HostIOMMUDeviceCaps's elements map to the host IOMMU's capabilities.
Different platform IOMMU can support different elements.

Currently only two elements, type and aw_bits, type hints the host
platform IOMMU type, i.e., INTEL vtd, ARM smmu, etc; aw_bits hints
host IOMMU address width.

Introduce .check_cap() handler to check if HOST_IOMMU_DEVICE_CAP_XXX
is supported.

Introduce a HostIOMMUDevice API host_iommu_device_check_cap() which
is a wrapper of .check_cap().

Introduce a HostIOMMUDevice API host_iommu_device_check_cap_common()
to check common capabalities of different host platform IOMMUs.

Suggested-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
 include/sysemu/host_iommu_device.h | 44 ++++++++++++++++++++++++++++++
 backends/host_iommu_device.c       | 29 ++++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/include/sysemu/host_iommu_device.h b/include/sysemu/host_iommu_device.h
index 2b58a94d62..12b6afb463 100644
--- a/include/sysemu/host_iommu_device.h
+++ b/include/sysemu/host_iommu_device.h
@@ -14,12 +14,27 @@
 
 #include "qom/object.h"
 #include "qapi/error.h"
+#include "linux/iommufd.h"
+
+/**
+ * struct HostIOMMUDeviceCaps - Define host IOMMU device capabilities.
+ *
+ * @type: host platform IOMMU type.
+ *
+ * @aw_bits: host IOMMU address width. 0xff if no limitation.
+ */
+typedef struct HostIOMMUDeviceCaps {
+    enum iommu_hw_info_type type;
+    uint8_t aw_bits;
+} HostIOMMUDeviceCaps;
 
 #define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
 OBJECT_DECLARE_TYPE(HostIOMMUDevice, HostIOMMUDeviceClass, HOST_IOMMU_DEVICE)
 
 struct HostIOMMUDevice {
     Object parent_obj;
+
+    HostIOMMUDeviceCaps caps;
 };
 
 /**
@@ -47,5 +62,34 @@ struct HostIOMMUDeviceClass {
      * Returns: true on success, false on failure.
      */
     bool (*realize)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
+    /**
+     * @check_cap: check if a host IOMMU device capability is supported.
+     *
+     * Optional callback, if not implemented, hint not supporting query
+     * of @cap.
+     *
+     * @hiod: pointer to a host IOMMU device instance.
+     *
+     * @cap: capability to check.
+     *
+     * @errp: pass an Error out when fails to query capability.
+     *
+     * Returns: <0 on failure, 0 if a @cap is unsupported, or else
+     * 1 or some positive value for some special @cap,
+     * i.e., HOST_IOMMU_DEVICE_CAP_AW_BITS.
+     */
+    int (*check_cap)(HostIOMMUDevice *hiod, int cap, Error **errp);
 };
+
+/*
+ * Host IOMMU device capability list.
+ */
+#define HOST_IOMMU_DEVICE_CAP_IOMMUFD       0
+#define HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE    1
+#define HOST_IOMMU_DEVICE_CAP_AW_BITS       2
+
+
+int host_iommu_device_check_cap(HostIOMMUDevice *hiod, int cap, Error **errp);
+int host_iommu_device_check_cap_common(HostIOMMUDevice *hiod, int cap,
+                                       Error **errp);
 #endif
diff --git a/backends/host_iommu_device.c b/backends/host_iommu_device.c
index 41f2fdce20..b97d008cc7 100644
--- a/backends/host_iommu_device.c
+++ b/backends/host_iommu_device.c
@@ -28,3 +28,32 @@ static void host_iommu_device_init(Object *obj)
 static void host_iommu_device_finalize(Object *obj)
 {
 }
+
+/* Wrapper of HostIOMMUDeviceClass:check_cap */
+int host_iommu_device_check_cap(HostIOMMUDevice *hiod, int cap, Error **errp)
+{
+    HostIOMMUDeviceClass *hiodc = HOST_IOMMU_DEVICE_GET_CLASS(hiod);
+    if (!hiodc->check_cap) {
+        error_setg(errp, ".check_cap() not implemented");
+        return -EINVAL;
+    }
+
+    return hiodc->check_cap(hiod, cap, errp);
+}
+
+/* Implement check on common IOMMU capabilities */
+int host_iommu_device_check_cap_common(HostIOMMUDevice *hiod, int cap,
+                                       Error **errp)
+{
+    HostIOMMUDeviceCaps *caps = &hiod->caps;
+
+    switch (cap) {
+    case HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE:
+        return caps->type;
+    case HOST_IOMMU_DEVICE_CAP_AW_BITS:
+        return caps->aw_bits;
+    default:
+        error_setg(errp, "Not support query cap %x", cap);
+        return -EINVAL;
+    }
+}
-- 
2.34.1

