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Commit 69f55cb1 authored by Gleb Natapov's avatar Gleb Natapov Committed by Avi Kivity
Browse files

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: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent ceffb459

arch/x86/kvm/emulate.c

+29 −37
Original line number Diff line number Diff line
@@ -1057,6 +1057,10 @@ done_prefixes: 


	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 @@ done_prefixes: 
			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 @@ done_prefixes: 
		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 @@ done_prefixes: 
			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 @@ done_prefixes: 
		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_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;
@@ -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;
@@ -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;
@@ -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) {
@@ -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,
@@ -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,
@@ -2477,26 +2482,13 @@ 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 ((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;



special_insn:
@@ -3062,7 +3054,7 @@ twobyte_insn: 
			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 @@ twobyte_insn: 
							(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;