On 2/19/25 9:22 AM, Zhenzhong Duan wrote:
> Currently we have realize() callback which is called before attachment.
> But there are still some elements e.g., hwpt_id is not ready before
> attachment. So we need a realize_late() callback to further initialize
> them.
from the description it is not obvious why the realize() could not have
been called after the attach. Could you remind the reader what is the
reason?
Thanks
Eric
>
> Currently, this callback is only useful for iommufd backend. For legacy
> backend nothing needs to be initialized after attachment.
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>
> ---
> include/system/host_iommu_device.h | 17 +++++++++++++++++
> hw/vfio/common.c | 17 ++++++++++++++---
> 2 files changed, 31 insertions(+), 3 deletions(-)
>
> diff --git a/include/system/host_iommu_device.h
> b/include/system/host_iommu_device.h
> index 809cced4ba..df782598f2 100644
> --- a/include/system/host_iommu_device.h
> +++ b/include/system/host_iommu_device.h
> @@ -66,6 +66,23 @@ struct HostIOMMUDeviceClass {
> * Returns: true on success, false on failure.
> */
> bool (*realize)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
> + /**
> + * @realize_late: initialize host IOMMU device instance after attachment,
> + * some elements e.g., ioas are ready only after
> attachment.
> + * This callback initialize them.
> + *
> + * Optional callback.
> + *
> + * @hiod: pointer to a host IOMMU device instance.
> + *
> + * @opaque: pointer to agent device of this host IOMMU device,
> + * e.g., VFIO base device or VDPA device.
> + *
> + * @errp: pass an Error out when realize fails.
> + *
> + * Returns: true on success, false on failure.
> + */
> + bool (*realize_late)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
> /**
> * @get_cap: check if a host IOMMU device capability is supported.
> *
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index abbdc56b6d..e198b1e5a2 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -1550,6 +1550,7 @@ bool vfio_attach_device(char *name, VFIODevice
> *vbasedev,
> const VFIOIOMMUClass *ops =
> VFIO_IOMMU_CLASS(object_class_by_name(TYPE_VFIO_IOMMU_LEGACY));
> HostIOMMUDevice *hiod = NULL;
> + HostIOMMUDeviceClass *hiod_ops = NULL;
>
> if (vbasedev->iommufd) {
> ops =
> VFIO_IOMMU_CLASS(object_class_by_name(TYPE_VFIO_IOMMU_IOMMUFD));
> @@ -1560,16 +1561,26 @@ bool vfio_attach_device(char *name, VFIODevice
> *vbasedev,
>
> if (!vbasedev->mdev) {
> hiod = HOST_IOMMU_DEVICE(object_new(ops->hiod_typename));
> + hiod_ops = HOST_IOMMU_DEVICE_GET_CLASS(hiod);
> vbasedev->hiod = hiod;
> }
>
> if (!ops->attach_device(name, vbasedev, as, errp)) {
> - object_unref(hiod);
> - vbasedev->hiod = NULL;
> - return false;
> + goto err_attach;
> + }
> +
> + if (hiod_ops && hiod_ops->realize_late &&
> + !hiod_ops->realize_late(hiod, vbasedev, errp)) {
> + ops->detach_device(vbasedev);
> + goto err_attach;
> }
>
> return true;
> +
> +err_attach:
> + object_unref(hiod);
> + vbasedev->hiod = NULL;
> + return false;
> }
>
> void vfio_detach_device(VFIODevice *vbasedev)
