diff --git a/hw/boards.h b/hw/boards.h
index 6374dd1b2c..712d3cd39b 100644
--- a/hw/boards.h
+++ b/hw/boards.h
@@ -52,7 +52,7 @@ extern QEMUMachine shix_machine;
 extern QEMUMachine r2d_machine;
 
 /* sun4m.c */
-extern QEMUMachine ss5_machine, ss10_machine, ss600mp_machine;
+extern QEMUMachine ss5_machine, ss10_machine, ss600mp_machine, ss20_machine;
 
 /* sun4u.c */
 extern QEMUMachine sun4u_machine;
diff --git a/hw/sun4m.c b/hw/sun4m.c
index 3385adb915..693fa696ac 100644
--- a/hw/sun4m.c
+++ b/hw/sun4m.c
@@ -600,6 +600,44 @@ static const struct hwdef hwdefs[] = {
         .max_mem = 0xffffffff, // XXX actually first 62GB ok
         .default_cpu_model = "TI SuperSparc II",
     },
+    /* SS-20 */
+    {
+        .iommu_base   = 0xfe0000000ULL,
+        .tcx_base     = 0xe20000000ULL,
+        .cs_base      = -1,
+        .slavio_base  = 0xff0000000ULL,
+        .ms_kb_base   = 0xff1000000ULL,
+        .serial_base  = 0xff1100000ULL,
+        .nvram_base   = 0xff1200000ULL,
+        .fd_base      = 0xff1700000ULL,
+        .counter_base = 0xff1300000ULL,
+        .intctl_base  = 0xff1400000ULL,
+        .dma_base     = 0xef0400000ULL,
+        .esp_base     = 0xef0800000ULL,
+        .le_base      = 0xef0c00000ULL,
+        .power_base   = 0xefa000000ULL,
+        .ecc_base     = 0xf00000000ULL,
+        .ecc_version  = 0x20000000, // version 0, implementation 2
+        .vram_size    = 0x00100000,
+        .nvram_size   = 0x2000,
+        .esp_irq = 18,
+        .le_irq = 16,
+        .clock_irq = 7,
+        .clock1_irq = 19,
+        .ms_kb_irq = 14,
+        .ser_irq = 15,
+        .fd_irq = 22,
+        .me_irq = 30,
+        .cs_irq = -1,
+        .machine_id = 0x72,
+        .iommu_version = 0x13000000,
+        .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,
+        },
+        .max_mem = 0xffffffff, // XXX actually first 62GB ok
+        .default_cpu_model = "TI SuperSparc II",
+    },
 };
 
 /* SPARCstation 5 hardware initialisation */
@@ -632,6 +670,16 @@ static void ss600mp_init(int RAM_size, int vga_ram_size,
                   kernel_cmdline, initrd_filename, cpu_model);
 }
 
+/* SPARCstation 20 hardware initialisation */
+static void ss20_init(int RAM_size, int vga_ram_size,
+                      const char *boot_device, DisplayState *ds,
+                      const char *kernel_filename, const char *kernel_cmdline,
+                      const char *initrd_filename, const char *cpu_model)
+{
+    sun4m_hw_init(&hwdefs[3], RAM_size, boot_device, ds, kernel_filename,
+                  kernel_cmdline, initrd_filename, cpu_model);
+}
+
 QEMUMachine ss5_machine = {
     "SS-5",
     "Sun4m platform, SPARCstation 5",
@@ -649,3 +697,10 @@ QEMUMachine ss600mp_machine = {
     "Sun4m platform, SPARCserver 600MP",
     ss600mp_init,
 };
+
+QEMUMachine ss20_machine = {
+    "SS-20",
+    "Sun4m platform, SPARCstation 20",
+    ss20_init,
+};
+
diff --git a/vl.c b/vl.c
index 5b7e97e6de..9cb81ce47c 100644
--- a/vl.c
+++ b/vl.c
@@ -7838,6 +7838,7 @@ static void register_machines(void)
     qemu_register_machine(&ss5_machine);
     qemu_register_machine(&ss10_machine);
     qemu_register_machine(&ss600mp_machine);
+    qemu_register_machine(&ss20_machine);
 #endif
 #elif defined(TARGET_ARM)
     qemu_register_machine(&integratorcp_machine);