[Qemu-devel] [PATCH 1/4] migration: allow unplug during migration for failover devices

[Jens Freimann <jfreimann@redhat.com>]

In "b06424de62 migration: Disable hotplug/unplug during migration" we
added a check to disable unplug for all devices until we have figured
out what works. For failover primary devices qdev_unplug() is called
from the migration handler, i.e. during migration.

This patch adds a flag to DeviceState which is set to false for all
devices and makes an exception for vfio-pci devices that are also
primary devices in a failover pair.

Signed-off-by: Jens Freimann <jfreimann@redhat.com>
---
 hw/core/qdev.c         | 1 +
 include/hw/qdev-core.h | 1 +
 qdev-monitor.c         | 2 +-
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index f9b6efe509..98cdaa6bf7 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -954,6 +954,7 @@ static void device_initfn(Object *obj)
 
     dev->instance_id_alias = -1;
     dev->realized = false;
+    dev->allow_unplug_during_migration = false;
 
     object_property_add_bool(obj, "realized",
                              device_get_realized, device_set_realized, NULL);
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index 33ed3b8dde..5437395779 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -146,6 +146,7 @@ struct DeviceState {
     bool pending_deleted_event;
     QemuOpts *opts;
     int hotplugged;
+    bool allow_unplug_during_migration;
     BusState *parent_bus;
     QLIST_HEAD(, NamedGPIOList) gpios;
     QLIST_HEAD(, BusState) child_bus;
diff --git a/qdev-monitor.c b/qdev-monitor.c
index 373b9ad445..9cce8b93c2 100644
--- a/qdev-monitor.c
+++ b/qdev-monitor.c
@@ -867,7 +867,7 @@ void qdev_unplug(DeviceState *dev, Error **errp)
         return;
     }
 
-    if (!migration_is_idle()) {
+    if (!migration_is_idle() && !dev->allow_unplug_during_migration) {
         error_setg(errp, "device_del not allowed while migrating");
         return;
     }
-- 
2.21.0