Re: [Xen-devel] hvmemul_virtual_to_linear() doesn't care about direction-flag?

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

This affects hvmemul_linear_to_phys() too, and would for example mean that a
backwards I/O string instruction in userspace that crosses a page boundary
would very likely cause I/O to/from the wrong physical pages. I've confirmed
this with a small testing patch to hvmloader. I think we need to work out
how to maintain a test suite of this kind of thing to check for regressions
in these kinds of rarer corner cases.

Obviously I'll fix this for 3.3.0 and probably roll out another release
candidate.

 -- Keir

On 19/8/08 09:20, "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx> wrote:

> Quite a nasty omission though, and quite easily fixed. Thanks for pointing
> it out.
> 
>  -- Keir
> 
> On 18/8/08 19:41, "Byrne, John (HP Labs)" <john.l.byrne@xxxxxx> wrote:
> 
>> I was following the emulation code around in xen-unstable cs 18335 and I
>> noticed that the direction flag doesn't get taken into account for the
>> segment
>> bounds checking in the 32-bit case anywhere I could see. Does anyone know
>> better?
>> 
>> Maybe no one will care, but I thought I'd mention it.
>> 
>> John Byrne
>> 
>> 
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/xen-devel
> 



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