On Wed, Jun 13, 2018 at 04:13:57PM +0200, BALATON Zoltan wrote:
I don't see the problem. The addr register selects the register to read or
write. It is set by the first write when the device is accessed the first
time (this is denoted by addr == -1 (or really any negative value). The
device has 20 registers and trying to read any register outside addr between
0-19 will result in returning 0 and logging a warning about invalid register
in m41t80_recv. What could fail here when guest sends garbage? It will set
addr to invalid value and try to read non-exitent register and get an error
just like for any other nonexistent value of addr (or start to read from
register 0 if it manages to set a negative value). All writes of registers
are ignored currently (except setting addr by the first write). What should
be enforced here?
Ah, I see your point. I mean strictly we should match the hardware
behaviour if you write garbage addresses here, but really I don't
think it matters much.