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>

4 files changed, 116 insertions, 0 deletions

diff --git a/tools/testing/selftests/dt/.gitignore b/tools/testing/selftests/dt/.gitignore
new file mode 100644
index 000000000..f6476c9f2
--- /dev/null
+++ b/tools/testing/selftests/dt/.gitignore
@@ -0,0 +1 @@
+compatible_list
diff --git a/tools/testing/selftests/dt/Makefile b/tools/testing/selftests/dt/Makefile
new file mode 100644
index 000000000..2d33ee9e9
--- /dev/null
+++ b/tools/testing/selftests/dt/Makefile
@@ -0,0 +1,21 @@
+PY3 = $(shell which python3 2>/dev/null)
+
+ifneq ($(PY3),)
+
+TEST_PROGS := test_unprobed_devices.sh
+TEST_GEN_FILES := compatible_list
+TEST_FILES := compatible_ignore_list
+
+include ../lib.mk
+
+$(OUTPUT)/compatible_list:
+	$(top_srcdir)/scripts/dtc/dt-extract-compatibles -d $(top_srcdir) > $@
+
+else
+
+all: no_py3_warning
+
+no_py3_warning:
+	@echo "Missing python3. This test will be skipped."
+
+endif
diff --git a/tools/testing/selftests/dt/compatible_ignore_list b/tools/testing/selftests/dt/compatible_ignore_list
new file mode 100644
index 000000000..1323903fe
--- /dev/null
+++ b/tools/testing/selftests/dt/compatible_ignore_list
@@ -0,0 +1 @@
+simple-mfd
diff --git a/tools/testing/selftests/dt/test_unprobed_devices.sh b/tools/testing/selftests/dt/test_unprobed_devices.sh
new file mode 100755
index 000000000..5e3f42ef2
--- /dev/null
+++ b/tools/testing/selftests/dt/test_unprobed_devices.sh
@@ -0,0 +1,93 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2023 Collabora Ltd
+#
+# Based on Frank Rowand's dt_stat script.
+#
+# This script tests for devices that were declared on the Devicetree and are
+# expected to bind to a driver, but didn't.
+#
+# To achieve this, two lists are used:
+# * a list of the compatibles that can be matched by a Devicetree node
+# * a list of compatibles that should be ignored
+#
+
+DIR="$(dirname $(readlink -f "$0"))"
+
+source "${DIR}"/../kselftest/ktap_helpers.sh
+
+PDT=/proc/device-tree/
+COMPAT_LIST="${DIR}"/compatible_list
+IGNORE_LIST="${DIR}"/compatible_ignore_list
+
+ktap_print_header
+
+if [[ ! -d "${PDT}" ]]; then
+	ktap_skip_all "${PDT} doesn't exist."
+	exit "${KSFT_SKIP}"
+fi
+
+nodes_compatible=$(
+	for node in $(find ${PDT} -type d); do
+		[ ! -f "${node}"/compatible ] && continue
+		# Check if node is available
+		if [[ -e "${node}"/status ]]; then
+			status=$(tr -d '\000' < "${node}"/status)
+			if [[ "${status}" != "okay" && "${status}" != "ok" ]]; then
+				if [ -n "${disabled_nodes_regex}" ]; then
+					disabled_nodes_regex="${disabled_nodes_regex}|${node}"
+				else
+					disabled_nodes_regex="${node}"
+				fi
+				continue
+			fi
+		fi
+
+		# Ignore this node if one of its ancestors was disabled
+		if [ -n "${disabled_nodes_regex}" ]; then
+			echo "${node}" | grep -q -E "${disabled_nodes_regex}" && continue
+		fi
+
+		echo "${node}" | sed -e 's|\/proc\/device-tree||'
+	done | sort
+	)
+
+nodes_dev_bound=$(
+	IFS=$'\n'
+	for dev_dir in $(find /sys/devices -type d); do
+		[ ! -f "${dev_dir}"/uevent ] && continue
+		[ ! -d "${dev_dir}"/driver ] && continue
+
+		grep '^OF_FULLNAME=' "${dev_dir}"/uevent | sed -e 's|OF_FULLNAME=||'
+	done
+	)
+
+num_tests=$(echo ${nodes_compatible} | wc -w)
+ktap_set_plan "${num_tests}"
+
+retval="${KSFT_PASS}"
+for node in ${nodes_compatible}; do
+	if ! echo "${nodes_dev_bound}" | grep -E -q "(^| )${node}( |\$)"; then
+		compatibles=$(tr '\000' '\n' < "${PDT}"/"${node}"/compatible)
+
+		for compatible in ${compatibles}; do
+			if grep -x -q "${compatible}" "${IGNORE_LIST}"; then
+				continue
+			fi
+
+			if grep -x -q "${compatible}" "${COMPAT_LIST}"; then
+				ktap_test_fail "${node}"
+				retval="${KSFT_FAIL}"
+				continue 2
+			fi
+		done
+		ktap_test_skip "${node}"
+	else
+		ktap_test_pass "${node}"
+	fi
+
+done
+
+ktap_print_totals
+exit "${retval}"