Re: [Qemu-devel] [PATCH v7 07/13] vfio: Add migration state change notifier

[Yan Zhao <yan.y.zhao@intel.com>]

On Wed, Aug 21, 2019 at 04:24:27AM +0800, Kirti Wankhede wrote:
> 
> 
> On 7/17/2019 7:55 AM, Yan Zhao wrote:
> > On Tue, Jul 09, 2019 at 05:49:14PM +0800, Kirti Wankhede wrote:
> >> Added migration state change notifier to get notification on migration state
> >> change. These states are translated to VFIO device state and conveyed to vendor
> >> driver.
> >>
> >> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
> >> Reviewed-by: Neo Jia <cjia@nvidia.com>
> >> ---
> >>  hw/vfio/migration.c           | 54 +++++++++++++++++++++++++++++++++++++++++++
> >>  hw/vfio/trace-events          |  1 +
> >>  include/hw/vfio/vfio-common.h |  1 +
> >>  3 files changed, 56 insertions(+)
> >>
> >> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> >> index c01f08b659d0..e4a89a6f9bc7 100644
> >> --- a/hw/vfio/migration.c
> >> +++ b/hw/vfio/migration.c
> >> @@ -132,6 +132,53 @@ static void vfio_vmstate_change(void *opaque, int running, RunState state)
> >>      }
> >>  }
> >>  
> >> +static void vfio_migration_state_notifier(Notifier *notifier, void *data)
> >> +{
> >> +    MigrationState *s = data;
> >> +    VFIODevice *vbasedev = container_of(notifier, VFIODevice, migration_state);
> >> +    int ret;
> >> +
> >> +    trace_vfio_migration_state_notifier(vbasedev->name, s->state);
> >> +
> >> +    switch (s->state) {
> >> +    case MIGRATION_STATUS_ACTIVE:
> >> +        if (vbasedev->device_state & VFIO_DEVICE_STATE_RUNNING) {
> >> +            if (vbasedev->vm_running) {
> >> +                ret = vfio_migration_set_state(vbasedev,
> >> +                          VFIO_DEVICE_STATE_RUNNING | VFIO_DEVICE_STATE_SAVING);
> >> +                if (ret) {
> >> +                    error_report("%s: Failed to set state RUNNING and SAVING",
> >> +                                  vbasedev->name);
> >> +                }
> >> +            } else {
> >> +                ret = vfio_migration_set_state(vbasedev,
> >> +                                               VFIO_DEVICE_STATE_SAVING);
> >> +                if (ret) {
> >> +                    error_report("%s: Failed to set state STOP and SAVING",
> >> +                                 vbasedev->name);
> >> +                }
> >> +            }
> >> +        } else {
> >> +            ret = vfio_migration_set_state(vbasedev,
> >> +                                           VFIO_DEVICE_STATE_RESUMING);
> >> +            if (ret) {
> >> +                error_report("%s: Failed to set state RESUMING",
> >> +                             vbasedev->name);
> >> +            }
> >> +        }
> >> +        return;
> >> +
> > hi Kirti
> > currently, migration state notifiers are only notified in below 3 interfaces:
> > migrate_fd_connect, migrate_fd_cleanup, postcopy_start, where
> > MIGRATION_STATUS_ACTIVE is not an valid state.
> > Have you tested the above code? what's the purpose of the code?
> > 
> 
> Sorry for delayed response.
> 
> migration_iteration_finish() -> qemu_bh_schedule(s->cleanup_bh) which is
> migrate_fd_cleanup().
> 
> migration_iteration_finish() can be called with MIGRATION_STATUS_ACTIVE
> state. So migration state notifiers can be called with
> MIGRATION_STATUS_ACTIVE. So handled that case here.
>
hi Kirti

I checked the code, the MIGRATION_STATUS_ACTIVE case you mentioned is
colo only, and there's actually an assert in migrate_fd_cleanup

	assert((s->state != MIGRATION_STATUS_ACTIVE) &&
		(s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE));

before it calls notifier_list_notify(&migration_state_notifiers, s).

Thanks
Yan

> 
> 
> > 
> >> +    case MIGRATION_STATUS_CANCELLING:
> >> +    case MIGRATION_STATUS_CANCELLED:
> >> +    case MIGRATION_STATUS_FAILED:
> >> +        ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RUNNING);
> >> +        if (ret) {
> >> +            error_report("%s: Failed to set state RUNNING", vbasedev->name);
> >> +        }
> >> +        return;
> >> +    }
> >> +}
> >> +
> >>  static int vfio_migration_init(VFIODevice *vbasedev,
> >>                                 struct vfio_region_info *info)
> >>  {
> >> @@ -152,6 +199,9 @@ static int vfio_migration_init(VFIODevice *vbasedev,
> >>      vbasedev->vm_state = qemu_add_vm_change_state_handler(vfio_vmstate_change,
> >>                                                            vbasedev);
> >>  
> >> +    vbasedev->migration_state.notify = vfio_migration_state_notifier;
> >> +    add_migration_state_change_notifier(&vbasedev->migration_state);
> >> +
> >>      return 0;
> >>  }
> >>  
> >> @@ -194,6 +244,10 @@ void vfio_migration_finalize(VFIODevice *vbasedev)
> >>          return;
> >>      }
> >>  
> >> +    if (vbasedev->migration_state.notify) {
> >> +        remove_migration_state_change_notifier(&vbasedev->migration_state);
> >> +    }
> >> +
> >>      if (vbasedev->vm_state) {
> >>          qemu_del_vm_change_state_handler(vbasedev->vm_state);
> >>      }
> >> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
> >> index 3d15bacd031a..69503228f20e 100644
> >> --- a/hw/vfio/trace-events
> >> +++ b/hw/vfio/trace-events
> >> @@ -148,3 +148,4 @@ vfio_display_edid_write_error(void) ""
> >>  vfio_migration_probe(char *name, uint32_t index) " (%s) Region %d"
> >>  vfio_migration_set_state(char *name, uint32_t state) " (%s) state %d"
> >>  vfio_vmstate_change(char *name, int running, const char *reason, uint32_t dev_state) " (%s) running %d reason %s device state %d"
> >> +vfio_migration_state_notifier(char *name, int state) " (%s) state %d"
> >> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> >> index f6c70db3a9c1..a022484d2636 100644
> >> --- a/include/hw/vfio/vfio-common.h
> >> +++ b/include/hw/vfio/vfio-common.h
> >> @@ -128,6 +128,7 @@ typedef struct VFIODevice {
> >>      uint32_t device_state;
> >>      VMChangeStateEntry *vm_state;
> >>      int vm_running;
> >> +    Notifier migration_state;
> >>  } VFIODevice;
> >>  
> >>  struct VFIODeviceOps {
> >> -- 
> >> 2.7.0
> >>