This patch change to disable writeback when decode dest
operand if the dest type is ImplicitOps or not specified.
Signed-off-by: Wei Yongjun <yj...@cn.fujitsu.com>
---
arch/x86/kvm/emulate.c | 23 ++++++-----------------
1 files changed, 6 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 4624b11..31c33f4 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2569,9 +2569,6 @@ done_prefixes:
/* Decode and fetch the destination operand: register or memory. */
switch (c->d & DstMask) {
- case ImplicitOps:
- /* Special instructions do their own operand decoding. */
- return 0;
case DstReg:
decode_register_operand(&c->dst, c,
c->twobyte && (c->b == 0xb6 || c->b == 0xb7));
@@ -2606,6 +2603,11 @@ done_prefixes:
c->regs[VCPU_REGS_RDI]);
c->dst.val = 0;
break;
+ case ImplicitOps:
+ /* Special instructions do their own operand decoding. */
+ default:
+ c->dst.type = OP_NONE; /* Disable writeback. */
+ return 0;
}
done:
@@ -3040,7 +3042,6 @@ special_insn:
case 0xf5: /* cmc */
/* complement carry flag from eflags reg */
ctxt->eflags ^= EFLG_CF;
- c->dst.type = OP_NONE; /* Disable writeback. */
break;
case 0xf6 ... 0xf7: /* Grp3 */
if (!emulate_grp3(ctxt, ops))
@@ -3048,16 +3049,13 @@ special_insn:
break;
case 0xf8: /* clc */
ctxt->eflags &= ~EFLG_CF;
- c->dst.type = OP_NONE; /* Disable writeback. */
break;
case 0xfa: /* cli */
if (emulator_bad_iopl(ctxt, ops)) {
emulate_gp(ctxt, 0);
goto done;
- } else {
+ } else
ctxt->eflags &= ~X86_EFLAGS_IF;
- c->dst.type = OP_NONE; /* Disable writeback. */
- }
break;
case 0xfb: /* sti */
if (emulator_bad_iopl(ctxt, ops)) {
@@ -3066,16 +3064,13 @@ special_insn:
} else {
ctxt->interruptibility = KVM_X86_SHADOW_INT_STI;
ctxt->eflags |= X86_EFLAGS_IF;
- c->dst.type = OP_NONE; /* Disable writeback. */
}
break;
case 0xfc: /* cld */
ctxt->eflags &= ~EFLG_DF;
- c->dst.type = OP_NONE; /* Disable writeback. */
break;
case 0xfd: /* std */
ctxt->eflags |= EFLG_DF;
- c->dst.type = OP_NONE; /* Disable writeback. */
break;
case 0xfe: /* Grp4 */
grp45:
@@ -3212,16 +3207,13 @@ twobyte_insn:
break;
case 0x06:
emulate_clts(ctxt->vcpu);
- c->dst.type = OP_NONE;
break;
case 0x09: /* wbinvd */
kvm_emulate_wbinvd(ctxt->vcpu);
- c->dst.type = OP_NONE;
break;
case 0x08: /* invd */
case 0x0d: /* GrpP (prefetch) */
case 0x18: /* Grp16 (prefetch/nop) */
- c->dst.type = OP_NONE;
break;
case 0x20: /* mov cr, reg */
switch (c->modrm_reg) {
@@ -3274,7 +3266,6 @@ twobyte_insn:
goto done;
}
rc = X86EMUL_CONTINUE;
- c->dst.type = OP_NONE;
break;
case 0x32:
/* rdmsr */
@@ -3286,7 +3277,6 @@ twobyte_insn:
c->regs[VCPU_REGS_RDX] = msr_data >> 32;
}
rc = X86EMUL_CONTINUE;
- c->dst.type = OP_NONE;
break;
case 0x34: /* sysenter */
rc = emulate_sysenter(ctxt, ops);
@@ -3310,7 +3300,6 @@ twobyte_insn:
case 0x80 ... 0x8f: /* jnz rel, etc*/
if (test_cc(c->b, ctxt->eflags))
jmp_rel(c, c->src.val);
- c->dst.type = OP_NONE;
break;
case 0xa0: /* push fs */
emulate_push_sreg(ctxt, ops, VCPU_SREG_FS);
--
1.7.0.4
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