KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 103 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/Makefile b/Documentation/devicetree/bindings/Makefile
new file mode 100644
index 000000000..6b4b4f51c
--- /dev/null
+++ b/Documentation/devicetree/bindings/Makefile
@@ -0,0 +1,103 @@
+# SPDX-License-Identifier: GPL-2.0
+DT_DOC_CHECKER ?= dt-doc-validate
+DT_EXTRACT_EX ?= dt-extract-example
+DT_MK_SCHEMA ?= dt-mk-schema
+
+DT_SCHEMA_LINT = $(shell which yamllint || \
+  echo "warning: python package 'yamllint' not installed, skipping" >&2)
+
+DT_SCHEMA_MIN_VERSION = 2024.4
+
+PHONY += check_dtschema_version
+check_dtschema_version:
+	@which $(DT_DOC_CHECKER) >/dev/null || \
+		{ echo "Error: '$(DT_DOC_CHECKER)' not found!" >&2; \
+		  echo "Ensure dtschema python package is installed and in your PATH." >&2; \
+		  echo "Current PATH is:" >&2; \
+		  echo "$$PATH" >&2; false; }
+	@{ echo $(DT_SCHEMA_MIN_VERSION); \
+	$(DT_DOC_CHECKER) --version 2>/dev/null || echo 0; } | sort -Vc >/dev/null || \
+	{ echo "ERROR: dtschema minimum version is v$(DT_SCHEMA_MIN_VERSION)" >&2; false; }
+
+quiet_cmd_extract_ex = DTEX    $@
+      cmd_extract_ex = $(DT_EXTRACT_EX) $< > $@
+
+$(obj)/%.example.dts: $(src)/%.yaml check_dtschema_version FORCE
+	$(call if_changed,extract_ex)
+
+find_all_cmd = find $(src) \( -name '*.yaml' ! \
+		-name 'processed-schema*' \)
+
+find_cmd = $(find_all_cmd) | \
+		sed 's|^$(srctree)/||' | \
+		grep -F -e "$(subst :," -e ",$(DT_SCHEMA_FILES))" | \
+		sed 's|^|$(srctree)/|'
+CHK_DT_EXAMPLES := $(patsubst $(srctree)/%.yaml,%.example.dtb, \
+			      $(shell $(find_cmd) | xargs grep -l '^examples:'))
+
+quiet_cmd_yamllint = LINT    $(src)
+      cmd_yamllint = ($(find_cmd) | \
+                     xargs -n200 -P$$(nproc) \
+		     $(DT_SCHEMA_LINT) -f parsable -c $(src)/.yamllint >&2) \
+		     && touch $@ || true
+
+quiet_cmd_chk_bindings = CHKDT   $(src)
+      cmd_chk_bindings = ($(find_cmd) | \
+			  xargs -n200 -P$$(nproc) $(DT_DOC_CHECKER) -u $(src)) \
+			  && touch $@ || true
+
+DT_CHK_STYLE = $(srctree)/scripts/dtc/dt-check-style
+
+# Feed the file list to the checker via @argfile in a single Python
+# process so the ruamel.yaml import is paid once. scripts/jobserver-exec
+# claims slots from the GNU make jobserver and exposes the count via
+# $PARALLELISM, which dt-check-style picks up to size its worker pool.
+quiet_cmd_chk_style = STYLE   $(src)
+      cmd_chk_style = f=$$(mktemp) && $(find_cmd) > $$f && \
+		      $(PYTHON3) $(srctree)/scripts/jobserver-exec \
+		      $(PYTHON3) $(DT_CHK_STYLE) @$$f \
+		      && touch $@ || true; rm -f $$f
+
+quiet_cmd_mk_schema = SCHEMA  $@
+      cmd_mk_schema = f=$$(mktemp) ; \
+                      $(find_all_cmd) > $$f ; \
+                      $(DT_MK_SCHEMA) -j $(DT_MK_SCHEMA_FLAGS) @$$f > $@ ; \
+		      rm -f $$f
+
+DT_DOCS = $(patsubst $(srctree)/%,%,$(shell $(find_all_cmd)))
+
+override DTC_FLAGS := \
+	-Wno-avoid_unnecessary_addr_size \
+	-Wno-unique_unit_address \
+	-Wunique_unit_address_if_enabled
+
+$(obj)/processed-schema.json: $(DT_DOCS) check_dtschema_version FORCE
+	$(call if_changed,mk_schema)
+
+targets += .dt-binding.checked .yamllint.checked .dt-style.checked
+$(obj)/.yamllint.checked: $(DT_DOCS) $(src)/.yamllint FORCE
+	$(if $(DT_SCHEMA_LINT),$(call if_changed,yamllint),)
+
+$(obj)/.dt-binding.checked: $(DT_DOCS) FORCE
+	$(call if_changed,chk_bindings)
+
+$(obj)/.dt-style.checked: $(DT_DOCS) FORCE
+	$(call if_changed,chk_style)
+
+always-y += processed-schema.json
+targets += $(patsubst $(obj)/%,%, $(CHK_DT_EXAMPLES))
+targets += $(patsubst $(obj)/%.dtb,%.dts, $(CHK_DT_EXAMPLES))
+
+# Hack: avoid 'Argument list too long' error for 'make clean'. Remove most of
+# build artifacts here before they are processed by scripts/Makefile.clean
+clean-files = $(shell find $(obj) \( -name '*.example.dts' -o \
+			-name '*.example.dtb' \) -delete 2>/dev/null)
+
+dt_compatible_check: $(obj)/processed-schema.json
+	$(Q)$(srctree)/scripts/dtc/dt-extract-compatibles $(srctree) | xargs dt-check-compatible -v -s $<
+
+PHONY += dt_binding_check_one
+dt_binding_check_one: $(obj)/.dt-binding.checked $(obj)/.yamllint.checked $(obj)/.dt-style.checked
+
+PHONY += dt_binding_check
+dt_binding_check: dt_binding_check_one $(CHK_DT_EXAMPLES)