Merge: selftests/mm: fix va_high_addr_switch.sh failure on x86_64

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/1628

JIRA: https://issues.redhat.com/browse/RHEL-110506

The patch2 and patch3 fix kselftest hugevm va_high_addr_switch test failure caused by no enough hugepage and mismatched hint addr align. The first patch is added as dependency.

Signed-off-by: Chunyu Hu <chuhu@redhat.com>

Approved-by: Waiman Long <longman@redhat.com>
Approved-by: Rafael Aquini <raquini@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: CKI GitLab Kmaint Pipeline Bot <26919896-cki-kmaint-pipeline-bot@users.noreply.gitlab.com>

Author: CKI KWF Bot

tools/testing/selftests/mm/va_high_addr_switch.c

@@ -230,10 +230,10 @@ void testcases_init(void)
 			.msg = "mmap(-1, MAP_HUGETLB) again",
 		},
 		{
-			.addr = (void *)(addr_switch_hint - pagesize),
+			.addr = (void *)(addr_switch_hint - hugepagesize),
 			.size = 2 * hugepagesize,
 			.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
-			.msg = "mmap(addr_switch_hint - pagesize, 2*hugepagesize, MAP_HUGETLB)",
+			.msg = "mmap(addr_switch_hint - hugepagesize, 2*hugepagesize, MAP_HUGETLB)",
 			.low_addr_required = 1,
 			.keep_mapped = 1,
 		},

tools/testing/selftests/mm/va_high_addr_switch.sh

@@ -7,23 +7,21 @@
 # real test to check that the kernel is configured to support at least 5
 # pagetable levels.
 
-# 1 means the test failed
-exitcode=1
-
 # Kselftest framework requirement - SKIP code is 4.
 ksft_skip=4
+orig_nr_hugepages=0
 
-fail()
+skip()
 {
 	echo "$1"
-	exit $exitcode
+	exit $ksft_skip
 }
 
 check_supported_x86_64()
 {
 	local config="/proc/config.gz"
 	[[ -f "${config}" ]] || config="/boot/config-$(uname -r)"
-	[[ -f "${config}" ]] || fail "Cannot find kernel config in /proc or /boot"
+	[[ -f "${config}" ]] || skip "Cannot find kernel config in /proc or /boot"
 
 	# gzip -dcfq automatically handles both compressed and plaintext input.
 	# See man 1 gzip under '-f'.
@@ -33,36 +31,31 @@ check_supported_x86_64()
 		else {print 1}; exit}' /proc/cpuinfo 2>/dev/null)
 
 	if [[ "${pg_table_levels}" -lt 5 ]]; then
-		echo "$0: PGTABLE_LEVELS=${pg_table_levels}, must be >= 5 to run this test"
-		exit $ksft_skip
+		skip "$0: PGTABLE_LEVELS=${pg_table_levels}, must be >= 5 to run this test"
 	elif [[ "${cpu_supports_pl5}" -ne 0 ]]; then
-		echo "$0: CPU does not have the necessary la57 flag to support page table level 5"
-		exit $ksft_skip
+		skip "$0: CPU does not have the necessary la57 flag to support page table level 5"
 	fi
 }
 
 check_supported_ppc64()
 {
 	local config="/proc/config.gz"
 	[[ -f "${config}" ]] || config="/boot/config-$(uname -r)"
-	[[ -f "${config}" ]] || fail "Cannot find kernel config in /proc or /boot"
+	[[ -f "${config}" ]] || skip "Cannot find kernel config in /proc or /boot"
 
 	local pg_table_levels=$(gzip -dcfq "${config}" | grep PGTABLE_LEVELS | cut -d'=' -f 2)
 	if [[ "${pg_table_levels}" -lt 5 ]]; then
-		echo "$0: PGTABLE_LEVELS=${pg_table_levels}, must be >= 5 to run this test"
-		exit $ksft_skip
+		skip "$0: PGTABLE_LEVELS=${pg_table_levels}, must be >= 5 to run this test"
 	fi
 
 	local mmu_support=$(grep -m1 "mmu" /proc/cpuinfo | awk '{print $3}')
 	if [[ "$mmu_support" != "radix" ]]; then
-		echo "$0: System does not use Radix MMU, required for 5-level paging"
-		exit $ksft_skip
+		skip "$0: System does not use Radix MMU, required for 5-level paging"
 	fi
 
 	local hugepages_total=$(awk '/HugePages_Total/ {print $2}' /proc/meminfo)
 	if [[ "${hugepages_total}" -eq 0 ]]; then
-		echo "$0: HugePages are not enabled, required for some tests"
-		exit $ksft_skip
+		skip "$0: HugePages are not enabled, required for some tests"
 	fi
 }
 
@@ -84,5 +77,41 @@ check_test_requirements()
 	esac
 }
 
+save_nr_hugepages()
+{
+	orig_nr_hugepages=$(cat /proc/sys/vm/nr_hugepages)
+}
+
+restore_nr_hugepages()
+{
+	echo "$orig_nr_hugepages" > /proc/sys/vm/nr_hugepages
+}
+
+setup_nr_hugepages()
+{
+	local needpgs=$1
+	while read -r name size unit; do
+		if [ "$name" = "HugePages_Free:" ]; then
+			freepgs="$size"
+			break
+		fi
+	done < /proc/meminfo
+	if [ "$freepgs" -ge "$needpgs" ]; then
+		return
+	fi
+	local hpgs=$((orig_nr_hugepages + needpgs))
+	echo $hpgs > /proc/sys/vm/nr_hugepages
+
+	local nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages)
+	if [ "$nr_hugepgs" != "$hpgs" ]; then
+		restore_nr_hugepages
+		skip "$0: no enough hugepages for testing"
+	fi
+}
+
 check_test_requirements
+save_nr_hugepages
+# 4 keep_mapped pages, and one for tmp usage
+setup_nr_hugepages 5
 ./va_high_addr_switch --run-hugetlb
+restore_nr_hugepages