Re: [PATCH] virtio_bt: Fix alignment in configuration struct

Michael S. Tsirkin
2022-08-30T13:48:05Z

On Thu, Aug 11, 2022 at 10:02:31AM -0700, Luiz Augusto von Dentz wrote:
> Hi Michael,
>
> On Thu, Aug 11, 2022 at 1:00 AM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Mon, Aug 08, 2022 at 08:16:11AM -0400, Michael S. Tsirkin wrote:
> > > On Mon, Aug 08, 2022 at 02:04:43PM +0200, Igor Skalkin wrote:
> > > > On 8/8/22 01:00, Michael S. Tsirkin wrote:
> > > >
> > > > On Mon, Aug 08, 2022 at 12:11:52AM +0200, Igor Skalkin wrote:
> > > >
> > > > According to specification [1], "For the device-specific configuration
> > > > space, the driver MUST use 8 bit wide accesses for 8 bit wide fields,
> > > > 16 bit wide and aligned accesses for 16 bit wide fields and 32 bit wide
> > > > and aligned accesses for 32 and 64 bit wide fields.".
> > > >
> > > > Current version of the configuration structure:
> > > >
> > > > struct virtio_bt_config {
> > > > __u8 type;
> > > > __u16 vendor;
> > > > __u16 msft_opcode;
> > > > } __attribute__((packed));
> > > >
> > > > has both 16bit fields non-aligned.
> > > >
> > > > This commit fixes it.
> > > >
> > > > [1] https://ddec1-0-en-ctp.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2fdocs.oasis%2dopen.org%2fvirtio%2fvirtio%2fv1.1%2fvirtio%2dv1.1.pdf&umid=d1786ace-e8ea-40e8-9665-96c0949174e5&auth=53c7c7de28b92dfd96e93d9dd61a23e634d2fbec-39b15885ceebe9fda9357320aec1ccbac416a470
> > > >
> > > > Signed-off-by: Igor Skalkin <Igor.Skalkin@opensynergy.com>
> > > >
> > > > This is all true enough, but the problem is
> > > > 1. changing uapi like this can't be done, will break userspace
> > > > 2. the driver has more issues and no one seems to want to
> > > > maintain it.
> > > > I posted a patch "Bluetooth: virtio_bt: mark broken" and intend
> > > > to merge it for this release.
> > > >
> > > > This is very sad. We already use this driver in our projects.
> > >
> > > Really? Can you step up to maintain it? Then we can fix the issues
> > > and it won't be broken.
> >
> > Just a reminder that I'm waiting for a response on that.
> > I just don't know enough about bluetooth.
>
> Just a heads up that Marcel is on vacation, he did mention that he had
> done some work to update virtio_bt thus why I didn't apply any of the
> changes yet.

Any update? when does Marcel return?

> > --
> > MST
> >
>
>
> --
> Luiz Augusto von Dentz