drm/i915/gt: Fix reservation address in ggtt_reserve_guc_top

From Javier Pello
69dd84470b4deed45658f2717aef533ec4ceb43d in linux-6.1.y/6.1.56
b7599d241778d0b10cdf7a5c755aa7db9b83250c in mainline linux

diff --git a/sys/dev/pci/drm/i915/gt/intel_ggtt.c b/sys/dev/pci/drm/i915/gt/intel_ggtt.c
index ec9465e..96fc3dd 100644 (file)
--- a/sys/dev/pci/drm/i915/gt/intel_ggtt.c
+++ b/sys/dev/pci/drm/i915/gt/intel_ggtt.c
@@ -529,20 +529,31 @@ void intel_ggtt_unbind_vma(struct i915_address_space *vm,
        vm->clear_range(vm, vma_res->start, vma_res->vma_size);
 }
 
+/*
+ * Reserve the top of the GuC address space for firmware images. Addresses
+ * beyond GUC_GGTT_TOP in the GuC address space are inaccessible by GuC,
+ * which makes for a suitable range to hold GuC/HuC firmware images if the
+ * size of the GGTT is 4G. However, on a 32-bit platform the size of the GGTT
+ * is limited to 2G, which is less than GUC_GGTT_TOP, but we reserve a chunk
+ * of the same size anyway, which is far more than needed, to keep the logic
+ * in uc_fw_ggtt_offset() simple.
+ */
+#define GUC_TOP_RESERVE_SIZE (SZ_4G - GUC_GGTT_TOP)
+
 static int ggtt_reserve_guc_top(struct i915_ggtt *ggtt)
 {
-       u64 size;
+       u64 offset;
        int ret;
 
        if (!intel_uc_uses_guc(&ggtt->vm.gt->uc))
                return 0;
 
-       GEM_BUG_ON(ggtt->vm.total <= GUC_GGTT_TOP);
-       size = ggtt->vm.total - GUC_GGTT_TOP;
+       GEM_BUG_ON(ggtt->vm.total <= GUC_TOP_RESERVE_SIZE);
+       offset = ggtt->vm.total - GUC_TOP_RESERVE_SIZE;
 
-       ret = i915_gem_gtt_reserve(&ggtt->vm, NULL, &ggtt->uc_fw, size,
-                                  GUC_GGTT_TOP, I915_COLOR_UNEVICTABLE,
-                                  PIN_NOEVICT);
+       ret = i915_gem_gtt_reserve(&ggtt->vm, NULL, &ggtt->uc_fw,
+                                  GUC_TOP_RESERVE_SIZE, offset,
+                                  I915_COLOR_UNEVICTABLE, PIN_NOEVICT);
        if (ret)
                drm_dbg(&ggtt->vm.i915->drm,
                        "Failed to reserve top of GGTT for GuC\n");