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>

32 files changed, 253 insertions, 389 deletions

diff --git a/cpus.c b/cpus.c
index f38b858f9b..b85fb5f03f 100644
--- a/cpus.c
+++ b/cpus.c
@@ -480,6 +480,7 @@ static const VMStateDescription icount_vmstate_timers = {
     .name = "timer/icount",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = icount_state_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT64(qemu_icount_bias, TimersState),
         VMSTATE_INT64(qemu_icount, TimersState),
@@ -497,13 +498,9 @@ static const VMStateDescription vmstate_timers = {
         VMSTATE_INT64_V(cpu_clock_offset, TimersState, 2),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &icount_vmstate_timers,
-            .needed = icount_state_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &icount_vmstate_timers,
+        NULL
     }
 };
 
diff --git a/docs/migration.txt b/docs/migration.txt
index 0492a4547a..f6df4beb2a 100644
--- a/docs/migration.txt
+++ b/docs/migration.txt
@@ -257,6 +257,7 @@ const VMStateDescription vmstate_ide_drive_pio_state = {
     .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,
@@ -279,13 +280,9 @@ const VMStateDescription vmstate_ide_drive = {
         .... several fields ....
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_ide_drive_pio_state,
-            .needed = ide_drive_pio_state_needed,
-        }, {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_ide_drive_pio_state,
+        NULL
     }
 };
 
diff --git a/exec.c b/exec.c
index 487583b1bd..ba3f2cf6df 100644
--- a/exec.c
+++ b/exec.c
@@ -454,6 +454,7 @@ static const VMStateDescription vmstate_cpu_common_exception_index = {
     .name = "cpu_common/exception_index",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = cpu_common_exception_index_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32(exception_index, CPUState),
         VMSTATE_END_OF_LIST()
@@ -471,13 +472,9 @@ const VMStateDescription vmstate_cpu_common = {
         VMSTATE_UINT32(interrupt_request, CPUState),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_cpu_common_exception_index,
-            .needed = cpu_common_exception_index_needed,
-        } , {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_cpu_common_exception_index,
+        NULL
     }
 };
 
diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index 25bc023882..8a64ffb38f 100644
--- a/hw/acpi/ich9.c
+++ b/hw/acpi/ich9.c
@@ -152,6 +152,7 @@ static const VMStateDescription vmstate_memhp_state = {
     .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 @@ const VMStateDescription vmstate_ich9_pm = {
         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 b730ca6ced..3bd1d5a865 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -260,6 +260,7 @@ static const VMStateDescription vmstate_memhp_state = {
     .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 @@ static const VMStateDescription vmstate_acpi = {
                             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 6e794597dc..5e1b67ee43 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -699,6 +699,7 @@ static const VMStateDescription vmstate_fdrive_media_changed = {
     .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 @@ static const VMStateDescription vmstate_fdrive_media_rate = {
     .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 @@ static const VMStateDescription vmstate_fdrive_perpendicular = {
     .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 @@ static const VMStateDescription vmstate_fdrive = {
         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 @@ static const VMStateDescription vmstate_fdc_reset_sensei = {
     .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 @@ static const VMStateDescription vmstate_fdc_result_timer = {
     .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 @@ static const VMStateDescription vmstate_fdc_phase = {
     .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 @@ static const VMStateDescription vmstate_fdc = {
                              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 55011cfd26..513d73c27f 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -662,6 +662,7 @@ static const VMStateDescription vmstate_serial_thr_ipending = {
     .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 @@ static const VMStateDescription vmstate_serial_tsr = {
     .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 @@ static const VMStateDescription vmstate_serial_recv_fifo = {
     .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 @@ static const VMStateDescription vmstate_serial_xmit_fifo = {
     .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 @@ static const VMStateDescription vmstate_serial_fifo_timeout_timer = {
     .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 @@ static const VMStateDescription vmstate_serial_timeout_ipending = {
     .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 bool serial_poll_needed(void *opaque)
 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 @@ const VMStateDescription vmstate_serial = {
         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 b220e2d5d2..722146ec3a 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -2220,6 +2220,7 @@ static VMStateDescription qxl_vmstate_monitors_config = {
     .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 @@ static VMStateDescription qxl_vmstate = {
         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 d1d296c74e..b35d523e65 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -2035,6 +2035,7 @@ static const VMStateDescription vmstate_vga_endian = {
     .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 @@ const VMStateDescription vmstate_vga_common = {
         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 fcb908061c..1efd98af63 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -2561,6 +2561,7 @@ static const VMStateDescription vmstate_ide_atapi_gesn_state = {
     .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 @@ static const VMStateDescription vmstate_ide_tray_state = {
     .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 @@ static const VMStateDescription vmstate_ide_drive_pio_state = {
     .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 @@ const VMStateDescription vmstate_ide_drive = {
         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 @@ static const VMStateDescription vmstate_ide_error_status = {
     .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 @@ const VMStateDescription vmstate_ide_bus = {
         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 4b5e32dcbe..4afd0cfe8c 100644
--- a/hw/ide/pci.c
+++ b/hw/ide/pci.c
@@ -350,6 +350,7 @@ static const VMStateDescription vmstate_bmdma_current = {
     .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 @@ static const VMStateDescription vmstate_bmdma_status = {
     .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 @@ static const VMStateDescription vmstate_bmdma = {
         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 9b9a7d7a8a..ddac69df6f 100644
--- a/hw/input/pckbd.c
+++ b/hw/input/pckbd.c
@@ -391,23 +391,24 @@ static int kbd_outport_post_load(void *opaque, int version_id)
     return 0;
 }
 
+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 bool kbd_outport_needed(void *opaque)
-{
-    KBDState *s = opaque;
-    return s->outport != kbd_outport_default(s);
-}
-
 static int kbd_post_load(void *opaque, int version_id)
 {
     KBDState *s = opaque;
@@ -430,12 +431,9 @@ static const VMStateDescription vmstate_kbd = {
         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 4baeea2b56..fdbe565e62 100644
--- a/hw/input/ps2.c
+++ b/hw/input/ps2.c
@@ -677,6 +677,7 @@ static const VMStateDescription vmstate_ps2_keyboard_ledstate = {
     .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 @@ static const VMStateDescription vmstate_ps2_keyboard = {
         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 d595d63a51..0032b97c5f 100644
--- a/hw/intc/apic_common.c
+++ b/hw/intc/apic_common.c
@@ -369,6 +369,7 @@ static const VMStateDescription vmstate_apic_common_sipi = {
     .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 @@ static const VMStateDescription vmstate_apic_common = {
                       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 71a9f7a716..b3e0b1fd52 100644
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -650,6 +650,7 @@ static const VMStateDescription vmstate_ich9_rst_cnt = {
     .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 @@ static const VMStateDescription vmstate_ich9_lpc = {
         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 091d61acc3..bab8e2abfb 100644
--- a/hw/net/e1000.c
+++ b/hw/net/e1000.c
@@ -1370,6 +1370,7 @@ static const VMStateDescription vmstate_e1000_mit_state = {
     .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 @@ static const VMStateDescription vmstate_e1000 = {
         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 f868108dfe..e0db4727ae 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -3240,6 +3240,7 @@ static const VMStateDescription vmstate_rtl8139_hotplug_ready ={
     .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 @@ static const VMStateDescription vmstate_rtl8139 = {
         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 dfb328debd..8bcdf3ed77 100644
--- a/hw/net/vmxnet3.c
+++ b/hw/net/vmxnet3.c
@@ -2226,6 +2226,7 @@ static const VMStateDescription vmxstate_vmxnet3_mcast_list = {
     .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 @@ static const VMStateDescription vmstate_vmxnet3 = {
 
