Re: [PATCH QEMU v23 17/18] vfio: Make vfio-pci device migration capable

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Kirti Wankhede (kwankhede@nvidia.com) wrote:
> If device is not failover primary device call vfio_migration_probe()
> and vfio_migration_finalize() functions for vfio-pci device to enable
> migration for vfio PCI device which support migration.
> Removed vfio_pci_vmstate structure.
> Removed migration blocker from VFIO PCI device specific structure and use
> migration blocker from generic structure of  VFIO device.
> 
> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
> Reviewed-by: Neo Jia <cjia@nvidia.com>
> ---
>  hw/vfio/pci.c | 32 +++++++++++---------------------
>  hw/vfio/pci.h |  1 -
>  2 files changed, 11 insertions(+), 22 deletions(-)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 94535f0e27cd..573b28753bfd 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2916,22 +2916,11 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>          return;
>      }
>  
> -    if (!pdev->failover_pair_id) {
> -        error_setg(&vdev->migration_blocker,
> -                "VFIO device doesn't support migration");
> -        ret = migrate_add_blocker(vdev->migration_blocker, &err);
> -        if (ret) {
> -            error_propagate(errp, err);
> -            error_free(vdev->migration_blocker);
> -            vdev->migration_blocker = NULL;
> -            return;
> -        }
> -    }
> -
>      vdev->vbasedev.name = g_path_get_basename(vdev->vbasedev.sysfsdev);
>      vdev->vbasedev.ops = &vfio_pci_ops;
>      vdev->vbasedev.type = VFIO_DEVICE_TYPE_PCI;
>      vdev->vbasedev.dev = DEVICE(vdev);
> +    vdev->vbasedev.device_state = 0;
>  
>      tmp = g_strdup_printf("%s/iommu_group", vdev->vbasedev.sysfsdev);
>      len = readlink(tmp, group_path, sizeof(group_path));
> @@ -3195,6 +3184,14 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>          }
>      }
>  
> +    if (!pdev->failover_pair_id) {
> +        ret = vfio_migration_probe(&vdev->vbasedev, errp);

OK, and I can see vfio_migration_probe adds a blocker if the device
doesn't support migration.

> +        if (ret) {
> +            error_report("%s: Failed to setup for migration",
> +                         vdev->vbasedev.name);
> +        }
> +    }
> +
>      vfio_register_err_notifier(vdev);
>      vfio_register_req_notifier(vdev);
>      vfio_setup_resetfn_quirk(vdev);
> @@ -3209,11 +3206,6 @@ out_teardown:
>      vfio_bars_exit(vdev);
>  error:
>      error_prepend(errp, VFIO_MSG_PREFIX, vdev->vbasedev.name);
> -    if (vdev->migration_blocker) {
> -        migrate_del_blocker(vdev->migration_blocker);
> -        error_free(vdev->migration_blocker);
> -        vdev->migration_blocker = NULL;
> -    }
>  }
>  
>  static void vfio_instance_finalize(Object *obj)
> @@ -3225,10 +3217,7 @@ static void vfio_instance_finalize(Object *obj)
>      vfio_bars_finalize(vdev);
>      g_free(vdev->emulated_config_bits);
>      g_free(vdev->rom);
> -    if (vdev->migration_blocker) {
> -        migrate_del_blocker(vdev->migration_blocker);
> -        error_free(vdev->migration_blocker);
> -    }
> +
>      /*
>       * XXX Leaking igd_opregion is not an oversight, we can't remove the
>       * fw_cfg entry therefore leaking this allocation seems like the safest
> @@ -3256,6 +3245,7 @@ static void vfio_exitfn(PCIDevice *pdev)
>      }
>      vfio_teardown_msi(vdev);
>      vfio_bars_exit(vdev);
> +    vfio_migration_finalize(&vdev->vbasedev);

Which this removes at the end.
So,


Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

>  }
>  
>  static void vfio_pci_reset(DeviceState *dev)
> diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
> index 0da7a20a7ec2..b148c937ef72 100644
> --- a/hw/vfio/pci.h
> +++ b/hw/vfio/pci.h
> @@ -168,7 +168,6 @@ typedef struct VFIOPCIDevice {
>      bool no_vfio_ioeventfd;
>      bool enable_ramfb;
>      VFIODisplay *dpy;
> -    Error *migration_blocker;
>      Notifier irqchip_change_notifier;
>  } VFIOPCIDevice;
>  
> -- 
> 2.7.0
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK