From 0b646f44d9976c33aee78b0427d1b357dde5dd50 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Mon, 1 Aug 2016 10:25:05 +0200
Subject: [PATCH] mptsas: really fix migration compatibility

Commit 2e2aa316 removed internal flag msi_in_use, but it
existed in vmstate.  Restore it for migration to older QEMU
versions.

Reported-by: Amit Shah <amit.shah@redhat.com>
Suggested-by: Amit Shah <amit.shah@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Marcel Apfelbaum <marcel@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Amit Shah <amit.shah@redhat.com>
Cc: Cao jin <caoj.fnst@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/scsi/mptsas.c | 4 +++-
 hw/scsi/mptsas.h | 2 ++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/scsi/mptsas.c b/hw/scsi/mptsas.c
index bebe5130fe..0e0a22f696 100644
--- a/hw/scsi/mptsas.c
+++ b/hw/scsi/mptsas.c
@@ -1295,6 +1295,8 @@ static void mptsas_scsi_init(PCIDevice *dev, Error **errp)
         /* With msi=auto, we fall back to MSI off silently */
         error_free(err);
 
+        /* Only used for migration.  */
+        s->msi_in_use = (ret == 0);
     }
 
     memory_region_init_io(&s->mmio_io, OBJECT(s), &mptsas_mmio_ops, s,
@@ -1370,7 +1372,7 @@ static const VMStateDescription vmstate_mptsas = {
     .post_load = mptsas_post_load,
     .fields      = (VMStateField[]) {
         VMSTATE_PCI_DEVICE(dev, MPTSASState),
-        VMSTATE_UNUSED(sizeof(bool)), /* Was msi_in_use */
+        VMSTATE_BOOL(msi_in_use, MPTSASState),
         VMSTATE_UINT32(state, MPTSASState),
         VMSTATE_UINT8(who_init, MPTSASState),
         VMSTATE_UINT8(doorbell_state, MPTSASState),
diff --git a/hw/scsi/mptsas.h b/hw/scsi/mptsas.h
index da014a397e..0436a33911 100644
--- a/hw/scsi/mptsas.h
+++ b/hw/scsi/mptsas.h
@@ -31,6 +31,8 @@ struct MPTSASState {
     OnOffAuto msi;
     uint64_t sas_addr;
 
+    bool msi_in_use;
+
     /* Doorbell register */
     uint32_t state;
     uint8_t who_init;