Hello Zhenzhong,

On 4/29/24 08:50, Zhenzhong Duan wrote:
> HostIOMMUDeviceCaps's elements map to the host IOMMU's capabilities.
> Different platform IOMMU can support different elements.
> 
> Currently only two elements, type and aw_bits, type hints the host
> platform IOMMU type, i.e., INTEL vtd, ARM smmu, etc; aw_bits hints
> host IOMMU address width.
> 
> Introduce .check_cap() handler to check if HOST_IOMMU_DEVICE_CAP_XXX
> is supported.
> 
> Introduce a HostIOMMUDevice API host_iommu_device_check_cap() which
> is a wrapper of .check_cap().
> 
> Introduce a HostIOMMUDevice API host_iommu_device_check_cap_common()
> to check common capabalities of different host platform IOMMUs.
> 
> Suggested-by: Cédric Le Goater <clg@redhat.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>   include/sysemu/host_iommu_device.h | 44 ++++++++++++++++++++++++++++++
>   backends/host_iommu_device.c       | 29 ++++++++++++++++++++
>   2 files changed, 73 insertions(+)
> 
> diff --git a/include/sysemu/host_iommu_device.h b/include/sysemu/host_iommu_device.h
> index 2b58a94d62..12b6afb463 100644
> --- a/include/sysemu/host_iommu_device.h
> +++ b/include/sysemu/host_iommu_device.h
> @@ -14,12 +14,27 @@
>   
>   #include "qom/object.h"
>   #include "qapi/error.h"
> +#include "linux/iommufd.h"


Please use instead :

    #include <linux/iommufd.h>


Thanks,

C.


> +
> +/**
> + * struct HostIOMMUDeviceCaps - Define host IOMMU device capabilities.
> + *
> + * @type: host platform IOMMU type.
> + *
> + * @aw_bits: host IOMMU address width. 0xff if no limitation.
> + */
> +typedef struct HostIOMMUDeviceCaps {
> +    enum iommu_hw_info_type type;
> +    uint8_t aw_bits;
> +} HostIOMMUDeviceCaps;
>   
>   #define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
>   OBJECT_DECLARE_TYPE(HostIOMMUDevice, HostIOMMUDeviceClass, HOST_IOMMU_DEVICE)
>   
>   struct HostIOMMUDevice {
>       Object parent_obj;
> +
> +    HostIOMMUDeviceCaps caps;
>   };
>   
>   /**
> @@ -47,5 +62,34 @@ struct HostIOMMUDeviceClass {
>        * Returns: true on success, false on failure.
>        */
>       bool (*realize)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
> +    /**
> +     * @check_cap: check if a host IOMMU device capability is supported.
> +     *
> +     * Optional callback, if not implemented, hint not supporting query
> +     * of @cap.
> +     *
> +     * @hiod: pointer to a host IOMMU device instance.
> +     *
> +     * @cap: capability to check.
> +     *
> +     * @errp: pass an Error out when fails to query capability.
> +     *
> +     * Returns: <0 on failure, 0 if a @cap is unsupported, or else
> +     * 1 or some positive value for some special @cap,
> +     * i.e., HOST_IOMMU_DEVICE_CAP_AW_BITS.
> +     */
> +    int (*check_cap)(HostIOMMUDevice *hiod, int cap, Error **errp);
>   };
> +
> +/*
> + * Host IOMMU device capability list.
> + */
> +#define HOST_IOMMU_DEVICE_CAP_IOMMUFD       0
> +#define HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE    1
> +#define HOST_IOMMU_DEVICE_CAP_AW_BITS       2
> +
> +
> +int host_iommu_device_check_cap(HostIOMMUDevice *hiod, int cap, Error **errp);
> +int host_iommu_device_check_cap_common(HostIOMMUDevice *hiod, int cap,
> +                                       Error **errp);
>   #endif
> diff --git a/backends/host_iommu_device.c b/backends/host_iommu_device.c
> index 41f2fdce20..b97d008cc7 100644
> --- a/backends/host_iommu_device.c
> +++ b/backends/host_iommu_device.c
> @@ -28,3 +28,32 @@ static void host_iommu_device_init(Object *obj)
>   static void host_iommu_device_finalize(Object *obj)
>   {
>   }
> +
> +/* Wrapper of HostIOMMUDeviceClass:check_cap */
> +int host_iommu_device_check_cap(HostIOMMUDevice *hiod, int cap, Error **errp)
> +{
> +    HostIOMMUDeviceClass *hiodc = HOST_IOMMU_DEVICE_GET_CLASS(hiod);
> +    if (!hiodc->check_cap) {
> +        error_setg(errp, ".check_cap() not implemented");
> +        return -EINVAL;
> +    }
> +
> +    return hiodc->check_cap(hiod, cap, errp);
> +}
> +
> +/* Implement check on common IOMMU capabilities */
> +int host_iommu_device_check_cap_common(HostIOMMUDevice *hiod, int cap,
> +                                       Error **errp)
> +{
> +    HostIOMMUDeviceCaps *caps = &hiod->caps;
> +
> +    switch (cap) {
> +    case HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE:
> +        return caps->type;
> +    case HOST_IOMMU_DEVICE_CAP_AW_BITS:
> +        return caps->aw_bits;
> +    default:
> +        error_setg(errp, "Not support query cap %x", cap);
> +        return -EINVAL;
> +    }
> +}

