[kvm-unit-tests PATCH v4 3/4] s390x: topology: Check the Perform Topology Function

[Pierre Morel <pmorel@linux.ibm.com>]

We check the PTF instruction.

- We do not expect to support vertical polarization.

- We do not expect the Modified Topology Change Report to be
pending or not at the moment the first PTF instruction with
PTF_CHECK function code is done as some code already did run
a polarization change may have occur.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
 s390x/Makefile      |   1 +
 s390x/topology.c    | 115 ++++++++++++++++++++++++++++++++++++++++++++
 s390x/unittests.cfg |   3 ++
 3 files changed, 119 insertions(+)
 create mode 100644 s390x/topology.c

diff --git a/s390x/Makefile b/s390x/Makefile
index 53b0fe04..d833d6a3 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -26,6 +26,7 @@ tests += $(TEST_DIR)/edat.elf
 tests += $(TEST_DIR)/mvpg-sie.elf
 tests += $(TEST_DIR)/spec_ex-sie.elf
 tests += $(TEST_DIR)/firq.elf
+tests += $(TEST_DIR)/topology.elf
 
 pv-tests += $(TEST_DIR)/pv-diags.elf
 
diff --git a/s390x/topology.c b/s390x/topology.c
new file mode 100644
index 00000000..a1f9ce51
--- /dev/null
+++ b/s390x/topology.c
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * CPU Topology
+ *
+ * Copyright IBM Corp. 2022
+ *
+ * Authors:
+ *  Pierre Morel <pmorel@linux.ibm.com>
+ */
+
+#include <libcflat.h>
+#include <asm/page.h>
+#include <asm/asm-offsets.h>
+#include <asm/interrupt.h>
+#include <asm/facility.h>
+#include <smp.h>
+#include <sclp.h>
+#include <s390x/vm.h>
+
+#define PTF_REQ_HORIZONTAL	0
+#define PTF_REQ_VERTICAL	1
+#define PTF_REQ_CHECK		2
+
+#define PTF_ERR_NO_REASON	0
+#define PTF_ERR_ALRDY_POLARIZED	1
+#define PTF_ERR_IN_PROGRESS	2
+
+static int ptf(unsigned long fc, unsigned long *rc)
+{
+	int cc;
+
+	asm volatile(
+		"       .insn   rre,0xb9a20000,%1,0\n"
+		"       ipm     %0\n"
+		"       srl     %0,28\n"
+		: "=d" (cc), "+d" (fc)
+		: "d" (fc)
+		: "cc");
+
+	*rc = fc >> 8;
+	return cc;
+}
+
+static void test_ptf(void)
+{
+	unsigned long rc;
+	int cc;
+
+	report_prefix_push("Topology Report pending");
+	/*
+	 * At this moment the topology may already have changed
+	 * since the VM has been started.
+	 * However, we can test if a second PTF instruction
+	 * reports that the topology did not change since the
+	 * preceding PFT instruction.
+	 */
+	ptf(PTF_REQ_CHECK, &rc);
+	cc = ptf(PTF_REQ_CHECK, &rc);
+	report(cc == 0, "PTF check should clear topology report");
+
+	report_prefix_pop();
+
+	report_prefix_push("Topology polarisation check");
+	/*
+	 * We can not assume the state of the polarization for
+	 * any Virtual Machine but KVM.
+	 * Let's skip the polarisation tests for other VMs.
+	 */
+	if (!vm_is_kvm()) {
+		report_skip("Topology polarisation check is done for KVM only");
+		goto end;
+	}
+
+	cc = ptf(PTF_REQ_HORIZONTAL, &rc);
+	report(cc == 2 && rc == PTF_ERR_ALRDY_POLARIZED,
+	       "KVM always provides horizontal polarization");
+
+	cc = ptf(PTF_REQ_VERTICAL, &rc);
+	report(cc == 2 && rc == PTF_ERR_NO_REASON,
+	       "KVM doesn't support vertical polarization.");
+
+end:
+	report_prefix_pop();
+}
+
+static struct {
+	const char *name;
+	void (*func)(void);
+} tests[] = {
+	{ "PTF", test_ptf},
+	{ NULL, NULL }
+};
+
+int main(int argc, char *argv[])
+{
+	int i;
+
+	report_prefix_push("CPU Topology");
+
+	if (!test_facility(11)) {
+		report_skip("Topology facility not present");
+		goto end;
+	}
+
+	report_info("Machine level %ld", stsi_get_fc());
+
+	for (i = 0; tests[i].name; i++) {
+		report_prefix_push(tests[i].name);
+		tests[i].func();
+		report_prefix_pop();
+	}
+end:
+	report_prefix_pop();
+	return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index 054560c2..e2d3e6a5 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -122,3 +122,6 @@ extra_params = -smp 1,maxcpus=3 -cpu qemu -device qemu-s390x-cpu,core-id=1 -devi
 file = firq.elf
 timeout = 20
 extra_params = -smp 1,maxcpus=3 -cpu qemu -device qemu-s390x-cpu,core-id=2 -device qemu-s390x-cpu,core-id=1
+
+[topology]
+file = topology.elf
-- 
2.27.0