Re: [Qemu-devel] Re: backdoor

[Anthony Liguori <aliguori@linux.vnet.ibm.com>]

On 10/25/2010 05:48 PM, Lluís wrote:
>> For instance, a CPUID leaf could be used in the 0x40001xxx range.
>>      
> Right, I commented this in a previous mail as a much nicer way to do it,
> but I was just too lazy to look up how CPUID works and instead ported
> the implementation I already had in bochs :)
>
> Although I can port it to CPUID if people find it useful to have
> upstream. I just need a way to provide an immediate and a register-based
> argument (at the same time), which does not require executing more than
> a couple of extra instructions (right now everything fits on a single
> instruction).
>
> Being able te receive back information would be a plus, which I think
> CPUID already does to return its results; although I think the ISA says
> that _all_ registers are "used" after executing it.
>    

I think just the base 6 GP registers.  I don't think any of the extended 
registers in 64-bit mode are affected but I would have to look it up.

Regards,

Anthony Liguori

> Lluis
>
>