Re: [PULL 03/20] nubus-device: expose separate super slot memory region

[Laurent Vivier]

Le 02/10/2021 à 12:33, Peter Maydell a écrit :
> On Wed, 29 Sept 2021 at 10:49, Laurent Vivier <laurent@vivier.eu> wrote:
>>
>> From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
>>
>> According to "Designing Cards and Drivers for the Macintosh Family" each 
>> physical
>> nubus slot can access 2 separate address ranges: a super slot memory region 
>> which
>> is 256MB and a standard slot memory region which is 16MB.
>>
>> Currently a Nubus device uses the physical slot number to determine whether 
>> it is
>> using a standard slot memory region or a super slot memory region rather than
>> exposing both memory regions for use as required.
> 
> 
>> +    /* Super */
>> +    slot_offset = nd->slot * NUBUS_SUPER_SLOT_SIZE;
> 
> Hi; Coverity thinks this multiply might overflow, because
> we're calculating a hw_addr (64-bits) but the multiply is only
> done at 32-bits. Adding an explicit cast or using 'ULL' in the
> constant #define rather than just 'U' would fix this.
> This is CID 1464070.
> 

I'm wondering if adding "assert(nd->slot < NUBUS_SUPER_SLOT_NB)" would help 
coverity to avoid the
error without using 64bit arithmetic?


>> +
>> +    name = g_strdup_printf("nubus-super-slot-%x", nd->slot);
>> +    memory_region_init(&nd->super_slot_mem, OBJECT(dev), name,
>> +                       NUBUS_SUPER_SLOT_SIZE);
>> +    memory_region_add_subregion(&nubus->super_slot_io, slot_offset,
>> +                                &nd->super_slot_mem);
>> +    g_free(name);
>> +
>> +    /* Normal */
>> +    slot_offset = nd->slot * NUBUS_SLOT_SIZE;
> 
> Same with this one.

assert(nb->slot < NUBUS_SLOT_NB)

> thanks
> -- PMM
> 

Laurent