ide save/restore current transfer fields

If migration takes place between write of the bmdma address register and
write of the command register (to initiate DMA), the destination will
not properly start the DMA op, hanging the guest:

ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
ata1.00: cmd c8/00:16:41:00:00/00:00:00:00:00/e0 tag 0 dma 11264 in
         res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
ata1.00: status: { DRDY }

Fix by sending current transfer information in the migration data.

We need to update ide version to 4 for this to work.  As we don't
have subsectios, we need to chain the update increase until
vmstate_ide_pci (quintela)
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/ide/pci.c

@@ -123,7 +123,7 @@ void bmdma_addr_writel(void *opaque, uint32_t addr, uint32_t val)
 
 static const VMStateDescription vmstate_bmdma = {
     .name = "ide bmdma",
-    .version_id = 3,
+    .version_id = 4,
     .minimum_version_id = 0,
     .minimum_version_id_old = 0,
     .fields      = (VMStateField []) {
@@ -133,6 +133,10 @@ static const VMStateDescription vmstate_bmdma = {
         VMSTATE_INT64(sector_num, BMDMAState),
         VMSTATE_UINT32(nsector, BMDMAState),
         VMSTATE_UINT8(unit, BMDMAState),
+        VMSTATE_UINT32_V(cur_addr, BMDMAState, 4),
+        VMSTATE_UINT32_V(cur_prd_last, BMDMAState, 4),
+        VMSTATE_UINT32_V(cur_prd_addr, BMDMAState, 4),
+        VMSTATE_UINT32_V(cur_prd_len, BMDMAState, 4),
         VMSTATE_END_OF_LIST()
     }
 };
@@ -152,7 +156,7 @@ static int ide_pci_post_load(void *opaque, int version_id)
 
 const VMStateDescription vmstate_ide_pci = {
     .name = "ide",
-    .version_id = 3,
+    .version_id = 4,
     .minimum_version_id = 0,
     .minimum_version_id_old = 0,
     .post_load = ide_pci_post_load,