Re: [Qemu-devel] [PATCH] [m25p80] Abort in case we overrun the internal data buffer

[Peter Maydell]

On 5 January 2017 at 20:18, Jean-Christophe DUBOIS <address@hidden> wrote:
> Le 05/01/2017 à 21:04, mar.krzeminski a écrit :
>> Peter Maydell wrote:
>>> If these are "can't happen unless some other part of QEMU
>>> is buggy" cases, then we can just assert():

>>> (If they're "could happen if the guest does something wrong"
>>> cases, we shouldn't just abort(), but if I'm reading the previous
>>> mail thread correctly, that's not the situation here.)
>
>> Indeed this case is about error in Qemu itself, but the same situation could
>> be generated from the guest (guest deasert CS only once).
>> IMHO we should reset m26p80 state in such case:
>> s->len = 0;
>> s->pos = 0;
>> s->state = STATE_IDLE;
>> This will be a bit closer to real HW behaviour too.

> So what would be the preferred behavior?
>
> Asserting (and ending Qemu)
> Resetting (and hiding the misbehavior).

If the guest can trigger this behaviour, then we should
not assert or abort or otherwise cause QEMU to exit.
The preferred behaviour is:
 * act like the real hardware does in this situation
   (whatever that is)
 * if this is something that only broken guest code would
   do, log it with qemu_log_mask(LOG_GUEST_ERROR, ...)

thanks
-- PMM