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KVM: Fix SS default ESP/EBP based addressing

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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>
This commit is contained in:
Avi Kivity 2012-06-10 17:15:39 +03:00
parent cbd27ee783
commit a6e3407bb1
1 changed files with 14 additions and 3 deletions
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17
arch/x86/kvm/emulate.c
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@ -974,6 +974,12 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
op->orig_val = op->val;
}
static void adjust_modrm_seg(struct x86_emulate_ctxt *ctxt, int base_reg)
{
if (base_reg == VCPU_REGS_RSP || base_reg == VCPU_REGS_RBP)
ctxt->modrm_seg = VCPU_SREG_SS;
}
static int decode_modrm(struct x86_emulate_ctxt *ctxt,
struct operand *op)
{
@ -1077,15 +1083,20 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
if ((base_reg & 7) == 5 && ctxt->modrm_mod == 0)
modrm_ea += insn_fetch(s32, ctxt);
else
else {
modrm_ea += ctxt->regs[base_reg];
adjust_modrm_seg(ctxt, base_reg);
}
if (index_reg != 4)
modrm_ea += ctxt->regs[index_reg] << scale;
} else if ((ctxt->modrm_rm & 7) == 5 && ctxt->modrm_mod == 0) {
if (ctxt->mode == X86EMUL_MODE_PROT64)
ctxt->rip_relative = 1;
} else
modrm_ea += ctxt->regs[ctxt->modrm_rm];
} else {
base_reg = ctxt->modrm_rm;
modrm_ea += ctxt->regs[base_reg];
adjust_modrm_seg(ctxt, base_reg);
}
switch (ctxt->modrm_mod) {
case 0:
if (ctxt->modrm_rm == 5)