diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index 931ed4d..97f70f3 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -47,6 +47,11 @@
 #define MMU_USER_IDX 1
 
 #define MAX_EXT_QUEUE 16
+#define MAX_IO_QUEUE 16
+#define MAX_MCHK_QUEUE 16
+
+#define PSW_MCHK_MASK 0x0004000000000000
+#define PSW_IO_MASK 0x0200000000000000
 
 typedef struct PSW {
     uint64_t mask;
@@ -59,6 +64,17 @@ typedef struct ExtQueue {
     uint32_t param64;
 } ExtQueue;
 
+typedef struct IOIntQueue {
+    uint16_t id;
+    uint16_t nr;
+    uint32_t parm;
+    uint32_t word;
+} IOIntQueue;
+
+typedef struct MchkQueue {
+    uint16_t type;
+} MchkQueue;
+
 typedef struct CPUS390XState {
     uint64_t regs[16];     /* GP registers */
     CPU_DoubleU fregs[16]; /* FP registers */
@@ -90,9 +106,17 @@ typedef struct CPUS390XState {
     uint64_t cregs[16]; /* control registers */
 
     ExtQueue ext_queue[MAX_EXT_QUEUE];
-    int pending_int;
+    IOIntQueue io_queue[MAX_IO_QUEUE][8];
+    MchkQueue mchk_queue[MAX_MCHK_QUEUE];
 
+    int pending_int;
     int ext_index;
+    int io_index[8];
+    int mchk_index;
+
+    uint64_t ckc;
+    uint64_t cputm;
+    uint32_t todpr;
 
     CPU_COMMON
 
@@ -373,10 +397,14 @@ static inline void cpu_set_tls(CPUS390XState *env, target_ulong newtls)
 #define EXCP_EXT 1 /* external interrupt */
 #define EXCP_SVC 2 /* supervisor call (syscall) */
 #define EXCP_PGM 3 /* program interruption */
+#define EXCP_IO  7 /* I/O interrupt */
+#define EXCP_MCHK 8 /* machine check */
 
 #define INTERRUPT_EXT        (1 << 0)
 #define INTERRUPT_TOD        (1 << 1)
 #define INTERRUPT_CPUTIMER   (1 << 2)
+#define INTERRUPT_IO         (1 << 3)
+#define INTERRUPT_MCHK       (1 << 4)
 
 /* Program Status Word.  */
 #define S390_PSWM_REGNUM 0
@@ -920,6 +948,45 @@ static inline void cpu_inject_ext(CPUS390XState *env, uint32_t code, uint32_t pa
     cpu_interrupt(env, CPU_INTERRUPT_HARD);
 }
 
+static inline void cpu_inject_io(CPUS390XState *env, uint16_t subchannel_id,
+                                 uint16_t subchannel_number,
+                                 uint32_t io_int_parm, uint32_t io_int_word)
+{
+    int isc = ffs(io_int_word << 2) - 1;
+
+    if (env->io_index[isc] == MAX_IO_QUEUE - 1) {
+        /* ugh - can't queue anymore. Let's drop. */
+        return;
+    }
+
+    env->io_index[isc]++;
+    assert(env->io_index[isc] < MAX_IO_QUEUE);
+
+    env->io_queue[env->io_index[isc]][isc].id = subchannel_id;
+    env->io_queue[env->io_index[isc]][isc].nr = subchannel_number;
+    env->io_queue[env->io_index[isc]][isc].parm = io_int_parm;
+    env->io_queue[env->io_index[isc]][isc].word = io_int_word;
+
+    env->pending_int |= INTERRUPT_IO;
+    cpu_interrupt(env, CPU_INTERRUPT_HARD);
+}
+
+static inline void cpu_inject_crw_mchk(CPUS390XState *env)
+{
+    if (env->mchk_index == MAX_MCHK_QUEUE - 1) {
+        /* ugh - can't queue anymore. Let's drop. */
+        return;
+    }
+
+    env->mchk_index++;
+    assert(env->mchk_index < MAX_MCHK_QUEUE);
+
+    env->mchk_queue[env->mchk_index].type = 1;
+
+    env->pending_int |= INTERRUPT_MCHK;
+    cpu_interrupt(env, CPU_INTERRUPT_HARD);
+}
+
 static inline bool cpu_has_work(CPUState *cpu)
 {
     CPUS390XState *env = &S390_CPU(cpu)->env;
diff --git a/target-s390x/helper.c b/target-s390x/helper.c
index d350f28..6e0a2d2 100644
--- a/target-s390x/helper.c
+++ b/target-s390x/helper.c
@@ -618,12 +618,142 @@ static void do_ext_interrupt(CPUS390XState *env)
     load_psw(env, mask, addr);
 }
 
