diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h
index 853529b..6ecfb0a 100644
--- a/lib/s390x/sclp.h
+++ b/lib/s390x/sclp.h
@@ -150,7 +150,8 @@ typedef struct ReadInfo {
 	SCCBHeader h;
 	uint16_t rnmax;
 	uint8_t rnsize;
-	uint8_t  _reserved1[16 - 11];       /* 11-15 */
+	uint8_t  _reserved1[15 - 11];       /* 11-14 */
+	uint8_t stsi_parm;                  /* 15-15 */
 	uint16_t entries_cpu;               /* 16-17 */
 	uint16_t offset_cpu;                /* 18-19 */
 	uint8_t  _reserved2[24 - 20];       /* 20-23 */
diff --git a/lib/s390x/stsi.h b/lib/s390x/stsi.h
index bebc492..8dbbfc2 100644
--- a/lib/s390x/stsi.h
+++ b/lib/s390x/stsi.h
@@ -29,4 +29,48 @@ struct sysinfo_3_2_2 {
 	uint8_t ext_names[8][256];
 };
 
+struct topology_core {
+	uint8_t nl;
+	uint8_t reserved1[3];
+	uint8_t reserved4:5;
+	uint8_t d:1;
+	uint8_t pp:2;
+	uint8_t type;
+	uint16_t origin;
+	uint64_t mask;
+};
+
+struct topology_container {
+	uint8_t nl;
+	uint8_t reserved[6];
+	uint8_t id;
+};
+
+union topology_entry {
+	uint8_t nl;
+	struct topology_core cpu;
+	struct topology_container container;
+};
+
+#define CPU_TOPOLOGY_MAX_LEVEL 6
+struct sysinfo_15_1_x {
+	uint8_t reserved0[2];
+	uint16_t length;
+	uint8_t mag[CPU_TOPOLOGY_MAX_LEVEL];
+	uint8_t reserved0a;
+	uint8_t mnest;
+	uint8_t reserved0c[4];
+	union topology_entry tle[0];
+};
+
+static inline int cpus_in_tle_mask(uint64_t val)
+{
+	int i, n;
+
+	for (i = 0, n = 0; i < 64; i++, val >>= 1)
+		if (val & 0x01)
+			n++;
+	return n;
+}
+
 #endif  /* _S390X_STSI_H_ */
diff --git a/s390x/topology.c b/s390x/topology.c
index 20f7ba2..f21c653 100644
--- a/s390x/topology.c
+++ b/s390x/topology.c
@@ -16,6 +16,18 @@
 #include <smp.h>
 #include <sclp.h>
 #include <s390x/hardware.h>
+#include <s390x/stsi.h>
+
+static uint8_t pagebuf[PAGE_SIZE * 2] __attribute__((aligned(PAGE_SIZE * 2)));
+
+static int max_nested_lvl;
+static int number_of_cpus;
+static int max_cpus = 1;
+
+/* Topology level as defined by architecture */
+static int arch_topo_lvl[CPU_TOPOLOGY_MAX_LEVEL];
+/* Topology nested level as reported in STSI */
+static int stsi_nested_lvl[CPU_TOPOLOGY_MAX_LEVEL];
 
 #define PTF_REQ_HORIZONTAL	0
 #define PTF_REQ_VERTICAL	1
@@ -122,11 +134,241 @@ end:
 	report_prefix_pop();
 }
 
