migration: Use normal VMStateDescriptions for Subsections

We create optional sections with this patch.  But we already have
optional subsections.  Instead of having two mechanism that do the
same, we can just generalize it.

For subsections we just change:

- Add a needed function to VMStateDescription
- Remove VMStateSubsection (after removal of the needed function
  it is just a VMStateDescription)
- Adjust the whole tree, moving the needed function to the corresponding
  VMStateDescription

Signed-off-by: Juan Quintela <quintela@redhat.com>
diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index 25bc023..8a64ffb 100644
--- a/hw/acpi/ich9.c
+++ b/hw/acpi/ich9.c
@@ -152,6 +152,7 @@
     .version_id = 1,
     .minimum_version_id = 1,
     .minimum_version_id_old = 1,
+    .needed = vmstate_test_use_memhp,
     .fields      = (VMStateField[]) {
         VMSTATE_MEMORY_HOTPLUG(acpi_memory_hotplug, ICH9LPCPMRegs),
         VMSTATE_END_OF_LIST()
@@ -175,12 +176,9 @@
         VMSTATE_UINT32(smi_sts, ICH9LPCPMRegs),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_memhp_state,
-            .needed = vmstate_test_use_memhp,
-        },
-        VMSTATE_END_OF_LIST()
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_memhp_state,
+        NULL
     }
 };
 
diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index b730ca6..3bd1d5a 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -260,6 +260,7 @@
     .version_id = 1,
     .minimum_version_id = 1,
     .minimum_version_id_old = 1,
+    .needed = vmstate_test_use_memhp,
     .fields      = (VMStateField[]) {
         VMSTATE_MEMORY_HOTPLUG(acpi_memory_hotplug, PIIX4PMState),
         VMSTATE_END_OF_LIST()
@@ -298,12 +299,9 @@
                             vmstate_test_use_acpi_pci_hotplug),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_memhp_state,
-            .needed = vmstate_test_use_memhp,
-        },
-        VMSTATE_END_OF_LIST()
+    .subsections = (const VMStateDescription*[]) {
+         &vmstate_memhp_state,
+         NULL
     }
 };
 
diff --git a/hw/block/fdc.c b/hw/block/fdc.c
index 6e79459..5e1b67e 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -699,6 +699,7 @@
     .name = "fdrive/media_changed",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = fdrive_media_changed_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(media_changed, FDrive),
         VMSTATE_END_OF_LIST()
@@ -716,6 +717,7 @@
     .name = "fdrive/media_rate",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = fdrive_media_rate_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(media_rate, FDrive),
         VMSTATE_END_OF_LIST()
@@ -733,6 +735,7 @@
     .name = "fdrive/perpendicular",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = fdrive_perpendicular_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(perpendicular, FDrive),
         VMSTATE_END_OF_LIST()
@@ -756,19 +759,11 @@
         VMSTATE_UINT8(sect, FDrive),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_fdrive_media_changed,
-            .needed = &fdrive_media_changed_needed,
-        } , {
-            .vmsd = &vmstate_fdrive_media_rate,
-            .needed = &fdrive_media_rate_needed,
-        } , {
-            .vmsd = &vmstate_fdrive_perpendicular,
-            .needed = &fdrive_perpendicular_needed,
-        } , {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_fdrive_media_changed,
+        &vmstate_fdrive_media_rate,
+        &vmstate_fdrive_perpendicular,
+        NULL
     }
 };
 
@@ -833,6 +828,7 @@
     .name = "fdc/reset_sensei",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = fdc_reset_sensei_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32(reset_sensei, FDCtrl),
         VMSTATE_END_OF_LIST()
@@ -850,6 +846,7 @@
     .name = "fdc/result_timer",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = fdc_result_timer_needed,
     .fields = (VMStateField[]) {
         VMSTATE_TIMER_PTR(result_timer, FDCtrl),
         VMSTATE_END_OF_LIST()
@@ -867,6 +864,7 @@
     .name = "fdc/phase",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = fdc_phase_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(phase, FDCtrl),
         VMSTATE_END_OF_LIST()
@@ -911,19 +909,11 @@
                              vmstate_fdrive, FDrive),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_fdc_reset_sensei,
-            .needed = fdc_reset_sensei_needed,
-        } , {
-            .vmsd = &vmstate_fdc_result_timer,
-            .needed = fdc_result_timer_needed,
-        } , {
-            .vmsd = &vmstate_fdc_phase,
-            .needed = fdc_phase_needed,
-        } , {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_fdc_reset_sensei,
+        &vmstate_fdc_result_timer,
+        &vmstate_fdc_phase,
+        NULL
     }
 };
 
