[GIT PULL 15/19] hw/display/virtio-gpu: Propagate udmabuf errors

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

From: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>

Propagate udmabuf errors so that the requested operation will be
canceled instead of producing an incomplete result and the user can
notice the failure.

Fixes: e0933d91b1cd ("virtio-gpu: Add virtio_gpu_resource_create_blob")
Fixes: f66767f75c9c ("virtio-gpu: add virtio-gpu/blob vmstate subsection")
Fixes: 4ae1c5c7d6f3 ("hw/display/virtio-gpu: Initialize blob mapping for ATTACH_BACKING")
Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-ID: <20260825-dmabuf-v2-3-b3d64d3b9a0e@rsg.ci.i.u-tokyo.ac.jp>
---
 hw/display/virtio-gpu-udmabuf-stubs.c |  3 ++-
 hw/display/virtio-gpu-udmabuf.c       |  8 +++++---
 hw/display/virtio-gpu.c               | 18 ++++++++++++++----
 include/hw/virtio/virtio-gpu.h        |  2 +-
 4 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/hw/display/virtio-gpu-udmabuf-stubs.c b/hw/display/virtio-gpu-udmabuf-stubs.c
index 85d03935a332..0883bf05fac1 100644
--- a/hw/display/virtio-gpu-udmabuf-stubs.c
+++ b/hw/display/virtio-gpu-udmabuf-stubs.c
@@ -7,9 +7,10 @@ bool virtio_gpu_have_udmabuf(void)
     return false;
 }
 
-void virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res)
+bool virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res)
 {
     /* nothing (stub) */
+    return false;
 }
 
 void virtio_gpu_fini_udmabuf(VirtIOGPU *g, struct virtio_gpu_simple_resource *res)
diff --git a/hw/display/virtio-gpu-udmabuf.c b/hw/display/virtio-gpu-udmabuf.c
index ba02ba9e8616..c230509852ff 100644
--- a/hw/display/virtio-gpu-udmabuf.c
+++ b/hw/display/virtio-gpu-udmabuf.c
@@ -131,7 +131,7 @@ bool virtio_gpu_have_udmabuf(void)
     return memfd_backend;
 }
 
-void virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res)
+bool virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res)
 {
     void *pdata = NULL;
 
@@ -142,17 +142,19 @@ void virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res)
     } else if (res->blob_size) {
         virtio_gpu_create_udmabuf(res);
         if (res->dmabuf_fd < 0) {
-            return;
+            return false;
         }
         virtio_gpu_remap_udmabuf(res);
         if (!res->remapped) {
             virtio_gpu_destroy_udmabuf(res);
-            return;
+            return false;
         }
         pdata = res->remapped;
     }
 
     res->blob = pdata;
+
+    return true;
 }
 
 static void virtio_gpu_free_dmabuf(VirtIOGPU *g, VGPUDMABuf *dmabuf)
diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
index 50c4dcd408bb..7f3301a9ac57 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -383,7 +383,12 @@ static void virtio_gpu_resource_create_blob(VirtIOGPU *g,
             return;
         }
 
-        virtio_gpu_init_udmabuf(res);
+        if (!virtio_gpu_init_udmabuf(res)) {
+            cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
+            virtio_gpu_cleanup_mapping(g, res);
+            g_free(res);
+            return;
+        }
     }
 
     QTAILQ_INSERT_HEAD(&g->reslist, res, next);
@@ -1045,8 +1050,9 @@ virtio_gpu_resource_attach_backing(VirtIOGPU *g,
         return;
     }
 
-    if (!res->image) {
-        virtio_gpu_init_udmabuf(res);
+    if (!res->image && !virtio_gpu_init_udmabuf(res)) {
+        cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
+        virtio_gpu_cleanup_mapping(g, res);
     }
 }
 
@@ -1558,7 +1564,11 @@ static int virtio_gpu_blob_load(QEMUFile *f, void *opaque, size_t size,
                 return -EINVAL;
             }
 
-            virtio_gpu_init_udmabuf(res);
+            if (!virtio_gpu_init_udmabuf(res)) {
+                virtio_gpu_cleanup_mapping(g, res);
+                g_free(res);
+                return -EINVAL;
+            }
         }
 
         QTAILQ_INSERT_HEAD(&g->reslist, res, next);
diff --git a/include/hw/virtio/virtio-gpu.h b/include/hw/virtio/virtio-gpu.h
index 220231ec9d43..69b5ee2e382f 100644
--- a/include/hw/virtio/virtio-gpu.h
+++ b/include/hw/virtio/virtio-gpu.h
@@ -388,7 +388,7 @@ bool virtio_gpu_scanout_blob_to_fb(struct virtio_gpu_framebuffer *fb,
 
 /* virtio-gpu-udmabuf.c */
 bool virtio_gpu_have_udmabuf(void);
-void virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res);
+bool virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res);
 void virtio_gpu_fini_udmabuf(VirtIOGPU *g,
                              struct virtio_gpu_simple_resource *res);
 int virtio_gpu_update_dmabuf(VirtIOGPU *g,

-- 
2.55.0.543.g5ebe2ebe4ea8