diff --git a/lib/s390x/css.h b/lib/s390x/css.h
index 794321d..17b917f 100644
--- a/lib/s390x/css.h
+++ b/lib/s390x/css.h
@@ -82,6 +82,8 @@ struct pmcw {
 	uint32_t intparm;
 #define PMCW_DNV	0x0001
 #define PMCW_ENABLE	0x0080
+#define PMCW_MBUE	0x0010
+#define PMCW_DCTME	0x0008
 #define PMCW_ISC_MASK	0x3800
 #define PMCW_ISC_SHIFT	11
 	uint16_t flags;
@@ -94,6 +96,7 @@ struct pmcw {
 	uint8_t  pom;
 	uint8_t  pam;
 	uint8_t  chpid[8];
+#define PMCW_MBF1	0x0004
 	uint32_t flags2;
 };
 #define PMCW_CHANNEL_TYPE(pmcw) (pmcw->flags2 >> 21)
@@ -101,7 +104,8 @@ struct pmcw {
 struct schib {
 	struct pmcw pmcw;
 	struct scsw scsw;
-	uint8_t  md[12];
+	uint64_t mbo;
+	uint8_t  md[4];
 } __attribute__ ((aligned(4)));
 
 struct irb {
@@ -306,6 +310,7 @@ struct chsc_scsc {
 	u32 res_04[2];
 	struct chsc_header res;
 	u32 res_fmt;
+#define CSSC_EXTENDED_MEASUREMENT_BLOCK 48
 	u64 general_char[255];
 	u64 chsc_char[254];
 };
@@ -356,4 +361,18 @@ int chsc(void *p, uint16_t code, uint16_t len);
 #define css_general_feature(bit) test_bit_inv(bit, chsc_scsc->general_char)
 #define css_chsc_feature(bit) test_bit_inv(bit, chsc_scsc->chsc_char)
 
+#define SCHM_DCTM	1 /* activate Device Connection TiMe */
+#define SCHM_MBU	2 /* activate Measurement Block Update */
+
+static inline void schm(void *mbo, unsigned int flags)
+{
+	register void *__gpr2 asm("2") = mbo;
+	register long __gpr1 asm("1") = flags;
+
+	asm("schm" : : "d" (__gpr2), "d" (__gpr1));
+}
+
+bool css_enable_mb(int sid, uint64_t mb, uint16_t mbi, uint16_t flg, bool fmt1);
+bool css_disable_mb(int schid);
+
 #endif
diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c
index 65b58ff..4c8a6ae 100644
--- a/lib/s390x/css_lib.c
+++ b/lib/s390x/css_lib.c
@@ -265,6 +265,106 @@ retry:
 	return -1;
 }
 
