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[PATCH v5 01/19] backends: Introduce HostIOMMUDevice abstract

Zhenzhong Duan posted 19 patches 1 year, 9 months ago
There is a newer version of this series
[PATCH v5 01/19] backends: Introduce HostIOMMUDevice abstract
Posted by Zhenzhong Duan 1 year, 9 months ago 
Introduce HostIOMMUDevice as an abstraction of host IOMMU device.

Introduce .realize() to initialize HostIOMMUDevice further after
instance init.

Introduce a macro CONFIG_HOST_IOMMU_DEVICE to define the usage
for VFIO, and VDPA in the future.

Suggested-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
 MAINTAINERS                        |  2 ++
 include/sysemu/host_iommu_device.h | 51 ++++++++++++++++++++++++++++++
 backends/host_iommu_device.c       | 30 ++++++++++++++++++
 backends/Kconfig                   |  5 +++
 backends/meson.build               |  1 +
 5 files changed, 89 insertions(+)
 create mode 100644 include/sysemu/host_iommu_device.h
 create mode 100644 backends/host_iommu_device.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 84391777db..5dab60bd04 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2191,6 +2191,8 @@ M: Zhenzhong Duan <zhenzhong.duan@intel.com>
 S: Supported
 F: backends/iommufd.c
 F: include/sysemu/iommufd.h
+F: backends/host_iommu_device.c
+F: include/sysemu/host_iommu_device.h
 F: include/qemu/chardev_open.h
 F: util/chardev_open.c
 F: docs/devel/vfio-iommufd.rst
diff --git a/include/sysemu/host_iommu_device.h b/include/sysemu/host_iommu_device.h
new file mode 100644
index 0000000000..2b58a94d62
--- /dev/null
+++ b/include/sysemu/host_iommu_device.h
@@ -0,0 +1,51 @@
+/*
+ * Host IOMMU device abstract declaration
+ *
+ * Copyright (C) 2024 Intel Corporation.
+ *
+ * Authors: Zhenzhong Duan <zhenzhong.duan@intel.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#ifndef HOST_IOMMU_DEVICE_H
+#define HOST_IOMMU_DEVICE_H
+
+#include "qom/object.h"
+#include "qapi/error.h"
+
+#define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
+OBJECT_DECLARE_TYPE(HostIOMMUDevice, HostIOMMUDeviceClass, HOST_IOMMU_DEVICE)
+
+struct HostIOMMUDevice {
+    Object parent_obj;
+};
+
+/**
+ * struct HostIOMMUDeviceClass - The base class for all host IOMMU devices.
+ *
+ * Different type of host devices (e.g., VFIO or VDPA device) or devices
+ * with different backend (e.g., VFIO legacy container or IOMMUFD backend)
+ * can have different sub-classes.
+ */
+struct HostIOMMUDeviceClass {
+    ObjectClass parent_class;
+
+    /**
+     * @realize: initialize host IOMMU device instance further.
+     *
+     * Mandatory callback.
+     *
+     * @hiod: pointer to a host IOMMU device instance.
+     *
+     * @opaque: pointer to agent device of this host IOMMU device,
+     *          i.e., for VFIO, pointer to VFIODevice
+     *
+     * @errp: pass an Error out when realize fails.
+     *
+     * Returns: true on success, false on failure.
+     */
+    bool (*realize)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
+};
+#endif
diff --git a/backends/host_iommu_device.c b/backends/host_iommu_device.c
new file mode 100644
index 0000000000..41f2fdce20
--- /dev/null
+++ b/backends/host_iommu_device.c
@@ -0,0 +1,30 @@
+/*
+ * Host IOMMU device abstract
+ *
+ * Copyright (C) 2024 Intel Corporation.
+ *
+ * Authors: Zhenzhong Duan <zhenzhong.duan@intel.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "sysemu/host_iommu_device.h"
+
+OBJECT_DEFINE_ABSTRACT_TYPE(HostIOMMUDevice,
+                            host_iommu_device,
+                            HOST_IOMMU_DEVICE,
+                            OBJECT)
+
+static void host_iommu_device_class_init(ObjectClass *oc, void *data)
+{
+}
+
+static void host_iommu_device_init(Object *obj)
+{
+}
+
+static void host_iommu_device_finalize(Object *obj)
+{
+}
diff --git a/backends/Kconfig b/backends/Kconfig
index 2cb23f62fa..34ab29e994 100644
--- a/backends/Kconfig
+++ b/backends/Kconfig
@@ -3,3 +3,8 @@ source tpm/Kconfig
 config IOMMUFD
     bool
     depends on VFIO
+
+config HOST_IOMMU_DEVICE
+    bool
+    default y
+    depends on VFIO
diff --git a/backends/meson.build b/backends/meson.build
index 8b2b111497..2e975d641e 100644
--- a/backends/meson.build
+++ b/backends/meson.build
@@ -25,6 +25,7 @@ if have_vhost_user
 endif
 system_ss.add(when: 'CONFIG_VIRTIO_CRYPTO', if_true: files('cryptodev-vhost.c'))
 system_ss.add(when: 'CONFIG_IOMMUFD', if_true: files('iommufd.c'))
+system_ss.add(when: 'CONFIG_HOST_IOMMU_DEVICE', if_true: files('host_iommu_device.c'))
 if have_vhost_user_crypto
   system_ss.add(when: 'CONFIG_VIRTIO_CRYPTO', if_true: files('cryptodev-vhost-user.c'))
 endif
-- 
2.34.1
Re: [PATCH v5 01/19] backends: Introduce HostIOMMUDevice abstract
Posted by Cédric Le Goater 1 year, 9 months ago 
Hello Zhenzhong,