diff --git a/hw/char/serial.c b/hw/char/serial.c
index 55011cf..513d73c 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -662,6 +662,7 @@
     .name = "serial/thr_ipending",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = serial_thr_ipending_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32(thr_ipending, SerialState),
         VMSTATE_END_OF_LIST()
@@ -678,6 +679,7 @@
     .name = "serial/tsr",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = serial_tsr_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32(tsr_retry, SerialState),
         VMSTATE_UINT8(thr, SerialState),
@@ -697,6 +699,7 @@
     .name = "serial/recv_fifo",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = serial_recv_fifo_needed,
     .fields = (VMStateField[]) {
         VMSTATE_STRUCT(recv_fifo, SerialState, 1, vmstate_fifo8, Fifo8),
         VMSTATE_END_OF_LIST()
@@ -713,6 +716,7 @@
     .name = "serial/xmit_fifo",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = serial_xmit_fifo_needed,
     .fields = (VMStateField[]) {
         VMSTATE_STRUCT(xmit_fifo, SerialState, 1, vmstate_fifo8, Fifo8),
         VMSTATE_END_OF_LIST()
@@ -729,6 +733,7 @@
     .name = "serial/fifo_timeout_timer",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = serial_fifo_timeout_timer_needed,
     .fields = (VMStateField[]) {
         VMSTATE_TIMER_PTR(fifo_timeout_timer, SerialState),
         VMSTATE_END_OF_LIST()
@@ -745,6 +750,7 @@
     .name = "serial/timeout_ipending",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = serial_timeout_ipending_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32(timeout_ipending, SerialState),
         VMSTATE_END_OF_LIST()
@@ -760,6 +766,7 @@
 static const VMStateDescription vmstate_serial_poll = {
     .name = "serial/poll",
     .version_id = 1,
+    .needed = serial_poll_needed,
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_INT32(poll_msl, SerialState),
@@ -788,31 +795,15 @@
         VMSTATE_UINT8_V(fcr_vmstate, SerialState, 3),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_serial_thr_ipending,
-            .needed = &serial_thr_ipending_needed,
-        } , {
-            .vmsd = &vmstate_serial_tsr,
-            .needed = &serial_tsr_needed,
-        } , {
-            .vmsd = &vmstate_serial_recv_fifo,
-            .needed = &serial_recv_fifo_needed,
-        } , {
-            .vmsd = &vmstate_serial_xmit_fifo,
-            .needed = &serial_xmit_fifo_needed,
-        } , {
-            .vmsd = &vmstate_serial_fifo_timeout_timer,
-            .needed = &serial_fifo_timeout_timer_needed,
-        } , {
-            .vmsd = &vmstate_serial_timeout_ipending,
-            .needed = &serial_timeout_ipending_needed,
-        } , {
-            .vmsd = &vmstate_serial_poll,
-            .needed = &serial_poll_needed,
-        } , {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_serial_thr_ipending,
+        &vmstate_serial_tsr,
+        &vmstate_serial_recv_fifo,
+        &vmstate_serial_xmit_fifo,
+        &vmstate_serial_fifo_timeout_timer,
+        &vmstate_serial_timeout_ipending,
+        &vmstate_serial_poll,
+        NULL
     }
 };
 
diff --git a/hw/display/qxl.c b/hw/display/qxl.c
index b220e2d..722146e 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -2220,6 +2220,7 @@
     .name               = "qxl/monitors-config",
     .version_id         = 1,
     .minimum_version_id = 1,
+    .needed = qxl_monitors_config_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(guest_monitors_config, PCIQXLDevice),
         VMSTATE_END_OF_LIST()
@@ -2253,13 +2254,9 @@
         VMSTATE_UINT64(guest_cursor, PCIQXLDevice),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &qxl_vmstate_monitors_config,
-            .needed = qxl_monitors_config_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &qxl_vmstate_monitors_config,
+        NULL
     }
 };
 