>-----Original Message-----
>From: Cédric Le Goater <clg@redhat.com>
>Subject: Re: [PATCH v3 05/19] backends/host_iommu_device: Introduce
>HostIOMMUDeviceCaps
>
>Hello Zhenzhong,
>
>On 4/29/24 08:50, Zhenzhong Duan wrote:
>> HostIOMMUDeviceCaps's elements map to the host IOMMU's capabilities.
>> Different platform IOMMU can support different elements.
>>
>> Currently only two elements, type and aw_bits, type hints the host
>> platform IOMMU type, i.e., INTEL vtd, ARM smmu, etc; aw_bits hints
>> host IOMMU address width.
>>
>> Introduce .check_cap() handler to check if
>HOST_IOMMU_DEVICE_CAP_XXX
>> is supported.
>>
>> Introduce a HostIOMMUDevice API host_iommu_device_check_cap()
>which
>> is a wrapper of .check_cap().
>>
>> Introduce a HostIOMMUDevice API
>host_iommu_device_check_cap_common()
>> to check common capabalities of different host platform IOMMUs.
>>
>> Suggested-by: Cédric Le Goater <clg@redhat.com>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> ---
>>   include/sysemu/host_iommu_device.h | 44
>++++++++++++++++++++++++++++++
>>   backends/host_iommu_device.c       | 29 ++++++++++++++++++++
>>   2 files changed, 73 insertions(+)
>>
>> diff --git a/include/sysemu/host_iommu_device.h
>b/include/sysemu/host_iommu_device.h
>> index 2b58a94d62..12b6afb463 100644
>> --- a/include/sysemu/host_iommu_device.h
>> +++ b/include/sysemu/host_iommu_device.h
>> @@ -14,12 +14,27 @@
>>
>>   #include "qom/object.h"
>>   #include "qapi/error.h"
>> +#include "linux/iommufd.h"
>
>
>Please use instead :
>
>    #include <linux/iommufd.h>

Got it.