On 5/8/24 11:03, Zhenzhong Duan wrote:
> Introduce HostIOMMUDevice as an abstraction of host IOMMU device.
> 
> Introduce .realize() to initialize HostIOMMUDevice further after
> instance init.
> 
> Introduce a macro CONFIG_HOST_IOMMU_DEVICE to define the usage
> for VFIO, and VDPA in the future.

This looks like a way to work around some other problem, like
avoiding exposing Linux definitions on windows build.

Thanks,

C.




> 
> Suggested-by: Cédric Le Goater <clg@redhat.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>   MAINTAINERS                        |  2 ++
>   include/sysemu/host_iommu_device.h | 51 ++++++++++++++++++++++++++++++
>   backends/host_iommu_device.c       | 30 ++++++++++++++++++
>   backends/Kconfig                   |  5 +++
>   backends/meson.build               |  1 +
>   5 files changed, 89 insertions(+)
>   create mode 100644 include/sysemu/host_iommu_device.h
>   create mode 100644 backends/host_iommu_device.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 84391777db..5dab60bd04 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2191,6 +2191,8 @@ M: Zhenzhong Duan <zhenzhong.duan@intel.com>
>   S: Supported
>   F: backends/iommufd.c
>   F: include/sysemu/iommufd.h
> +F: backends/host_iommu_device.c
> +F: include/sysemu/host_iommu_device.h
>   F: include/qemu/chardev_open.h
>   F: util/chardev_open.c
>   F: docs/devel/vfio-iommufd.rst
> diff --git a/include/sysemu/host_iommu_device.h b/include/sysemu/host_iommu_device.h
> new file mode 100644
> index 0000000000..2b58a94d62
> --- /dev/null
> +++ b/include/sysemu/host_iommu_device.h
> @@ -0,0 +1,51 @@
> +/*
> + * Host IOMMU device abstract declaration
> + *
> + * Copyright (C) 2024 Intel Corporation.
> + *
> + * Authors: Zhenzhong Duan <zhenzhong.duan@intel.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + */
> +
> +#ifndef HOST_IOMMU_DEVICE_H
> +#define HOST_IOMMU_DEVICE_H
> +
> +#include "qom/object.h"
> +#include "qapi/error.h"
> +
> +#define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
> +OBJECT_DECLARE_TYPE(HostIOMMUDevice, HostIOMMUDeviceClass, HOST_IOMMU_DEVICE)
> +
> +struct HostIOMMUDevice {
> +    Object parent_obj;
> +};
> +
> +/**
> + * struct HostIOMMUDeviceClass - The base class for all host IOMMU devices.
> + *
> + * Different type of host devices (e.g., VFIO or VDPA device) or devices
> + * with different backend (e.g., VFIO legacy container or IOMMUFD backend)
> + * can have different sub-classes.
> + */
> +struct HostIOMMUDeviceClass {
> +    ObjectClass parent_class;
> +
> +    /**
> +     * @realize: initialize host IOMMU device instance further.
> +     *
> +     * Mandatory callback.
> +     *
> +     * @hiod: pointer to a host IOMMU device instance.
> +     *
> +     * @opaque: pointer to agent device of this host IOMMU device,
> +     *          i.e., for VFIO, pointer to VFIODevice
> +     *
> +     * @errp: pass an Error out when realize fails.
> +     *
> +     * Returns: true on success, false on failure.
> +     */
> +    bool (*realize)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
> +};
> +#endif
> diff --git a/backends/host_iommu_device.c b/backends/host_iommu_device.c
> new file mode 100644
> index 0000000000..41f2fdce20
> --- /dev/null
> +++ b/backends/host_iommu_device.c
> @@ -0,0 +1,30 @@
> +/*
> + * Host IOMMU device abstract
> + *
> + * Copyright (C) 2024 Intel Corporation.
> + *
> + * Authors: Zhenzhong Duan <zhenzhong.duan@intel.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "sysemu/host_iommu_device.h"
> +
> +OBJECT_DEFINE_ABSTRACT_TYPE(HostIOMMUDevice,
> +                            host_iommu_device,
> +                            HOST_IOMMU_DEVICE,
> +                            OBJECT)
> +
> +static void host_iommu_device_class_init(ObjectClass *oc, void *data)
> +{
> +}
> +
> +static void host_iommu_device_init(Object *obj)
> +{
> +}
> +
> +static void host_iommu_device_finalize(Object *obj)
> +{
> +}
> diff --git a/backends/Kconfig b/backends/Kconfig
> index 2cb23f62fa..34ab29e994 100644
> --- a/backends/Kconfig
> +++ b/backends/Kconfig
> @@ -3,3 +3,8 @@ source tpm/Kconfig
>   config IOMMUFD
>       bool
>       depends on VFIO
> +
> +config HOST_IOMMU_DEVICE
> +    bool
> +    default y
> +    depends on VFIO
> diff --git a/backends/meson.build b/backends/meson.build
> index 8b2b111497..2e975d641e 100644
> --- a/backends/meson.build
> +++ b/backends/meson.build
> @@ -25,6 +25,7 @@ if have_vhost_user
>   endif
>   system_ss.add(when: 'CONFIG_VIRTIO_CRYPTO', if_true: files('cryptodev-vhost.c'))
>   system_ss.add(when: 'CONFIG_IOMMUFD', if_true: files('iommufd.c'))
> +system_ss.add(when: 'CONFIG_HOST_IOMMU_DEVICE', if_true: files('host_iommu_device.c'))

Euh. Why is that ?