+/*
+ * stsi_check_maxcpus
+ * @info: Pointer to the stsi information
+ *
+ * The product of the numbers of containers per level
+ * is the maximum number of CPU allowed by the machine.
+ */
+static void stsi_check_maxcpus(struct sysinfo_15_1_x *info)
+{
+	int n, i;
+
+	report_prefix_push("maximum cpus");
+
+	for (i = 0, n = 1; i < CPU_TOPOLOGY_MAX_LEVEL; i++) {
+		report_info("Mag%d: %d", CPU_TOPOLOGY_MAX_LEVEL - i, info->mag[i]);
+		n *= info->mag[i] ? info->mag[i] : 1;
+	}
+	report(n == max_cpus, "Maximum CPUs %d expected %d", n, max_cpus);
+
+	report_prefix_pop();
+}
+
+/*
+ * stsi_check_tle_coherency
+ * @info: Pointer to the stsi information
+ * @sel2: Topology level to check.
+ *
+ * We verify that we get the expected number of Topology List Entry
+ * containers for a specific level.
+ */
+static void stsi_check_tle_coherency(struct sysinfo_15_1_x *info, int sel2)
+{
+	struct topology_container *tc, *end;
+	struct topology_core *cpus;
+	int n = 0;
+	int i;
+
+	report_prefix_push("TLE coherency");
+
+	tc = &info->tle[0].container;
+	end = (struct topology_container *)((unsigned long)info + info->length);
+
+	for (i = 0; i < CPU_TOPOLOGY_MAX_LEVEL; i++)
+		stsi_nested_lvl[i] = 0;
+
+	while (tc < end) {
+		if (tc->nl > 5) {
+			report_abort("Unexpected TL Entry: tle->nl: %d", tc->nl);
+			return;
+		}
+		if (tc->nl == 0) {
+			cpus = (struct topology_core *)tc;
+			n += cpus_in_tle_mask(cpus->mask);
+			report_info("cpu type %02x  d: %d pp: %d", cpus->type, cpus->d, cpus->pp);
+			report_info("origin : %04x mask %016lx", cpus->origin, cpus->mask);
+		}
+
+		stsi_nested_lvl[tc->nl]++;
+		report_info("level %d: lvl: %d id: %d cnt: %d",
+			    tc->nl, tc->nl, tc->id, stsi_nested_lvl[tc->nl]);
+
+		/* trick: CPU TLEs are twice the size of containers TLE */
+		if (tc->nl == 0)
+			tc++;
+		tc++;
+	}
+	report(n == number_of_cpus, "Number of CPUs  : %d expect %d", n, number_of_cpus);
+	/*
+	 * For KVM we accept
+	 * - only 1 type of CPU
+	 * - only horizontal topology
+	 * - only dedicated CPUs
+	 * This leads to expect the number of entries of level 0 CPU
+	 * Topology Level Entry (TLE) to be:
+	 * 1 + (number_of_cpus - 1)  / arch_topo_lvl[0]
+	 *
+	 * For z/VM or LPAR this number can only be greater if different
+	 * polarity, CPU types because there may be a nested level 0 CPU TLE
+	 * for each of the CPU/polarity/sharing types in a level 1 container TLE.
+	 */
+	n =  (number_of_cpus - 1)  / arch_topo_lvl[0];
+	report(stsi_nested_lvl[0] >=  n + 1,
+	       "CPU Type TLE    : %d expect %d", stsi_nested_lvl[0], n + 1);
+
+	/* For each level found in STSI */
+	for (i = 1; i < CPU_TOPOLOGY_MAX_LEVEL; i++) {
+		/*
+		 * For non QEMU/KVM hypervisor the concatenation of the levels
+		 * above level 1 are architecture dependent.
+		 * Skip these checks.
+		 */
+		if (!host_is_kvm() && sel2 != 2)
+			continue;
+
+		/* For QEMU/KVM we expect a simple calculation */
+		if (sel2 > i) {
+			report(stsi_nested_lvl[i] ==  n + 1,
+			       "Container TLE  %d: %d expect %d", i, stsi_nested_lvl[i], n + 1);
+			n /= arch_topo_lvl[i];
+		}
+	}
+
+	report_prefix_pop();
+}
+
+/*
+ * check_sysinfo_15_1_x
+ * @info: pointer to the STSI info structure
+ * @sel2: the selector giving the topology level to check
+ *
+ * Check if the validity of the STSI instruction and then
+ * calls specific checks on the information buffer.
+ */
+static void check_sysinfo_15_1_x(struct sysinfo_15_1_x *info, int sel2)
+{
+	int ret;
+
+	report_prefix_pushf("mnested %d 15_1_%d", max_nested_lvl, sel2);
+
+	ret = stsi(pagebuf, 15, 1, sel2);
+	if (max_nested_lvl >= sel2) {
+		report(!ret, "Valid stsi instruction");
+	} else {