Thanks
Zhenzhong

On 4/29/24 08:50, Zhenzhong Duan wrote:
> HostIOMMUDeviceCaps's elements map to the host IOMMU's capabilities.
> Different platform IOMMU can support different elements.
> 
> Currently only two elements, type and aw_bits, type hints the host
> platform IOMMU type, i.e., INTEL vtd, ARM smmu, etc; aw_bits hints
> host IOMMU address width.
> 
> Introduce .check_cap() handler to check if HOST_IOMMU_DEVICE_CAP_XXX
> is supported.
> 
> Introduce a HostIOMMUDevice API host_iommu_device_check_cap() which
> is a wrapper of .check_cap().
> 
> Introduce a HostIOMMUDevice API host_iommu_device_check_cap_common()
> to check common capabalities of different host platform IOMMUs.
> 
> Suggested-by: Cédric Le Goater <clg@redhat.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>   include/sysemu/host_iommu_device.h | 44 ++++++++++++++++++++++++++++++
>   backends/host_iommu_device.c       | 29 ++++++++++++++++++++
>   2 files changed, 73 insertions(+)
> 
> diff --git a/include/sysemu/host_iommu_device.h b/include/sysemu/host_iommu_device.h
> index 2b58a94d62..12b6afb463 100644
> --- a/include/sysemu/host_iommu_device.h
> +++ b/include/sysemu/host_iommu_device.h
> @@ -14,12 +14,27 @@
>   
>   #include "qom/object.h"
>   #include "qapi/error.h"
> +#include "linux/iommufd.h"
> +
> +/**
> + * struct HostIOMMUDeviceCaps - Define host IOMMU device capabilities.
> + *
> + * @type: host platform IOMMU type.
> + *
> + * @aw_bits: host IOMMU address width. 0xff if no limitation.
> + */
> +typedef struct HostIOMMUDeviceCaps {
> +    enum iommu_hw_info_type type;
> +    uint8_t aw_bits;
> +} HostIOMMUDeviceCaps;
>   
>   #define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
>   OBJECT_DECLARE_TYPE(HostIOMMUDevice, HostIOMMUDeviceClass, HOST_IOMMU_DEVICE)
>   
>   struct HostIOMMUDevice {
>       Object parent_obj;
> +
> +    HostIOMMUDeviceCaps caps;
>   };
>   
>   /**
> @@ -47,5 +62,34 @@ struct HostIOMMUDeviceClass {
>        * Returns: true on success, false on failure.
>        */
>       bool (*realize)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
> +    /**
> +     * @check_cap: check if a host IOMMU device capability is supported.
> +     *
> +     * Optional callback, if not implemented, hint not supporting query
> +     * of @cap.
> +     *
> +     * @hiod: pointer to a host IOMMU device instance.
> +     *
> +     * @cap: capability to check.
> +     *
> +     * @errp: pass an Error out when fails to query capability.
> +     *
> +     * Returns: <0 on failure, 0 if a @cap is unsupported, or else
> +     * 1 or some positive value for some special @cap,
> +     * i.e., HOST_IOMMU_DEVICE_CAP_AW_BITS.
> +     */
> +    int (*check_cap)(HostIOMMUDevice *hiod, int cap, Error **errp);
>   };
> +
> +/*
> + * Host IOMMU device capability list.
> + */
> +#define HOST_IOMMU_DEVICE_CAP_IOMMUFD       0
> +#define HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE    1
> +#define HOST_IOMMU_DEVICE_CAP_AW_BITS       2
> +
> +
> +int host_iommu_device_check_cap(HostIOMMUDevice *hiod, int cap, Error **errp);
> +int host_iommu_device_check_cap_common(HostIOMMUDevice *hiod, int cap,
> +                                       Error **errp);
>   #endif
> diff --git a/backends/host_iommu_device.c b/backends/host_iommu_device.c
> index 41f2fdce20..b97d008cc7 100644
> --- a/backends/host_iommu_device.c
> +++ b/backends/host_iommu_device.c
> @@ -28,3 +28,32 @@ static void host_iommu_device_init(Object *obj)
>   static void host_iommu_device_finalize(Object *obj)
>   {
>   }
> +
> +/* Wrapper of HostIOMMUDeviceClass:check_cap */
> +int host_iommu_device_check_cap(HostIOMMUDevice *hiod, int cap, Error **errp)

Since we have an 'Error **errp', we could return a bool instead,
unless this is a 'get_cap' routine ?

Thanks,

C.


