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From:   Jason Wang <jasowang@redhat.com>
Date:   Tue, 3 Jan 2023 16:15:27 +0800
Message-ID: <CACGkMEuP9DaWq7kiFrkYqt2CxwuTqc4iMpypUOLLLzBzn1rm2Q@mail.gmail.com>
Subject: Re: [PATCH v5 4/4] vdpa_sim: Implement resume vdpa op
To:     "Boeuf, Sebastien" <sebastien.boeuf@intel.com>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "virtualization@lists.linux-foundation.org" 
        <virtualization@lists.linux-foundation.org>,
        "mst@redhat.com" <mst@redhat.com>,
        "eperezma@redhat.com" <eperezma@redhat.com>
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On Tue, Jan 3, 2023 at 12:52 AM Boeuf, Sebastien
<sebastien.boeuf@intel.com> wrote:
>
> Hi Jason,
>
> Are you suggesting we do something like the following:
>
> if ((!vdpasim->running) && (vdpasim->status =3D=3D DRIVER_OK)) {
> =E2=80=82=E2=80=82=E2=80=82=E2=80=82=E2=80=82=E2=80=82vdpasim->pending_ki=
ck =3D true;
> =E2=80=82=E2=80=82=E2=80=82=E2=80=82=E2=80=82=E2=80=82return;
> }
>
> ?

Yes.

Thanks

>
> Thanks,
> Sebastien
> ________________________________
> From: Jason Wang <jasowang@redhat.com>
> Sent: Monday, November 7, 2022 8:43 AM
> To: Boeuf, Sebastien <sebastien.boeuf@intel.com>
> Cc: linux-kernel@vger.kernel.org <linux-kernel@vger.kernel.org>; virtuali=
zation@lists.linux-foundation.org <virtualization@lists.linux-foundation.or=
g>; mst@redhat.com <mst@redhat.com>; eperezma@redhat.com <eperezma@redhat.c=
om>
> Subject: Re: [PATCH v5 4/4] vdpa_sim: Implement resume vdpa op
>
> On Wed, Oct 26, 2022 at 11:09 PM <sebastien.boeuf@intel.com> wrote:
> >
> > From: Sebastien Boeuf <sebastien.boeuf@intel.com>
> >
> > Implement resume operation for vdpa_sim devices, so vhost-vdpa will
> > offer that backend feature and userspace can effectively resume the
> > device.
> >
> > Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
> > ---
> >  drivers/vdpa/vdpa_sim/vdpa_sim.c | 28 ++++++++++++++++++++++++++++
> >  drivers/vdpa/vdpa_sim/vdpa_sim.h |  1 +
> >  2 files changed, 29 insertions(+)
> >
> > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/v=
dpa_sim.c
> > index b071f0d842fb..84fee8bb2929 100644
> > --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> > @@ -357,6 +357,11 @@ static void vdpasim_kick_vq(struct vdpa_device *vd=
pa, u16 idx)
> >         struct vdpasim *vdpasim =3D vdpa_to_sim(vdpa);
> >         struct vdpasim_virtqueue *vq =3D &vdpasim->vqs[idx];
> >
> > +       if (!vdpasim->running) {
> > +               vdpasim->pending_kick =3D true;
> > +               return;
>
> I think we may hit here when the driver kicks vq before DRIVER_OK. Do
> we need to check device status in this case and resume?
>
> Thanks
>
> > +       }
> > +
> >         if (vq->ready)
> >                 schedule_work(&vdpasim->work);
> >  }
> > @@ -527,6 +532,27 @@ static int vdpasim_suspend(struct vdpa_device *vdp=
a)
> >         return 0;
> >  }
> >
> > +static int vdpasim_resume(struct vdpa_device *vdpa)
> > +{
> > +       struct vdpasim *vdpasim =3D vdpa_to_sim(vdpa);
> > +       int i;
> > +
> > +       spin_lock(&vdpasim->lock);
> > +       vdpasim->running =3D true;
> > +
> > +       if (vdpasim->pending_kick) {
> > +               /* Process pending descriptors */
> > +               for (i =3D 0; i < vdpasim->dev_attr.nvqs; ++i)
> > +                       vdpasim_kick_vq(vdpa, i);
> > +
> > +               vdpasim->pending_kick =3D false;
> > +       }
> > +
> > +       spin_unlock(&vdpasim->lock);
> > +
> > +       return 0;
> > +}
> > +
> >  static size_t vdpasim_get_config_size(struct vdpa_device *vdpa)
> >  {
> >         struct vdpasim *vdpasim =3D vdpa_to_sim(vdpa);
> > @@ -717,6 +743,7 @@ static const struct vdpa_config_ops vdpasim_config_=
ops =3D {
> >         .set_status             =3D vdpasim_set_status,
> >         .reset                  =3D vdpasim_reset,
> >         .suspend                =3D vdpasim_suspend,
> > +       .resume                 =3D vdpasim_resume,
> >         .get_config_size        =3D vdpasim_get_config_size,
> >         .get_config             =3D vdpasim_get_config,
> >         .set_config             =3D vdpasim_set_config,
> > @@ -750,6 +777,7 @@ static const struct vdpa_config_ops vdpasim_batch_c=
onfig_ops =3D {
> >         .set_status             =3D vdpasim_set_status,
> >         .reset                  =3D vdpasim_reset,
> >         .suspend                =3D vdpasim_suspend,
> > +       .resume                 =3D vdpasim_resume,
> >         .get_config_size        =3D vdpasim_get_config_size,
> >         .get_config             =3D vdpasim_get_config,
> >         .set_config             =3D vdpasim_set_config,
> > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/v=
dpa_sim.h
> > index 0e78737dcc16..a745605589e2 100644
> > --- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
> > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> > @@ -67,6 +67,7 @@ struct vdpasim {
> >         u64 features;
> >         u32 groups;
> >         bool running;
> > +       bool pending_kick;
> >         /* spinlock to synchronize iommu table */
> >         spinlock_t iommu_lock;
> >  };
> > --
> > 2.34.1
> >
> > ---------------------------------------------------------------------
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> ---------------------------------------------------------------------
> Intel Corporation SAS (French simplified joint stock company)
> Registered headquarters: "Les Montalets"- 2, rue de Paris,
> 92196 Meudon Cedex, France
> Registration Number:  302 456 199 R.C.S. NANTERRE
> Capital: 5 208 026.16 Euros
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