rendervulkan: check DRM and Vulkan devices match

References: https://github.com/Plagman/gamescope/issues/158

src/main.cpp

@@ -5,6 +5,7 @@
 #include <vector>
 #include <cstring>
 #include <sys/capability.h>
+#include <sys/stat.h>
 
 #include <signal.h>
 #include <unistd.h>
@@ -186,6 +187,23 @@ int main(int argc, char **argv)
 		return 1;
 	}
 
+	// TODO: get the DRM device from the Vulkan device
+	if ( g_bIsNested == false && g_vulkanHasDrmDevId )
+	{
+		struct stat drmStat = {};
+		if ( fstat( g_DRM.fd, &drmStat ) != 0 )
+		{
+			perror( "fstat failed on DRM FD" );
+			return 1;
+		}
+
+		if ( drmStat.st_rdev != g_vulkanDrmDevId )
+		{
+			fprintf( stderr, "Mismatch between DRM and Vulkan devices\n" );
+			return 1;
+		}
+	}
+
 	// Prevent our clients from connecting to the parent compositor
 	unsetenv("WAYLAND_DISPLAY");
 

src/rendervulkan.cpp

@@ -75,6 +75,9 @@ VkDescriptorPool descriptorPool;
 
 bool g_vulkanSupportsModifiers;
 
+bool g_vulkanHasDrmDevId = false;
+dev_t g_vulkanDrmDevId = 0;
+
 VkDescriptorSetLayout descriptorSetLayout;
 VkPipelineLayout pipelineLayout;
 VkDescriptorSet descriptorSet;
@@ -880,7 +883,7 @@ retry:
 
 	VkPhysicalDeviceProperties props = {};
 	vkGetPhysicalDeviceProperties( physicalDevice, &props );
-	fprintf(stderr, "vulkan: selecting physical device '%s'\n", props.deviceName);
+	fprintf( stderr, "vulkan: selecting physical device '%s'\n", props.deviceName );
 
 	vkGetPhysicalDeviceMemoryProperties( physicalDevice, &memoryProperties );
 
@@ -896,11 +899,31 @@ retry:
 		if ( strcmp(vecSupportedExtensions[i].extensionName,
 		     VK_EXT_IMAGE_DRM_FORMAT_MODIFIER_EXTENSION_NAME) == 0 )
 			g_vulkanSupportsModifiers = true;
+
+		if ( strcmp(vecSupportedExtensions[i].extensionName,
+		            VK_EXT_PHYSICAL_DEVICE_DRM_EXTENSION_NAME) == 0 )
+			g_vulkanHasDrmDevId = true;
 	}
 
-	fprintf( stderr, "Vulkan %s DRM format modifiers\n",
+	fprintf( stderr, "vulkan: physical device %s DRM format modifiers\n",
 			g_vulkanSupportsModifiers ? "supports" : "does not support" );
 
+	if ( g_vulkanHasDrmDevId ) {
+		VkPhysicalDeviceDrmPropertiesEXT drmProps = {
+			.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_DRM_PROPERTIES_EXT,
+		};
+		VkPhysicalDeviceProperties2 props2 = {
+			.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2,
+			.pNext = &drmProps,
+		};
+		vkGetPhysicalDeviceProperties2( physicalDevice, &props2 );
+		if ( !drmProps.hasPrimary ) {
+			fprintf( stderr, "vulkan: physical device has no primary node\n" );
+			return false;
+		}
+		g_vulkanDrmDevId = makedev( drmProps.primaryMajor, drmProps.primaryMinor );
+	}
+
 	init_formats();
 
 	float queuePriorities = 1.0f;

src/rendervulkan.hpp

@@ -127,6 +127,9 @@ public:
 extern std::vector< const char * > g_vecSDLInstanceExts;
 extern bool g_vulkanSupportsModifiers;
 
+extern bool g_vulkanHasDrmDevId;
+extern dev_t g_vulkanDrmDevId;
+
 bool vulkan_init(void);
 
 VulkanTexture_t vulkan_create_texture_from_dmabuf( struct wlr_dmabuf_attributes *pDMA );