Date:   Sun, 28 Nov 2021 02:45:26 -0500
From:   "Michael S. Tsirkin" <mst@redhat.com>
To:     Eli Cohen <elic@nvidia.com>
Cc:     Jason Wang <jasowang@redhat.com>, Parav Pandit <parav@nvidia.com>,
        virtualization <virtualization@lists.linux-foundation.org>,
        Eric Dumazet <edumazet@google.com>, kbuild-all@lists.01.org,
        kernel test robot <lkp@intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>, kbuild@lists.01.org,
        Dan Carpenter <dan.carpenter@oracle.com>
Subject: Re: [PATCH] vdpa: Consider device id larger than 31
Message-ID: <20211128024206-mutt-send-email-mst@kernel.org>
References: <20211125180915.649652-1-parav@nvidia.com>
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 <20211128071435.GB99190@mtl-vdi-166.wap.labs.mlnx>
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On Sun, Nov 28, 2021 at 09:14:35AM +0200, Eli Cohen wrote:
> On Fri, Nov 26, 2021 at 10:48:12AM +0800, Jason Wang wrote:
> > On Fri, Nov 26, 2021 at 2:09 AM Parav Pandit <parav@nvidia.com> wrote:
> > >
> > > virtio device id value can be more than 31. Hence, use BIT_ULL in
> > > assignment.
> > >
> > > Fixes: 33b347503f01 ("vdpa: Define vdpa mgmt device, ops and a netlink interface")
> > > Reported-by: kernel test robot <lkp@intel.com>
> > > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > > Signed-off-by: Parav Pandit <parav@nvidia.com>
> > 
> > Acked-by: Jason Wang <jasowang@redhat.com>
> > 
> > > ---
> > >  drivers/vdpa/vdpa.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> > > index 7332a74a4b00..e91c71aeeddf 100644
> > > --- a/drivers/vdpa/vdpa.c
> > > +++ b/drivers/vdpa/vdpa.c
> > > @@ -404,7 +404,7 @@ static int vdpa_mgmtdev_fill(const struct vdpa_mgmt_dev *mdev, struct sk_buff *m
> > >                 goto msg_err;
> > >
> > >         while (mdev->id_table[i].device) {
> > > -               supported_classes |= BIT(mdev->id_table[i].device);
> > > +               supported_classes |= BIT_ULL(mdev->id_table[i].device);
> > >                 i++;
> > >         }
> > >
> 
> type of mdev->id_table[i].device is __u32 so in theory you're limited
> to device ID's up to 63.
> Maybe add assert here?

I think 1 << 63 is illegal though.

> > > --
> > > 2.26.2
> > >
> >