Re: [PATCH] hw/usb/hcd-dwc2: fix divide-by-zero in dwc2_handle_packet()

[Mauro Matteo Cascella]

On Tue, Oct 13, 2020 at 10:41 AM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> On Tue, Oct 13, 2020 at 12:19:40AM -0700, Paul Zimmerman wrote:
> > I sent you a patch to fix up several assert()s, including that one, about a
> > month ago. Did you miss it?
> > https://lore.kernel.org/qemu-devel/20200920021449.830-1-pauldzim@gmail.com
>
> I'll check.  There is a bunch of pending stuff in my qemu-patches
> mailbox I'll try to process this week ...
>
> > > Also: What would be the effect of simply returning here? Would dwc2
> > > emulation simply stop processing queues? Should we maybe raise an
> > > error IRQ?
> >
> > Not entirely sure, I imagine the emulation will just stop working. I can
> > test it tomorrow. Also, can you give me a hint what an error IRQ is?
> > Is that a Qemu thing, or do you mean we should emulate what the
> > real core does in this case?
>
> Same real hardware does.  ehci for example has the USBSTS_ERRINT bit in
> the IRQ status register to signal errors.
>
> take care,
>   Gerd
>

I'll send a new version of the patch with the check moved earlier in
the function, as suggested by Paul. If raising an error turns out to
be the right thing to do, I think other checks may need to be updated
in addition to this one. Hence we can possibly address that in a later
patch. Thanks a lot for your comments.

-- 
Mauro Matteo Cascella, Red Hat Product Security
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