> +{
> +    HostIOMMUDeviceClass *hiodc = HOST_IOMMU_DEVICE_GET_CLASS(hiod);
> +    if (!hiodc->check_cap) {
> +        error_setg(errp, ".check_cap() not implemented");
> +        return -EINVAL;
> +    }
> +
> +    return hiodc->check_cap(hiod, cap, errp);
> +}
> +
> +/* Implement check on common IOMMU capabilities */
> +int host_iommu_device_check_cap_common(HostIOMMUDevice *hiod, int cap,
> +                                       Error **errp)
> +{
> +    HostIOMMUDeviceCaps *caps = &hiod->caps;
> +
> +    switch (cap) {
> +    case HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE:
> +        return caps->type;
> +    case HOST_IOMMU_DEVICE_CAP_AW_BITS:
> +        return caps->aw_bits;
> +    default:
> +        error_setg(errp, "Not support query cap %x", cap);
> +        return -EINVAL;
> +    }
> +}

>-----Original Message-----
>From: Cédric Le Goater <clg@redhat.com>
>Subject: Re: [PATCH v3 05/19] backends/host_iommu_device: Introduce
>HostIOMMUDeviceCaps
>
>On 4/29/24 08:50, Zhenzhong Duan wrote:
>> HostIOMMUDeviceCaps's elements map to the host IOMMU's capabilities.
>> Different platform IOMMU can support different elements.
>>
>> Currently only two elements, type and aw_bits, type hints the host
>> platform IOMMU type, i.e., INTEL vtd, ARM smmu, etc; aw_bits hints
>> host IOMMU address width.
>>
>> Introduce .check_cap() handler to check if
>HOST_IOMMU_DEVICE_CAP_XXX
>> is supported.
>>
>> Introduce a HostIOMMUDevice API host_iommu_device_check_cap()
>which
>> is a wrapper of .check_cap().
>>
>> Introduce a HostIOMMUDevice API
>host_iommu_device_check_cap_common()
>> to check common capabalities of different host platform IOMMUs.
>>
>> Suggested-by: Cédric Le Goater <clg@redhat.com>
>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>> ---
>>   include/sysemu/host_iommu_device.h | 44
>++++++++++++++++++++++++++++++
>>   backends/host_iommu_device.c       | 29 ++++++++++++++++++++
>>   2 files changed, 73 insertions(+)
>>
>> diff --git a/include/sysemu/host_iommu_device.h
>b/include/sysemu/host_iommu_device.h
>> index 2b58a94d62..12b6afb463 100644
>> --- a/include/sysemu/host_iommu_device.h
>> +++ b/include/sysemu/host_iommu_device.h
>> @@ -14,12 +14,27 @@
>>
>>   #include "qom/object.h"
>>   #include "qapi/error.h"
>> +#include "linux/iommufd.h"
>> +
>> +/**
>> + * struct HostIOMMUDeviceCaps - Define host IOMMU device capabilities.
>> + *
>> + * @type: host platform IOMMU type.
>> + *
>> + * @aw_bits: host IOMMU address width. 0xff if no limitation.
>> + */
>> +typedef struct HostIOMMUDeviceCaps {
>> +    enum iommu_hw_info_type type;
>> +    uint8_t aw_bits;
>> +} HostIOMMUDeviceCaps;
>>
>>   #define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
>>   OBJECT_DECLARE_TYPE(HostIOMMUDevice, HostIOMMUDeviceClass,
>HOST_IOMMU_DEVICE)
>>
>>   struct HostIOMMUDevice {
>>       Object parent_obj;
>> +
>> +    HostIOMMUDeviceCaps caps;
>>   };
>>
>>   /**
>> @@ -47,5 +62,34 @@ struct HostIOMMUDeviceClass {
>>        * Returns: true on success, false on failure.
>>        */
>>       bool (*realize)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
>> +    /**
>> +     * @check_cap: check if a host IOMMU device capability is supported.
>> +     *
>> +     * Optional callback, if not implemented, hint not supporting query
>> +     * of @cap.
>> +     *
>> +     * @hiod: pointer to a host IOMMU device instance.
>> +     *
>> +     * @cap: capability to check.
>> +     *
>> +     * @errp: pass an Error out when fails to query capability.
>> +     *
>> +     * Returns: <0 on failure, 0 if a @cap is unsupported, or else
>> +     * 1 or some positive value for some special @cap,
>> +     * i.e., HOST_IOMMU_DEVICE_CAP_AW_BITS.
>> +     */
>> +    int (*check_cap)(HostIOMMUDevice *hiod, int cap, Error **errp);
>>   };
>> +
>> +/*
>> + * Host IOMMU device capability list.
>> + */
>> +#define HOST_IOMMU_DEVICE_CAP_IOMMUFD       0
>> +#define HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE    1
>> +#define HOST_IOMMU_DEVICE_CAP_AW_BITS       2
>> +
>> +
>> +int host_iommu_device_check_cap(HostIOMMUDevice *hiod, int cap,
>Error **errp);
>> +int host_iommu_device_check_cap_common(HostIOMMUDevice *hiod,
>int cap,
>> +                                       Error **errp);
>>   #endif
>> diff --git a/backends/host_iommu_device.c
>b/backends/host_iommu_device.c
>> index 41f2fdce20..b97d008cc7 100644
>> --- a/backends/host_iommu_device.c
>> +++ b/backends/host_iommu_device.c
>> @@ -28,3 +28,32 @@ static void host_iommu_device_init(Object *obj)
>>   static void host_iommu_device_finalize(Object *obj)
>>   {
>>   }
>> +
>> +/* Wrapper of HostIOMMUDeviceClass:check_cap */
>> +int host_iommu_device_check_cap(HostIOMMUDevice *hiod, int cap,
>Error **errp)
>
>Since we have an 'Error **errp', we could return a bool instead,
>unless this is a 'get_cap' routine ?

