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, 53 insertions, 0 deletions

diff --git a/scripts/checkdeclares.pl b/scripts/checkdeclares.pl
new file mode 100755
index 000000000..f6d551c84
--- /dev/null
+++ b/scripts/checkdeclares.pl
@@ -0,0 +1,53 @@
+#!/usr/bin/env perl
+# SPDX-License-Identifier: GPL-2.0
+#
+# checkdeclares: find struct declared more than once
+#
+# Copyright 2021 Wan Jiabing<wanjiabing@vivo.com>
+# Inspired by checkincludes.pl
+#
+# This script checks for duplicate struct declares.
+# Note that this will not take into consideration macros so
+# you should run this only if you know you do have real dups
+# and do not have them under #ifdef's.
+# You could also just review the results.
+
+use strict;
+
+sub usage {
+	print "Usage: checkdeclares.pl file1.h ...\n";
+	print "Warns of struct declaration duplicates\n";
+	exit 1;
+}
+
+if ($#ARGV < 0) {
+	usage();
+}
+
+my $dup_counter = 0;
+
+foreach my $file (@ARGV) {
+	open(my $f, '<', $file)
+	    or die "Cannot open $file: $!.\n";
+
+	my %declaredstructs = ();
+
+	while (<$f>) {
+		if (m/^\s*struct\s*(\w*);$/o) {
+			++$declaredstructs{$1};
+		}
+	}
+
+	close($f);
+
+	foreach my $structname (keys %declaredstructs) {
+		if ($declaredstructs{$structname} > 1) {
+			print "$file: struct $structname is declared more than once.\n";
+			++$dup_counter;
+		}
+	}
+}
+
+if ($dup_counter == 0) {
+	print "No duplicate struct declares found.\n";
+}