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, 44 insertions, 0 deletions

diff --git a/scripts/install.sh b/scripts/install.sh
new file mode 100755
index 000000000..05d62ac51
--- /dev/null
+++ b/scripts/install.sh
@@ -0,0 +1,44 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Copyright (C) 1995 by Linus Torvalds
+#
+# Adapted from code in arch/i386/boot/Makefile by H. Peter Anvin
+# Common code factored out by Masahiro Yamada
+
+set -e
+
+# Make sure the files actually exist
+for file in "${KBUILD_IMAGE}" System.map
+do
+	if [ ! -f "${file}" ]; then
+		echo >&2
+		echo >&2 " *** Missing file: ${file}"
+		echo >&2 ' *** You need to run "make" before "make install".'
+		echo >&2
+		exit 1
+	fi
+done
+
+if [ -n "${INSTALL_PATH}" ] && ! [ -e "${INSTALL_PATH}" ]; then
+	mkdir -p "${INSTALL_PATH}"
+fi
+
+# User/arch may have a custom install script
+for file in "${HOME}/bin/${INSTALLKERNEL}"		\
+	    "/sbin/${INSTALLKERNEL}"			\
+	    "${srctree}/arch/${SRCARCH}/install.sh"	\
+	    "${srctree}/arch/${SRCARCH}/boot/install.sh"
+do
+	if [ ! -x "${file}" ]; then
+		continue
+	fi
+
+	# installkernel(8) says the parameters are like follows:
+	#
+	#   installkernel version zImage System.map [directory]
+	exec "${file}" "${KERNELRELEASE}" "${KBUILD_IMAGE}" System.map "${INSTALL_PATH}"
+done
+
+echo "No install script found" >&2
+exit 1