Re: [RFC 1/2] vduse: validate block features only with block devices

[Maxime Coquelin]

On 4/20/23 06:06, Jason Wang wrote:
> On Wed, Apr 19, 2023 at 9:43 PM Maxime Coquelin
> <maxime.coquelin@xxxxxxxxxx> wrote:
> > This patch is preliminary work to enable network device
> > type support to VDUSE.
> >
> > As VIRTIO_BLK_F_CONFIG_WCE shares the same value as
> > VIRTIO_NET_F_HOST_TSO4, we need to restrict its check
> > to Virtio-blk device type.
> >
> > Signed-off-by: Maxime Coquelin <maxime.coquelin@xxxxxxxxxx>
> > ---
> >   drivers/vdpa/vdpa_user/vduse_dev.c | 9 +++++----
> >   1 file changed, 5 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> > index 0c3b48616a9f..6fa598a03d8e 100644
> > --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> > @@ -1416,13 +1416,14 @@ static bool device_is_allowed(u32 device_id)
> >          return false;
> >   }
> >
> > -static bool features_is_valid(u64 features)
> > +static bool features_is_valid(struct vduse_dev_config *config)
> >   {
> > -       if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
> > +       if (!(config->features & (1ULL << VIRTIO_F_ACCESS_PLATFORM)))
> >                  return false;
> >
> >          /* Now we only support read-only configuration space */
> > -       if (features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE))
> > +       if ((config->device_id == VIRTIO_ID_BLOCK) &&
> > +                       (config->features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE)))
>
> The reason we filter WCE out is to avoid writable config space which
> might block the driver with a buggy userspace.
>
> For networking, I guess we should fail if VERSION_1 is not negotiated,
> then we can avoid setting mac addresses via the config space.

 Ok, I will add it to patch 2 in V1.

Thanks,
Maxime

> Thanks
>
> >                  return false;
> >
> >          return true;
> > @@ -1446,7 +1447,7 @@ static bool vduse_validate_config(struct vduse_dev_config *config)
> >          if (!device_is_allowed(config->device_id))
> >                  return false;
> >
> > -       if (!features_is_valid(config->features))
> > +       if (!features_is_valid(config))
> >                  return false;
> >
> >          return true;
> > --
> > 2.39.2