Commit 120df890 authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: x86 emulator: allow specifying group directly in opcode 



Instead of having a group number, store the group table pointer directly in
the opcode.

Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 793d5a8d

arch/x86/kvm/emulate.c

+38 −9
Original line number Diff line number Diff line
@@ -110,10 +110,21 @@ enum { 


struct opcode {

	u32 flags;

	union {

		struct opcode *group;

		struct group_dual *gdual;

	} u;

};



struct group_dual {

	struct opcode mod012[8];

	struct opcode mod3[8];

};



#define D(_y) { .flags = (_y) }

#define N    D(0)

#define G(_f, _g) { .flags = ((_f) | Group), .u.group = (_g) }

#define GD(_f, _g) { .flags = ((_f) | Group | GroupDual), .u.gdual = (_g) }



static struct opcode group_table[] = {

	[Group1*8] =
@@ -331,6 +342,8 @@ static struct opcode twobyte_table[256] = { 


#undef D

#undef N

#undef G

#undef GD



/* EFLAGS bit definitions. */

#define EFLG_ID (1<<21)
@@ -930,8 +943,8 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
	struct decode_cache *c = &ctxt->decode;

	int rc = X86EMUL_CONTINUE;

	int mode = ctxt->mode;

	int def_op_bytes, def_ad_bytes, group, dual;



	int def_op_bytes, def_ad_bytes, group, dual, goffset;

	struct opcode opcode, *g_mod012, *g_mod3;



	/* we cannot decode insn before we complete previous rep insn */

	WARN_ON(ctxt->restart);
@@ -1018,15 +1031,16 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
			c->op_bytes = 8;	/* REX.W */



	/* Opcode byte(s). */

	c->d = opcode_table[c->b].flags;

	if (c->d == 0) {

	opcode = opcode_table[c->b];

	if (opcode.flags == 0) {

		/* Two-byte opcode? */

		if (c->b == 0x0f) {

			c->twobyte = 1;

			c->b = insn_fetch(u8, 1, c->eip);

			c->d = twobyte_table[c->b].flags;

			opcode = twobyte_table[c->b];

		}

	}

	c->d = opcode.flags;



	if (c->d & Group) {

		group = c->d & GroupMask;
@@ -1034,12 +1048,27 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
		c->modrm = insn_fetch(u8, 1, c->eip);

		--c->eip;



		group = (group << 3) + ((c->modrm >> 3) & 7);

		if (group) {

			g_mod012 = g_mod3 = &group_table[group * 8];

			if (c->d & GroupDual)

				g_mod3 = &group2_table[group * 8];

		} else {

			if (c->d & GroupDual) {

				g_mod012 = opcode.u.gdual->mod012;

				g_mod3 = opcode.u.gdual->mod3;

			} else

				g_mod012 = g_mod3 = opcode.u.group;

		}



		c->d &= ~(Group | GroupDual | GroupMask);

		if (dual && (c->modrm >> 6) == 3)

			c->d |= group2_table[group].flags;



		goffset = (c->modrm >> 3) & 7;



		if ((c->modrm >> 6) == 3)

			opcode = g_mod3[goffset];

		else

			c->d |= group_table[group].flags;

			opcode = g_mod012[goffset];

		c->d |= opcode.flags;

	}



	/* Unrecognised? */