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KVM: x86 emulator: populate OP_MEM operand during decoding.
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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>
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Gleb Natapov authored and Avi Kivity committed May 17, 2010
1 parent ceffb45 commit 69f55cb
Showing 1 changed file with 29 additions and 37 deletions.
66 changes: 29 additions & 37 deletions arch/x86/kvm/emulate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1057,6 +1057,10 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)

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.
Expand Down Expand Up @@ -1091,6 +1095,8 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
break;
}
c->src.type = OP_MEM;
c->src.ptr = (unsigned long *)c->modrm_ea;
c->src.val = 0;
break;
case SrcImm:
case SrcImmU:
Expand Down Expand Up @@ -1169,8 +1175,10 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
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;
}

Expand All @@ -1192,6 +1200,15 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
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;
Expand All @@ -1215,9 +1232,6 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
break;
}

if (c->rip_relative)
c->modrm_ea += c->eip;

done:
return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
}
Expand Down Expand Up @@ -1638,14 +1652,13 @@ static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt,
}

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;

Expand All @@ -1660,7 +1673,7 @@ static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt,
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;
Expand Down Expand Up @@ -2382,7 +2395,6 @@ int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
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;
Expand Down Expand Up @@ -2417,9 +2429,6 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
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) {
Expand Down Expand Up @@ -2451,8 +2460,6 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
}

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,
Expand All @@ -2463,8 +2470,6 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
}

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,
Expand All @@ -2477,25 +2482,12 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
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;

Expand Down Expand Up @@ -3062,7 +3054,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
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;
Expand Down Expand Up @@ -3263,7 +3255,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
(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;
Expand Down

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