Re: [PATCH v3 2/4] vfio/migration: Emit VFIO migration QAPI event

[Cédric Le Goater]

On 5/15/24 15:21, Avihai Horon wrote:
> Emit VFIO migration QAPI event when a VFIO device changes its migration
> state. This can be used by management applications to get updates on the
> current state of the VFIO device for their own purposes.
>
> A new per VFIO device capability, "migration-events", is added so events
> can be enabled only for the required devices. It is disabled by default.
>
> Signed-off-by: Avihai Horon <avihaih@nvidia.com>


Reviewed-by: Cédric Le Goater <clg@redhat.com>

Thanks,

C.


> ---
>   include/hw/vfio/vfio-common.h |  1 +
>   hw/vfio/migration.c           | 59 +++++++++++++++++++++++++++++++++--
>   hw/vfio/pci.c                 |  2 ++
>   3 files changed, 59 insertions(+), 3 deletions(-)
>
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index b9da6c08ef..3ec5f2425e 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -115,6 +115,7 @@ typedef struct VFIODevice {
>       bool no_mmap;
>       bool ram_block_discard_allowed;
>       OnOffAuto enable_migration;
> +    bool migration_events;
>       VFIODeviceOps *ops;
>       unsigned int num_irqs;
>       unsigned int num_regions;
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index 06ae40969b..2e1a8f6031 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -24,6 +24,7 @@
>   #include "migration/register.h"
>   #include "migration/blocker.h"
>   #include "qapi/error.h"
> +#include "qapi/qapi-events-vfio.h"
>   #include "exec/ramlist.h"
>   #include "exec/ram_addr.h"
>   #include "pci.h"
> @@ -80,6 +81,58 @@ static const char *mig_state_to_str(enum 
> vfio_device_mig_state state)
>       }
>   }
>   
> +static VfioMigrationState
> +mig_state_to_qapi_state(enum vfio_device_mig_state state)
> +{
> +    switch (state) {
> +    case VFIO_DEVICE_STATE_STOP:
> +        return QAPI_VFIO_MIGRATION_STATE_STOP;
> +    case VFIO_DEVICE_STATE_RUNNING:
> +        return QAPI_VFIO_MIGRATION_STATE_RUNNING;
> +    case VFIO_DEVICE_STATE_STOP_COPY:
> +        return QAPI_VFIO_MIGRATION_STATE_STOP_COPY;
> +    case VFIO_DEVICE_STATE_RESUMING:
> +        return QAPI_VFIO_MIGRATION_STATE_RESUMING;
> +    case VFIO_DEVICE_STATE_RUNNING_P2P:
> +        return QAPI_VFIO_MIGRATION_STATE_RUNNING_P2P;
> +    case VFIO_DEVICE_STATE_PRE_COPY:
> +        return QAPI_VFIO_MIGRATION_STATE_PRE_COPY;
> +    case VFIO_DEVICE_STATE_PRE_COPY_P2P:
> +        return QAPI_VFIO_MIGRATION_STATE_PRE_COPY_P2P;
> +    default:
> +        g_assert_not_reached();
> +    }
> +}
> +
> +static void vfio_migration_send_event(VFIODevice *vbasedev)
> +{
> +    VFIOMigration *migration = vbasedev->migration;
> +    DeviceState *dev = vbasedev->dev;
> +    g_autofree char *qom_path = NULL;
> +    Object *obj;
> +
> +    if (!vbasedev->migration_events) {
> +        return;
> +    }
> +
> +    g_assert(vbasedev->ops->vfio_get_object);
> +    obj = vbasedev->ops->vfio_get_object(vbasedev);
> +    g_assert(obj);
> +    qom_path = object_get_canonical_path(obj);
> +
> +    qapi_event_send_vfio_migration(
> +        dev->id, qom_path, mig_state_to_qapi_state(migration->device_state));
> +}
> +
> +static void vfio_migration_set_device_state(VFIODevice *vbasedev,
> +                                            enum vfio_device_mig_state state)
> +{
> +    VFIOMigration *migration = vbasedev->migration;
> +
> +    migration->device_state = state;
> +    vfio_migration_send_event(vbasedev);
> +}
> +
>   static int vfio_migration_set_state(VFIODevice *vbasedev,
>                                       enum vfio_device_mig_state new_state,
>                                       enum vfio_device_mig_state recover_state)
> @@ -125,12 +178,12 @@ static int vfio_migration_set_state(VFIODevice *vbasedev,
>               goto reset_device;
>           }
>   
> -        migration->device_state = recover_state;
> +        vfio_migration_set_device_state(vbasedev, recover_state);
>   
>           return ret;
>       }
>   
> -    migration->device_state = new_state;
> +    vfio_migration_set_device_state(vbasedev, new_state);
>       if (mig_state->data_fd != -1) {
>           if (migration->data_fd != -1) {
>               /*
> @@ -156,7 +209,7 @@ reset_device:
>                    strerror(errno));
>       }
>   
> -    migration->device_state = VFIO_DEVICE_STATE_RUNNING;
> +    vfio_migration_set_device_state(vbasedev, VFIO_DEVICE_STATE_RUNNING);
>   
>       return ret;
>   }
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 64780d1b79..8840602c50 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -3362,6 +3362,8 @@ static 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_BOOL("migration-events", VFIOPCIDevice,
> +                     vbasedev.migration_events, false),
>       DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false),
>       DEFINE_PROP_BOOL("x-balloon-allowed", VFIOPCIDevice,
>                        vbasedev.ram_block_discard_allowed, false),