Enhance HostIOMMUDeviceIOMMUFD object with 3 new members, specific
to the iommufd BE + 2 new class functions.

IOMMUFD BE includes IOMMUFD handle, devid and hwpt_id. IOMMUFD handle
and devid are used to allocate/free ioas and hwpt. hwpt_id is used to
re-attach IOMMUFD backed device to its default VFIO sub-system created
hwpt, i.e., when vIOMMU is disabled by guest. These properties are
initialized in hiod::realize() after attachment.

2 new class functions are [at|de]tach_hwpt(). They are used to
attach/detach hwpt. VFIO and VDPA can have different implementions,
so implementation will be in sub-class instead of HostIOMMUDeviceIOMMUFD,
e.g., in HostIOMMUDeviceIOMMUFDVFIO.

Add two wrappers host_iommu_device_iommufd_[at|de]tach_hwpt to wrap the
two functions.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
---
 include/system/iommufd.h | 50 ++++++++++++++++++++++++++++++++++++++++
 backends/iommufd.c       | 22 ++++++++++++++++++
 hw/vfio/iommufd.c        |  6 +++++
 3 files changed, 78 insertions(+)

diff --git a/include/system/iommufd.h b/include/system/iommufd.h
index 83ab8e1e4c..283861b924 100644
--- a/include/system/iommufd.h
+++ b/include/system/iommufd.h
@@ -67,4 +67,54 @@ bool iommufd_backend_invalidate_cache(IOMMUFDBackend *be, uint32_t id,
                                       Error **errp);
 
 #define TYPE_HOST_IOMMU_DEVICE_IOMMUFD TYPE_HOST_IOMMU_DEVICE "-iommufd"
+OBJECT_DECLARE_TYPE(HostIOMMUDeviceIOMMUFD, HostIOMMUDeviceIOMMUFDClass,
+                    HOST_IOMMU_DEVICE_IOMMUFD)
+
+/* Overload of the host IOMMU device for the iommufd backend */
+struct HostIOMMUDeviceIOMMUFD {
+    HostIOMMUDevice parent_obj;
+
+    IOMMUFDBackend *iommufd;
+    uint32_t devid;
+    uint32_t hwpt_id;
+};
+
+struct HostIOMMUDeviceIOMMUFDClass {
+    HostIOMMUDeviceClass parent_class;
+
+    /**
+     * @attach_hwpt: attach host IOMMU device to IOMMUFD hardware page table.
+     * VFIO and VDPA device can have different implementation.
+     *
+     * Mandatory callback.
+     *
+     * @idev: host IOMMU device backed by IOMMUFD backend.
+     *
+     * @hwpt_id: ID of IOMMUFD hardware page table.
+     *
+     * @errp: pass an Error out when attachment fails.
+     *
+     * Returns: true on success, false on failure.
+     */
+    bool (*attach_hwpt)(HostIOMMUDeviceIOMMUFD *idev, uint32_t hwpt_id,
+                        Error **errp);
+    /**
+     * @detach_hwpt: detach host IOMMU device from IOMMUFD hardware page table.
+     * VFIO and VDPA device can have different implementation.
+     *
+     * Mandatory callback.
+     *
+     * @idev: host IOMMU device backed by IOMMUFD backend.
+     *
+     * @errp: pass an Error out when attachment fails.
+     *
+     * Returns: true on success, false on failure.
+     */
+    bool (*detach_hwpt)(HostIOMMUDeviceIOMMUFD *idev, Error **errp);
+};
+
+bool host_iommu_device_iommufd_attach_hwpt(HostIOMMUDeviceIOMMUFD *idev,
+                                           uint32_t hwpt_id, Error **errp);
+bool host_iommu_device_iommufd_detach_hwpt(HostIOMMUDeviceIOMMUFD *idev,
+                                           Error **errp);
 #endif
diff --git a/backends/iommufd.c b/backends/iommufd.c
index 8bcdb60fe7..c2c47abf7e 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -347,6 +347,26 @@ bool iommufd_backend_invalidate_cache(IOMMUFDBackend *be, uint32_t id,
     return !ret;
 }
 