+static void do_io_interrupt(CPUS390XState *env)
+{
+    uint64_t mask, addr;
+    LowCore *lowcore;
+    hwaddr len = TARGET_PAGE_SIZE;
+    IOIntQueue *q;
+    uint8_t isc;
+    int disable = 1;
+    int found = 0;
+
+    if (!(env->psw.mask & PSW_MASK_IO)) {
+        cpu_abort(env, "I/O int w/o I/O mask\n");
+    }
+
+    for (isc = 0; isc < 8; isc++) {
+        if (env->io_index[isc] < 0) {
+            continue;
+        }
+        if (env->io_index[isc] > MAX_IO_QUEUE) {
+            cpu_abort(env, "I/O queue overrun for isc %d: %d\n",
+                      isc, env->io_index[isc]);
+        }
+
+        q = &env->io_queue[env->io_index[isc]][isc];
+        if (!(env->cregs[6] & q->word)) {
+            disable = 0;
+            continue;
+        }
+        found = 1;
+        lowcore = cpu_map_lowcore(env, &len);
+
+        lowcore->subchannel_id = cpu_to_be16(q->id);
+        lowcore->subchannel_nr = cpu_to_be16(q->nr);
+        lowcore->io_int_parm = cpu_to_be32(q->parm);
+        lowcore->io_int_word = cpu_to_be32(q->word);
+        lowcore->io_old_psw.mask = cpu_to_be64(get_psw_mask(env));
+        lowcore->io_old_psw.addr = cpu_to_be64(env->psw.addr);
+        mask = be64_to_cpu(lowcore->io_new_psw.mask);
+        addr = be64_to_cpu(lowcore->io_new_psw.addr);
+
+        cpu_unmap_lowcore(lowcore, len);
+
+        env->io_index[isc]--;
+        if (env->io_index >= 0) {
+            disable = 0;
+        }
+        break;
+    }
+
+    if (disable) {
+        env->pending_int &= ~INTERRUPT_IO;
+    }
+
+    if (found) {
+        DPRINTF("%s: %" PRIx64 " %" PRIx64 "\n", __func__,
+                env->psw.mask, env->psw.addr);
+        load_psw(env, mask, addr);
+    }
+}
+
+static void do_mchk_interrupt(CPUS390XState *env)
+{
+    uint64_t mask, addr;
+    LowCore *lowcore;
+    hwaddr len = TARGET_PAGE_SIZE;
+    MchkQueue *q;
+    int i;
+
+    if (!(env->psw.mask & PSW_MASK_MCHECK)) {
+        cpu_abort(env, "Machine check w/o mchk mask\n");
+    }
+
+    if (env->mchk_index < 0 || env->mchk_index > MAX_MCHK_QUEUE) {
+        cpu_abort(env, "Mchk queue overrun: %d\n", env->mchk_index);
+    }
+
+    q = &env->mchk_queue[env->mchk_index];
+
+    if (q->type != 1) {
+        /* Don't know how to handle this... */
+        cpu_abort(env, "Unknown machine check type %d\n", q->type);
+    }
+    if (!(env->cregs[14] & (1 << 28))) {
+        /* CRW machine checks disabled */
+        return;
+    }
+
+    lowcore = cpu_map_lowcore(env, &len);
+
+    for (i = 0; i < 16; i++) {
+        lowcore->floating_pt_save_area[i] = cpu_to_be64(env->fregs[i].ll);
+        lowcore->gpregs_save_area[i] = cpu_to_be64(env->regs[i]);
+        lowcore->access_regs_save_area[i] = cpu_to_be32(env->aregs[i]);
+        lowcore->cregs_save_area[i] = cpu_to_be64(env->cregs[i]);
+    }
+    lowcore->prefixreg_save_area = cpu_to_be32(env->psa);
+    lowcore->fpt_creg_save_area = cpu_to_be32(env->fpc);
+    lowcore->tod_progreg_save_area = cpu_to_be32(env->todpr);
+    lowcore->cpu_timer_save_area[0] = cpu_to_be32(env->cputm >> 32);
+    lowcore->cpu_timer_save_area[1] = cpu_to_be32((uint32_t)env->cputm);
+    lowcore->clock_comp_save_area[0] = cpu_to_be32(env->ckc >> 32);
+    lowcore->clock_comp_save_area[1] = cpu_to_be32((uint32_t)env->ckc);
+
+    lowcore->mcck_interruption_code[0] = cpu_to_be32(0x00400f1d);
+    lowcore->mcck_interruption_code[1] = cpu_to_be32(0x40330000);
+    lowcore->mcck_old_psw.mask = cpu_to_be64(get_psw_mask(env));
+    lowcore->mcck_old_psw.addr = cpu_to_be64(env->psw.addr);
+    mask = be64_to_cpu(lowcore->mcck_new_psw.mask);
+    addr = be64_to_cpu(lowcore->mcck_new_psw.addr);
+
+    cpu_unmap_lowcore(lowcore, len);
+
+    env->mchk_index--;
+    if (env->mchk_index == -1) {
+        env->pending_int &= ~INTERRUPT_MCHK;
+    }
+
+    DPRINTF("%s: %" PRIx64 " %" PRIx64 "\n", __func__,
+            env->psw.mask, env->psw.addr);
+
+    load_psw(env, mask, addr);
+}
+
 void do_interrupt(CPUS390XState *env)
 {
     qemu_log_mask(CPU_LOG_INT, "%s: %d at pc=%" PRIx64 "\n",
                   __func__, env->exception_index, env->psw.addr);
 