>   if have_vhost_user_crypto
>     system_ss.add(when: 'CONFIG_VIRTIO_CRYPTO', if_true: files('cryptodev-vhost-user.c'))
>   endif
RE: [PATCH v5 01/19] backends: Introduce HostIOMMUDevice abstract
Posted by Duan, Zhenzhong 1 year, 9 months ago 
Hi Cédric,

>-----Original Message-----
>From: Cédric Le Goater <clg@redhat.com>
>Subject: Re: [PATCH v5 01/19] backends: Introduce HostIOMMUDevice
>abstract
>
>Hello Zhenzhong,
>
>On 5/8/24 11:03, Zhenzhong Duan wrote:
>> Introduce HostIOMMUDevice as an abstraction of host IOMMU device.
>>
>> Introduce .realize() to initialize HostIOMMUDevice further after
>> instance init.
>>
>> Introduce a macro CONFIG_HOST_IOMMU_DEVICE to define the usage
>> for VFIO, and VDPA in the future.
>
>This looks like a way to work around some other problem, like
>avoiding exposing Linux definitions on windows build.

Yes, I have used this MACRO in patch19 to fix build failure on windows.
Also need change HostIOMMUDeviceCaps::type to be uint32_t type.

>
>Thanks,
>
>C.
>
>
>
>
>>
>> Suggested-by: Cédric Le Goater <clg@redhat.com>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> ---
>>   MAINTAINERS                        |  2 ++
>>   include/sysemu/host_iommu_device.h | 51
>++++++++++++++++++++++++++++++
>>   backends/host_iommu_device.c       | 30 ++++++++++++++++++
>>   backends/Kconfig                   |  5 +++
>>   backends/meson.build               |  1 +
>>   5 files changed, 89 insertions(+)
>>   create mode 100644 include/sysemu/host_iommu_device.h
>>   create mode 100644 backends/host_iommu_device.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 84391777db..5dab60bd04 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -2191,6 +2191,8 @@ M: Zhenzhong Duan
><zhenzhong.duan@intel.com>
>>   S: Supported
>>   F: backends/iommufd.c
>>   F: include/sysemu/iommufd.h
>> +F: backends/host_iommu_device.c
>> +F: include/sysemu/host_iommu_device.h
>>   F: include/qemu/chardev_open.h
>>   F: util/chardev_open.c
>>   F: docs/devel/vfio-iommufd.rst
>> diff --git a/include/sysemu/host_iommu_device.h
>b/include/sysemu/host_iommu_device.h
>> new file mode 100644
>> index 0000000000..2b58a94d62
>> --- /dev/null
>> +++ b/include/sysemu/host_iommu_device.h
>> @@ -0,0 +1,51 @@
>> +/*
>> + * Host IOMMU device abstract declaration
>> + *
>> + * Copyright (C) 2024 Intel Corporation.
>> + *
>> + * Authors: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2.  See
>> + * the COPYING file in the top-level directory.
>> + */
>> +
>> +#ifndef HOST_IOMMU_DEVICE_H
>> +#define HOST_IOMMU_DEVICE_H
>> +
>> +#include "qom/object.h"
>> +#include "qapi/error.h"
>> +
>> +#define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
>> +OBJECT_DECLARE_TYPE(HostIOMMUDevice, HostIOMMUDeviceClass,
>HOST_IOMMU_DEVICE)
>> +
