Hi Marcel,
On Tue, Oct 12, 2021 at 8:50 AM Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote:
>
> Hi Luiz,
>
> > This adds a debugfs entry to set msft_opcode enabling vhci to emulate
> > controllers with MSFT extention support.
> >
> > Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
> > ---
> > drivers/bluetooth/hci_vhci.c | 32 ++++++++++++++++++++++++++++++++
> > 1 file changed, 32 insertions(+)
> >
> > diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c
> > index 56c6b22be10b..ac122299bacc 100644
> > --- a/drivers/bluetooth/hci_vhci.c
> > +++ b/drivers/bluetooth/hci_vhci.c
> > @@ -194,6 +194,34 @@ static const struct file_operations force_wakeup_fops = {
> > .llseek = default_llseek,
> > };
> >
> > +
> > +static int msft_opcode_set(void *data, u64 val)
> > +{
> > + struct vhci_data *vhci = data;
> > + uint16_t ogf = (val & 0xffff >> 10);
> > +
> > + if (val > 0xffff || ogf != 0x3f)
>
> I would actually just include it here to avoid any 16-bit overflow.
>
> if (val > 0xffff || (val & 0xffff >> 10) != 0x3f)
Ack.
> > + return -EINVAL;
> > +
> > + hci_set_msft_opcode(vhci->hdev, val);
> > +
> > + return 0;
> > +}
> > +
> > +static int msft_opcode_get(void *data, u64 *val)
> > +{
> > + struct vhci_data *vhci = data;
> > +
> > + hci_dev_lock(vhci->hdev);
> > + *val = vhci->hdev->msft_opcode;
> > + hci_dev_unlock(vhci->hdev);
> > +
> > + return 0;
> > +}
> > +
> > +DEFINE_DEBUGFS_ATTRIBUTE(msft_opcode_fops, msft_opcode_get, msft_opcode_set,
> > + "%llu\n");
> > +
> > static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
> > {
> > struct hci_dev *hdev;
> > @@ -259,6 +287,10 @@ static int __vhci_create_device(struct vhci_data *data, __u8 opcode)
> > debugfs_create_file("force_wakeup", 0644, hdev->debugfs, data,
> > &force_wakeup_fops);
> >
> > + if (IS_ENABLED(CONFIG_BT_MSFTEXT))
> > + debugfs_create_file("msft_opcode", 0644, hdev->debugfs, data,
> > + &msft_opcode_fops);
> > +
>
> So my concern is that you can modify this value when the device is up and running. That will cause havoc.
>
> Just checking HCI_UP is kinda bad since we just removed that access from the drivers.
Right but we could add a check to HCI_UP inside hci_set_msft_opcode
and make it return an error, actually this might be a good idea anyway
even with existing so we prevent bad usage of hci_set_msft_opcode when
already up.
> Regards
>
> Marcel
>
--
Luiz Augusto von Dentz
