor
>> caps raw data in "include/system/iommufd.h".
>>
>> This is a prepare work for moving .realize() after .attach_device().
>>
>> Suggested-by: Cédric Le Goater <c...@redhat.com>
>> Suggested-by: Eric Auger <eric.au...@redhat.com>
>> Suggested-by: Nicolin Chen <nicol...@nvidia.com>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
>> ---
>> include/hw/vfio/vfio-device.h | 1 +
>> include/system/iommufd.h | 22 ++++++++++++++++++++++
>> hw/vfio/iommufd.c | 10 +++++++++-
>> 3 files changed, 32 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
>> index 66797b4c92..09a7af891a 100644
>> --- a/include/hw/vfio/vfio-device.h
>> +++ b/include/hw/vfio/vfio-device.h
>> @@ -77,6 +77,7 @@ typedef struct VFIODevice {
>> bool dirty_tracking; /* Protected by BQL */
>> bool iommu_dirty_tracking;
>> HostIOMMUDevice *hiod;
>> + HostIOMMUDeviceIOMMUFDCaps caps;
>
>IMO, these capabilities belong to HostIOMMUDevice and not VFIODevice.
This was trying to address suggestions in [1], caps is generated by IOMMUFD
backend
and is only used by hiod_iommufd_get_cap(), hiod_legacy_vfio_get_cap() never
check it. By putting it in VFIODevice, I can save vendor caps in a union and raw
data format, hiod_iommufd_get_cap() recognizes the raw data format and can
check it for a cap support.
If keep caps in HostIOMMUDevice, I can think of a change like below to address
Eric and Nicolin's suggestion:
https://github.com/yiliu1765/qemu/commit/e05f91b2a724cefa8356969cb43284f7c3ec11d1
https://github.com/yiliu1765/qemu/commit/e05f91b2a724cefa8356969cb43284f7c3ec11d1
Does the change make sense for you?
[1] https://lists.gnu.org/archive/html/qemu-devel/2025-03/msg01552.html
>
>I would simply call iommufd_backend_get_device_info() twice where needed :
>iommufd_cdev_autodomains_get() and hiod_iommufd_vfio_realize()
OK, will do, that's simpler than current change.
Thanks
Zhenzhong
