[PATCH v4 04/13] virtio-gpu: Add virtio_gpu_find_check_resource

[Vivek Kasireddy <vivek.kasireddy@intel.com>]

Move finding the resource and validating its backing storage into one
function.

Based-on-patch-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
---
 hw/display/virtio-gpu.c | 66 +++++++++++++++++++++++++++++------------
 1 file changed, 47 insertions(+), 19 deletions(-)

diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
index 3607d3cab4..fec0bcf5c5 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -35,6 +35,10 @@
 
 static struct virtio_gpu_simple_resource*
 virtio_gpu_find_resource(VirtIOGPU *g, uint32_t resource_id);
+static struct virtio_gpu_simple_resource *
+virtio_gpu_find_check_resource(VirtIOGPU *g, uint32_t resource_id,
+                               bool require_backing,
+                               const char *caller, uint32_t *error);
 
 static void virtio_gpu_cleanup_mapping(VirtIOGPU *g,
                                        struct virtio_gpu_simple_resource *res);
@@ -46,7 +50,8 @@ void virtio_gpu_update_cursor_data(VirtIOGPU *g,
     struct virtio_gpu_simple_resource *res;
     uint32_t pixels;
 
-    res = virtio_gpu_find_resource(g, resource_id);
+    res = virtio_gpu_find_check_resource(g, resource_id, false,
+                                         __func__, NULL);
     if (!res) {
         return;
     }
@@ -114,6 +119,37 @@ virtio_gpu_find_resource(VirtIOGPU *g, uint32_t resource_id)
     return NULL;
 }
 
+static struct virtio_gpu_simple_resource *
+virtio_gpu_find_check_resource(VirtIOGPU *g, uint32_t resource_id,
+                               bool require_backing,
+                               const char *caller, uint32_t *error)
+{
+    struct virtio_gpu_simple_resource *res;
+
+    res = virtio_gpu_find_resource(g, resource_id);
+    if (!res) {
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid resource specified %d\n",
+                      caller, resource_id);
+        if (error) {
+            *error = VIRTIO_GPU_RESP_ERR_INVALID_RESOURCE_ID;
+        }
+        return NULL;
+    }
+
+    if (require_backing) {
+        if (!res->iov || !res->image) {
+            qemu_log_mask(LOG_GUEST_ERROR, "%s: no backing storage %d\n",
+                          caller, resource_id);
+            if (error) {
+                *error = VIRTIO_GPU_RESP_ERR_UNSPEC;
+            }
+            return NULL;
+        }
+    }
+
+    return res;
+}
+
 void virtio_gpu_ctrl_response(VirtIOGPU *g,
                               struct virtio_gpu_ctrl_command *cmd,
                               struct virtio_gpu_ctrl_hdr *resp,
@@ -352,11 +388,9 @@ static void virtio_gpu_transfer_to_host_2d(VirtIOGPU *g,
     virtio_gpu_t2d_bswap(&t2d);
     trace_virtio_gpu_cmd_res_xfer_toh_2d(t2d.resource_id);
 
-    res = virtio_gpu_find_resource(g, t2d.resource_id);
-    if (!res || !res->iov) {
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: illegal resource specified %d\n",
-                      __func__, t2d.resource_id);
-        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_RESOURCE_ID;
+    res = virtio_gpu_find_check_resource(g, t2d.resource_id, true,
+                                         __func__, &cmd->error);
+    if (!res) {
         return;
     }
 
@@ -410,11 +444,9 @@ static void virtio_gpu_resource_flush(VirtIOGPU *g,
     trace_virtio_gpu_cmd_res_flush(rf.resource_id,
                                    rf.r.width, rf.r.height, rf.r.x, rf.r.y);
 
-    res = virtio_gpu_find_resource(g, rf.resource_id);
+    res = virtio_gpu_find_check_resource(g, rf.resource_id, false,
+                                         __func__, &cmd->error);
     if (!res) {
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: illegal resource specified %d\n",
-                      __func__, rf.resource_id);
-        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_RESOURCE_ID;
         return;
     }
 
@@ -497,11 +529,9 @@ static void virtio_gpu_set_scanout(VirtIOGPU *g,
     }
 
     /* create a surface for this scanout */
-    res = virtio_gpu_find_resource(g, ss.resource_id);
+    res = virtio_gpu_find_check_resource(g, ss.resource_id, true,
+                                         __func__, &cmd->error);
     if (!res) {
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: illegal resource specified %d\n",
-                      __func__, ss.resource_id);
-        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_RESOURCE_ID;
         return;
     }
 
@@ -708,11 +738,9 @@ virtio_gpu_resource_detach_backing(VirtIOGPU *g,
     virtio_gpu_bswap_32(&detach, sizeof(detach));
     trace_virtio_gpu_cmd_res_back_detach(detach.resource_id);
 
-    res = virtio_gpu_find_resource(g, detach.resource_id);
-    if (!res || !res->iov) {
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: illegal resource specified %d\n",
-                      __func__, detach.resource_id);
-        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_RESOURCE_ID;
+    res = virtio_gpu_find_check_resource(g, detach.resource_id, true,
+                                         __func__, &cmd->error);
+    if (!res) {
         return;
     }
     virtio_gpu_cleanup_mapping(g, res);
-- 
2.30.2