stubs: Add stubs for udmabuf helpers

This is needed to ensure that virtio-gpu device works for
non-linux builds.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Message-Id: <20210526231429.1045476-5-vivek.kasireddy@intel.com>

[ kraxel: add virtio-gpu-udmabuf.c stubs only when building
          system emulation ]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

meson.build

@@ -1899,7 +1899,7 @@ util_ss.add_all(trace_ss)
 util_ss = util_ss.apply(config_all, strict: false)
 libqemuutil = static_library('qemuutil',
                              sources: util_ss.sources() + stub_ss.sources() + genh,
-                             dependencies: [util_ss.dependencies(), m, glib, socket, malloc])
+                             dependencies: [util_ss.dependencies(), m, glib, socket, malloc, pixman])
 qemuutil = declare_dependency(link_with: libqemuutil,
                               sources: genh + version_res)
 

stubs/meson.build

@@ -52,6 +52,7 @@ if have_system
   stub_ss.add(files('semihost.c'))
   stub_ss.add(files('usb-dev-stub.c'))
   stub_ss.add(files('xen-hw-stub.c'))
+  stub_ss.add(files('virtio-gpu-udmabuf.c'))
 else
   stub_ss.add(files('qdev.c'))
 endif

stubs/virtio-gpu-udmabuf.c

@@ -0,0 +1,18 @@
+#include "qemu/osdep.h"
+#include "hw/virtio/virtio-gpu.h"
+
+bool virtio_gpu_have_udmabuf(void)
+{
+    /* nothing (stub) */
+    return false;
+}
+
+void virtio_gpu_init_udmabuf(struct virtio_gpu_simple_resource *res)
+{
+    /* nothing (stub) */
+}
+
+void virtio_gpu_fini_udmabuf(struct virtio_gpu_simple_resource *res)
+{
+    /* nothing (stub) */
+}