Re: [PATCH v6 4/4] vdpa_sim: Implement suspend vdpa op

[Jason Wang]

On Fri, Jun 24, 2022 at 12:08 AM Eugenio Pérez <eperezma@xxxxxxxxxx> wrote:
>
> Implement suspend operation for vdpa_sim devices, so vhost-vdpa will
> offer that backend feature and userspace can effectively suspend the
> device.
>
> This is a must before get virtqueue indexes (base) for live migration,
> since the device could modify them after userland gets them. There are
> individual ways to perform that action for some devices
> (VHOST_NET_SET_BACKEND, VHOST_VSOCK_SET_RUNNING, ...) but there was no
> way to perform it for any vhost device (and, in particular, vhost-vdpa).
>
> Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
> Signed-off-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
> ---
>  drivers/vdpa/vdpa_sim/vdpa_sim.c     | 21 +++++++++++++++++++++
>  drivers/vdpa/vdpa_sim/vdpa_sim.h     |  1 +
>  drivers/vdpa/vdpa_sim/vdpa_sim_blk.c |  3 +++
>  drivers/vdpa/vdpa_sim/vdpa_sim_net.c |  3 +++
>  4 files changed, 28 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index 0f2865899647..213883487f9b 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -107,6 +107,7 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim)
>         for (i = 0; i < vdpasim->dev_attr.nas; i++)
>                 vhost_iotlb_reset(&vdpasim->iommu[i]);
>
> +       vdpasim->running = true;
>         spin_unlock(&vdpasim->iommu_lock);
>
>         vdpasim->features = 0;
> @@ -505,6 +506,24 @@ static int vdpasim_reset(struct vdpa_device *vdpa)
>         return 0;
>  }
>
> +static int vdpasim_suspend(struct vdpa_device *vdpa)
> +{
> +       struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> +       int i;
> +
> +       spin_lock(&vdpasim->lock);
> +       vdpasim->running = false;
> +       if (vdpasim->running) {
> +               /* Check for missed buffers */
> +               for (i = 0; i < vdpasim->dev_attr.nvqs; ++i)
> +                       vdpasim_kick_vq(vdpa, i);

This seems only valid if we allow resuming?

Thanks

> +
> +       }
> +       spin_unlock(&vdpasim->lock);
> +
> +       return 0;
> +}
> +
>  static size_t vdpasim_get_config_size(struct vdpa_device *vdpa)
>  {
>         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> @@ -694,6 +713,7 @@ static const struct vdpa_config_ops vdpasim_config_ops = {
>         .get_status             = vdpasim_get_status,
>         .set_status             = vdpasim_set_status,
>         .reset                  = vdpasim_reset,
> +       .suspend                = vdpasim_suspend,
>         .get_config_size        = vdpasim_get_config_size,
>         .get_config             = vdpasim_get_config,
>         .set_config             = vdpasim_set_config,
> @@ -726,6 +746,7 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = {
>         .get_status             = vdpasim_get_status,
>         .set_status             = vdpasim_set_status,
>         .reset                  = vdpasim_reset,
> +       .suspend                = vdpasim_suspend,
>         .get_config_size        = vdpasim_get_config_size,
>         .get_config             = vdpasim_get_config,
>         .set_config             = vdpasim_set_config,
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> index 622782e92239..061986f30911 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> @@ -66,6 +66,7 @@ struct vdpasim {
>         u32 generation;
>         u64 features;
>         u32 groups;
> +       bool running;
>         /* spinlock to synchronize iommu table */
>         spinlock_t iommu_lock;
>  };
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
> index 42d401d43911..bcdb1982c378 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
> @@ -204,6 +204,9 @@ static void vdpasim_blk_work(struct work_struct *work)
>         if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
>                 goto out;
>
> +       if (!vdpasim->running)
> +               goto out;
> +
>         for (i = 0; i < VDPASIM_BLK_VQ_NUM; i++) {
>                 struct vdpasim_virtqueue *vq = &vdpasim->vqs[i];
>
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> index 5125976a4df8..886449e88502 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim_net.c
> @@ -154,6 +154,9 @@ static void vdpasim_net_work(struct work_struct *work)
>
>         spin_lock(&vdpasim->lock);
>
> +       if (!vdpasim->running)
> +               goto out;
> +
>         if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
>                 goto out;
>
> --
> 2.31.1
>