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SubjectRe: [RFC PATCH v2 3/6] KVM: emulate: cleanup decode_rm
Il 10/04/2014 20:03, Bandan Das ha scritto:
> - if (ctxt->rex_prefix) {
> - ctxt->modrm_reg = (ctxt->rex_prefix & 4) << 1; /* REX.R */
> - index_reg = (ctxt->rex_prefix & 2) << 2; /* REX.X */
> - ctxt->modrm_rm = base_reg = (ctxt->rex_prefix & 1) << 3; /* REG.B */
> - }
> + index_reg = (ctxt->rex_prefix << 2) & 8; /* REX.X */
> + base_reg = (ctxt->rex_prefix << 3) & 8; /* REG.B */

This is REX.B (preexisting typo), and please leave REX.R here too for
clarity.

Also, the function is "decode_modrm", not "decode_rm" (in the commit
message).

Otherwise the series seems okay from a somewhat cursory review.

Paolo

>
> - ctxt->modrm_mod |= (ctxt->modrm & 0xc0) >> 6;
> - ctxt->modrm_reg |= (ctxt->modrm & 0x38) >> 3;
> - ctxt->modrm_rm |= (ctxt->modrm & 0x07);
> + ctxt->modrm_mod = (ctxt->modrm & 0xc0) >> 6;
> + ctxt->modrm_reg = ((ctxt->rex_prefix << 1) & 8) | /* REX.R */
> + ((ctxt->modrm & 0x38) >> 3);
> + ctxt->modrm_rm = base_reg | (ctxt->modrm & 0x07);
> ctxt->modrm_seg = VCPU_SREG_DS;
>



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