Commit a01af5ec authored by Laurent Vivier's avatar Laurent Vivier Committed by Avi Kivity
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KVM: x86 emulator: Remove no_wb, use dst.type = OP_NONE instead 



Remove no_wb, use dst.type = OP_NONE instead, idea stollen from xen-3.1

Signed-off-by: default avatarLaurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 05f086f8

drivers/kvm/x86_emulate.c

+24 −52
Original line number Diff line number Diff line
@@ -1016,8 +1016,7 @@ static inline int emulate_grp3(struct x86_emulate_ctxt *ctxt, 
}



static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt,

			       struct x86_emulate_ops *ops,

			       int *no_wb)

			       struct x86_emulate_ops *ops)

{

	struct decode_cache *c = &ctxt->decode;

	int rc;
@@ -1055,7 +1054,7 @@ static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt, 
				    c->dst.bytes, ctxt->vcpu);

		if (rc != 0)

			return rc;

		*no_wb = 1;

		c->dst.type = OP_NONE;

		break;

	default:

		DPRINTF("Cannot emulate %02x\n", c->b);
@@ -1137,6 +1136,10 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt, 
					ctxt->vcpu);

		if (rc != 0)

			return rc;

		break;

	case OP_NONE:

		/* no writeback */

		break;

	default:

		break;

	}
@@ -1147,7 +1150,6 @@ int 
x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)

{

	unsigned long cr2 = ctxt->cr2;

	int no_wb = 0;

	u64 msr_data;

	unsigned long saved_eip = 0;

	struct decode_cache *c = &ctxt->decode;
@@ -1344,18 +1346,16 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
			goto done;

		break;

	case 0xfe ... 0xff:	/* Grp4/Grp5 */

		rc = emulate_grp45(ctxt, ops, &no_wb);

		rc = emulate_grp45(ctxt, ops);

		if (rc != 0)

			goto done;

		break;

	}



writeback:

	if (!no_wb) {

	rc = writeback(ctxt, ops);

	if (rc != 0)

		goto done;

	}



	/* Commit shadow register state. */

	memcpy(ctxt->vcpu->regs, c->regs, sizeof c->regs);
@@ -1395,7 +1395,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 


		register_address_increment(c->regs[VCPU_REGS_RSP],

					   c->op_bytes);

		no_wb = 1; /* Disable writeback. */

		c->dst.type = OP_NONE;	/* Disable writeback. */

		break;

	case 0x6a: /* push imm8 */

		c->src.val = 0L;
@@ -1538,7 +1538,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
	case 0xe9: /* jmp rel */

	case 0xeb: /* jmp rel short */

		JMP_REL(c->src.val);

		no_wb = 1; /* Disable writeback. */

		c->dst.type = OP_NONE; /* Disable writeback. */

		break;
@@ -1548,8 +1548,6 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
twobyte_insn:

	switch (c->b) {

	case 0x01: /* lgdt, lidt, lmsw */

		/* Disable writeback. */

		no_wb = 1;

		switch (c->modrm_reg) {

			u16 size;

			unsigned long address;
@@ -1604,56 +1602,30 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
		default:

			goto cannot_emulate;

		}

		/* Disable writeback. */

		c->dst.type = OP_NONE;

		break;

	case 0x21: /* mov from dr to reg */

		no_wb = 1;

		if (c->modrm_mod != 3)

			goto cannot_emulate;

		rc = emulator_get_dr(ctxt, c->modrm_reg, &c->regs[c->modrm_rm]);

		if (rc)

			goto cannot_emulate;

		c->dst.type = OP_NONE;	/* no writeback */

		break;

	case 0x23: /* mov from reg to dr */

		no_wb = 1;

		if (c->modrm_mod != 3)

			goto cannot_emulate;

		rc = emulator_set_dr(ctxt, c->modrm_reg,

				     c->regs[c->modrm_rm]);

		if (rc)

			goto cannot_emulate;

		c->dst.type = OP_NONE;	/* no writeback */

		break;

	case 0x40 ... 0x4f:	/* cmov */

		c->dst.val = c->dst.orig_val = c->src.val;

		no_wb = 1;

		/*

		 * First, assume we're decoding an even cmov opcode

		 * (lsb == 0).

		 */

		switch ((c->b & 15) >> 1) {

		case 0:	/* cmovo */

			no_wb = (ctxt->eflags & EFLG_OF) ? 0 : 1;

			break;

		case 1:	/* cmovb/cmovc/cmovnae */

			no_wb = (ctxt->eflags & EFLG_CF) ? 0 : 1;

			break;

		case 2:	/* cmovz/cmove */

			no_wb = (ctxt->eflags & EFLG_ZF) ? 0 : 1;

			break;

		case 3:	/* cmovbe/cmovna */

			no_wb = (ctxt->eflags & (EFLG_CF | EFLG_ZF)) ? 0 : 1;

			break;

		case 4:	/* cmovs */

			no_wb = (ctxt->eflags & EFLG_SF) ? 0 : 1;

			break;

		case 5:	/* cmovp/cmovpe */

			no_wb = (ctxt->eflags & EFLG_PF) ? 0 : 1;

			break;

		case 7:	/* cmovle/cmovng */

			no_wb = (ctxt->eflags & EFLG_ZF) ? 0 : 1;

			/* fall through */

		case 6:	/* cmovl/cmovnge */

			no_wb &= (!(ctxt->eflags & EFLG_SF) !=

			      !(ctxt->eflags & EFLG_OF)) ? 0 : 1;

			break;

		}

		/* Odd cmov opcodes (lsb == 1) have inverted sense. */

		no_wb ^= c->b & 1;

		if (!test_cc(c->b, ctxt->eflags))

			c->dst.type = OP_NONE; /* no writeback */

		break;

	case 0xa3:

	      bt:		/* bt */
@@ -1727,8 +1699,6 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
	goto writeback;



twobyte_special_insn:

	/* Disable writeback. */

	no_wb = 1;

	switch (c->b) {

	case 0x06:

		emulate_clts(ctxt->vcpu);
@@ -1802,6 +1772,8 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
			goto done;

		break;

	}

	/* Disable writeback. */

	c->dst.type = OP_NONE;

	goto writeback;



cannot_emulate:

drivers/kvm/x86_emulate.h

+1 −1
Original line number Diff line number Diff line
@@ -114,7 +114,7 @@ struct x86_emulate_ops { 


/* Type, address-of, and value of an instruction's operand. */

struct operand {

	enum { OP_REG, OP_MEM, OP_IMM } type;

	enum { OP_REG, OP_MEM, OP_IMM, OP_NONE } type;

	unsigned int bytes;

	unsigned long val, orig_val, *ptr;

};