>> +struct HostIOMMUDevice {
>> +    Object parent_obj;
>> +};
>> +
>> +/**
>> + * struct HostIOMMUDeviceClass - The base class for all host IOMMU
>devices.
>> + *
>> + * Different type of host devices (e.g., VFIO or VDPA device) or devices
>> + * with different backend (e.g., VFIO legacy container or IOMMUFD
>backend)
>> + * can have different sub-classes.
>> + */
>> +struct HostIOMMUDeviceClass {
>> +    ObjectClass parent_class;
>> +
>> +    /**
>> +     * @realize: initialize host IOMMU device instance further.
>> +     *
>> +     * Mandatory callback.
>> +     *
>> +     * @hiod: pointer to a host IOMMU device instance.
>> +     *
>> +     * @opaque: pointer to agent device of this host IOMMU device,
>> +     *          i.e., for VFIO, pointer to VFIODevice
>> +     *
>> +     * @errp: pass an Error out when realize fails.
>> +     *
>> +     * Returns: true on success, false on failure.
>> +     */
>> +    bool (*realize)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
>> +};
>> +#endif
>> diff --git a/backends/host_iommu_device.c
>b/backends/host_iommu_device.c
>> new file mode 100644
>> index 0000000000..41f2fdce20
>> --- /dev/null
>> +++ b/backends/host_iommu_device.c
>> @@ -0,0 +1,30 @@
>> +/*
>> + * Host IOMMU device abstract
>> + *
>> + * Copyright (C) 2024 Intel Corporation.
>> + *
>> + * Authors: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2.  See
>> + * the COPYING file in the top-level directory.
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "sysemu/host_iommu_device.h"
>> +
>> +OBJECT_DEFINE_ABSTRACT_TYPE(HostIOMMUDevice,
>> +                            host_iommu_device,
>> +                            HOST_IOMMU_DEVICE,
>> +                            OBJECT)
>> +
>> +static void host_iommu_device_class_init(ObjectClass *oc, void *data)
>> +{
>> +}
>> +
>> +static void host_iommu_device_init(Object *obj)
>> +{
>> +}
>> +
>> +static void host_iommu_device_finalize(Object *obj)
>> +{
>> +}
>> diff --git a/backends/Kconfig b/backends/Kconfig
>> index 2cb23f62fa..34ab29e994 100644
>> --- a/backends/Kconfig
>> +++ b/backends/Kconfig
>> @@ -3,3 +3,8 @@ source tpm/Kconfig
>>   config IOMMUFD
>>       bool
>>       depends on VFIO
>> +
>> +config HOST_IOMMU_DEVICE
>> +    bool
>> +    default y
>> +    depends on VFIO
>> diff --git a/backends/meson.build b/backends/meson.build
>> index 8b2b111497..2e975d641e 100644
>> --- a/backends/meson.build
>> +++ b/backends/meson.build
>> @@ -25,6 +25,7 @@ if have_vhost_user
>>   endif
>>   system_ss.add(when: 'CONFIG_VIRTIO_CRYPTO', if_true: files('cryptodev-
>vhost.c'))
>>   system_ss.add(when: 'CONFIG_IOMMUFD', if_true: files('iommufd.c'))
>> +system_ss.add(when: 'CONFIG_HOST_IOMMU_DEVICE', if_true:
>files('host_iommu_device.c'))
>
>Euh. Why is that ?