diff --git a/hw/display/vga.c b/hw/display/vga.c
index d1d296c..b35d523 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -2035,6 +2035,7 @@
     .name = "vga.endian",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = vga_endian_state_needed,
     .fields = (VMStateField[]) {
         VMSTATE_BOOL(big_endian_fb, VGACommonState),
         VMSTATE_END_OF_LIST()
@@ -2078,13 +2079,9 @@
         VMSTATE_UINT32(vbe_bank_mask, VGACommonState),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_vga_endian,
-            .needed = vga_endian_state_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_vga_endian,
+        NULL
     }
 };
 
diff --git a/hw/ide/core.c b/hw/ide/core.c
index fcb9080..1efd98a 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -2561,6 +2561,7 @@
     .name ="ide_drive/atapi/gesn_state",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = ide_atapi_gesn_needed,
     .fields = (VMStateField[]) {
         VMSTATE_BOOL(events.new_media, IDEState),
         VMSTATE_BOOL(events.eject_request, IDEState),
@@ -2572,6 +2573,7 @@
     .name = "ide_drive/tray_state",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = ide_tray_state_needed,
     .fields = (VMStateField[]) {
         VMSTATE_BOOL(tray_open, IDEState),
         VMSTATE_BOOL(tray_locked, IDEState),
@@ -2585,6 +2587,7 @@
     .minimum_version_id = 1,
     .pre_save = ide_drive_pio_pre_save,
     .post_load = ide_drive_pio_post_load,
+    .needed = ide_drive_pio_state_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32(req_nb_sectors, IDEState),
         VMSTATE_VARRAY_INT32(io_buffer, IDEState, io_buffer_total_len, 1,
@@ -2626,19 +2629,11 @@
         VMSTATE_UINT8_V(cdrom_changed, IDEState, 3),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_ide_drive_pio_state,
-            .needed = ide_drive_pio_state_needed,
-        }, {
-            .vmsd = &vmstate_ide_tray_state,
-            .needed = ide_tray_state_needed,
-        }, {
-            .vmsd = &vmstate_ide_atapi_gesn_state,
-            .needed = ide_atapi_gesn_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_ide_drive_pio_state,
+        &vmstate_ide_tray_state,
+        &vmstate_ide_atapi_gesn_state,
+        NULL
     }
 };
 
@@ -2646,6 +2641,7 @@
     .name ="ide_bus/error",
     .version_id = 2,
     .minimum_version_id = 1,
+    .needed = ide_error_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32(error_status, IDEBus),
         VMSTATE_INT64_V(retry_sector_num, IDEBus, 2),
@@ -2664,13 +2660,9 @@
         VMSTATE_UINT8(unit, IDEBus),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_ide_error_status,
-            .needed = ide_error_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_ide_error_status,
+        NULL
     }
 };
 
diff --git a/hw/ide/pci.c b/hw/ide/pci.c
index 4b5e32d..4afd0cf 100644
--- a/hw/ide/pci.c
+++ b/hw/ide/pci.c
@@ -350,6 +350,7 @@
     .name = "ide bmdma_current",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = ide_bmdma_current_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(cur_addr, BMDMAState),
         VMSTATE_UINT32(cur_prd_last, BMDMAState),
@@ -363,6 +364,7 @@
     .name ="ide bmdma/status",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = ide_bmdma_status_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(status, BMDMAState),
         VMSTATE_END_OF_LIST()
@@ -383,16 +385,10 @@
         VMSTATE_UINT8(migration_retry_unit, BMDMAState),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_bmdma_current,
-            .needed = ide_bmdma_current_needed,
-        }, {
-            .vmsd = &vmstate_bmdma_status,
-            .needed = ide_bmdma_status_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_bmdma_current,
+        &vmstate_bmdma_status,
+        NULL
     }
 };
 
diff --git a/hw/input/pckbd.c b/hw/input/pckbd.c
index 9b9a7d7..ddac69d 100644
--- a/hw/input/pckbd.c
+++ b/hw/input/pckbd.c
@@ -391,23 +391,24 @@
     return 0;
 }
 
