diff options
| author | Avi Kivity <avi@redhat.com> | 2012-06-10 17:15:39 +0300 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2012-07-09 14:19:02 +0300 |
| commit | a6e3407bb1570ac5d8d7fc471bca07d531d1dde7 (patch) | |
| tree | c0bb9742c418f8633256b90f4eac43387638d838 /arch/x86/kvm/emulate.c | |
| parent | cbd27ee783f1e56d56415e8c5f2492ccedd565c4 (diff) | |
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>
Diffstat (limited to 'arch/x86/kvm/emulate.c')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 33ccd757cb1..7552c0ac6e7 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -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) |