From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001
From: Zeng Chi <zengchi@kylinos.cn>
Date: Mon, 21 Sep 2026 18:24:42 +0800
Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL
 attributes

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>
---
 scripts/gfp-translate | 118 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100755 scripts/gfp-translate

(limited to 'scripts/gfp-translate')

diff --git a/scripts/gfp-translate b/scripts/gfp-translate
new file mode 100755
index 000000000..8385ae0d5
--- /dev/null
+++ b/scripts/gfp-translate
@@ -0,0 +1,118 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-only
+# Translate the bits making up a GFP mask
+# (c) 2009, Mel Gorman <mel@csn.ul.ie>
+SOURCE=
+GFPMASK=none
+
+# Helper function to report failures and exit
+die() {
+	echo ERROR: $@
+	if [ "$TMPFILE" != "" ]; then
+		rm -f $TMPFILE
+	fi
+	exit -1
+}
+
+usage() {
+	echo "usage: gfp-translate [-h] [ --source DIRECTORY ] gfpmask"
+	exit 0
+}
+
+# Parse command-line arguments
+while [ $# -gt 0 ]; do
+	case $1 in
+		--source)
+			SOURCE=$2
+			shift 2
+			;;
+		-h)
+			usage
+			;;
+		--help)
+			usage
+			;;
+		*)
+			GFPMASK=$1
+			shift
+			;;
+	esac
+done
+
+# Guess the kernel source directory if it's not set. Preference is in order of
+# o current directory
+# o /usr/src/linux
+if [ "$SOURCE" = "" ]; then
+	if [ -r "/usr/src/linux/Makefile" ]; then
+		SOURCE=/usr/src/linux
+	fi
+	if [ -r "`pwd`/Makefile" ]; then
+		SOURCE=`pwd`
+	fi
+fi
+
+# Confirm that a source directory exists
+if [ ! -r "$SOURCE/Makefile" ]; then
+	die "Could not locate kernel source directory or it is invalid"
+fi
+
+# Confirm that a GFP mask has been specified
+if [ "$GFPMASK" = "none" ]; then
+	usage
+fi
+
+# Extract GFP flags from the kernel source
+TMPFILE=`mktemp -t gfptranslate-XXXXXX.c` || exit 1
+
+echo Source: $SOURCE
+echo Parsing: $GFPMASK
+
+(
+    cat <<EOF
+#include <stdint.h>
+#include <stdio.h>
+
+// Try to fool compiler.h into not including extra stuff
+#define __ASSEMBLY__	1
+
+#include <generated/autoconf.h>
+#include <linux/gfp_types.h>
+
+static const char *masks[] = {
+EOF
+
+    sed -nEe 's/^[[:space:]]+(___GFP_.*)_BIT,.*$/\1/p' $SOURCE/include/linux/gfp_types.h |
+	while read b; do
+	    cat <<EOF
+#if defined($b) && ($b > 0)
+	[${b}_BIT]	= "$b",
+#endif
+EOF
+	done
+
+    cat <<EOF
+};
+
+int main(int argc, char *argv[])
+{
+	unsigned long long mask = $GFPMASK;
+
+	for (int i = 0; i < sizeof(mask) * 8; i++) {
+		unsigned long long bit = 1ULL << i;
+		if (mask & bit)
+			printf("\t%-25s0x%llx\n",
+			       (i < ___GFP_LAST_BIT && masks[i]) ?
+					masks[i] : "*** INVALID ***",
+			       bit);
+	}
+
+	return 0;
+}
+EOF
+) > $TMPFILE
+
+${CC:-gcc} -Wall -o ${TMPFILE}.bin -I $SOURCE/include $TMPFILE && ${TMPFILE}.bin
+
+rm -f $TMPFILE ${TMPFILE}.bin
+
+exit 0
-- 
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