intel: Return a bool from intel_aux_map_add_mapping

Make intel_aux_map_add_mapping return false if a mapping is attempted
that would conflict with an existing one. If this function doesn't
return false, it will either fail to return or return true.

The Vulkan driver will make use of this feature to opportunistically
enable CCS if a BO's VMA range has not been already mapped.

Reviewed-by: Jianxun Zhang <jianxun.zhang@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25003>

src/gallium/drivers/iris/iris_resource.c

@@ -646,9 +646,12 @@ map_aux_addresses(struct iris_screen *screen, struct iris_resource *res,
          iris_format_for_usage(screen->devinfo, pfmt, res->surf.usage).fmt;
       const uint64_t format_bits =
          intel_aux_map_format_bits(res->surf.tiling, format, plane);
-      intel_aux_map_add_mapping(aux_map_ctx, res->bo->address + res->offset,
-                                res->aux.bo->address + aux_offset,
-                                res->surf.size_B, format_bits);
+      const bool mapped =
+         intel_aux_map_add_mapping(aux_map_ctx,
+                                   res->bo->address + res->offset,
+                                   res->aux.bo->address + aux_offset,
+                                   res->surf.size_B, format_bits);
+      assert(mapped);
       res->bo->aux_map_address = res->aux.bo->address;
    }
 }

src/intel/common/intel_aux_map.c

@@ -559,7 +559,7 @@ get_aux_entry(struct intel_aux_map_context *ctx, uint64_t main_address,
       *l1_entry_map_out = &l1_map[l1_index];
 }
 
-static void
+static bool
 add_mapping(struct intel_aux_map_context *ctx, uint64_t main_address,
             uint64_t aux_address, uint64_t format_bits,
             bool *state_changed)
@@ -597,8 +597,18 @@ add_mapping(struct intel_aux_map_context *ctx, uint64_t main_address,
       if (aux_map_debug)
          fprintf(stderr, "AUX-MAP L1[0x%x] is already marked valid!\n",
                  l1_index);
-      assert(*l1_entry == l1_data);
+
+      if (*l1_entry != l1_data) {
+         if (aux_map_debug)
+            fprintf(stderr,
+                    "AUX-MAP L1[0x%x] overwrite 0x%"PRIx64" != 0x%"PRIx64"\n",
+                    l1_index, current_l1_data, l1_data);
+
+         return false;
+      }
    }
+
+   return true;
 }
 
 uint64_t *
@@ -614,7 +624,7 @@ intel_aux_map_get_entry(struct intel_aux_map_context *ctx,
    return l1_entry_map;
 }
 
-void
+bool
 intel_aux_map_add_mapping(struct intel_aux_map_context *ctx, uint64_t main_address,
                           uint64_t aux_address, uint64_t main_size_B,
                           uint64_t format_bits)
@@ -628,13 +638,18 @@ intel_aux_map_add_mapping(struct intel_aux_map_context *ctx, uint64_t main_addre
    const uint64_t aux_page_size = get_meta_page_size(ctx->format);
    assert((aux_address & get_page_mask(aux_page_size)) == 0);
    while (main_inc_addr - main_address < main_size_B) {
-      add_mapping(ctx, main_inc_addr, aux_inc_addr, format_bits, &state_changed);
+      if (!add_mapping(ctx, main_inc_addr, aux_inc_addr, format_bits,
+                       &state_changed)) {
+         break;
+      }
       main_inc_addr = main_inc_addr + main_page_size;
       aux_inc_addr = aux_inc_addr + aux_page_size;
    }
    pthread_mutex_unlock(&ctx->mutex);
    if (state_changed)
       p_atomic_inc(&ctx->state_num);
+
+   return main_inc_addr - main_address >= main_size_B;
 }
 
 /**

src/intel/common/intel_aux_map.h

@@ -109,7 +109,9 @@ intel_aux_map_get_entry(struct intel_aux_map_context *ctx,
                         uint64_t main_address,
                         uint64_t *aux_entry_address);
 
-void
+/* Fails if a mapping is attempted that would conflict with an existing one.
+ */
+bool
 intel_aux_map_add_mapping(struct intel_aux_map_context *ctx, uint64_t main_address,
                           uint64_t aux_address, uint64_t main_size_B,
                           uint64_t format_bits);

src/intel/vulkan/anv_allocator.c

@@ -1510,9 +1510,11 @@ anv_device_alloc_bo(struct anv_device *device,
 
    if (new_bo._ccs_size > 0) {
       assert(device->info->has_aux_map);
-      intel_aux_map_add_mapping(device->aux_map_ctx, new_bo.offset,
-                                intel_canonical_address(new_bo.offset + new_bo.size),
-                                new_bo.size, 0 /* format_bits */);
+      const bool mapped =
+         intel_aux_map_add_mapping(device->aux_map_ctx, new_bo.offset,
+                                   intel_canonical_address(new_bo.offset + new_bo.size),
+                                   new_bo.size, 0 /* format_bits */);
+      assert(mapped);
    }
 
    assert(new_bo.gem_handle);