             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 f1712b86fe..ed2424c4cd 100644
--- a/hw/pci-host/piix.c
+++ b/hw/pci-host/piix.c
@@ -582,6 +582,7 @@ static const VMStateDescription vmstate_piix3_rcr = {
     .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 @@ static const VMStateDescription vmstate_piix3 = {
                               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 bd2c0e4caa..f50b2f08af 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -1968,6 +1968,7 @@ static const VMStateDescription vmstate_scsi_sense_state = {
     .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 @@ const VMStateDescription vmstate_scsi_device = {
         },
         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 b6b8a2063d..b50071ef93 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -283,6 +283,7 @@ static const VMStateDescription vmstate_hpet_rtc_irq_level = {
     .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 @@ static const VMStateDescription vmstate_hpet = {
                                     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 f2b77fa118..32048258c9 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -733,22 +733,23 @@ static int rtc_post_load(void *opaque, int version_id)
     return 0;
 }
 
+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 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 = {
     .name = "mc146818rtc",
     .version_id = 3,
@@ -770,13 +771,9 @@ static const VMStateDescription vmstate_rtc = {
         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 1a22c9c0cb..7d65818064 100644
--- a/hw/usb/hcd-ohci.c
+++ b/hw/usb/hcd-ohci.c
@@ -2034,6 +2034,7 @@ static const VMStateDescription vmstate_ohci_eof_timer = {
     .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 @@ static const VMStateDescription vmstate_ohci_state = {
         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 242a654583..6b4218c037 100644
--- a/hw/usb/redirect.c
+++ b/hw/usb/redirect.c
@@ -2257,40 +2257,42 @@ static const VMStateInfo usbredir_ep_bufpq_vmstate_info = {
 
 
 /* For endp_data migration */
+static bool usbredir_bulk_receiving_needed(void *priv)
+{
+    struct endp_data *endp = priv;
+
+    return endp->bulk_receiving_started;
+}
+
 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_UINT8(bulk_receiving_started, struct endp_data),
         VMSTATE_END_OF_LIST()
     }
 };
 
-static bool usbredir_bulk_receiving_needed(void *priv)
+static bool usbredir_stream_needed(void *priv)
 {
     struct endp_data *endp = priv;
 
-    return endp->bulk_receiving_started;
+    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 bool usbredir_stream_needed(void *priv)
-{
-    struct endp_data *endp = priv;
-
-    return endp->max_streams;
-}
-
 static const VMStateDescription usbredir_ep_vmstate = {
     .name = "usb-redir-ep",
     .version_id = 1,
@@ -2318,16 +2320,10 @@ static const VMStateDescription usbredir_ep_vmstate = {
         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 fb49ffcb2d..ee4e07c5e7 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -1053,6 +1053,7 @@ static const VMStateDescription vmstate_virtio_device_endian = {
     .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 @@ static const VMStateDescription vmstate_virtio_64bit_features = {
     .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 @@ static const VMStateDescription vmstate_virtio = {
     .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
     }
 };
 
diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index bc7616aaa8..fc5e6439e4 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -120,11 +120,6 @@ typedef struct {
     bool (*field_exists)(void *opaque, int version_id);
 } VMStateField;
 
-typedef struct VMStateSubsection {
-    const VMStateDescription *vmsd;
-    bool (*needed)(void *opaque);
-} VMStateSubsection;
-
 struct VMStateDescription {
     const char *name;
     int unmigratable;
@@ -135,8 +130,9 @@ struct VMStateDescription {
     int (*pre_load)(void *opaque);
     int (*post_load)(void *opaque, int version_id);
     void (*pre_save)(void *opaque);
+    bool (*needed)(void *opaque);
     VMStateField *fields;
-    const VMStateSubsection *subsections;
+    const VMStateDescription **subsections;
 };
 
 extern const VMStateDescription vmstate_dummy;
diff --git a/migration/savevm.c b/migration/savevm.c
index 1a45d39a4b..002f9b8948 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -272,11 +272,11 @@ static void dump_vmstate_vmsf(FILE *out_file, const VMStateField *field,
 }
 
 static void dump_vmstate_vmss(FILE *out_file,
-                              const VMStateSubsection *subsection,
+                              const VMStateDescription **subsection,
                               int indent)
 {
-    if (subsection->vmsd != NULL) {
-        dump_vmstate_vmsd(out_file, subsection->vmsd, indent, true);
+    if (*subsection != NULL) {
+        dump_vmstate_vmsd(out_file, *subsection, indent, true);
     }
 }
 
@@ -317,12 +317,12 @@ static void dump_vmstate_vmsd(FILE *out_file,
         fprintf(out_file, "\n%*s]", indent, "");
     }
     if (vmsd->subsections != NULL) {
-        const VMStateSubsection *subsection = vmsd->subsections;
+        const VMStateDescription **subsection = vmsd->subsections;
         bool first;
 
         fprintf(out_file, ",\n%*s\"Subsections\": [\n", indent, "");
         first = true;
-        while (subsection->vmsd != NULL) {
+        while (*subsection != NULL) {
             if (!first) {
                 fprintf(out_file, ",\n");
             }
diff --git a/migration/vmstate.c b/migration/vmstate.c
index e5388f0596..108995ec78 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -341,11 +341,11 @@ void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
 }
 
 static const VMStateDescription *
-    vmstate_get_subsection(const VMStateSubsection *sub, char *idstr)
+vmstate_get_subsection(const VMStateDescription **sub, char *idstr)
 {
-    while (sub && sub->needed) {
-        if (strcmp(idstr, sub->vmsd->name) == 0) {
-            return sub->vmsd;
+    while (sub && *sub && (*sub)->needed) {
+        if (strcmp(idstr, (*sub)->name) == 0) {
+            return *sub;
         }
         sub++;
     }
@@ -405,12 +405,12 @@ static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
 static void vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
                                     void *opaque, QJSON *vmdesc)
 {
-    const VMStateSubsection *sub = vmsd->subsections;
+    const VMStateDescription **sub = vmsd->subsections;
     bool subsection_found = false;
 
-    while (sub && sub->needed) {
-        if (sub->needed(opaque)) {
-            const VMStateDescription *vmsd = sub->vmsd;
+    while (sub && *sub && (*sub)->needed) {
+        if ((*sub)->needed(opaque)) {
+            const VMStateDescription *vmsd = *sub;
             uint8_t len;
 
             if (vmdesc) {
diff --git a/target-arm/machine.c b/target-arm/machine.c
index 9446e5a8ab..36365a57c7 100644
--- a/target-arm/machine.c
+++ b/target-arm/machine.c
@@ -40,6 +40,7 @@ static const VMStateDescription vmstate_vfp = {
     .name = "cpu/vfp",
     .version_id = 3,
     .minimum_version_id = 3,
+    .needed = vfp_needed,
     .fields = (VMStateField[]) {
         VMSTATE_FLOAT64_ARRAY(env.vfp.regs, ARMCPU, 64),
         /* The xregs array is a little awkward because element 1 (FPSCR)
@@ -72,6 +73,7 @@ static const VMStateDescription vmstate_iwmmxt = {
     .name = "cpu/iwmmxt",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = iwmmxt_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64_ARRAY(env.iwmmxt.regs, ARMCPU, 16),
         VMSTATE_UINT32_ARRAY(env.iwmmxt.cregs, ARMCPU, 16),
@@ -91,6 +93,7 @@ static const VMStateDescription vmstate_m = {
     .name = "cpu/m",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = m_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(env.v7m.other_sp, ARMCPU),
         VMSTATE_UINT32(env.v7m.vecbase, ARMCPU),
@@ -114,6 +117,7 @@ static const VMStateDescription vmstate_thumb2ee = {
     .name = "cpu/thumb2ee",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = thumb2ee_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(env.teecr, ARMCPU),
         VMSTATE_UINT32(env.teehbr, ARMCPU),
@@ -282,21 +286,11 @@ const VMStateDescription vmstate_arm_cpu = {
         VMSTATE_BOOL(powered_off, ARMCPU),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_vfp,
-            .needed = vfp_needed,
-        } , {
-            .vmsd = &vmstate_iwmmxt,
-            .needed = iwmmxt_needed,
-        } , {
-            .vmsd = &vmstate_m,
-            .needed = m_needed,
-        } , {
-            .vmsd = &vmstate_thumb2ee,
-            .needed = thumb2ee_needed,
-        } , {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_vfp,
+        &vmstate_iwmmxt,
+        &vmstate_m,
+        &vmstate_thumb2ee,
+        NULL
     }
 };
diff --git a/target-i386/machine.c b/target-i386/machine.c
index 69d86cb476..a0df64b577 100644
--- a/target-i386/machine.c
+++ b/target-i386/machine.c
@@ -403,6 +403,7 @@ static const VMStateDescription vmstate_steal_time_msr = {
     .name = "cpu/steal_time_msr",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = steal_time_msr_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.steal_time_msr, X86CPU),
         VMSTATE_END_OF_LIST()
@@ -413,6 +414,7 @@ static const VMStateDescription vmstate_async_pf_msr = {
     .name = "cpu/async_pf_msr",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = async_pf_msr_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.async_pf_en_msr, X86CPU),
         VMSTATE_END_OF_LIST()
@@ -423,6 +425,7 @@ static const VMStateDescription vmstate_pv_eoi_msr = {
     .name = "cpu/async_pv_eoi_msr",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = pv_eoi_msr_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.pv_eoi_en_msr, X86CPU),
         VMSTATE_END_OF_LIST()
@@ -441,6 +444,7 @@ static const VMStateDescription vmstate_fpop_ip_dp = {
     .name = "cpu/fpop_ip_dp",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = fpop_ip_dp_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT16(env.fpop, X86CPU),
         VMSTATE_UINT64(env.fpip, X86CPU),
@@ -461,6 +465,7 @@ static const VMStateDescription vmstate_msr_tsc_adjust = {
     .name = "cpu/msr_tsc_adjust",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = tsc_adjust_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.tsc_adjust, X86CPU),
         VMSTATE_END_OF_LIST()
@@ -479,6 +484,7 @@ static const VMStateDescription vmstate_msr_tscdeadline = {
     .name = "cpu/msr_tscdeadline",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = tscdeadline_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.tsc_deadline, X86CPU),
         VMSTATE_END_OF_LIST()
@@ -505,6 +511,7 @@ static const VMStateDescription vmstate_msr_ia32_misc_enable = {
     .name = "cpu/msr_ia32_misc_enable",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = misc_enable_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.msr_ia32_misc_enable, X86CPU),
         VMSTATE_END_OF_LIST()
@@ -515,6 +522,7 @@ static const VMStateDescription vmstate_msr_ia32_feature_control = {
     .name = "cpu/msr_ia32_feature_control",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = feature_control_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.msr_ia32_feature_control, X86CPU),
         VMSTATE_END_OF_LIST()
@@ -549,6 +557,7 @@ static const VMStateDescription vmstate_msr_architectural_pmu = {
     .name = "cpu/msr_architectural_pmu",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = pmu_enable_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.msr_fixed_ctr_ctrl, X86CPU),
         VMSTATE_UINT64(env.msr_global_ctrl, X86CPU),
@@ -584,6 +593,7 @@ static const VMStateDescription vmstate_mpx = {
     .name = "cpu/mpx",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = mpx_needed,
     .fields = (VMStateField[]) {
         VMSTATE_BND_REGS(env.bnd_regs, X86CPU, 4),
         VMSTATE_UINT64(env.bndcs_regs.cfgu, X86CPU),
@@ -605,6 +615,7 @@ static const VMStateDescription vmstate_msr_hypercall_hypercall = {
     .name = "cpu/msr_hyperv_hypercall",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = hyperv_hypercall_enable_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.msr_hv_guest_os_id, X86CPU),
         VMSTATE_UINT64(env.msr_hv_hypercall, X86CPU),
@@ -624,6 +635,7 @@ static const VMStateDescription vmstate_msr_hyperv_vapic = {
     .name = "cpu/msr_hyperv_vapic",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = hyperv_vapic_enable_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.msr_hv_vapic, X86CPU),
         VMSTATE_END_OF_LIST()
@@ -642,6 +654,7 @@ static const VMStateDescription vmstate_msr_hyperv_time = {
     .name = "cpu/msr_hyperv_time",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = hyperv_time_enable_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.msr_hv_tsc, X86CPU),
         VMSTATE_END_OF_LIST()