+bool host_iommu_device_iommufd_attach_hwpt(HostIOMMUDeviceIOMMUFD *idev,
+                                           uint32_t hwpt_id, Error **errp)
+{
+    HostIOMMUDeviceIOMMUFDClass *idevc =
+        HOST_IOMMU_DEVICE_IOMMUFD_GET_CLASS(idev);
+
+    g_assert(idevc->attach_hwpt);
+    return idevc->attach_hwpt(idev, hwpt_id, errp);
+}
+
+bool host_iommu_device_iommufd_detach_hwpt(HostIOMMUDeviceIOMMUFD *idev,
+                                           Error **errp)
+{
+    HostIOMMUDeviceIOMMUFDClass *idevc =
+        HOST_IOMMU_DEVICE_IOMMUFD_GET_CLASS(idev);
+
+    g_assert(idevc->detach_hwpt);
+    return idevc->detach_hwpt(idev, errp);
+}
+
 static int hiod_iommufd_get_cap(HostIOMMUDevice *hiod, int cap, Error **errp)
 {
     HostIOMMUDeviceCaps *caps = &hiod->caps;
@@ -385,6 +405,8 @@ static const TypeInfo types[] = {
     }, {
         .name = TYPE_HOST_IOMMU_DEVICE_IOMMUFD,
         .parent = TYPE_HOST_IOMMU_DEVICE,
+        .instance_size = sizeof(HostIOMMUDeviceIOMMUFD),
+        .class_size = sizeof(HostIOMMUDeviceIOMMUFDClass),
         .class_init = hiod_iommufd_class_init,
         .abstract = true,
     }
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index af1c7ab10a..5fde2b633a 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -814,6 +814,7 @@ static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
                                       Error **errp)
 {
     VFIODevice *vdev = opaque;
+    HostIOMMUDeviceIOMMUFD *idev;
     HostIOMMUDeviceCaps *caps = &hiod->caps;
     enum iommu_hw_info_type type;
     union {
@@ -833,6 +834,11 @@ static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
     caps->type = type;
     caps->hw_caps = hw_caps;
 
+    idev = HOST_IOMMU_DEVICE_IOMMUFD(hiod);
+    idev->iommufd = vdev->iommufd;
+    idev->devid = vdev->devid;
+    idev->hwpt_id = vdev->hwpt->hwpt_id;
+
     return true;
 }
 
