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, 80 insertions, 0 deletions

diff --git a/scripts/dtc/update-dtc-source.sh b/scripts/dtc/update-dtc-source.sh
new file mode 100755
index 000000000..946275415
--- /dev/null
+++ b/scripts/dtc/update-dtc-source.sh
@@ -0,0 +1,80 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Simple script to update the version of DTC carried by the Linux kernel
+#
+# This script assumes that the dtc and the linux git trees are in the
+# same directory. After building dtc in the dtc directory, it copies the
+# source files and generated source file(s) into the scripts/dtc directory
+# in the kernel and creates a git commit updating them to the new
+# version.
+#
+# Usage: from the top level Linux source tree, run:
+# $ ./scripts/dtc/update-dtc-source.sh
+#
+# The script will change into the dtc tree, build and test dtc, copy the
+# relevant files into the kernel tree and create a git commit. The commit
+# message will need to be modified to reflect the version of DTC being
+# imported
+#
+# TODO:
+# This script is pretty basic, but it is seldom used so a few manual tasks
+# aren't a big deal. If anyone is interested in making it more robust, the
+# the following would be nice:
+# * Actually fail to complete if any testcase fails.
+#   - The dtc "make check" target needs to return a failure
+# * Extract the version number from the dtc repo for the commit message
+# * Build dtc in the kernel tree
+# * run 'make check" on dtc built from the kernel tree
+
+set -ev
+
+DTC_UPSTREAM_PATH=`pwd`/../dtc
+DTC_LINUX_PATH=`pwd`/scripts/dtc
+
+DTC_SOURCE="checks.c data.c dtc.c dtc.h flattree.c fstree.c livetree.c srcpos.c \
+		srcpos.h treesource.c util.c util.h version_gen.h \
+		dtc-lexer.l dtc-parser.y"
+LIBFDT_SOURCE="fdt.c fdt.h fdt_addresses.c fdt_empty_tree.c \
+		fdt_overlay.c fdt_ro.c fdt_rw.c fdt_strerror.c fdt_sw.c \
+		fdt_wip.c libfdt.h libfdt_env.h libfdt_internal.h"
+FDTOVERLAY_SOURCE=fdtoverlay.c
+
+get_last_dtc_version() {
+	git log --oneline scripts/dtc/ | grep 'upstream' | head -1 | sed -e 's/^.* \(.*\)/\1/'
+}
+
+last_dtc_ver=$(get_last_dtc_version)
+
+# Build DTC
+cd $DTC_UPSTREAM_PATH
+make clean
+make check
+dtc_version=$(git describe HEAD)
+dtc_log=$(git log --oneline ${last_dtc_ver}..)
+
+
+# Copy the files into the Linux tree
+cd $DTC_LINUX_PATH
+for f in $DTC_SOURCE $FDTOVERLAY_SOURCE; do
+	cp ${DTC_UPSTREAM_PATH}/${f} ${f}
+	git add ${f}
+done
+for f in $LIBFDT_SOURCE; do
+       cp ${DTC_UPSTREAM_PATH}/libfdt/${f} libfdt/${f}
+       git add libfdt/${f}
+done
+
+sed -i -- 's/#include <libfdt_env.h>/#include "libfdt_env.h"/g' ./libfdt/libfdt.h
+sed -i -- 's/#include <fdt.h>/#include "fdt.h"/g' ./libfdt/libfdt.h
+git add ./libfdt/libfdt.h
+
+commit_msg=$(cat << EOF
+scripts/dtc: Update to upstream version ${dtc_version}
+
+This adds the following commits from upstream:
+
+${dtc_log}
+EOF
+)
+
+git commit -e -v -s -m "${commit_msg}"