1 files changed, 47 insertions, 10 deletions

diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
index 61e2e57da9..6b01accf61 100644
--- a/hw/scsi/vhost-scsi.c
+++ b/hw/scsi/vhost-scsi.c
@@ -114,6 +114,10 @@ static void vhost_scsi_set_status(VirtIODevice *vdev, uint8_t val)
     VHostSCSICommon *vsc = VHOST_SCSI_COMMON(s);
     bool start = (val & VIRTIO_CONFIG_S_DRIVER_OK);
 
+    if (!vdev->vm_running) {
+        start = false;
+    }
+
     if (vsc->dev.started == start) {
         return;
     }
@@ -135,6 +139,28 @@ static void vhost_dummy_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 {
 }
 
+static int vhost_scsi_pre_save(void *opaque)
+{
+    VHostSCSICommon *vsc = opaque;
+
+    /* At this point, backend must be stopped, otherwise
+     * it might keep writing to memory. */
+    assert(!vsc->dev.started);
+
+    return 0;
+}
+
+static const VMStateDescription vmstate_virtio_vhost_scsi = {
+    .name = "virtio-vhost_scsi",
+    .minimum_version_id = 1,
+    .version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_VIRTIO_DEVICE,
+        VMSTATE_END_OF_LIST()
+    },
+    .pre_save = vhost_scsi_pre_save,
+};
+
 static void vhost_scsi_realize(DeviceState *dev, Error **errp)
 {
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(dev);
@@ -173,13 +199,18 @@ static void vhost_scsi_realize(DeviceState *dev, Error **errp)
         goto close_fd;
     }
 
-    error_setg(&vsc->migration_blocker,
-               "vhost-scsi does not support migration");
-    migrate_add_blocker(vsc->migration_blocker, &err);
-    if (err) {
-        error_propagate(errp, err);
-        error_free(vsc->migration_blocker);
-        goto close_fd;
+    if (!vsc->migratable) {
+        error_setg(&vsc->migration_blocker,
+                "vhost-scsi does not support migration in all cases. "
+                "When external environment supports it (Orchestrator migrates "
+                "target SCSI device state or use shared storage over network), "
+                "set 'migratable' property to true to enable migration.");
+        migrate_add_blocker(vsc->migration_blocker, &err);
+        if (err) {
+            error_propagate(errp, err);
+            error_free(vsc->migration_blocker);
+            goto close_fd;
+        }
     }
 
     vsc->dev.nvqs = VHOST_SCSI_VQ_NUM_FIXED + vs->conf.num_queues;
@@ -204,7 +235,9 @@ static void vhost_scsi_realize(DeviceState *dev, Error **errp)
     return;
 
  free_vqs:
-    migrate_del_blocker(vsc->migration_blocker);
+    if (!vsc->migratable) {
+        migrate_del_blocker(vsc->migration_blocker);
+    }
     g_free(vsc->dev.vqs);
  close_fd:
     close(vhostfd);
@@ -217,8 +250,10 @@ static void vhost_scsi_unrealize(DeviceState *dev, Error **errp)
     VHostSCSICommon *vsc = VHOST_SCSI_COMMON(dev);
     struct vhost_virtqueue *vqs = vsc->dev.vqs;
 
-    migrate_del_blocker(vsc->migration_blocker);
-    error_free(vsc->migration_blocker);
+    if (!vsc->migratable) {
+        migrate_del_blocker(vsc->migration_blocker);
+        error_free(vsc->migration_blocker);
+    }
 
     /* This will stop vhost backend. */
     vhost_scsi_set_status(vdev, 0);
@@ -242,6 +277,7 @@ static Property vhost_scsi_properties[] = {
     DEFINE_PROP_BIT64("t10_pi", VHostSCSICommon, host_features,
                                                  VIRTIO_SCSI_F_T10_PI,
                                                  false),
+    DEFINE_PROP_BOOL("migratable", VHostSCSICommon, migratable, false),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -252,6 +288,7 @@ static void vhost_scsi_class_init(ObjectClass *klass, void *data)
     FWPathProviderClass *fwc = FW_PATH_PROVIDER_CLASS(klass);
 
     dc->props = vhost_scsi_properties;
+    dc->vmsd = &vmstate_virtio_vhost_scsi;
     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
     vdc->realize = vhost_scsi_realize;
     vdc->unrealize = vhost_scsi_unrealize;