RE: [PATCH rfcv3 05/21] vfio/iommufd: Save vendor specific device info

[Duan, Zhenzhong]

>-----Original Message-----
>From: Nicolin Chen <nicol...@nvidia.com>
>Subject: Re: [PATCH rfcv3 05/21] vfio/iommufd: Save vendor specific device info
>
>On Wed, May 21, 2025 at 07:14:35PM +0800, Zhenzhong Duan wrote:
>> @@ -852,6 +853,17 @@ static bool
>hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
>>      caps->type = type;
>>      caps->hw_caps = hw_caps;
>>
>> +    switch (type) {
>> +    case IOMMU_HW_INFO_TYPE_INTEL_VTD:
>> +        vendor_caps->vtd.flags = data.vtd.flags;
>> +        vendor_caps->vtd.cap_reg = data.vtd.cap_reg;
>> +        vendor_caps->vtd.ecap_reg = data.vtd.ecap_reg;
>> +        break;
>> +    case IOMMU_HW_INFO_TYPE_ARM_SMMUV3:
>> +    case IOMMU_HW_INFO_TYPE_NONE:
>
>Should this be a part of hiod_iommufd_get_vendor_cap() in backends?

Made following  adjustments which save raw data in VendorCaps,
let me know if it matches your thought.

diff --git a/include/system/host_iommu_device.h 
b/include/system/host_iommu_device.h
index 38070aff09..14cda4fdc3 100644
--- a/include/system/host_iommu_device.h
+++ b/include/system/host_iommu_device.h
@@ -14,16 +14,12 @@

 #include "qom/object.h"
 #include "qapi/error.h"
-
-/* This is mirror of struct iommu_hw_info_vtd */
-typedef struct Vtd_Caps {
-    uint32_t flags;
-    uint64_t cap_reg;
-    uint64_t ecap_reg;
-} Vtd_Caps;
+#ifdef CONFIG_LINUX
+#include "linux/iommufd.h"

 typedef union VendorCaps {
-    Vtd_Caps vtd;
+    struct iommu_hw_info_vtd vtd;
+    struct iommu_hw_info_arm_smmuv3 smmuv3;
 } VendorCaps;

 /**
@@ -43,6 +39,7 @@ typedef struct HostIOMMUDeviceCaps {
     uint64_t hw_caps;
     VendorCaps vendor_caps;
 } HostIOMMUDeviceCaps;
+#endif

 #define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"
 OBJECT_DECLARE_TYPE(HostIOMMUDevice, HostIOMMUDeviceClass, HOST_IOMMU_DEVICE)
@@ -54,7 +51,9 @@ struct HostIOMMUDevice {
     void *agent; /* pointer to agent device, ie. VFIO or VDPA device */
     PCIBus *aliased_bus;
     int aliased_devfn;
+#ifdef CONFIG_LINUX
     HostIOMMUDeviceCaps caps;
+#endif
 };

 /**
diff --git a/backends/iommufd.c b/backends/iommufd.c
index d91c1eb8b8..63209659f3 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -368,7 +368,7 @@ bool 
host_iommu_device_iommufd_detach_hwpt(HostIOMMUDeviceIOMMUFD *idev,
 static int hiod_iommufd_get_vtd_cap(HostIOMMUDevice *hiod, int cap,
                                     Error **errp)
 {
-    Vtd_Caps *caps = &hiod->caps.vendor_caps.vtd;
+    struct iommu_hw_info_vtd *caps = &hiod->caps.vendor_caps.vtd;

     switch (cap) {
     case HOST_IOMMU_DEVICE_CAP_NESTING:
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 5c740222e5..fbf47cab09 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -836,15 +836,12 @@ static bool hiod_iommufd_vfio_realize(HostIOMMUDevice 
*hiod, void *opaque,
     HostIOMMUDeviceCaps *caps = &hiod->caps;
     VendorCaps *vendor_caps = &caps->vendor_caps;
     enum iommu_hw_info_type type;
-    union {
-        struct iommu_hw_info_vtd vtd;
-    } data;
     uint64_t hw_caps;

     hiod->agent = opaque;

-    if (!iommufd_backend_get_device_info(vdev->iommufd, vdev->devid,
-                                         &type, &data, sizeof(data),
+    if (!iommufd_backend_get_device_info(vdev->iommufd, vdev->devid, &type,
+                                         vendor_caps, sizeof(*vendor_caps),
                                          &hw_caps, errp)) {
         return false;
     }
@@ -853,17 +850,6 @@ static bool hiod_iommufd_vfio_realize(HostIOMMUDevice 
*hiod, void *opaque,
     caps->type = type;
     caps->hw_caps = hw_caps;

-    switch (type) {
-    case IOMMU_HW_INFO_TYPE_INTEL_VTD:
-        vendor_caps->vtd.flags = data.vtd.flags;
-        vendor_caps->vtd.cap_reg = data.vtd.cap_reg;
-        vendor_caps->vtd.ecap_reg = data.vtd.ecap_reg;
-        break;
-    case IOMMU_HW_INFO_TYPE_ARM_SMMUV3:
-    case IOMMU_HW_INFO_TYPE_NONE:
-        break;
-    }
-
     idev = HOST_IOMMU_DEVICE_IOMMUFD(hiod);
     idev->iommufd = vdev->iommufd;
     idev->devid = vdev->devid;