-- 
2.34.1

On 5/30/25 11:35 AM, Zhenzhong Duan wrote:
> Enhance HostIOMMUDeviceIOMMUFD object with 3 new members, specific
> to the iommufd BE + 2 new class functions.
>
> IOMMUFD BE includes IOMMUFD handle, devid and hwpt_id. IOMMUFD handle
> and devid are used to allocate/free ioas and hwpt. hwpt_id is used to
> re-attach IOMMUFD backed device to its default VFIO sub-system created
> hwpt, i.e., when vIOMMU is disabled by guest. These properties are
> initialized in hiod::realize() after attachment.
>
> 2 new class functions are [at|de]tach_hwpt(). They are used to
> attach/detach hwpt. VFIO and VDPA can have different implementions,
> so implementation will be in sub-class instead of HostIOMMUDeviceIOMMUFD,
> e.g., in HostIOMMUDeviceIOMMUFDVFIO.
>
> Add two wrappers host_iommu_device_iommufd_[at|de]tach_hwpt to wrap the
> two functions.
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Eric
> ---
>  include/system/iommufd.h | 50 ++++++++++++++++++++++++++++++++++++++++
>  backends/iommufd.c       | 22 ++++++++++++++++++
>  hw/vfio/iommufd.c        |  6 +++++
>  3 files changed, 78 insertions(+)
>
> diff --git a/include/system/iommufd.h b/include/system/iommufd.h
> index 83ab8e1e4c..283861b924 100644
> --- a/include/system/iommufd.h
> +++ b/include/system/iommufd.h
> @@ -67,4 +67,54 @@ bool iommufd_backend_invalidate_cache(IOMMUFDBackend *be, uint32_t id,
>                                        Error **errp);
>  
>  #define TYPE_HOST_IOMMU_DEVICE_IOMMUFD TYPE_HOST_IOMMU_DEVICE "-iommufd"
> +OBJECT_DECLARE_TYPE(HostIOMMUDeviceIOMMUFD, HostIOMMUDeviceIOMMUFDClass,
> +                    HOST_IOMMU_DEVICE_IOMMUFD)
> +
> +/* Overload of the host IOMMU device for the iommufd backend */
> +struct HostIOMMUDeviceIOMMUFD {
> +    HostIOMMUDevice parent_obj;
> +
> +    IOMMUFDBackend *iommufd;
> +    uint32_t devid;
> +    uint32_t hwpt_id;
> +};
> +
> +struct HostIOMMUDeviceIOMMUFDClass {
> +    HostIOMMUDeviceClass parent_class;
> +
> +    /**
> +     * @attach_hwpt: attach host IOMMU device to IOMMUFD hardware page table.
> +     * VFIO and VDPA device can have different implementation.
> +     *
> +     * Mandatory callback.
> +     *
> +     * @idev: host IOMMU device backed by IOMMUFD backend.
> +     *
> +     * @hwpt_id: ID of IOMMUFD hardware page table.
> +     *
> +     * @errp: pass an Error out when attachment fails.
> +     *
> +     * Returns: true on success, false on failure.
> +     */
> +    bool (*attach_hwpt)(HostIOMMUDeviceIOMMUFD *idev, uint32_t hwpt_id,
> +                        Error **errp);
> +    /**
> +     * @detach_hwpt: detach host IOMMU device from IOMMUFD hardware page table.
> +     * VFIO and VDPA device can have different implementation.
> +     *
> +     * Mandatory callback.
> +     *
> +     * @idev: host IOMMU device backed by IOMMUFD backend.
> +     *
> +     * @errp: pass an Error out when attachment fails.
> +     *
> +     * Returns: true on success, false on failure.
> +     */
> +    bool (*detach_hwpt)(HostIOMMUDeviceIOMMUFD *idev, Error **errp);
> +};
> +
> +bool host_iommu_device_iommufd_attach_hwpt(HostIOMMUDeviceIOMMUFD *idev,
> +                                           uint32_t hwpt_id, Error **errp);
> +bool host_iommu_device_iommufd_detach_hwpt(HostIOMMUDeviceIOMMUFD *idev,
> +                                           Error **errp);
>  #endif
> diff --git a/backends/iommufd.c b/backends/iommufd.c
> index 8bcdb60fe7..c2c47abf7e 100644
> --- a/backends/iommufd.c
> +++ b/backends/iommufd.c
> @@ -347,6 +347,26 @@ bool iommufd_backend_invalidate_cache(IOMMUFDBackend *be, uint32_t id,
>      return !ret;
>  }
>  
> +bool host_iommu_device_iommufd_attach_hwpt(HostIOMMUDeviceIOMMUFD *idev,
> +                                           uint32_t hwpt_id, Error **errp)
> +{
> +    HostIOMMUDeviceIOMMUFDClass *idevc =
> +        HOST_IOMMU_DEVICE_IOMMUFD_GET_CLASS(idev);
> +
> +    g_assert(idevc->attach_hwpt);
> +    return idevc->attach_hwpt(idev, hwpt_id, errp);
> +}
> +
> +bool host_iommu_device_iommufd_detach_hwpt(HostIOMMUDeviceIOMMUFD *idev,
> +                                           Error **errp)
> +{
> +    HostIOMMUDeviceIOMMUFDClass *idevc =
> +        HOST_IOMMU_DEVICE_IOMMUFD_GET_CLASS(idev);
> +
> +    g_assert(idevc->detach_hwpt);
> +    return idevc->detach_hwpt(idev, errp);
> +}
> +
>  static int hiod_iommufd_get_cap(HostIOMMUDevice *hiod, int cap, Error **errp)
>  {
>      HostIOMMUDeviceCaps *caps = &hiod->caps;
> @@ -385,6 +405,8 @@ static const TypeInfo types[] = {
>      }, {
>          .name = TYPE_HOST_IOMMU_DEVICE_IOMMUFD,
>          .parent = TYPE_HOST_IOMMU_DEVICE,
> +        .instance_size = sizeof(HostIOMMUDeviceIOMMUFD),
> +        .class_size = sizeof(HostIOMMUDeviceIOMMUFDClass),
>          .class_init = hiod_iommufd_class_init,
>          .abstract = true,
>      }
> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
> index af1c7ab10a..5fde2b633a 100644
> --- a/hw/vfio/iommufd.c
> +++ b/hw/vfio/iommufd.c
> @@ -814,6 +814,7 @@ static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
>                                        Error **errp)
>  {
>      VFIODevice *vdev = opaque;
> +    HostIOMMUDeviceIOMMUFD *idev;
>      HostIOMMUDeviceCaps *caps = &hiod->caps;
>      enum iommu_hw_info_type type;
>      union {
> @@ -833,6 +834,11 @@ static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
>      caps->type = type;
>      caps->hw_caps = hw_caps;
>  
> +    idev = HOST_IOMMU_DEVICE_IOMMUFD(hiod);
> +    idev->iommufd = vdev->iommufd;
> +    idev->devid = vdev->devid;
> +    idev->hwpt_id = vdev->hwpt->hwpt_id;
> +
>      return true;
>  }
>  