+/*
+ * schib_update_mb: update the subchannel Mesurement Block
+ * @schid: Subchannel Identifier
+ * @mb   : 64bit address of the measurement block
+ * @mbi : the measurement block offset
+ * @flags : PMCW_MBUE to enable measurement block update
+ *	    PMCW_DCTME to enable device connect time
+ *	    0 to disable measurement
+ * @format1: set if format 1 is to be used
+ */
+static bool schib_update_mb(int schid, uint64_t mb, uint16_t mbi,
+			    uint16_t flags, bool format1)
+{
+	struct pmcw *pmcw = &schib.pmcw;
+	int cc;
+
+	/* Read the SCHIB for this subchannel */
+	cc = stsch(schid, &schib);
+	if (cc) {
+		report_info("stsch: sch %08x failed with cc=%d", schid, cc);
+		return false;
+	}
+
+	/* Update the SCHIB to enable the measurement block */
+	if (flags) {
+		pmcw->flags |= flags;
+
+		if (format1)
+			pmcw->flags2 |= PMCW_MBF1;
+		else
+			pmcw->flags2 &= ~PMCW_MBF1;
+
+		pmcw->mbi = mbi;
+		schib.mbo = mb;
+	} else {
+		pmcw->flags &= ~(PMCW_MBUE | PMCW_DCTME);
+	}
+
+	/* Tell the CSS we want to modify the subchannel */
+	cc = msch(schid, &schib);
+	if (cc) {
+		/*
+		 * If the subchannel is status pending or
+		 * if a function is in progress,
+		 * we consider both cases as errors.
+		 */
+		report_info("msch: sch %08x failed with cc=%d", schid, cc);
+		return false;
+	}
+
+	/*
+	 * Read the SCHIB again
+	 */
+	cc = stsch(schid, &schib);
+	if (cc) {
+		report_info("stsch: updating sch %08x failed with cc=%d",
+			    schid, cc);
+		return false;
+	}
+
+	return true;
+}
+
+/*
+ * css_enable_mb: enable the subchannel Mesurement Block
+ * @schid: Subchannel Identifier
+ * @mb   : 64bit address of the measurement block
+ * @format1: set if format 1 is to be used
+ * @mbi : the measurement block offset
+ * @flags : PMCW_MBUE to enable measurement block update
+ *	    PMCW_DCTME to enable device connect time
+ */
+bool css_enable_mb(int schid, uint64_t mb, uint16_t mbi, uint16_t flags,
+		   bool format1)
+{
+	int retry_count = MAX_ENABLE_RETRIES;
+	struct pmcw *pmcw = &schib.pmcw;
+
+	while (retry_count-- &&
+	       !schib_update_mb(schid, mb, mbi, flags, format1))
+		mdelay(10); /* the hardware was not ready, give it some time */
+
+	return schib.mbo == mb && pmcw->mbi == mbi;
+}
+
+/*
+ * css_disable_mb: enable the subchannel Mesurement Block
+ * @schid: Subchannel Identifier
+ */
+bool css_disable_mb(int schid)
+{
+	int retry_count = MAX_ENABLE_RETRIES;
+
+	while (retry_count-- &&
+	       !schib_update_mb(schid, 0, 0, 0, 0))
+		mdelay(10); /* the hardware was not ready, give it some time */
+
+	return retry_count > 0;
+}
+
 static struct irb irb;
 
 void css_irq_io(void)
diff --git a/s390x/css.c b/s390x/css.c
index d4b3cc8..fc693f3 100644
--- a/s390x/css.c
+++ b/s390x/css.c
@@ -157,6 +157,40 @@ static void css_init(void)
 	report(1, "CSS initialized");
 }
 
+static void test_schm(void)
+{
+	if (css_general_feature(CSSC_EXTENDED_MEASUREMENT_BLOCK))
+		report_info("Extended measurement block available");
+
+	/* bits 59-63 of MB address must be 0  if MBU is defined */
+	report_prefix_push("Unaligned operand");
+	expect_pgm_int();
+	schm((void *)0x01, SCHM_MBU);
+	check_pgm_int_code(PGM_INT_CODE_OPERAND);
+	report_prefix_pop();
+
+	/* bits 36-61 of register 1 (flags) must be 0 */
+	report_prefix_push("Bad flags");
+	expect_pgm_int();
+	schm(NULL, 0xfffffffc);
+	check_pgm_int_code(PGM_INT_CODE_OPERAND);
+	report_prefix_pop();
+
+	/* SCHM is a privilege operation */
+	report_prefix_push("Privilege");
+	enter_pstate();
+	expect_pgm_int();
+	schm(NULL, SCHM_MBU);
+	check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION);
+	report_prefix_pop();
+
+	/* Normal operation */
+	report_prefix_push("Normal operation");
+	schm(NULL, SCHM_MBU);
+	report(1, "SCHM call without address");
+	report_prefix_pop();
+}
+
 static struct {
 	const char *name;
 	void (*func)(void);
@@ -166,6 +200,7 @@ static struct {
 	{ "enumerate (stsch)", test_enumerate },
 	{ "enable (msch)", test_enable },
 	{ "sense (ssch/tsch)", test_sense },
+	{ "measurement block (schm)", test_schm },
 	{ NULL, NULL }
 };
 
