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Date: Sat, 28 Mar 2015 20:25:58 +0000
From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
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Subject: Re: [Qemu-devel] [Qemu-discuss] error - Guest has not initialized
 the display yet.
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To: Paolo Bonzini <pbonzini@redhat.com>, Peter Maydell <peter.maydell@linaro.org>
Cc: Programmingkid <programmingkidx@gmail.com>, Peter Crosthwaite <peter.crosthwaite@xilinx.com>, anandk1386@gmail.com, qemu-devel qemu-devel <qemu-devel@nongnu.org>

On 26/03/15 21:00, Paolo Bonzini wrote:

> On 26/03/2015 21:55, Peter Maydell wrote:
>> I feel like we're recapitulating history here -- is
>> c3c1bb99d undoing the fix that a87f39543a made for when we
>> tried this a year ago in 360e607, or is there something
>> more subtle going on ?
> 
> It's more subtle.  The patch should only make a difference when
> address_space_translate_internal modifies *plen.
> 
> The crux of the change is the first operand of this MIN:
> 
> -        len = MIN(len, (addr | iotlb.addr_mask) - addr + 1);
> +        *plen = MIN(*plen, (addr | iotlb.addr_mask) - addr + 1);
> 
> changing from len to *plen.

Ah so it's related to the VGA VBE register accesses again? Given that
this seems to be a bit of a corner case, is there any way of writing a
regression test to catch this?


ATB,

Mark.