On Fri, May 30, 2025 at 05:35:10PM +0800, Zhenzhong Duan wrote:
> Enhance HostIOMMUDeviceIOMMUFD object with 3 new members, specific
> to the iommufd BE + 2 new class functions.
> 
> IOMMUFD BE includes IOMMUFD handle, devid and hwpt_id. IOMMUFD handle
> and devid are used to allocate/free ioas and hwpt. hwpt_id is used to
> re-attach IOMMUFD backed device to its default VFIO sub-system created
> hwpt, i.e., when vIOMMU is disabled by guest. These properties are
> initialized in hiod::realize() after attachment.
>
> 2 new class functions are [at|de]tach_hwpt(). They are used to
> attach/detach hwpt. VFIO and VDPA can have different implementions,
> so implementation will be in sub-class instead of HostIOMMUDeviceIOMMUFD,
> e.g., in HostIOMMUDeviceIOMMUFDVFIO.

You mean HostIOMMUDeviceVFIO and HostIOMMUDeviceVDPA?

I wonder what are the difference between their implementations.

Main reason for asking this is that we have alloc_hwpt (and will
have alloc_viommu soon) too, and should that/those be a part of
the Class op(s) too?

> @@ -833,6 +834,11 @@ static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
>      caps->type = type;
>      caps->hw_caps = hw_caps;
>  
> +    idev = HOST_IOMMU_DEVICE_IOMMUFD(hiod);
> +    idev->iommufd = vdev->iommufd;
> +    idev->devid = vdev->devid;
> +    idev->hwpt_id = vdev->hwpt->hwpt_id;

Since it's the default hwpt that VFIO contain allocated, perhaps
it's better to call it default_hwpt_id, indicating that won't be
changed by further HWPT attachment.

Thanks
Nicolin

>-----Original Message-----
>From: Nicolin Chen <nicolinc@nvidia.com>
>Subject: Re: [PATCH v2 2/4] vfio/iommufd: Add properties and handlers to
>TYPE_HOST_IOMMU_DEVICE_IOMMUFD
>
>On Fri, May 30, 2025 at 05:35:10PM +0800, Zhenzhong Duan wrote:
>> Enhance HostIOMMUDeviceIOMMUFD object with 3 new members, specific
>> to the iommufd BE + 2 new class functions.
>>
>> IOMMUFD BE includes IOMMUFD handle, devid and hwpt_id. IOMMUFD handle
>> and devid are used to allocate/free ioas and hwpt. hwpt_id is used to
>> re-attach IOMMUFD backed device to its default VFIO sub-system created
>> hwpt, i.e., when vIOMMU is disabled by guest. These properties are
>> initialized in hiod::realize() after attachment.
>>
>> 2 new class functions are [at|de]tach_hwpt(). They are used to
>> attach/detach hwpt. VFIO and VDPA can have different implementions,
>> so implementation will be in sub-class instead of HostIOMMUDeviceIOMMUFD,
>> e.g., in HostIOMMUDeviceIOMMUFDVFIO.
>
>You mean HostIOMMUDeviceVFIO and HostIOMMUDeviceVDPA?

HostIOMMUDeviceIOMMUFDVFIO and HostIOMMUDeviceIOMMUFDVDPA.

>
>I wonder what are the difference between their implementations.

They have different way to transform HOST_IOMMU_DEVICE(idev)->agent.
See host_iommu_device_iommufd_vfio_attach_hwpt()

>
>Main reason for asking this is that we have alloc_hwpt (and will
>have alloc_viommu soon) too, and should that/those be a part of
>the Class op(s) too?

I think vIOMMU could call alloc_viommu and alloc_hwpt directly,
they are common IOMMUFD interface no matter VFIO or VDPA backend device.

>
>> @@ -833,6 +834,11 @@ static bool
>hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
>>      caps->type = type;
>>      caps->hw_caps = hw_caps;
>>
>> +    idev = HOST_IOMMU_DEVICE_IOMMUFD(hiod);
>> +    idev->iommufd = vdev->iommufd;
>> +    idev->devid = vdev->devid;
>> +    idev->hwpt_id = vdev->hwpt->hwpt_id;
>
>Since it's the default hwpt that VFIO contain allocated, perhaps
>it's better to call it default_hwpt_id, indicating that won't be
>changed by further HWPT attachment.

hiod_iommufd_vfio_realize() is called only once, no one will change idev->hwpt_id.

Thanks
Zhenzhong