i915_address_space_fini(&ggtt->vm);
 
        arch_phys_wc_del(ggtt->mtrr);
-       io_mapping_fini(&ggtt->iomap);
+
+       if (ggtt->iomap.size)
+               io_mapping_fini(&ggtt->iomap);
 }
 
 /**
                bdw_setup_private_ppat(uncore);
 }
 
+static struct resource pci_resource(struct pci_dev *pdev, int bar)
+{
+       return (struct resource)DEFINE_RES_MEM(pci_resource_start(pdev, bar),
+                                              pci_resource_len(pdev, bar));
+}
+
 static int gen8_gmch_probe(struct i915_ggtt *ggtt)
 {
        struct drm_i915_private *dev_priv = ggtt->vm.i915;
        int err;
 
        /* TODO: We're not aware of mappable constraints on gen8 yet */
-       ggtt->gmadr =
-               (struct resource) DEFINE_RES_MEM(pci_resource_start(pdev, 2),
-                                                pci_resource_len(pdev, 2));
-       ggtt->mappable_end = resource_size(&ggtt->gmadr);
+       if (!IS_DGFX(dev_priv)) {
+               ggtt->gmadr = pci_resource(pdev, 2);
+               ggtt->mappable_end = resource_size(&ggtt->gmadr);
+       }
 
        err = pci_set_dma_mask(pdev, DMA_BIT_MASK(39));
        if (!err)
        if (!HAS_LLC(i915) && !HAS_PPGTT(i915))
                ggtt->vm.mm.color_adjust = i915_ggtt_color_adjust;
 
-       if (!io_mapping_init_wc(&ggtt->iomap,
-                               ggtt->gmadr.start,
-                               ggtt->mappable_end)) {
-               ggtt->vm.cleanup(&ggtt->vm);
-               return -EIO;
-       }
+       if (ggtt->mappable_end) {
+               if (!io_mapping_init_wc(&ggtt->iomap,
+                                       ggtt->gmadr.start,
+                                       ggtt->mappable_end)) {
+                       ggtt->vm.cleanup(&ggtt->vm);
+                       return -EIO;
+               }
 
-       ggtt->mtrr = arch_phys_wc_add(ggtt->gmadr.start, ggtt->mappable_end);
+               ggtt->mtrr = arch_phys_wc_add(ggtt->gmadr.start,
+                                             ggtt->mappable_end);
+       }
 
        i915_ggtt_init_fences(ggtt);