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KVM: Fix SS default ESP/EBP based addressing
We correctly default to SS when BP is used as a base in 16-bit address mode, but we don't do that for 32-bit mode. Fix by adjusting the default to SS when either ESP or EBP is used as the base register. Signed-off-by: Avi Kivity <avi@redhat.com>
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parent
cbd27ee783
commit
a6e3407bb1
1 changed files with 14 additions and 3 deletions
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@ -974,6 +974,12 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
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op->orig_val = op->val;
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}
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static void adjust_modrm_seg(struct x86_emulate_ctxt *ctxt, int base_reg)
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{
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if (base_reg == VCPU_REGS_RSP || base_reg == VCPU_REGS_RBP)
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ctxt->modrm_seg = VCPU_SREG_SS;
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}
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static int decode_modrm(struct x86_emulate_ctxt *ctxt,
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struct operand *op)
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{
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@ -1077,15 +1083,20 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
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if ((base_reg & 7) == 5 && ctxt->modrm_mod == 0)
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modrm_ea += insn_fetch(s32, ctxt);
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else
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else {
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modrm_ea += ctxt->regs[base_reg];
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adjust_modrm_seg(ctxt, base_reg);
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}
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if (index_reg != 4)
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modrm_ea += ctxt->regs[index_reg] << scale;
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} else if ((ctxt->modrm_rm & 7) == 5 && ctxt->modrm_mod == 0) {
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if (ctxt->mode == X86EMUL_MODE_PROT64)
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ctxt->rip_relative = 1;
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} else
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modrm_ea += ctxt->regs[ctxt->modrm_rm];
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} else {
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base_reg = ctxt->modrm_rm;
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modrm_ea += ctxt->regs[base_reg];
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adjust_modrm_seg(ctxt, base_reg);
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}
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switch (ctxt->modrm_mod) {
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case 0:
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if (ctxt->modrm_rm == 5)
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