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, 132 insertions, 0 deletions

diff --git a/scripts/kconfig/kconfig-sym-check.pl b/scripts/kconfig/kconfig-sym-check.pl
new file mode 100755
index 000000000..daa5285fd
--- /dev/null
+++ b/scripts/kconfig/kconfig-sym-check.pl
@@ -0,0 +1,132 @@
+#!/usr/bin/env perl
+# SPDX-License-Identifier: GPL-2.0
+
+use warnings;
+use strict;
+
+my $srctree = shift @ARGV;
+unless (defined $srctree) {
+	$srctree = `git rev-parse --show-toplevel 2>/dev/null`;
+	chomp $srctree;
+	my $msg = "Usage: $0 <srctree> [excludes file]\n";
+	$msg .= "Please provide <srctree>.";
+	$msg .= " Is it '$srctree'?" if $srctree;
+	$msg .= "\n";
+	die $msg;
+}
+my $kconfig_sym_check_excludes = defined $ARGV[0] ? $ARGV[0] : undef;
+
+sub indent_depth {
+	my ($ws) = @_;
+	my $col = 0;
+	for my $c (split //, $ws) {
+		$col = $c eq "\t" ? int($col / 8) * 8 + 8 : $col + 1;
+	}
+	return $col;
+}
+
+my @files = `git -C \Q$srctree\E ls-files '*Kconfig*' 2>/dev/null`;
+if (@files) {
+	chomp @files;
+	@files = map { "$srctree/$_" } @files;
+} else {
+	@files = `find \Q$srctree\E -name '*Kconfig*'`;
+	chomp @files;
+}
+
+@files = grep { !m{/scripts/kconfig/tests/} } @files;
+
+my %configs = ();
+my %refs = ();
+
+foreach my $file (@files) {
+	open F, $file or die "Cannot open $file: $!";
+
+	my $help = 0;
+	my $help_level;
+	my $level;
+
+	while (<F>) {
+		chomp;
+
+		while (/\\\s*$/) {
+			s/\\\s*$/ /;
+			my $cont = <F> // last;
+			chomp $cont;
+			$_ .= $cont;
+		}
+
+		next if /^\s*$/;
+		next if /^\s*#/;
+
+		/^(\s*)/;
+		$level = indent_depth($1);
+
+		if ($help && $level < $help_level) {
+			$help = 0;
+		}
+
+		next if ($help);
+
+		if (/^\s*(help|\-\-\-help\-\-\-)$/) {
+			$help = 1;
+			my $next;
+			while (defined($next = <F>)) {
+				last unless $next =~ /^\s*(?:#.*)?$/;
+			}
+			last unless defined $next;
+			$next =~ /^(\s*)/;
+			if (indent_depth($1) >= $level) {
+				$help_level = indent_depth($1);
+			} else {
+				$help = 0;
+			}
+			$_ = $next;
+			redo;
+		}
+
+		if (/^\s*(config|menuconfig)\s+([a-zA-Z0-9_]+)\s*(#.*)?$/) {
+			$configs{$2}++;
+			next;
+		}
+
+		if (/^\s*(default|def_bool|def_tristate|select|depends\s+on|imply|visible\s+if|range|if|bool|tristate|int|hex|string|prompt)\s+(.+)\s*$/) {
+			my $s = $2;
+			$s =~ s/"(?:[^"\\]|\\.)*"|'(?:[^'\\]|\\.)*'//g;
+			$s =~ s/#.*//;
+			$s =~ s/\$\((?:[^()]*|\((?:[^()]*|\([^()]*\))*\))*\)//g;
+			$s =~ s/%%[^%]*%%//g;
+			my @syms = split /[^a-zA-Z0-9_]+/, $s;
+			map {
+				$refs{$_}++ if (/[a-zA-Z]/ && $_ ne "if" && $_ ne "y" && $_ ne "n" && $_ ne "m" && !/^0[xX][0-9a-fA-F]+$/);
+			} @syms
+		}
+	}
+
+	close F;
+}
+
+my %known_syms = ();
+if (defined $kconfig_sym_check_excludes) {
+	my $file = $kconfig_sym_check_excludes;
+	open(F, "<", $file) or die "Cannot open $file: $!";
+	while (<F>) {
+		chomp;
+		next if /^\s*$/;
+		next if /^\s*#/;
+		$known_syms{$1}++ if (/^\s*([a-zA-Z0-9_]+)\s*(#.*)?$/);
+	}
+}
+
+my $ret = 0;
+foreach my $k (sort keys %refs) {
+	next if (exists $configs{$k} || exists $known_syms{$k});
+
+	print "$k";
+	print " - warning: '$k' is probably not what you want; Kconfig tristate literals are always lowercase ('n', 'y', 'm')" if ($k eq "N" || $k eq "Y" || $k eq "M");
+	print "\n";
+
+	$ret = 1;
+}
+
+exit $ret;