Re: [Qemu-devel] [PATCH for-4.1? 1/2] stellaris_input: Fix vmstate description of buttons field

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Peter Maydell (peter.maydell@linaro.org) wrote:
> On Thu, 25 Jul 2019 at 18:02, Dr. David Alan Gilbert
> <dgilbert@redhat.com> wrote:
> >
> > * Peter Maydell (peter.maydell@linaro.org) wrote:
> > > gamepad_state::buttons is a pointer to an array of structs,
> > > not an array of structs, so should be declared in the vmstate
> > > with VMSTATE_STRUCT_VARRAY_POINTER_INT32; otherwise we
> > > corrupt memory on incoming migration.
> > >
> > > We bump the vmstate version field as the easiest way to
> > > deal with the migration break, since migration wouldn't have
> > > worked reliably before anyway.
> > >
> > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> >
> > OK, it would be great to change num_buttons to uint32_t and make that a
> > UINT32 at some point;  it's hard to press negative buttons.
> 
> Is there much benefit though?

Not much and it's not urgent

> As an aside, I'm surprised also the macro doesn't complain
> that we said the num_buttons field is int32 but it's really "int"...
> arguably a different kind of missing type check.

I was just concerned what would happen if your migration stream
had a negative value in.

Dave

> thanks
> -- PMM
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK