[PATCH v3 04/42] esp: add vmstate_esp version to embedded ESPState

[Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>]

The QOM object representing ESPState is currently embedded within both the
SYSBUS_ESP and PCI_ESP devices with migration state handled by embedding
vmstate_esp within each device using VMSTATE_STRUCT.

Since the vmstate_esp fields are embedded directly within the migration
stream, the incoming vmstate_esp version_id is lost. The only version information
available is that from vmstate_sysbus_esp_scsi and vmstate_esp_pci_scsi, but
those versions represent their respective devices and not that of the underlying
ESPState.

Resolve this by adding a new version-dependent field in vmstate_sysbus_esp_scsi
and vmstate_esp_pci_scsi which stores the vmstate_esp version_id field within
ESPState to be used to allow migration from older QEMU versions.

Finally bump the vmstate_esp version to 5 to cover the upcoming ESPState changes
within this patch series.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
---
 hw/scsi/esp-pci.c     |  3 ++-
 hw/scsi/esp.c         | 23 +++++++++++++++++++++--
 include/hw/scsi/esp.h |  2 ++
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/hw/scsi/esp-pci.c b/hw/scsi/esp-pci.c
index 27a0d36e0b..c3d3dab05e 100644
--- a/hw/scsi/esp-pci.c
+++ b/hw/scsi/esp-pci.c
@@ -330,11 +330,12 @@ static void esp_pci_hard_reset(DeviceState *dev)
 
 static const VMStateDescription vmstate_esp_pci_scsi = {
     .name = "pciespscsi",
-    .version_id = 1,
+    .version_id = 2,
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_PCI_DEVICE(parent_obj, PCIESPState),
         VMSTATE_BUFFER_UNSAFE(dma_regs, PCIESPState, 0, 8 * sizeof(uint32_t)),
+        VMSTATE_UINT8_V(esp.mig_version_id, PCIESPState, 2),
         VMSTATE_STRUCT(esp, PCIESPState, 0, vmstate_esp, ESPState),
         VMSTATE_END_OF_LIST()
     }
diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index 6f8a1d1224..f65c675872 100644
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -795,10 +795,28 @@ static const VMStateDescription vmstate_esp_pdma = {
     }
 };
 
+static int esp_pre_save(void *opaque)
+{
+    ESPState *s = ESP(opaque);
+
+    s->mig_version_id = vmstate_esp.version_id;
+    return 0;
+}
+
+static int esp_post_load(void *opaque, int version_id)
+{
+    ESPState *s = ESP(opaque);
+
+    s->mig_version_id = vmstate_esp.version_id;
+    return 0;
+}
+
 const VMStateDescription vmstate_esp = {
     .name = "esp",
-    .version_id = 4,
+    .version_id = 5,
     .minimum_version_id = 3,
+    .pre_save = esp_pre_save,
+    .post_load = esp_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_BUFFER(rregs, ESPState),
         VMSTATE_BUFFER(wregs, ESPState),
@@ -997,9 +1015,10 @@ static void sysbus_esp_init(Object *obj)
 
 static const VMStateDescription vmstate_sysbus_esp_scsi = {
     .name = "sysbusespscsi",
-    .version_id = 1,
+    .version_id = 2,
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
+        VMSTATE_UINT8_V(esp.mig_version_id, SysBusESPState, 2),
         VMSTATE_STRUCT(esp, SysBusESPState, 0, vmstate_esp, ESPState),
         VMSTATE_END_OF_LIST()
     }
diff --git a/include/hw/scsi/esp.h b/include/hw/scsi/esp.h
index af23f813cb..9d149cbc9f 100644
--- a/include/hw/scsi/esp.h
+++ b/include/hw/scsi/esp.h
@@ -68,6 +68,8 @@ struct ESPState {
     uint32_t pdma_start;
     uint32_t pdma_cur;
     void (*pdma_cb)(ESPState *s);
+
+    uint8_t mig_version_id;
 };
 
 #define TYPE_SYSBUS_ESP "sysbus-esp"
-- 
2.20.1