-static const VMStateDescription vmstate_kbd_outport = {
-    .name = "pckbd_outport",
-    .version_id = 1,
-    .minimum_version_id = 1,
-    .post_load = kbd_outport_post_load,
-    .fields = (VMStateField[]) {
-        VMSTATE_UINT8(outport, KBDState),
-        VMSTATE_END_OF_LIST()
-    }
-};
-
 static bool kbd_outport_needed(void *opaque)
 {
     KBDState *s = opaque;
     return s->outport != kbd_outport_default(s);
 }
 
+static const VMStateDescription vmstate_kbd_outport = {
+    .name = "pckbd_outport",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .post_load = kbd_outport_post_load,
+    .needed = kbd_outport_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT8(outport, KBDState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static int kbd_post_load(void *opaque, int version_id)
 {
     KBDState *s = opaque;
@@ -430,12 +431,9 @@
         VMSTATE_UINT8(pending, KBDState),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_kbd_outport,
-            .needed = kbd_outport_needed,
-        },
-        VMSTATE_END_OF_LIST()
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_kbd_outport,
+        NULL
     }
 };
 
diff --git a/hw/input/ps2.c b/hw/input/ps2.c
index 4baeea2..fdbe565 100644
--- a/hw/input/ps2.c
+++ b/hw/input/ps2.c
@@ -677,6 +677,7 @@
     .version_id = 3,
     .minimum_version_id = 2,
     .post_load = ps2_kbd_ledstate_post_load,
+    .needed = ps2_keyboard_ledstate_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32(ledstate, PS2KbdState),
         VMSTATE_END_OF_LIST()
@@ -717,13 +718,9 @@
         VMSTATE_INT32_V(scancode_set, PS2KbdState,3),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_ps2_keyboard_ledstate,
-            .needed = ps2_keyboard_ledstate_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_ps2_keyboard_ledstate,
+        NULL
     }
 };
 
diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c
index d595d63..0032b97 100644
--- a/hw/intc/apic_common.c
+++ b/hw/intc/apic_common.c
@@ -369,6 +369,7 @@
     .name = "apic_sipi",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = apic_common_sipi_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32(sipi_vector, APICCommonState),
         VMSTATE_INT32(wait_for_sipi, APICCommonState),
@@ -408,12 +409,9 @@
                       APICCommonState), /* open-coded timer state */
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_apic_common_sipi,
-            .needed = apic_common_sipi_needed,
-        },
-        VMSTATE_END_OF_LIST()
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_apic_common_sipi,
+        NULL
     }
 };
 
diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
index 71a9f7a..b3e0b1f 100644
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -650,6 +650,7 @@
     .name = "ICH9LPC/rst_cnt",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = ich9_rst_cnt_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(rst_cnt, ICH9LPCState),
         VMSTATE_END_OF_LIST()
@@ -669,12 +670,9 @@
         VMSTATE_UINT32(sci_level, ICH9LPCState),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_ich9_rst_cnt,
-            .needed = ich9_rst_cnt_needed
-        },
-        { 0 }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_ich9_rst_cnt,
+        NULL
     }
 };
 
diff --git a/hw/net/e1000.c b/hw/net/e1000.c
index 091d61a..bab8e2a 100644
--- a/hw/net/e1000.c
+++ b/hw/net/e1000.c
@@ -1370,6 +1370,7 @@
     .name = "e1000/mit_state",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = e1000_mit_state_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(mac_reg[RDTR], E1000State),
         VMSTATE_UINT32(mac_reg[RADV], E1000State),
@@ -1457,13 +1458,9 @@
         VMSTATE_UINT32_SUB_ARRAY(mac_reg, E1000State, VFTA, 128),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_e1000_mit_state,
-            .needed = e1000_mit_state_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_e1000_mit_state,
+        NULL
     }
 };
 
diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
index f868108..e0db472 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -3240,6 +3240,7 @@
     .name = "rtl8139/hotplug_ready",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = rtl8139_hotplug_ready_needed,
     .fields = (VMStateField[]) {
         VMSTATE_END_OF_LIST()
     }
@@ -3335,13 +3336,9 @@
         VMSTATE_UINT32_V(cplus_enabled, RTL8139State, 4),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_rtl8139_hotplug_ready,
-            .needed = rtl8139_hotplug_ready_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_rtl8139_hotplug_ready,
+        NULL
     }
 };
 
diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
index dfb328d..8bcdf3e 100644
--- a/hw/net/vmxnet3.c
+++ b/hw/net/vmxnet3.c
@@ -2226,6 +2226,7 @@
     .version_id = 1,
     .minimum_version_id = 1,
     .pre_load = vmxnet3_mcast_list_pre_load,
+    .needed = vmxnet3_mc_list_needed,
     .fields = (VMStateField[]) {
         VMSTATE_VBUFFER_UINT32(mcast_list, VMXNET3State, 0, NULL, 0,
             mcast_list_buff_size),
@@ -2470,14 +2471,9 @@
 
             VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmxstate_vmxnet3_mcast_list,
-            .needed = vmxnet3_mc_list_needed
-        },
-        {
-            /* empty element. */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmxstate_vmxnet3_mcast_list,
+        NULL
     }
 };
 
diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
index f1712b8..ed2424c 100644
--- a/hw/pci-host/piix.c
+++ b/hw/pci-host/piix.c
@@ -582,6 +582,7 @@
     .name = "PIIX3/rcr",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = piix3_rcr_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(rcr, PIIX3State),
         VMSTATE_END_OF_LIST()
@@ -600,12 +601,9 @@
                               PIIX_NUM_PIRQS, 3),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_piix3_rcr,
-            .needed = piix3_rcr_needed,
-        },
-        { 0 }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_piix3_rcr,
+        NULL
     }
 };
 
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index bd2c0e4..f50b2f0 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -1968,6 +1968,7 @@
     .name = "SCSIDevice/sense",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = scsi_sense_state_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8_SUB_ARRAY(sense, SCSIDevice,
                                 SCSI_SENSE_BUF_SIZE_OLD,
@@ -1998,13 +1999,9 @@
         },
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_scsi_sense_state,
-            .needed = scsi_sense_state_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_scsi_sense_state,
+        NULL
     }
 };
 
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index b6b8a20..b50071e 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -283,6 +283,7 @@
     .name = "hpet/rtc_irq_level",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = hpet_rtc_irq_level_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(rtc_irq_level, HPETState),
         VMSTATE_END_OF_LIST()
@@ -322,13 +323,9 @@
                                     vmstate_hpet_timer, HPETTimer),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_hpet_rtc_irq_level,
-            .needed = hpet_rtc_irq_level_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_hpet_rtc_irq_level,
+        NULL
     }
 };
 
diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index f2b77fa..3204825 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -733,22 +733,23 @@
     return 0;
 }
 
-static const VMStateDescription vmstate_rtc_irq_reinject_on_ack_count = {
-    .name = "mc146818rtc/irq_reinject_on_ack_count",
-    .version_id = 1,
-    .minimum_version_id = 1,
-    .fields = (VMStateField[]) {
-        VMSTATE_UINT16(irq_reinject_on_ack_count, RTCState),
-        VMSTATE_END_OF_LIST()
-    }
-};
-
 static bool rtc_irq_reinject_on_ack_count_needed(void *opaque)
 {
     RTCState *s = (RTCState *)opaque;
     return s->irq_reinject_on_ack_count != 0;
 }
 