     s390_add_running_cpu(env);
+    /* handle machine checks */
+    if ((env->psw.mask & PSW_MASK_MCHECK) &&
+        (env->exception_index == -1)) {
+        if (env->pending_int & INTERRUPT_MCHK) {
+            env->exception_index = EXCP_MCHK;
+        }
+    }
     /* handle external interrupts */
     if ((env->psw.mask & PSW_MASK_EXT) &&
         env->exception_index == -1) {
@@ -642,6 +772,13 @@ void do_interrupt(CPUS390XState *env)
             env->pending_int &= ~INTERRUPT_TOD;
         }
     }
+    /* handle I/O interrupts */
+    if ((env->psw.mask & PSW_MASK_IO) &&
+        (env->exception_index == -1)) {
+        if (env->pending_int & INTERRUPT_IO) {
+            env->exception_index = EXCP_IO;
+        }
+    }
 
     switch (env->exception_index) {
     case EXCP_PGM:
@@ -653,6 +790,12 @@ void do_interrupt(CPUS390XState *env)
     case EXCP_EXT:
         do_ext_interrupt(env);
         break;
+    case EXCP_IO:
+        do_io_interrupt(env);
+        break;
+    case EXCP_MCHK:
+        do_mchk_interrupt(env);
+        break;
     }
     env->exception_index = -1;
 
