Re: [PATCH 03/15] hw/alpha/dp264: Validate kernel and initrd sizes

[Yodel Eldar <yodel.eldar@yodel.dev>]

On 25/03/2026 22:07, Richard Henderson wrote:
> On 3/26/26 12:04, Yodel Eldar wrote:
>> Hi, Richard
>>
>> On 25/03/2026 19:11, Richard Henderson wrote:
>>> On 3/11/26 08:31, Yodel Eldar wrote:
>>>> @@ -192,7 +192,15 @@ static void clipper_init(MachineState *machine)
>>>>               }
>>>>               /* Put the initrd image as high in memory as 
>>>> possible.  */
>>>> -            initrd_base = (ram_size - initrd_size) & TARGET_PAGE_MASK;
>>>> +            if (usub64_overflow(ram_size, initrd_size, 
>>>> &initrd_base)) {
>>>> +                error_report("initial ram disk exceeds allotted ram 
>>>> size");
>>>> +                exit(1);
>>>> +            }
>>>> +            initrd_base &= TARGET_PAGE_MASK;
>>>> +            if (initrd_base <= kernel_high) {
>>>> +                warn_report("initial ram disk overlaps with kernel");
>>>> +            }
>>>
>>> Why is the first an error and the second a warning?
>>>
>>
>> Initially, I had both as fatal, but then I figured a (mis)adventurous
>> user may actually want to experiment with kernel/initrd overlap, whereas
>> an underflow is something we can't allow (and initrd being larger than
>> RAM is physically impossible AFAIK). I could make the overlap fatal,
>> too, if that's better?
> 
> I can't see it being useful at all.
> 

Heh, fair enough; fatal, it is, then.

Thanks,
Yodel

> 
> r~
>