KVM: x86 emulator: populate OP_MEM operand during decoding.
All struct operand fields are initialized during decoding for all
operand types except OP_MEM, but there is no reason for that. Move
OP_MEM operand initialization into decoding stage for consistency.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 8225ec2..0eed683 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1057,6 +1057,10 @@
if (c->ad_bytes != 8)
c->modrm_ea = (u32)c->modrm_ea;
+
+ if (c->rip_relative)
+ c->modrm_ea += c->eip;
+
/*
* Decode and fetch the source operand: register, memory
* or immediate.
@@ -1091,6 +1095,8 @@
break;
}
c->src.type = OP_MEM;
+ c->src.ptr = (unsigned long *)c->modrm_ea;
+ c->src.val = 0;
break;
case SrcImm:
case SrcImmU:
@@ -1169,8 +1175,10 @@
c->src2.val = 1;
break;
case Src2Mem16:
- c->src2.bytes = 2;
c->src2.type = OP_MEM;
+ c->src2.bytes = 2;
+ c->src2.ptr = (unsigned long *)(c->modrm_ea + c->src.bytes);
+ c->src2.val = 0;
break;
}
@@ -1192,6 +1200,15 @@
break;
}
c->dst.type = OP_MEM;
+ c->dst.ptr = (unsigned long *)c->modrm_ea;
+ c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
+ c->dst.val = 0;
+ if (c->d & BitOp) {
+ unsigned long mask = ~(c->dst.bytes * 8 - 1);
+
+ c->dst.ptr = (void *)c->dst.ptr +
+ (c->src.val & mask) / 8;
+ }
break;
case DstAcc:
c->dst.type = OP_REG;
@@ -1215,9 +1232,6 @@
break;
}
- if (c->rip_relative)
- c->modrm_ea += c->eip;
-
done:
return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
}
@@ -1638,14 +1652,13 @@
}
static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt,
- struct x86_emulate_ops *ops,
- unsigned long memop)
+ struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
u64 old, new;
int rc;
- rc = ops->read_emulated(memop, &old, 8, ctxt->vcpu);
+ rc = ops->read_emulated(c->modrm_ea, &old, 8, ctxt->vcpu);
if (rc != X86EMUL_CONTINUE)
return rc;
@@ -1660,7 +1673,7 @@
new = ((u64)c->regs[VCPU_REGS_RCX] << 32) |
(u32) c->regs[VCPU_REGS_RBX];
- rc = ops->cmpxchg_emulated(memop, &old, &new, 8, ctxt->vcpu);
+ rc = ops->cmpxchg_emulated(c->modrm_ea, &old, &new, 8, ctxt->vcpu);
if (rc != X86EMUL_CONTINUE)
return rc;
ctxt->eflags |= EFLG_ZF;
@@ -2382,7 +2395,6 @@
int
x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
{
- unsigned long memop = 0;
u64 msr_data;
unsigned long saved_eip = 0;
struct decode_cache *c = &ctxt->decode;
@@ -2417,9 +2429,6 @@
goto done;
}
- if (((c->d & ModRM) && (c->modrm_mod != 3)) || (c->d & MemAbs))
- memop = c->modrm_ea;
-
if (c->rep_prefix && (c->d & String)) {
/* All REP prefixes have the same first termination condition */
if (address_mask(c, c->regs[VCPU_REGS_RCX]) == 0) {
@@ -2451,8 +2460,6 @@
}
if (c->src.type == OP_MEM) {
- c->src.ptr = (unsigned long *)memop;
- c->src.val = 0;
rc = ops->read_emulated((unsigned long)c->src.ptr,
&c->src.val,
c->src.bytes,
@@ -2463,8 +2470,6 @@
}
if (c->src2.type == OP_MEM) {
- c->src2.ptr = (unsigned long *)(memop + c->src.bytes);
- c->src2.val = 0;
rc = ops->read_emulated((unsigned long)c->src2.ptr,
&c->src2.val,
c->src2.bytes,
@@ -2477,25 +2482,12 @@
goto special_insn;
- if (c->dst.type == OP_MEM) {
- c->dst.ptr = (unsigned long *)memop;
- c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
- c->dst.val = 0;
- if (c->d & BitOp) {
- unsigned long mask = ~(c->dst.bytes * 8 - 1);
-
- c->dst.ptr = (void *)c->dst.ptr +
- (c->src.val & mask) / 8;
- }
- if (!(c->d & Mov)) {
- /* optimisation - avoid slow emulated read */
- rc = ops->read_emulated((unsigned long)c->dst.ptr,
- &c->dst.val,
- c->dst.bytes,
- ctxt->vcpu);
- if (rc != X86EMUL_CONTINUE)
- goto done;
- }
+ if ((c->dst.type == OP_MEM) && !(c->d & Mov)) {
+ /* optimisation - avoid slow emulated read if Mov */
+ rc = ops->read_emulated((unsigned long)c->dst.ptr, &c->dst.val,
+ c->dst.bytes, ctxt->vcpu);
+ if (rc != X86EMUL_CONTINUE)
+ goto done;
}
c->dst.orig_val = c->dst.val;
@@ -3062,7 +3054,7 @@
kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
goto done;
case 7: /* invlpg*/
- emulate_invlpg(ctxt->vcpu, memop);
+ emulate_invlpg(ctxt->vcpu, c->modrm_ea);
/* Disable writeback. */
c->dst.type = OP_NONE;
break;
@@ -3263,7 +3255,7 @@
(u64) c->src.val;
break;
case 0xc7: /* Grp9 (cmpxchg8b) */
- rc = emulate_grp9(ctxt, ops, memop);
+ rc = emulate_grp9(ctxt, ops);
if (rc != X86EMUL_CONTINUE)
goto done;
c->dst.type = OP_NONE;