diff --git a/hw/iommu.c b/hw/iommu.c
index 55d39b9fd7..c90f09bca6 100644
--- a/hw/iommu.c
+++ b/hw/iommu.c
@@ -37,7 +37,6 @@ do { printf("IOMMU: " fmt , ##args); } while (0)
 #define IOMMU_CTRL          (0x0000 >> 2)
 #define IOMMU_CTRL_IMPL     0xf0000000 /* Implementation */
 #define IOMMU_CTRL_VERS     0x0f000000 /* Version */
-#define IOMMU_VERSION       0x04000000
 #define IOMMU_CTRL_RNGE     0x0000001c /* Mapping RANGE */
 #define IOMMU_RNGE_16MB     0x00000000 /* 0xff000000 -> 0xffffffff */
 #define IOMMU_RNGE_32MB     0x00000004 /* 0xfe000000 -> 0xffffffff */
@@ -104,6 +103,7 @@ typedef struct IOMMUState {
     target_phys_addr_t addr;
     uint32_t regs[IOMMU_NREGS];
     target_phys_addr_t iostart;
+    uint32_t version;
 } IOMMUState;
 
 static uint32_t iommu_mem_readw(void *opaque, target_phys_addr_t addr)
@@ -158,7 +158,7 @@ static void iommu_mem_writew(void *opaque, target_phys_addr_t addr, uint32_t val
             break;
         }
         DPRINTF("iostart = " TARGET_FMT_plx "\n", s->iostart);
-        s->regs[saddr] = ((val & IOMMU_CTRL_MASK) | IOMMU_VERSION);
+        s->regs[saddr] = ((val & IOMMU_CTRL_MASK) | s->version);
         break;
     case IOMMU_BASE:
         s->regs[saddr] = val & IOMMU_BASE_MASK;
@@ -308,10 +308,11 @@ static void iommu_reset(void *opaque)
 
     memset(s->regs, 0, IOMMU_NREGS * 4);
     s->iostart = 0;
-    s->regs[IOMMU_CTRL] = IOMMU_VERSION;
+    s->regs[IOMMU_CTRL] = s->version;
+    s->regs[IOMMU_ARBEN] = IOMMU_MID;
 }
 
-void *iommu_init(target_phys_addr_t addr)
+void *iommu_init(target_phys_addr_t addr, uint32_t version)
 {
     IOMMUState *s;
     int iommu_io_memory;
@@ -321,12 +322,14 @@ void *iommu_init(target_phys_addr_t addr)
         return NULL;
 
     s->addr = addr;
+    s->version = version;
 
     iommu_io_memory = cpu_register_io_memory(0, iommu_mem_read, iommu_mem_write, s);
     cpu_register_physical_memory(addr, IOMMU_NREGS * 4, iommu_io_memory);
 
     register_savevm("iommu", addr, 2, iommu_save, iommu_load, s);
     qemu_register_reset(iommu_reset, s);
+    iommu_reset(s);
     return s;
 }
 
diff --git a/hw/sun4m.c b/hw/sun4m.c
index d589b29954..9f15e45b18 100644
--- a/hw/sun4m.c
+++ b/hw/sun4m.c
@@ -72,6 +72,7 @@ struct hwdef {
     int intctl_g_intr, esp_irq, le_irq, clock_irq, clock1_irq;
     int ser_irq, ms_kb_irq, fd_irq, me_irq, cs_irq;
     int machine_id; // For NVRAM
+    uint32_t iommu_version;
     uint32_t intbit_to_level[32];
 };
 
@@ -302,7 +303,7 @@ static void *sun4m_hw_init(const struct hwdef *hwdef, int RAM_size,
     /* allocate RAM */
     cpu_register_physical_memory(0, RAM_size, 0);
 
-    iommu = iommu_init(hwdef->iommu_base);
+    iommu = iommu_init(hwdef->iommu_base, hwdef->iommu_version);
     slavio_intctl = slavio_intctl_init(hwdef->intctl_base,
                                        hwdef->intctl_base + 0x10000ULL,
                                        &hwdef->intbit_to_level[0],
@@ -468,6 +469,7 @@ static const struct hwdef hwdefs[] = {
         .me_irq = 30,
         .cs_irq = 5,
         .machine_id = 0x80,
+        .iommu_version = 0x04000000,
         .intbit_to_level = {
             2, 3, 5, 7, 9, 11, 0, 14,   3, 5, 7, 9, 11, 13, 12, 12,
             6, 0, 4, 10, 8, 0, 11, 0,   0, 0, 0, 0, 15, 0, 15, 0,
@@ -501,6 +503,7 @@ static const struct hwdef hwdefs[] = {
         .me_irq = 30,
         .cs_irq = -1,
         .machine_id = 0x72,
+        .iommu_version = 0x03000000,
         .intbit_to_level = {
             2, 3, 5, 7, 9, 11, 0, 14,   3, 5, 7, 9, 11, 13, 12, 12,
             6, 0, 4, 10, 8, 0, 11, 0,   0, 0, 0, 0, 15, 0, 15, 0,
@@ -534,6 +537,7 @@ static const struct hwdef hwdefs[] = {
         .me_irq = 30,
         .cs_irq = -1,
         .machine_id = 0x71,
+        .iommu_version = 0x01000000,
         .intbit_to_level = {
             2, 3, 5, 7, 9, 11, 0, 14,   3, 5, 7, 9, 11, 13, 12, 12,
             6, 0, 4, 10, 8, 0, 11, 0,   0, 0, 0, 0, 15, 0, 15, 0,
diff --git a/vl.h b/vl.h
index cdcc3c95da..affffad939 100644
--- a/vl.h
+++ b/vl.h
@@ -1051,7 +1051,7 @@ void PPC_debug_write (void *opaque, uint32_t addr, uint32_t val);
 extern QEMUMachine ss5_machine, ss10_machine, ss600mp_machine;
 
 /* iommu.c */
-void *iommu_init(target_phys_addr_t addr);
+void *iommu_init(target_phys_addr_t addr, uint32_t version);
 void sparc_iommu_memory_rw(void *opaque, target_phys_addr_t addr,
                                  uint8_t *buf, int len, int is_write);
 static inline void sparc_iommu_memory_read(void *opaque,