Tried to reduce qemu binary size a bit.
When CONFIG_VFIO=n such as on windows,  CONFIG_HOST_IOMMU_DEVICE=n.
There is no user of host_iommu_device.c, so no need to build it.
But this way need to add '#ifdef CONFIG_HOST_IOMMU_DEVICE' in vtd_check_hdev() in intel_iommu.c.

The other way is to drop this build configuration, then there is no need to add '#ifdef CONFIG_HOST_IOMMU_DEVICE' in vtd_check_hdev() in intel_iommu.c, because
host_iommu_device.c is always built.

This series works in 1st way, I can change to 2nd way if you prefer.

Thanks
Zhenzhong
Re: [PATCH v5 01/19] backends: Introduce HostIOMMUDevice abstract
Posted by Cédric Le Goater 1 year, 8 months ago 
On 5/13/24 12:28, Duan, Zhenzhong wrote:
> Hi Cédric,
> 
>> -----Original Message-----
>> From: Cédric Le Goater <clg@redhat.com>
>> Subject: Re: [PATCH v5 01/19] backends: Introduce HostIOMMUDevice
>> abstract
>>
>> Hello Zhenzhong,
>>
>> On 5/8/24 11:03, Zhenzhong Duan wrote:
>>> Introduce HostIOMMUDevice as an abstraction of host IOMMU device.
>>>
>>> Introduce .realize() to initialize HostIOMMUDevice further after
>>> instance init.
>>>
>>> Introduce a macro CONFIG_HOST_IOMMU_DEVICE to define the usage
>>> for VFIO, and VDPA in the future.
>>
>> This looks like a way to work around some other problem, like
>> avoiding exposing Linux definitions on windows build.
> 
> Yes, I have used this MACRO in patch19 to fix build failure on windows.
> Also need change HostIOMMUDeviceCaps::type to be uint32_t type.

