[PATCH v4 32/33] vfio/migration: Add x-migration-multifd-transfer VFIO property

[Maciej S. Szmigiero]

From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>

This property allows configuring at runtime whether to transfer the
particular device state via multifd channels when live migrating that
device.

It defaults to AUTO, which means that VFIO device state transfer via
multifd channels is attempted in configurations that otherwise support it.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
---
 hw/vfio/pci.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 2700b355ecf1..cd24f386aaf9 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3353,6 +3353,8 @@ static void vfio_instance_init(Object *obj)
     pci_dev->cap_present |= QEMU_PCI_CAP_EXPRESS;
 }
 
+static PropertyInfo qdev_prop_on_off_auto_mutable;
+
 static const Property vfio_pci_dev_properties[] = {
     DEFINE_PROP_PCI_HOST_DEVADDR("host", VFIOPCIDevice, host),
     DEFINE_PROP_UUID_NODEFAULT("vf-token", VFIOPCIDevice, vf_token),
@@ -3377,6 +3379,10 @@ static const Property vfio_pci_dev_properties[] = {
                     VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT, false),
     DEFINE_PROP_ON_OFF_AUTO("enable-migration", VFIOPCIDevice,
                             vbasedev.enable_migration, ON_OFF_AUTO_AUTO),
+    DEFINE_PROP("x-migration-multifd-transfer", VFIOPCIDevice,
+                vbasedev.migration_multifd_transfer,
+                qdev_prop_on_off_auto_mutable, OnOffAuto,
+                .set_default = true, .defval.i = ON_OFF_AUTO_AUTO),
     DEFINE_PROP_ON_OFF_AUTO("x-migration-load-config-after-iter", 
VFIOPCIDevice,
                             vbasedev.migration_load_config_after_iter,
                             ON_OFF_AUTO_AUTO),
@@ -3477,6 +3483,9 @@ static const TypeInfo vfio_pci_nohotplug_dev_info = {
 
 static void register_vfio_pci_dev_type(void)
 {
+    qdev_prop_on_off_auto_mutable = qdev_prop_on_off_auto;
+    qdev_prop_on_off_auto_mutable.realized_set_allowed = true;
+
     type_register_static(&vfio_pci_dev_info);
     type_register_static(&vfio_pci_nohotplug_dev_info);
 }