[PATCH v6 4/5] KVM: PPC: selftests: Skip idle-page check when running nested on pseries LPAR

[Ritesh Harjani (IBM)]

Same nested TLB/access bit issue like x86. Use the is_pseries_lpar()
check to detect when running nested kvm on pseries LPAR to only warn on
idle-page check.

Reported-by: Anushree Mathur <anushree.mathur@xxxxxxxxxxxxx>
Tested-by: Anushree Mathur <anushree.mathur@xxxxxxxxxxxxx>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
---
 tools/testing/selftests/kvm/Makefile.kvm              |  1 +
 .../testing/selftests/kvm/access_tracking_perf_test.c | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index a7ecd7a242a9..57d1bf994fe8 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -263,6 +263,7 @@ TEST_GEN_PROGS_powerpc += kvm_page_table_test
 TEST_GEN_PROGS_powerpc += set_memory_region_test
 TEST_GEN_PROGS_powerpc += memslot_modification_stress_test
 TEST_GEN_PROGS_powerpc += memslot_perf_test
+TEST_GEN_PROGS_powerpc += access_tracking_perf_test
 
 SPLIT_TESTS += arch_timer
 SPLIT_TESTS += get-reg-list
diff --git a/tools/testing/selftests/kvm/access_tracking_perf_test.c b/tools/testing/selftests/kvm/access_tracking_perf_test.c
index 4415c94b2866..94bfb82f7b79 100644
--- a/tools/testing/selftests/kvm/access_tracking_perf_test.c
+++ b/tools/testing/selftests/kvm/access_tracking_perf_test.c
@@ -470,6 +470,17 @@ static int access_tracking_unreliable(void)
 		puts("Skipping idle page count sanity check, because the test is run nested");
 		return 1;
 	}
+#endif
+#ifdef __powerpc64__
+	/*
+	 * Nested KVM (pSeries LPAR) can hide accessed/idle, since KVM doesn't
+	 * explicitely flush the TLB for access bit update. L0 keeps
+	 * translations cached so the guest won't see the idle bit cleared.
+	 */
+	if (is_pseries_lpar()) {
+		puts("Skipping idle page count sanity check, because the test is run nested");
+		return 1;
+	}
 #endif
 	/*
 	 * When NUMA balancing is enabled, guest memory will be unmapped to get
-- 
2.39.5