OPCODE Emulation

OPCODE Emulation

[Matteo Signorini]

Dear Yaniv, Dear Avi,

I would like to add the "sidt emulation" feature in kvm, but in order to
implement it I need to know the details on how the OPCODE works and how 
exactly opcodes are emulated within kvm.
For example let's take the SIDT instruction.
I know the LIDT opcode is "0F 01 /1" but what does 0F, 01 and /1 mean?
I also know that this instruction has only the operand "ModRM:r/m (w)"
but where is this operand stored and how can I access it in emulation?
  Could you please suggest to me where can I found some detailed docs on 
the subject?
(I have already read the Intel Volume 2B Instruction Set Reference N-Z 
pag. 4-440 but I have not found enough detailed information)

Thank you

Matteo Signorini

Re: OPCODE Emulation

[Mohammed Gamal]

On Thu, May 6, 2010 at 11:37 PM, Matteo Signorini
<signorinimatteo@gmail.com> wrote:
>
> Dear Yaniv, Dear Avi,
>
> I would like to add the "sidt emulation" feature in kvm, but in order to
> implement it I need to know the details on how the OPCODE works and how exactly opcodes are emulated within kvm.
> For example let's take the SIDT instruction.
> I know the LIDT opcode is "0F 01 /1" but what does 0F, 01 and /1 mean?
> I also know that this instruction has only the operand "ModRM:r/m (w)"
> but where is this operand stored and how can I access it in emulation?
>  Could you please suggest to me where can I found some detailed docs on the subject?
> (I have already read the Intel Volume 2B Instruction Set Reference N-Z pag. 4-440 but I have not found enough detailed information)
>
> Thank you
>
> Matteo Signorini

Hi Matteo,
arch/x86/kvm/emulate.c is the best place to start. All you need to
look at is there.

Regards,
Mohammed
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