Maybe better to name it host_iommu_device_get_cap()?
Because not all results are bool, some are integer, i.e., aw_bits.

Thanks
Zhenzhong

>
>Thanks,
>
>C.
>
>
>> +{
>> +    HostIOMMUDeviceClass *hiodc =
>HOST_IOMMU_DEVICE_GET_CLASS(hiod);
>> +    if (!hiodc->check_cap) {
>> +        error_setg(errp, ".check_cap() not implemented");
>> +        return -EINVAL;
>> +    }
>> +
>> +    return hiodc->check_cap(hiod, cap, errp);
>> +}
>> +
>> +/* Implement check on common IOMMU capabilities */
>> +int host_iommu_device_check_cap_common(HostIOMMUDevice *hiod,
>int cap,
>> +                                       Error **errp)
>> +{
>> +    HostIOMMUDeviceCaps *caps = &hiod->caps;
>> +
>> +    switch (cap) {
>> +    case HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE:
>> +        return caps->type;
>> +    case HOST_IOMMU_DEVICE_CAP_AW_BITS:
>> +        return caps->aw_bits;
>> +    default:
>> +        error_setg(errp, "Not support query cap %x", cap);
>> +        return -EINVAL;
>> +    }
>> +}

On 4/30/24 11:55, Duan, Zhenzhong wrote:
> 
> 
>> -----Original Message-----
>> From: Cédric Le Goater <clg@redhat.com>
>> Subject: Re: [PATCH v3 05/19] backends/host_iommu_device: Introduce
>> HostIOMMUDeviceCaps
>>
>> On 4/29/24 08:50, Zhenzhong Duan wrote:
>>> HostIOMMUDeviceCaps's elements map to the host IOMMU's capabilities.
>>> Different platform IOMMU can support different elements.
>>>
>>> Currently only two elements, type and aw_bits, type hints the host
>>> platform IOMMU type, i.e., INTEL vtd, ARM smmu, etc; aw_bits hints
>>> host IOMMU address width.
>>>
>>> Introduce .check_cap() handler to check if
>> HOST_IOMMU_DEVICE_CAP_XXX
>>> is supported.
>>>
>>> Introduce a HostIOMMUDevice API host_iommu_device_check_cap()
>> which
>>> is a wrapper of .check_cap().
>>>
>>> Introduce a HostIOMMUDevice API
>> host_iommu_device_check_cap_common()
>>> to check common capabalities of different host platform IOMMUs.
>>>
>>> Suggested-by: Cédric Le Goater <clg@redhat.com>
>>> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
>>> ---
>>>    include/sysemu/host_iommu_device.h | 44
>> ++++++++++++++++++++++++++++++
>>>    backends/host_iommu_device.c       | 29 ++++++++++++++++++++
>>>    2 files changed, 73 insertions(+)
>>>
>>> diff --git a/include/sysemu/host_iommu_device.h
>> b/include/sysemu/host_iommu_device.h
>>> index 2b58a94d62..12b6afb463 100644
>>> --- a/include/sysemu/host_iommu_device.h
>>> +++ b/include/sysemu/host_iommu_device.h
>>> @@ -14,12 +14,27 @@
>>>
>>>    #include "qom/object.h"
>>>    #include "qapi/error.h"
>>> +#include "linux/iommufd.h"
>>> +
>>> +/**
>>> + * struct HostIOMMUDeviceCaps - Define host IOMMU device capabilities.