@@ -683,6 +696,7 @@ static const VMStateDescription vmstate_avx512 = {
     .name = "cpu/avx512",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = avx512_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64_ARRAY(env.opmask_regs, X86CPU, NB_OPMASK_REGS),
         VMSTATE_ZMMH_REGS_VARS(env.xmm_regs, X86CPU, 0),
@@ -705,6 +719,7 @@ static const VMStateDescription vmstate_xss = {
     .name = "cpu/xss",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = xss_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.xss, X86CPU),
         VMSTATE_END_OF_LIST()
@@ -813,54 +828,22 @@ VMStateDescription vmstate_x86_cpu = {
         VMSTATE_END_OF_LIST()
         /* The above list is not sorted /wrt version numbers, watch out! */
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_async_pf_msr,
-            .needed = async_pf_msr_needed,
-        } , {
-            .vmsd = &vmstate_pv_eoi_msr,
-            .needed = pv_eoi_msr_needed,
-        } , {
-            .vmsd = &vmstate_steal_time_msr,
-            .needed = steal_time_msr_needed,
-        } , {
-            .vmsd = &vmstate_fpop_ip_dp,
-            .needed = fpop_ip_dp_needed,
-        }, {
-            .vmsd = &vmstate_msr_tsc_adjust,
-            .needed = tsc_adjust_needed,
-        }, {
-            .vmsd = &vmstate_msr_tscdeadline,
-            .needed = tscdeadline_needed,
-        }, {
-            .vmsd = &vmstate_msr_ia32_misc_enable,
-            .needed = misc_enable_needed,
-        }, {
-            .vmsd = &vmstate_msr_ia32_feature_control,
-            .needed = feature_control_needed,
-        }, {
-            .vmsd = &vmstate_msr_architectural_pmu,
-            .needed = pmu_enable_needed,
-        } , {
-            .vmsd = &vmstate_mpx,
-            .needed = mpx_needed,
-        }, {
-            .vmsd = &vmstate_msr_hypercall_hypercall,
-            .needed = hyperv_hypercall_enable_needed,
-        }, {
-            .vmsd = &vmstate_msr_hyperv_vapic,
-            .needed = hyperv_vapic_enable_needed,
-        }, {
-            .vmsd = &vmstate_msr_hyperv_time,
-            .needed = hyperv_time_enable_needed,
-        }, {
-            .vmsd = &vmstate_avx512,
-            .needed = avx512_needed,
-         }, {
-            .vmsd = &vmstate_xss,
-            .needed = xss_needed,
-        } , {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_async_pf_msr,
+        &vmstate_pv_eoi_msr,
+        &vmstate_steal_time_msr,
+        &vmstate_fpop_ip_dp,
+        &vmstate_msr_tsc_adjust,
+        &vmstate_msr_tscdeadline,
+        &vmstate_msr_ia32_misc_enable,
+        &vmstate_msr_ia32_feature_control,
+        &vmstate_msr_architectural_pmu,
+        &vmstate_mpx,
+        &vmstate_msr_hypercall_hypercall,
+        &vmstate_msr_hyperv_vapic,
+        &vmstate_msr_hyperv_time,
+        &vmstate_avx512,
+        &vmstate_xss,
+        NULL
     }
 };
diff --git a/target-ppc/machine.c b/target-ppc/machine.c
index d875211a2d..f4ac7611dd 100644
--- a/target-ppc/machine.c
+++ b/target-ppc/machine.c
@@ -213,6 +213,7 @@ static const VMStateDescription vmstate_fpu = {
     .name = "cpu/fpu",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = fpu_needed,
     .fields = (VMStateField[]) {
         VMSTATE_FLOAT64_ARRAY(env.fpr, PowerPCCPU, 32),
         VMSTATE_UINTTL(env.fpscr, PowerPCCPU),
@@ -231,6 +232,7 @@ static const VMStateDescription vmstate_altivec = {
     .name = "cpu/altivec",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = altivec_needed,
     .fields = (VMStateField[]) {
         VMSTATE_AVR_ARRAY(env.avr, PowerPCCPU, 32),
         VMSTATE_UINT32(env.vscr, PowerPCCPU),
@@ -249,6 +251,7 @@ static const VMStateDescription vmstate_vsx = {
     .name = "cpu/vsx",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = vsx_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64_ARRAY(env.vsr, PowerPCCPU, 32),
         VMSTATE_END_OF_LIST()
@@ -269,6 +272,7 @@ static const VMStateDescription vmstate_tm = {
     .version_id = 1,
     .minimum_version_id = 1,
     .minimum_version_id_old = 1,
+    .needed = tm_needed,
     .fields      = (VMStateField []) {
         VMSTATE_UINTTL_ARRAY(env.tm_gpr, PowerPCCPU, 32),
         VMSTATE_AVR_ARRAY(env.tm_vsr, PowerPCCPU, 64),
@@ -302,6 +306,7 @@ static const VMStateDescription vmstate_sr = {
     .name = "cpu/sr",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = sr_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINTTL_ARRAY(env.sr, PowerPCCPU, 32),
         VMSTATE_END_OF_LIST()
@@ -351,6 +356,7 @@ static const VMStateDescription vmstate_slb = {
     .name = "cpu/slb",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = slb_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32_EQUAL(env.slb_nr, PowerPCCPU),
         VMSTATE_SLB_ARRAY(env.slb, PowerPCCPU, MAX_SLB_ENTRIES),
@@ -383,6 +389,7 @@ static const VMStateDescription vmstate_tlb6xx = {
     .name = "cpu/tlb6xx",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = tlb6xx_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32_EQUAL(env.nb_tlb, PowerPCCPU),
         VMSTATE_STRUCT_VARRAY_POINTER_INT32(env.tlb.tlb6, PowerPCCPU,
@@ -429,6 +436,7 @@ static const VMStateDescription vmstate_pbr403 = {
     .name = "cpu/pbr403",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = pbr403_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINTTL_ARRAY(env.pb, PowerPCCPU, 4),
         VMSTATE_END_OF_LIST()
@@ -439,6 +447,7 @@ static const VMStateDescription vmstate_tlbemb = {
     .name = "cpu/tlb6xx",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = tlbemb_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32_EQUAL(env.nb_tlb, PowerPCCPU),
         VMSTATE_STRUCT_VARRAY_POINTER_INT32(env.tlb.tlbe, PowerPCCPU,
@@ -448,13 +457,9 @@ static const VMStateDescription vmstate_tlbemb = {
         /* 403 protection registers */
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_pbr403,
-            .needed = pbr403_needed,
-        } , {
-            /* empty */
-        }
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_pbr403,
+        NULL
     }
 };
 
@@ -483,6 +488,7 @@ static const VMStateDescription vmstate_tlbmas = {
     .name = "cpu/tlbmas",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = tlbmas_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32_EQUAL(env.nb_tlb, PowerPCCPU),
         VMSTATE_STRUCT_VARRAY_POINTER_INT32(env.tlb.tlbm, PowerPCCPU,
@@ -533,38 +539,18 @@ const VMStateDescription vmstate_ppc_cpu = {
         VMSTATE_UINT32_EQUAL(env.nb_BATs, PowerPCCPU),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (VMStateSubsection []) {
-        {
-            .vmsd = &vmstate_fpu,
-            .needed = fpu_needed,
-        } , {
-            .vmsd = &vmstate_altivec,
-            .needed = altivec_needed,
-        } , {
-            .vmsd = &vmstate_vsx,
-            .needed = vsx_needed,
-        } , {
-            .vmsd = &vmstate_sr,
-            .needed = sr_needed,
-        } , {
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_fpu,
+        &vmstate_altivec,
+        &vmstate_vsx,
+        &vmstate_sr,
 #ifdef TARGET_PPC64
-            .vmsd = &vmstate_tm,
-            .needed = tm_needed,
-        } , {
-            .vmsd = &vmstate_slb,
-            .needed = slb_needed,
-        } , {
+        &vmstate_tm,
+        &vmstate_slb,
 #endif /* TARGET_PPC64 */
-            .vmsd = &vmstate_tlb6xx,
-            .needed = tlb6xx_needed,
-        } , {
-            .vmsd = &vmstate_tlbemb,
-            .needed = tlbemb_needed,
-        } , {
-            .vmsd = &vmstate_tlbmas,
-            .needed = tlbmas_needed,
-        } , {
-            /* empty */
-        }
+        &vmstate_tlb6xx,
+        &vmstate_tlbemb,
+        &vmstate_tlbmas,
+        NULL
     }
 };
diff --git a/target-s390x/machine.c b/target-s390x/machine.c
index 004474959a..b76fb08319 100644
--- a/target-s390x/machine.c
+++ b/target-s390x/machine.c
@@ -42,10 +42,17 @@ static void cpu_pre_save(void *opaque)
     }
 }
 
