igt/gem_mmap_gtt: Check coherency between GTT and CPU mmappings with LLC

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

lib/ioctl_wrappers.c

@@ -643,6 +643,22 @@ int gem_available_fences(int fd)
 	return val;
 }
 
+bool gem_has_llc(int fd)
+{
+	struct drm_i915_getparam gp;
+	int val = 0;
+
+	memset(&gp, 0, sizeof(gp));
+	gp.param = I915_PARAM_HAS_LLC;
+	gp.value = &val;
+
+	if (ioctl(fd, DRM_IOCTL_I915_GETPARAM, &gp, sizeof(gp)))
+		return 0;
+
+	errno = 0;
+	return val;
+}
+
 /**
  * gem_get_num_rings:
  * @fd: open i915 drm file descriptor

lib/ioctl_wrappers.h

@@ -78,6 +78,7 @@ void gem_sw_finish(int fd, uint32_t handle);
 bool gem_bo_busy(int fd, uint32_t handle);
 
 /* feature test helpers */
+bool gem_has_llc(int fd);
 int gem_get_num_rings(int fd);
 bool gem_has_enable_ring(int fd,int param);
 bool gem_has_bsd(int fd);