Re: [Qemu-devel] [PATCH v2] virtio-rng: Add human-readable error message for negative max-bytes parameter

[Amit Shah <amit.shah@redhat.com>]

On (Fri) 18 Jul 2014 [08:27:59], Markus Armbruster wrote:
> John Snow <jsnow@redhat.com> writes:
> 
> > If a negative integer is used for the max_bytes parameter, QEMU currently
> > calls abort() and leaves behind a core dump. This patch adds a simple
> > error message to make the reason for the termination clearer.
> >
> > Signed-off-by: John Snow <jsnow@redhat.com>
> > ---
> > v2: Changed 0L constant to (uint64_t)0 constant to match PRId64 format code
> >     on both 32bit and 64bit systems. Tested via -m32 flag.
> >
> >  hw/virtio/virtio-rng.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/virtio/virtio-rng.c b/hw/virtio/virtio-rng.c
> > index 1356aca..64c7d23 100644
> > --- a/hw/virtio/virtio-rng.c
> > +++ b/hw/virtio/virtio-rng.c
> > @@ -181,7 +181,11 @@ static void virtio_rng_device_realize(DeviceState *dev, Error **errp)
> >  
> >      vrng->vq = virtio_add_queue(vdev, 8, handle_input);
> >  
> > -    assert(vrng->conf.max_bytes <= INT64_MAX);
> > +    if (vrng->conf.max_bytes > INT64_MAX) {
> > +        error_set(errp, QERR_PROPERTY_VALUE_OUT_OF_RANGE, "virtio-rng",
> > +                  "max_bytes", vrng->conf.max_bytes, (uint64_t)0, INT64_MAX);
> > +        return;
> > +    }
> >      vrng->quota_remaining = vrng->conf.max_bytes;
> >  
> >      vrng->rate_limit_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
> 
> Elsewhere in this function, we use
> 
>         error_set(errp, QERR_INVALID_PARAMETER_VALUE, "period",
>                   "a positive number");
> 
> Existing uses of QERR_PROPERTY_VALUE_OUT_OF_RANGE are all for intervals
> with small bounds.

That's suggestion for a 2.2 patch, right?

Do you think the usage as in this patch is fine?

Thanks,

		Amit