[Xen-devel] Ping: [PATCH] x86emul: correct VEX.W handling for non-64-bit VPINSRD

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 10.07.17 at 09:24, <JBeulich@xxxxxxxx> wrote:
> Going though the XED commits from the last couple of months made me
> notice that VPINSRD, other than VPEXTRD, does not clear VEX.W for non-
> 64-bit modes, leading to an insertion of stray 32-bits of zero in case
> the original instruction had the bit set.
> 
> Also remove a pointless fall-through in VPEXTRW handling, bringing
> things in line with VPINSRW.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Together with this one also
x86emul: correct VEX.L handling for VCVT{,T}S{S,D}2SI
x86emul: correct EVEX register extension bit handling for non-64-bit modes
(not to speak of the AVX etc series sent even longer ago)

Jan

> ---
> Correcting this made me further notice that the SDM states that
> VPEXTR{B,W} and VPINSR{B,W} require VEX.W to be clear in other than
> their EVEX encodings (which we don't support so far). XED and reality
> disagree, so things are being left unchanged there.
> 
> --- a/xen/arch/x86/x86_emulate/x86_emulate.c
> +++ b/xen/arch/x86/x86_emulate/x86_emulate.c
> @@ -6730,10 +6730,9 @@ x86_emulate(
>          ea.type = OP_MEM;
>          goto simd_0f_int_imm8;
>  
> +    CASE_SIMD_PACKED_INT(0x0f, 0xc5):      /* pextrw $imm8,{,x}mm,reg */
>      case X86EMUL_OPC_VEX_66(0x0f, 0xc5):   /* vpextrw $imm8,xmm,reg */
>          generate_exception_if(vex.l, EXC_UD);
> -        /* fall through */
> -    CASE_SIMD_PACKED_INT(0x0f, 0xc5):      /* pextrw $imm8,{,x}mm,reg */
>          opc = init_prefixes(stub);
>          opc[0] = b;
>          /* Convert GPR destination to %rAX. */
> @@ -7512,6 +7511,8 @@ x86_emulate(
>      case X86EMUL_OPC_VEX_66(0x0f3a, 0x20): /* vpinsrb $imm8,r32/m8,xmm,xmm 
> */
>      case X86EMUL_OPC_VEX_66(0x0f3a, 0x22): /* vpinsr{d,q} $imm8,r/m,xmm,xmm 
> */
>          generate_exception_if(vex.l, EXC_UD);
> +        if ( !mode_64bit() )
> +            vex.w = 0;
>          memcpy(mmvalp, &src.val, op_bytes);
>          ea.type = OP_MEM;
>          op_bytes = src.bytes;
> 
> 
> 
> 
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