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

[Eugenio Perez Martin <eperezma@redhat.com>]

On Wed, Jun 29, 2022 at 6:18 AM Jason Wang <jasowang@redhat.com> wrote:
>
> On Fri, Jun 24, 2022 at 12:08 AM Eugenio Pérez <eperezma@redhat.com> 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@redhat.com>
> > Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> > ---
> >  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?
>

Right, deleting for v7.

Thanks!

> 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
> >
>