diff --git a/backends/iommufd.c b/backends/iommufd.c
index 60a3d14..06b1351 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -18,6 +18,7 @@
 #include "qemu/error-report.h"
 #include "monitor/monitor.h"
 #include "trace.h"
+#include "hw/vfio/vfio-common.h"
 #include <sys/ioctl.h>
 #include <linux/iommufd.h>
 
@@ -269,7 +270,7 @@
     case HOST_IOMMU_DEVICE_CAP_IOMMU_TYPE:
         return caps->type;
     case HOST_IOMMU_DEVICE_CAP_AW_BITS:
-        return caps->aw_bits;
+        return vfio_device_get_aw_bits(hiod->agent);
     default:
         error_setg(errp, "%s: unsupported capability %x", hiod->name, cap);
         return -EINVAL;
diff --git a/hw/vfio/container.c b/hw/vfio/container.c
index ce9a858..10cb4b4 100644
--- a/hw/vfio/container.c
+++ b/hw/vfio/container.c
@@ -1141,7 +1141,6 @@
     VFIODevice *vdev = opaque;
 
     hiod->name = g_strdup(vdev->name);
-    hiod->caps.aw_bits = vfio_device_get_aw_bits(vdev);
     hiod->agent = opaque;
 
     return true;
@@ -1150,11 +1149,9 @@
 static int hiod_legacy_vfio_get_cap(HostIOMMUDevice *hiod, int cap,
                                     Error **errp)
 {
-    HostIOMMUDeviceCaps *caps = &hiod->caps;
-
     switch (cap) {
     case HOST_IOMMU_DEVICE_CAP_AW_BITS:
-        return caps->aw_bits;
+        return vfio_device_get_aw_bits(hiod->agent);
     default:
         error_setg(errp, "%s: unsupported capability %x", hiod->name, cap);
         return -EINVAL;
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 58c11c9..f1e7cf3 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -725,7 +725,6 @@
 
     hiod->name = g_strdup(vdev->name);
     caps->type = type;
-    caps->aw_bits = vfio_device_get_aw_bits(vdev);
 
     return true;
 }
diff --git a/include/sysemu/host_iommu_device.h b/include/sysemu/host_iommu_device.h
index c1bf74a..d1c10ff 100644
--- a/include/sysemu/host_iommu_device.h
+++ b/include/sysemu/host_iommu_device.h
@@ -19,12 +19,9 @@
  * 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 {
     uint32_t type;
-    uint8_t aw_bits;
 } HostIOMMUDeviceCaps;
 
 #define TYPE_HOST_IOMMU_DEVICE "host-iommu-device"