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Date: Thu, 08 May 2014 16:49:18 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCHv3 1/2] sun4m: Add Sun CG3 framebuffer and
 corresponding OpenBIOS FCode ROM
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To: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Cc: Peter Maydell <peter.maydell@linaro.org>, qemu-devel@nongnu.org, Blue Swirl <blauwirbel@gmail.com>, Bob Breuer <breuerr@mc.net>, Anthony Liguori <aliguori@amazon.com>, Artyom Tarasenko <atar4qemu@gmail.com>

Il 08/05/2014 16:44, Mark Cave-Ayland ha scritto:
>>>
>>>> +    case CG3_REG_FBC_CURSTART ... CG3_REG_SIZE:
>>>> +        val = s->regs[addr - 0x10];
>>>> +        break;
>>>> +    default:
>>>
>>> Something weird here, you can access regs[16] if addr == CG3_REG_SIZE.
>>>
>>> The same happens in the write path.
>>
>> Ping.  I cannot fix it without access to the datasheet, though I suspect
>> you want CG3_REG_SIZE - 1.
>
> Hi Paolo,
>
> Sorry I didn't think you could access regs[16] since the MemoryRegion
> size is set to CG3_REG_SIZE too (and so I hope should only handle
> accesses from 0 to CG3_REG_SIZE - 1).
>
> Anyway, I've quickly tried a Solaris 8 boot test replacing CG3_REG_SIZE
> with CG3_REG_SIZE - 1 for the case statements in both the read and write
> paths and everything still works, so happy for you to go ahead and fix it.

Ah okay so it's a false positive.  But yes, it's better to fix it.  I'll 
try to send a patch for qemu-trivial.

Paolo