+static const VMStateDescription vmstate_rtc_irq_reinject_on_ack_count = {
+    .name = "mc146818rtc/irq_reinject_on_ack_count",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = rtc_irq_reinject_on_ack_count_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT16(irq_reinject_on_ack_count, RTCState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription vmstate_rtc = {
     .name = "mc146818rtc",
     .version_id = 3,
@@ -770,13 +771,9 @@
         VMSTATE_UINT64_V(next_alarm_time, RTCState, 3),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_rtc_irq_reinject_on_ack_count,
-            .needed = rtc_irq_reinject_on_ack_count_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_rtc_irq_reinject_on_ack_count,
+        NULL
     }
 };
 
diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
index 1a22c9c..7d65818 100644
--- a/hw/usb/hcd-ohci.c
+++ b/hw/usb/hcd-ohci.c
@@ -2034,6 +2034,7 @@
     .version_id = 1,
     .minimum_version_id = 1,
     .pre_load = ohci_eof_timer_pre_load,
+    .needed = ohci_eof_timer_needed,
     .fields = (VMStateField[]) {
         VMSTATE_TIMER_PTR(eof_timer, OHCIState),
         VMSTATE_END_OF_LIST()
@@ -2081,13 +2082,9 @@
         VMSTATE_BOOL(async_complete, OHCIState),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_ohci_eof_timer,
-            .needed = ohci_eof_timer_needed,
-        } , {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_ohci_eof_timer,
+        NULL
     }
 };
 
diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
index 242a654..6b4218c 100644
--- a/hw/usb/redirect.c
+++ b/hw/usb/redirect.c
@@ -2257,16 +2257,6 @@
 
 
 /* For endp_data migration */
-static const VMStateDescription usbredir_bulk_receiving_vmstate = {
-    .name = "usb-redir-ep/bulk-receiving",
-    .version_id = 1,
-    .minimum_version_id = 1,
-    .fields = (VMStateField[]) {
-        VMSTATE_UINT8(bulk_receiving_started, struct endp_data),
-        VMSTATE_END_OF_LIST()
-    }
-};
-
 static bool usbredir_bulk_receiving_needed(void *priv)
 {
     struct endp_data *endp = priv;
@@ -2274,12 +2264,13 @@
     return endp->bulk_receiving_started;
 }
 
-static const VMStateDescription usbredir_stream_vmstate = {
-    .name = "usb-redir-ep/stream-state",
+static const VMStateDescription usbredir_bulk_receiving_vmstate = {
+    .name = "usb-redir-ep/bulk-receiving",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = usbredir_bulk_receiving_needed,
     .fields = (VMStateField[]) {
-        VMSTATE_UINT32(max_streams, struct endp_data),
+        VMSTATE_UINT8(bulk_receiving_started, struct endp_data),
         VMSTATE_END_OF_LIST()
     }
 };
@@ -2291,6 +2282,17 @@
     return endp->max_streams;
 }
 
+static const VMStateDescription usbredir_stream_vmstate = {
+    .name = "usb-redir-ep/stream-state",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = usbredir_stream_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(max_streams, struct endp_data),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription usbredir_ep_vmstate = {
     .name = "usb-redir-ep",
     .version_id = 1,
@@ -2318,16 +2320,10 @@
         VMSTATE_INT32(bufpq_target_size, struct endp_data),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &usbredir_bulk_receiving_vmstate,
-            .needed = usbredir_bulk_receiving_needed,
-        }, {
-            .vmsd = &usbredir_stream_vmstate,
-            .needed = usbredir_stream_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &usbredir_bulk_receiving_vmstate,
+        &usbredir_stream_vmstate,
+        NULL
     }
 };
 
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index fb49ffc..ee4e07c 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -1053,6 +1053,7 @@
     .name = "virtio/device_endian",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = &virtio_device_endian_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(device_endian, VirtIODevice),
         VMSTATE_END_OF_LIST()
@@ -1063,6 +1064,7 @@
     .name = "virtio/64bit_features",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = &virtio_64bit_features_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(guest_features, VirtIODevice),
         VMSTATE_END_OF_LIST()
@@ -1077,16 +1079,10 @@
     .fields = (VMStateField[]) {
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_virtio_device_endian,
-            .needed = &virtio_device_endian_needed
-        },
-        {
-            .vmsd = &vmstate_virtio_64bit_features,
-            .needed = &virtio_64bit_features_needed
-        },
-        { 0 }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_virtio_device_endian,
+        &vmstate_virtio_64bit_features,
+        NULL
     }
 };