+static inline bool fpu_needed(void *opaque)
+{
+    /* This looks odd, but we might want to NOT transfer fprs in the future */
+    return true;
+}
+
 const VMStateDescription vmstate_fpu = {
     .name = "cpu/fpu",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = fpu_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT64(env.vregs[0][0].ll, S390CPU),
         VMSTATE_UINT64(env.vregs[1][0].ll, S390CPU),
@@ -68,16 +75,11 @@ const VMStateDescription vmstate_fpu = {
     }
 };
 
-static inline bool fpu_needed(void *opaque)
-{
-    /* This looks odd, but we might want to NOT transfer fprs in the future */
-    return true;
-}
-
 const VMStateDescription vmstate_vregs = {
     .name = "cpu/vregs",
     .version_id = 1,
     .minimum_version_id = 1,
+    .needed = vregs_needed,
     .fields = (VMStateField[]) {
         /* vregs[0][0] -> vregs[15][0] and fregs are overlays */
         VMSTATE_UINT64(env.vregs[16][0].ll, S390CPU),
@@ -159,16 +161,10 @@ const VMStateDescription vmstate_s390_cpu = {
         VMSTATE_VBUFFER_UINT32(irqstate, S390CPU, 4, NULL, 0,
                                irqstate_saved_size),
         VMSTATE_END_OF_LIST()
-     },
-    .subsections = (VMStateSubsection[]) {
-        {
-            .vmsd = &vmstate_fpu,
-            .needed = fpu_needed,
-        } , {
-            .vmsd = &vmstate_vregs,
-            .needed = vregs_needed,
-        } , {
-            /* empty */
-        }
+    },
+    .subsections = (const VMStateDescription*[]) {
+        &vmstate_fpu,
+        &vmstate_vregs,
+        NULL
     },
 };