vfio: Create device specific region info helper

Given a device specific region type and sub-type, find it.  Also
cleanup return point on error in vfio_get_region_info() so that we
always return 0 with a valid pointer or -errno and NULL.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 49121798ff..902a047947 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1145,6 +1145,7 @@ retry:
 
     if (ioctl(vbasedev->fd, VFIO_DEVICE_GET_REGION_INFO, *info)) {
         g_free(*info);
+        *info = NULL;
         return -errno;
     }
 
@@ -1158,6 +1159,41 @@ retry:
     return 0;
 }
 
+int vfio_get_dev_region_info(VFIODevice *vbasedev, uint32_t type,
+                             uint32_t subtype, struct vfio_region_info **info)
+{
+    int i;
+
+    for (i = 0; i < vbasedev->num_regions; i++) {
+        struct vfio_info_cap_header *hdr;
+        struct vfio_region_info_cap_type *cap_type;
+
+        if (vfio_get_region_info(vbasedev, i, info)) {
+            continue;
+        }
+
+        hdr = vfio_get_region_info_cap(*info, VFIO_REGION_INFO_CAP_TYPE);
+        if (!hdr) {
+            g_free(*info);
+            continue;
+        }
+
+        cap_type = container_of(hdr, struct vfio_region_info_cap_type, header);
+
+        trace_vfio_get_dev_region(vbasedev->name, i,
+                                  cap_type->type, cap_type->subtype);
+
+        if (cap_type->type == type && cap_type->subtype == subtype) {
+            return 0;
+        }
+
+        g_free(*info);
+    }
+
+    *info = NULL;
+    return -ENODEV;
+}
+
 /*
  * Interfaces for IBM EEH (Enhanced Error Handling)
  */