Commit 3f163489c6 for qemu.org

commit 3f163489c6efe8fb0de8e18097773f955ebaaa31
Author: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Date:   Tue Aug 25 16:28:48 2026 +0900

    hw/display/virtio-gpu: Avoid mmap() for empty blob

    Calling mmap() for an empty blob fails with EINVAL, causing QEMU to
    emit a spurious warning.

    Fixes: e0933d91b1cd ("virtio-gpu: Add virtio_gpu_resource_create_blob")
    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-v2-2-b3d64d3b9a0e@rsg.ci.i.u-tokyo.ac.jp>

diff --git a/hw/display/virtio-gpu-udmabuf.c b/hw/display/virtio-gpu-udmabuf.c
index 816f52a514..ba02ba9e86 100644
--- a/hw/display/virtio-gpu-udmabuf.c
+++ b/hw/display/virtio-gpu-udmabuf.c
@@ -139,7 +139,7 @@ void virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res)
     if (res->iov_cnt == 1 &&
         res->iov[0].iov_len < 4096) {
         pdata = res->iov[0].iov_base;
-    } else {
+    } else if (res->blob_size) {
         virtio_gpu_create_udmabuf(res);
         if (res->dmabuf_fd < 0) {
             return;