>>> + *
>>> + * @type: host platform IOMMU type.
>>> + *
>>> + * @aw_bits: host IOMMU address width. 0xff if no limitation.
>>> + */
>>> +typedef struct HostIOMMUDeviceCaps {
>>> +    enum iommu_hw_info_type type;
>>> +    uint8_t aw_bits;
>>> +} HostIOMMUDeviceCaps;
>>>
>>>    #define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
>>>    OBJECT_DECLARE_TYPE(HostIOMMUDevice, HostIOMMUDeviceClass,
>> HOST_IOMMU_DEVICE)
>>>
>>>    struct HostIOMMUDevice {
>>>        Object parent_obj;
>>> +
>>> +    HostIOMMUDeviceCaps caps;
>>>    };
>>>
>>>    /**
>>> @@ -47,5 +62,34 @@ struct HostIOMMUDeviceClass {
>>>         * Returns: true on success, false on failure.
>>>         */
>>>        bool (*realize)(HostIOMMUDevice *hiod, void *opaque, Error **errp);
>>> +    /**
>>> +     * @check_cap: check if a host IOMMU device capability is supported.
>>> +     *
>>> +     * Optional callback, if not implemented, hint not supporting query
>>> +     * of @cap.
>>> +     *
>>> +     * @hiod: pointer to a host IOMMU device instance.
>>> +     *
>>> +     * @cap: capability to check.
>>> +     *
>>> +     * @errp: pass an Error out when fails to query capability.
>>> +     *
>>> +     * Returns: <0 on failure, 0 if a @cap is unsupported, or else
>>> +     * 1 or some positive value for some special @cap,
>>> +     * i.e., HOST_IOMMU_DEVICE_CAP_AW_BITS.
>>> +     */
>>> +    int (*check_cap)(HostIOMMUDevice *hiod, int cap, Error **errp);
>>>    };
>>> +
>>> +/*
>>> + * Host IOMMU device capability list.
>>> + */
>>> +#define HOST_IOMMU_DEVICE_CAP_IOMMUFD       0
>>> +#define HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE    1
>>> +#define HOST_IOMMU_DEVICE_CAP_AW_BITS       2
>>> +
>>> +
>>> +int host_iommu_device_check_cap(HostIOMMUDevice *hiod, int cap,
>> Error **errp);
>>> +int host_iommu_device_check_cap_common(HostIOMMUDevice *hiod,
>> int cap,
>>> +                                       Error **errp);
>>>    #endif
>>> diff --git a/backends/host_iommu_device.c
>> b/backends/host_iommu_device.c
>>> index 41f2fdce20..b97d008cc7 100644
>>> --- a/backends/host_iommu_device.c
>>> +++ b/backends/host_iommu_device.c
>>> @@ -28,3 +28,32 @@ static void host_iommu_device_init(Object *obj)
>>>    static void host_iommu_device_finalize(Object *obj)
>>>    {
>>>    }
>>> +
>>> +/* Wrapper of HostIOMMUDeviceClass:check_cap */
>>> +int host_iommu_device_check_cap(HostIOMMUDevice *hiod, int cap,
>> Error **errp)
>>
>> Since we have an 'Error **errp', we could return a bool instead,
>> unless this is a 'get_cap' routine ?
> 
> Maybe better to name it host_iommu_device_get_cap()?
> Because not all results are bool, some are integer, i.e., aw_bits.

LGTM.


Thanks,

C.