Index: usr.sbin/bhyve/pci_nvme.c
===================================================================
--- usr.sbin/bhyve/pci_nvme.c
+++ usr.sbin/bhyve/pci_nvme.c
@@ -62,6 +62,7 @@
 #include <sys/errno.h>
 #include <sys/types.h>
 #include <net/ieee_oui.h>
+#include <sys/time.h>
 
 #include <assert.h>
 #include <pthread.h>
@@ -115,6 +116,9 @@
 #define NVME_NO_STATUS		0xffff
 #define NVME_COMPLETION_VALID(c)	((c).status != NVME_NO_STATUS)
 
+#define POWER_ON_HOURS(start, now) \
+	((now.tv_sec - start.tv_sec) / 3600)
+
 /* helpers */
 
 /* Convert a zero-based value into a one-based value */
@@ -300,6 +304,7 @@
 	__uint128_t	write_commands;
 	uint32_t	read_dunits_remainder;
 	uint32_t	write_dunits_remainder;
+	struct timeval	power_on_time;
 
 	STAILQ_HEAD(, pci_nvme_aer) aer_list;
 	uint32_t	aer_count;
@@ -503,6 +508,8 @@
 	cd->fna = 0x03;
 
 	cd->power_state[0].mp = 10;
+
+	gettimeofday(&sc->power_on_time, NULL);
 }
 
 /*
@@ -596,6 +603,7 @@
 static void
 pci_nvme_init_logpages(struct pci_nvme_softc *sc)
 {
+	__uint128_t power_cycles = 1;
 
 	memset(&sc->err_log, 0, sizeof(sc->err_log));
 	memset(&sc->health_log, 0, sizeof(sc->health_log));
@@ -609,6 +617,9 @@
 	sc->health_log.temperature = 310;
 	sc->health_log.available_spare = 100;
 	sc->health_log.available_spare_threshold = 10;
+
+	memcpy(&sc->health_log.power_cycles, &power_cycles,
+	    sizeof(sc->health_log.power_cycles));
 }
 
 static void
@@ -1071,6 +1082,8 @@
 {
 	uint32_t logsize;
 	uint8_t logpage = command->cdw10 & 0xFF;
+	struct timeval now;
+	__uint128_t power_on_hours;
 
 	DPRINTF("%s log page %u len %u", __func__, logpage, logsize);
 
@@ -1091,6 +1104,11 @@
 		    NVME_COPY_TO_PRP);
 		break;
 	case NVME_LOG_HEALTH_INFORMATION:
+		gettimeofday(&now, NULL);
+		power_on_hours = POWER_ON_HOURS(sc->power_on_time, now);
+		memcpy(&sc->health_log.power_on_hours, &power_on_hours,
+		    sizeof(sc->health_log.power_on_hours));
+
 		pthread_mutex_lock(&sc->mtx);
 		memcpy(&sc->health_log.data_units_read, &sc->read_data_units,
 		    sizeof(sc->health_log.data_units_read));