Re: [PATCH 1/2] vdpa/mlx5: Support creating resources with uid == 0

[Jason Wang]

在 2021/5/31 下午12:59, Eli Cohen 写道:
> On Mon, May 31, 2021 at 11:06:59AM +0800, Jason Wang wrote:
> > 在 2021/5/31 上午11:02, Jason Wang 写道:
> > > 在 2021/5/30 下午3:54, Eli Cohen 写道:
> > > > Currently all resources must be created with uid != 0 which is essential
> > > > userspace processes allocating virtquueue resources. Since this is a
> > > > kernel implementation, it is perfectly legal to open resources with
> > > > uid == 0.
> > > >
> > > > In case frimware supports, avoid allocating user context.
> > >
> > > Typo "frimware".
> > >
> > > Otherwise.
> > >
> > > Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
> > >
> > > (I don't see any code to check the firmware capability, is this
> > > intended?)
> >
> > Speak too fast. I see the MLX5_CAP_GEN(), so it's fine.
> And I responded too fast :-)


Right and thanks for the quick response :)


> > Thanks
> >
> >
> > > Thanks
> > >
> > >
> > > > Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
> > > > ---
> > > >    drivers/vdpa/mlx5/core/resources.c | 6 ++++++
> > > >    include/linux/mlx5/mlx5_ifc.h      | 4 +++-
> > > >    2 files changed, 9 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/vdpa/mlx5/core/resources.c
> > > > b/drivers/vdpa/mlx5/core/resources.c
> > > > index 6521cbd0f5c2..836ab9ef0fa6 100644
> > > > --- a/drivers/vdpa/mlx5/core/resources.c
> > > > +++ b/drivers/vdpa/mlx5/core/resources.c
> > > > @@ -54,6 +54,9 @@ static int create_uctx(struct mlx5_vdpa_dev
> > > > *mvdev, u16 *uid)
> > > >        void *in;
> > > >        int err;
> > > >    +    if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0))
> > > > +        return 0;
> > > > +
> > > >        /* 0 means not supported */
> > > >        if (!MLX5_CAP_GEN(mvdev->mdev, log_max_uctx))
> > > >            return -EOPNOTSUPP;
> > > > @@ -79,6 +82,9 @@ static void destroy_uctx(struct mlx5_vdpa_dev
> > > > *mvdev, u32 uid)
> > > >        u32 out[MLX5_ST_SZ_DW(destroy_uctx_out)] = {};
> > > >        u32 in[MLX5_ST_SZ_DW(destroy_uctx_in)] = {};
> > > >    +    if (!uid)
> > > > +        return;
> > > > +
> > > >        MLX5_SET(destroy_uctx_in, in, opcode, MLX5_CMD_OP_DESTROY_UCTX);
> > > >        MLX5_SET(destroy_uctx_in, in, uid, uid);
> > > >    diff --git a/include/linux/mlx5/mlx5_ifc.h
> > > > b/include/linux/mlx5/mlx5_ifc.h
> > > > index 9c68b2da14c6..606d2aeacad4 100644
> > > > --- a/include/linux/mlx5/mlx5_ifc.h
> > > > +++ b/include/linux/mlx5/mlx5_ifc.h
> > > > @@ -1487,7 +1487,9 @@ struct mlx5_ifc_cmd_hca_cap_bits {
> > > >        u8         uar_4k[0x1];
> > > >        u8         reserved_at_241[0x9];
> > > >        u8         uar_sz[0x6];
> > > > -    u8         reserved_at_250[0x8];
> > > > +    u8         reserved_at_248[0x2];
> > > > +    u8         umem_uid_0[0x1];
> > > > +    u8         reserved_at_250[0x5];
> > > >        u8         log_pg_sz[0x8];
> > > >          u8         bf[0x1];