Re: [PATCH v2 16/16] vfio/migration: Add tracepoints for precopy/stopcopy query ioctls

["Cédric Le Goater" <clg@redhat.com>]

On 4/21/26 22:21, Peter Xu wrote:
> Add two tracepoints for both precopy and stopcopy query ioctls.  When at
> it, add one warn_report_once() for each of them when it fails.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>



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

Thanks,

C.


> ---
>   hw/vfio/migration.c  | 33 +++++++++++++++++++++++----------
>   hw/vfio/trace-events |  2 ++
>   2 files changed, 25 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index e6e6a0d53d..04d9f94edb 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -329,6 +329,7 @@ static int vfio_query_stop_copy_size(VFIODevice *vbasedev)
>       struct vfio_device_feature_mig_data_size *mig_data_size =
>           (struct vfio_device_feature_mig_data_size *)feature->data;
>       VFIOMigration *migration = vbasedev->migration;
> +    int ret;
>   
>       feature->argsz = sizeof(buf);
>       feature->flags =
> @@ -340,12 +341,18 @@ static int vfio_query_stop_copy_size(VFIODevice *vbasedev)
>            * is reported so downtime limit won't be violated.
>            */
>           migration->stopcopy_size = VFIO_MIG_STOP_COPY_SIZE;
> -        return -errno;
> +        ret = -errno;
> +        warn_report_once("VFIO device %s ioctl(VFIO_DEVICE_FEATURE) on "
> +                         "VFIO_DEVICE_FEATURE_MIG_DATA_SIZE failed (%d)",
> +                         vbasedev->name, ret);
> +    } else {
> +        migration->stopcopy_size = mig_data_size->stop_copy_length;
> +        ret = 0;
>       }
>   
> -    migration->stopcopy_size = mig_data_size->stop_copy_length;
> +    trace_vfio_query_stop_copy_size(migration->stopcopy_size, ret);
>   
> -    return 0;
> +    return ret;
>   }
>   
>   static int vfio_query_precopy_size(VFIOMigration *migration)
> @@ -353,18 +360,24 @@ static int vfio_query_precopy_size(VFIOMigration *migration)
>       struct vfio_precopy_info precopy = {
>           .argsz = sizeof(precopy),
>       };
> -
> -    migration->precopy_init_size = 0;
> -    migration->precopy_dirty_size = 0;
> +    int ret;
>   
>       if (ioctl(migration->data_fd, VFIO_MIG_GET_PRECOPY_INFO, &precopy)) {
> -        return -errno;
> +        migration->precopy_init_size = 0;
> +        migration->precopy_dirty_size = 0;
> +        ret = -errno;
> +        warn_report_once("VFIO device %s ioctl(VFIO_MIG_GET_PRECOPY_INFO) "
> +                         "failed (%d)", migration->vbasedev->name, ret);
> +    } else {
> +        migration->precopy_init_size = precopy.initial_bytes;
> +        migration->precopy_dirty_size = precopy.dirty_bytes;
> +        ret = 0;
>       }
>   
> -    migration->precopy_init_size = precopy.initial_bytes;
> -    migration->precopy_dirty_size = precopy.dirty_bytes;
> +    trace_vfio_query_precopy_size(migration->precopy_init_size,
> +                                  migration->precopy_dirty_size, ret);
>   
> -    return 0;
> +    return ret;
>   }
>   
>   /* Returns the size of saved data on success and -errno on error */
> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
> index 287df0b8cb..854a7e4b19 100644
> --- a/hw/vfio/trace-events
> +++ b/hw/vfio/trace-events
> @@ -176,6 +176,8 @@ vfio_save_setup(const char *name, uint64_t data_buffer_size) " (%s) data buffer
>   vfio_state_pending(const char *name, uint64_t stopcopy_size, uint64_t precopy_init_size, uint64_t precopy_dirty_size, bool exact) " (%s) stopcopy size %"PRIu64" precopy initial size %"PRIu64" precopy dirty size %"PRIu64 " exact %d"
>   vfio_vmstate_change(const char *name, int running, const char *reason, const char *dev_state) " (%s) running %d reason %s device state %s"
>   vfio_vmstate_change_prepare(const char *name, int running, const char *reason, const char *dev_state) " (%s) running %d reason %s device state %s"
> +vfio_query_stop_copy_size(uint64_t size, int ret) "stopcopy size %"PRIu64" ret %d"
> +vfio_query_precopy_size(uint64_t init_size, uint64_t dirty_size, int ret) "init %"PRIu64" dirty %"PRIu64" ret %d"
>   
>   #iommufd.c
>