Re: [Xen-devel] [PATCH v3 08/25] x86emul: add tables for XOP 08 and 09 extension spaces

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 07/12/17 14:04, Jan Beulich wrote:
> Convert the few existing opcodes so far supported.
>
> Also adjust two vex_* case labels to better be ext_* (the values are
> identical).
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> --- a/xen/arch/x86/x86_emulate/x86_emulate.c
> +++ b/xen/arch/x86/x86_emulate/x86_emulate.c
> @@ -458,6 +458,20 @@ static const opcode_desc_t xop_table[] =
>      DstReg|SrcImm|ModRM,
>  };
>  
> +static const struct {
> +    uint8_t simd_size:5;
> +    uint8_t two_op:1;
> +    uint8_t four_op:1;
> +} ext8f08_table[256] = {
> +};
> +
> +static const struct {
> +    uint8_t simd_size:5;
> +    uint8_t two_op:1;
> +} ext8f09_table[256] = {
> +    [0x01 ... 0x02] = { .two_op = 1 },
> +};
> +

What about 8f0a ?  We've got emulation for bextr already, and might want
to consider #GRP4 seeing as we expose LWP to guests.

>  #define REX_PREFIX 0x40
>  #define REX_B 0x01
>  #define REX_X 0x02
> @@ -2726,7 +2740,7 @@ x86_decode(
>              }
>              break;
>  
> -        case vex_0f38:
> +        case ext_0f38:
>              d = ext0f38_table[b].to_mem ? DstMem | SrcReg
>                                          : DstReg | SrcMem;
>              if ( ext0f38_table[b].two_op )
> @@ -2736,7 +2750,14 @@ x86_decode(
>              state->simd_size = ext0f38_table[b].simd_size;
>              break;
>  
> -        case vex_0f3a:
> +        case ext_8f09:
> +            if ( ext8f09_table[b].two_op )
> +                d |= TwoOp;
> +            state->simd_size = ext8f09_table[b].simd_size;
> +            break;
> +
> +        case ext_0f3a:
> +        case ext_8f08:
>              /*
>               * Cannot update d here yet, as the immediate operand still
>               * needs fetching.
> @@ -2928,6 +2949,15 @@ x86_decode(
>          break;
>  
>      case ext_8f08:
> +        d = DstReg | SrcMem;
> +        if ( ext8f08_table[b].two_op )
> +            d |= TwoOp;
> +        else if ( ext8f08_table[b].four_op && !mode_64bit() )
> +            imm1 &= 0x7f;
> +        state->desc = d;
> +        state->simd_size = ext8f08_table[b].simd_size;
> +        break;

I presume that these don't actually impact our currently implemented XOP
instructions?

~Andrew

> +
>      case ext_8f09:
>      case ext_8f0a:
>          break;
>
>
>


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