+		report(ret, "Invalid stsi instruction");
+		goto end;
+	}
+
+	stsi_check_maxcpus(info);
+	stsi_check_tle_coherency(info, sel2);
+
+end:
+	report_prefix_pop();
+}
+
+static int sclp_get_mnest(void)
+{
+	ReadInfo *sccb = (void *)_sccb;
+
+	sclp_mark_busy();
+	memset(_sccb, 0, PAGE_SIZE);
+	sccb->h.length = PAGE_SIZE;
+
+	sclp_service_call(SCLP_CMDW_READ_SCP_INFO, sccb);
+	assert(sccb->h.response_code == SCLP_RC_NORMAL_READ_COMPLETION);
+
+	return sccb->stsi_parm;
+}
+
+/*
+ * test_stsi
+ *
+ * Retrieves the maximum nested topology level supported by the architecture
+ * and the number of CPUs.
+ * Calls the checking for the STSI instruction in sel2 reverse level order
+ * from 6 (CPU_TOPOLOGY_MAX_LEVEL) to 2 to have the most interesting level,
+ * the one triggering a topology-change-report-pending condition, level 2,
+ * at the end of the report.
+ *
+ */
+static void test_stsi(void)
+{
+	int sel2;
+
+	max_nested_lvl = sclp_get_mnest();
+	report_info("SCLP maximum nested level : %d", max_nested_lvl);
+
+	number_of_cpus = sclp_get_cpu_num();
+	report_info("SCLP number of CPU: %d", number_of_cpus);
+
+	/* STSI selector 2 can takes values between 2 and 6 */
+	for (sel2 = 6; sel2 >= 2; sel2--)
+		check_sysinfo_15_1_x((struct sysinfo_15_1_x *)pagebuf, sel2);
+}
+
+/*
+ * parse_topology_args
+ * @argc: number of arguments
+ * @argv: argument array
+ *
+ * This function initialize the architecture topology levels
+ * which should be the same as the one provided by the hypervisor.
+ *
+ * We use the current names found in IBM/Z literature, Linux and QEMU:
+ * cores, sockets/packages, books, drawers and nodes to facilitate the
+ * human machine interface but store the result in a machine abstract
+ * array of architecture topology levels.
+ * Note that when QEMU uses socket as a name for the topology level 1
+ * Linux uses package or physical_package.
+ */
+static void parse_topology_args(int argc, char **argv)
+{
+	int i;
+
+	report_info("%d arguments", argc);
+	for (i = 1; i < argc; i++) {
+		if (!strcmp("-cores", argv[i])) {
+			i++;
+			if (i >= argc)
+				report_abort("-cores needs a parameter");
+			arch_topo_lvl[0] = atol(argv[i]);
+			report_info("cores: %d", arch_topo_lvl[0]);
+		} else if (!strcmp("-sockets", argv[i])) {
+			i++;
+			if (i >= argc)
+				report_abort("-sockets needs a parameter");
+			arch_topo_lvl[1] = atol(argv[i]);
+			report_info("sockets: %d", arch_topo_lvl[1]);
+		} else if (!strcmp("-books", argv[i])) {
+			i++;
+			if (i >= argc)
+				report_abort("-books needs a parameter");
+			arch_topo_lvl[2] = atol(argv[i]);
+			report_info("books: %d", arch_topo_lvl[2]);
+		} else if (!strcmp("-drawers", argv[i])) {
+			i++;
+			if (i >= argc)
+				report_abort("-drawers needs a parameter");
+			arch_topo_lvl[3] = atol(argv[i]);
+			report_info("drawers: %d", arch_topo_lvl[3]);
+		}
+	}
+
+	for (i = 0; i < CPU_TOPOLOGY_MAX_LEVEL; i++) {
+		if (!arch_topo_lvl[i])
+			arch_topo_lvl[i] = 1;
+		max_cpus *= arch_topo_lvl[i];
+	}
+}
+
 static struct {
 	const char *name;
 	void (*func)(void);
 } tests[] = {
 	{ "PTF", test_ptf},
+	{ "STSI", test_stsi},
 	{ NULL, NULL }
 };
 
@@ -136,6 +378,8 @@ int main(int argc, char *argv[])
 
 	report_prefix_push("CPU Topology");
 
+	parse_topology_args(argc, argv);
+
 	if (!test_facility(11)) {
 		report_skip("Topology facility not present");
 		goto end;
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index 3530cc4..b697aca 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -211,3 +211,4 @@ smp = 2
 
 [topology]
 file = topology.elf
+extra_params=-smp 5,drawers=3,books=3,sockets=4,cores=4,maxcpus=144 -append '-drawers 3 -books 3 -sockets 4 -cores 4'