Routine host_iommu_device_get_cap() could be open coded in vtd_check_hdev()
to avoid CONFIG_HOST_IOMMU_DEVICE.

Thanks,

C.



> 
>>
>> Thanks,
>>
>> C.
>>
>>
>>
>>
>>>
>>> Suggested-by: Cédric Le Goater <clg@redhat.com>
>>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>>> ---
>>>    MAINTAINERS                        |  2 ++
>>>    include/sysemu/host_iommu_device.h | 51
>> ++++++++++++++++++++++++++++++
>>>    backends/host_iommu_device.c       | 30 ++++++++++++++++++
>>>    backends/Kconfig                   |  5 +++
>>>    backends/meson.build               |  1 +
>>>    5 files changed, 89 insertions(+)
>>>    create mode 100644 include/sysemu/host_iommu_device.h
>>>    create mode 100644 backends/host_iommu_device.c
>>>
>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>> index 84391777db..5dab60bd04 100644
>>> --- a/MAINTAINERS
>>> +++ b/MAINTAINERS
>>> @@ -2191,6 +2191,8 @@ M: Zhenzhong Duan
>> <zhenzhong.duan@intel.com>
>>>    S: Supported
>>>    F: backends/iommufd.c
>>>    F: include/sysemu/iommufd.h
>>> +F: backends/host_iommu_device.c
>>> +F: include/sysemu/host_iommu_device.h
>>>    F: include/qemu/chardev_open.h
>>>    F: util/chardev_open.c
>>>    F: docs/devel/vfio-iommufd.rst
>>> diff --git a/include/sysemu/host_iommu_device.h
>> b/include/sysemu/host_iommu_device.h
>>> new file mode 100644
>>> index 0000000000..2b58a94d62
>>> --- /dev/null
>>> +++ b/include/sysemu/host_iommu_device.h
>>> @@ -0,0 +1,51 @@
>>> +/*
>>> + * Host IOMMU device abstract declaration
>>> + *
>>> + * Copyright (C) 2024 Intel Corporation.
>>> + *
>>> + * Authors: Zhenzhong Duan <zhenzhong.duan@intel.com>
>>> + *
>>> + * This work is licensed under the terms of the GNU GPL, version 2.  See
>>> + * the COPYING file in the top-level directory.
>>> + */
>>> +
>>> +#ifndef HOST_IOMMU_DEVICE_H
>>> +#define HOST_IOMMU_DEVICE_H
>>> +
>>> +#include "qom/object.h"
>>> +#include "qapi/error.h"
>>> +
>>> +#define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
>>> +OBJECT_DECLARE_TYPE(HostIOMMUDevice, HostIOMMUDeviceClass,
>> HOST_IOMMU_DEVICE)
>>> +
>>> +struct HostIOMMUDevice {
>>> +    Object parent_obj;
>>> +};
>>> +
>>> +/**
>>> + * struct HostIOMMUDeviceClass - The base class for all host IOMMU
>> devices.
>>> + *
>>> + * Different type of host devices (e.g., VFIO or VDPA device) or devices
>>> + * with different backend (e.g., VFIO legacy container or IOMMUFD
>> backend)
>>> + * can have different sub-classes.
>>> + */
>>> +struct HostIOMMUDeviceClass {
>>> +    ObjectClass parent_class;
>>> +
>>> +    /**
>>> +     * @realize: initialize host IOMMU device instance further.
>>> +     *
>>> +     * Mandatory callback.
>>> +     *
>>> +     * @hiod: pointer to a host IOMMU device instance.
>>> +     *
>>> +     * @opaque: pointer to agent device of this host IOMMU device,
