ACRN:DM:VDisplay: vdpy_init connection returns the supported number of vScreen

Vdisplay module will create the gui_window (vScreen) based on the virtio-gpu
parameter. When virtio-gpu device tries to establish the connection with
vdisplay module, it will return the supported number of vScreen.
Then the virtio-gpu device can initialize the correct info for the guest_vm.

BTW: The number is fixed to 1.

Tracked-On: #7988
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Reviewed-by: Peng Sun <peng.p.sun@linux.intel.com>

devicemodel/hw/pci/virtio/virtio_gpu.c

@@ -1485,7 +1485,7 @@ virtio_gpu_init(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
 			gpu->vq,
 			BACKEND_VBSU);
 
-	gpu->vdpy_handle = vdpy_init();
+	gpu->vdpy_handle = vdpy_init(NULL);
 	gpu->base.mtx = &gpu->mtx;
 	gpu->base.device_caps = VIRTIO_GPU_S_HOSTCAPS;
 

devicemodel/hw/vdisplay_sdl.c

@@ -1069,7 +1069,7 @@ bool vdpy_submit_bh(int handle, struct vdpy_display_bh *bh_task)
 }
 
 int
-vdpy_init()
+vdpy_init(int *num_vscreens)
 {
 	int err, count;
 
@@ -1100,6 +1100,8 @@ vdpy_init()
 	}
 
 	vdpy.s.n_connect++;
+	if (num_vscreens)
+		*num_vscreens = 1;
 	return vdpy.s.n_connect;
 }
 

devicemodel/include/vdisplay.h

@@ -85,7 +85,7 @@ struct cursor {
 
 int vdpy_parse_cmd_option(const char *opts);
 int gfx_ui_init();
-int vdpy_init();
+int vdpy_init(int *num_vscreens);
 void vdpy_get_display_info(int handle, int scanout_id, struct display_info *info);
 void vdpy_surface_set(int handle, int scanout_id, struct surface *surf);
 void vdpy_surface_update(int handle, int scanout_id, struct surface *surf);