vkr: init and track gbm_device

Currently we do the below:
1. Open one render node fd per renderer process
2. Track gbm_device pointer per vkr_physical_device

The main reason is that the fallback path requiring the gbm_device
does not use drm render node for physical device.

Later we might:
1. Figure out render nodes for different physical devices
2. Open render node and create gbm_device per vkr_physical_device

Signed-off-by: Yiwei Zhang <zzyiwei@chromium.org>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>

src/venus/vkr_physical_device.c

@@ -7,11 +7,36 @@
 
 #include "venus-protocol/vn_protocol_renderer_device.h"
 #include "venus-protocol/vn_protocol_renderer_info.h"
+#include "vrend_winsys_gbm.h"
 
 #include "vkr_context.h"
 #include "vkr_device.h"
 #include "vkr_instance.h"
 
+/* TODO open render node and create gbm_device per vkr_physical_device */
+static struct gbm_device *vkr_gbm_dev;
+
+static void
+vkr_gbm_device_init_once()
+{
+   struct virgl_gbm *vkr_gbm = virgl_gbm_init(-1);
+   if (!vkr_gbm) {
+      vkr_log("virgl_gbm_init failed");
+      exit(-1);
+   }
+
+   vkr_gbm_dev = vkr_gbm->device;
+}
+
+static struct gbm_device *
+vkr_physical_device_get_gbm_device(UNUSED struct vkr_physical_device *physical_dev)
+{
+   static once_flag gbm_once_flag = ONCE_FLAG_INIT;
+   call_once(&gbm_once_flag, vkr_gbm_device_init_once);
+
+   return vkr_gbm_dev;
+}
+
 void
 vkr_physical_device_destroy(struct vkr_context *ctx,
                             struct vkr_physical_device *physical_dev)
@@ -120,6 +145,9 @@ vkr_physical_device_init_memory_properties(struct vkr_physical_device *physical_
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT) &&
       (props.externalMemoryProperties.exportFromImportedHandleTypes &
        VK_EXTERNAL_MEMORY_HANDLE_TYPE_DMA_BUF_BIT_EXT);
+
+   if (!physical_dev->is_memory_export_supported)
+      physical_dev->gbm_device = vkr_physical_device_get_gbm_device(physical_dev);
 }
 
 static void

src/venus/vkr_physical_device.h

@@ -8,6 +8,8 @@
 
 #include "vkr_common.h"
 
+struct gbm_device;
+
 struct vkr_physical_device {
    struct vkr_object base;
 
@@ -24,6 +26,7 @@ struct vkr_physical_device {
 
    VkPhysicalDeviceMemoryProperties memory_properties;
    bool is_memory_export_supported;
+   struct gbm_device *gbm_device;
 
    struct list_head devices;
 };