>>> +     *          i.e., for VFIO, pointer to VFIODevice
>>> +     *
>>> +     * @errp: pass an Error out when realize fails.
>>> +     *
>>> +     * Returns: true on success, false on failure.
>>> +     */
>>> +    bool (*realize)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
>>> +};
>>> +#endif
>>> diff --git a/backends/host_iommu_device.c
>> b/backends/host_iommu_device.c
>>> new file mode 100644
>>> index 0000000000..41f2fdce20
>>> --- /dev/null
>>> +++ b/backends/host_iommu_device.c
>>> @@ -0,0 +1,30 @@
>>> +/*
>>> + * Host IOMMU device abstract
>>> + *
>>> + * Copyright (C) 2024 Intel Corporation.
>>> + *
>>> + * Authors: Zhenzhong Duan <zhenzhong.duan@intel.com>
>>> + *
>>> + * This work is licensed under the terms of the GNU GPL, version 2.  See
>>> + * the COPYING file in the top-level directory.
>>> + */
>>> +
>>> +#include "qemu/osdep.h"
>>> +#include "sysemu/host_iommu_device.h"
>>> +
>>> +OBJECT_DEFINE_ABSTRACT_TYPE(HostIOMMUDevice,
>>> +                            host_iommu_device,
>>> +                            HOST_IOMMU_DEVICE,
>>> +                            OBJECT)
>>> +
>>> +static void host_iommu_device_class_init(ObjectClass *oc, void *data)
>>> +{
>>> +}
>>> +
>>> +static void host_iommu_device_init(Object *obj)
>>> +{
>>> +}
>>> +
>>> +static void host_iommu_device_finalize(Object *obj)
>>> +{
>>> +}
>>> diff --git a/backends/Kconfig b/backends/Kconfig
>>> index 2cb23f62fa..34ab29e994 100644
>>> --- a/backends/Kconfig
>>> +++ b/backends/Kconfig
>>> @@ -3,3 +3,8 @@ source tpm/Kconfig
>>>    config IOMMUFD
>>>        bool
>>>        depends on VFIO
>>> +
>>> +config HOST_IOMMU_DEVICE
>>> +    bool
>>> +    default y
>>> +    depends on VFIO
>>> diff --git a/backends/meson.build b/backends/meson.build
>>> index 8b2b111497..2e975d641e 100644
>>> --- a/backends/meson.build
>>> +++ b/backends/meson.build
>>> @@ -25,6 +25,7 @@ if have_vhost_user
>>>    endif
>>>    system_ss.add(when: 'CONFIG_VIRTIO_CRYPTO', if_true: files('cryptodev-
>> vhost.c'))
>>>    system_ss.add(when: 'CONFIG_IOMMUFD', if_true: files('iommufd.c'))
>>> +system_ss.add(when: 'CONFIG_HOST_IOMMU_DEVICE', if_true:
>> files('host_iommu_device.c'))
>>
>> Euh. Why is that ?
> 
> Tried to reduce qemu binary size a bit.
> When CONFIG_VFIO=n such as on windows,  CONFIG_HOST_IOMMU_DEVICE=n.
> There is no user of host_iommu_device.c, so no need to build it.
> But this way need to add '#ifdef CONFIG_HOST_IOMMU_DEVICE' in vtd_check_hdev() in intel_iommu.c.
> 
> The other way is to drop this build configuration, then there is no need to add '#ifdef CONFIG_HOST_IOMMU_DEVICE' in vtd_check_hdev() in intel_iommu.c, because
> host_iommu_device.c is always built.
> 
> This series works in 1st way, I can change to 2nd way if you prefer.
> 
> Thanks
> Zhenzhong
> 
> 
>

Patchew 2.1-devel-b67e4c2

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