Re: [PATCH 7/8] KVM: x86 emulator: simplify instruction decode flags for opcodes E0-FF

[Avi Kivity <avi@xxxxxxxxxx>]

 On 08/23/2010 04:33 PM, Gleb Natapov wrote:
> On Mon, Aug 23, 2010 at 02:06:16PM +0300, Avi Kivity wrote:
> > Use the new byte/word dual opcode decode.
> >
> > Signed-off-by: Avi Kivity<avi@xxxxxxxxxx>
> > ---
> >   arch/x86/kvm/emulate.c |    6 ++----
> >   1 files changed, 2 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> > index c61f73d..6cb5663 100644
> > --- a/arch/x86/kvm/emulate.c
> > +++ b/arch/x86/kvm/emulate.c
> > @@ -2464,13 +2464,11 @@ static struct opcode opcode_table[256] = {
> >   	N, N, N, N, N, N, N, N,
> >   	/* 0xE0 - 0xE7 */
> >   	X3(D(SrcImmByte)), N,
> > -	D(ByteOp | SrcImmUByte | DstAcc), D(SrcImmUByte | DstAcc),
> > -	D(ByteOp | SrcAcc | DstImmUByte), D(SrcAcc | DstImmUByte),
> > +	D2bv(SrcImmUByte | DstAcc), D2bv(SrcAcc | DstImmUByte),
> >   	/* 0xE8 - 0xEF */
> >   	D(SrcImm | Stack), D(SrcImm | ImplicitOps),
> >   	D(SrcImmFAddr | No64), D(SrcImmByte | ImplicitOps),
> > -	D(SrcNone | ByteOp | DstAcc), D(SrcNone | DstAcc),
> > -	D(ByteOp | SrcAcc | ImplicitOps), D(SrcAcc | ImplicitOps),
> > +	D2bv(SrcNone | DstAcc),	D2bv(SrcAcc | ImplicitOps),
> >   	/* 0xF0 - 0xF7 */
> >   	N, N, N, N,
> >   	D(ImplicitOps | Priv), D(ImplicitOps), G(ByteOp, group3), G(0, group3),
> Hmm. I actually have a patch that makes encoding of those to be different.
>
> ===
>      Some instructions has 32 bit operand even in long mode.
>
>      Decode this through decode table instead of during instruction
>      emulation.

This can still work.

> @@ -2750,6 +2751,9 @@ done_prefixes:
>   			c->op_bytes = 4;
>   	}
>
> +	if (mode == X86EMUL_MODE_PROT64&&  (c->d&  Op32in64))
> +		c->op_bytes = 4;

Just check that it isn't a ByteOp.

btw, shouldn't that be

    if (c->op_bytes == 8 && (c->d & Op32in64))

?  to account for c->op_bytes = 2 initially.


--
error compiling committee.c: too many arguments to function

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