Merge commit 'v2.6.35-rc1' into amd-iommu/2.6.35

1 files changed, 916 insertions, 331 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 4dade6ac0827..5ac0bb465ed6 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -33,6 +33,7 @@
 #include <asm/kvm_emulate.h>
 
 #include "x86.h"
+#include "tss.h"
 
 /*
  * Opcode effective-address decode tables.
@@ -50,6 +51,8 @@
 #define DstReg      (2<<1)	/* Register operand. */
 #define DstMem      (3<<1)	/* Memory operand. */
 #define DstAcc      (4<<1)      /* Destination Accumulator */
+#define DstDI       (5<<1)	/* Destination is in ES:(E)DI */
+#define DstMem64    (6<<1)	/* 64bit memory operand */
 #define DstMask     (7<<1)
 /* Source operand type. */
 #define SrcNone     (0<<4)	/* No source operand. */
@@ -63,6 +66,7 @@
 #define SrcOne      (7<<4)	/* Implied '1' */
 #define SrcImmUByte (8<<4)      /* 8-bit unsigned immediate operand. */
 #define SrcImmU     (9<<4)      /* Immediate operand, unsigned */
+#define SrcSI       (0xa<<4)	/* Source is in the DS:RSI */
 #define SrcMask     (0xf<<4)
 /* Generic ModRM decode. */
 #define ModRM       (1<<8)
@@ -85,6 +89,9 @@
 #define Src2ImmByte (2<<29)
 #define Src2One     (3<<29)
 #define Src2Imm16   (4<<29)
+#define Src2Mem16   (5<<29) /* Used for Ep encoding. First argument has to be
+			       in memory and second argument is located
+			       immediately after the first one in memory. */
 #define Src2Mask    (7<<29)
 
 enum {
@@ -147,8 +154,8 @@ static u32 opcode_table[256] = {
 	0, 0, 0, 0,
 	/* 0x68 - 0x6F */
 	SrcImm | Mov | Stack, 0, SrcImmByte | Mov | Stack, 0,
-	SrcNone  | ByteOp  | ImplicitOps, SrcNone  | ImplicitOps, /* insb, insw/insd */
-	SrcNone  | ByteOp  | ImplicitOps, SrcNone  | ImplicitOps, /* outsb, outsw/outsd */
+	DstDI | ByteOp | Mov | String, DstDI | Mov | String, /* insb, insw/insd */
+	SrcSI | ByteOp | ImplicitOps | String, SrcSI | ImplicitOps | String, /* outsb, outsw/outsd */
 	/* 0x70 - 0x77 */
 	SrcImmByte, SrcImmByte, SrcImmByte, SrcImmByte,
 	SrcImmByte, SrcImmByte, SrcImmByte, SrcImmByte,
@@ -173,12 +180,12 @@ static u32 opcode_table[256] = {
 	/* 0xA0 - 0xA7 */
 	ByteOp | DstReg | SrcMem | Mov | MemAbs, DstReg | SrcMem | Mov | MemAbs,
 	ByteOp | DstMem | SrcReg | Mov | MemAbs, DstMem | SrcReg | Mov | MemAbs,
-	ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
-	ByteOp | ImplicitOps | String, ImplicitOps | String,
+	ByteOp | SrcSI | DstDI | Mov | String, SrcSI | DstDI | Mov | String,
+	ByteOp | SrcSI | DstDI | String, SrcSI | DstDI | String,
 	/* 0xA8 - 0xAF */
-	0, 0, ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
-	ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
-	ByteOp | ImplicitOps | String, ImplicitOps | String,
+	0, 0, ByteOp | DstDI | Mov | String, DstDI | Mov | String,
+	ByteOp | SrcSI | DstAcc | Mov | String, SrcSI | DstAcc | Mov | String,
+	ByteOp | DstDI | String, DstDI | String,
 	/* 0xB0 - 0xB7 */
 	ByteOp | DstReg | SrcImm | Mov, ByteOp | DstReg | SrcImm | Mov,
 	ByteOp | DstReg | SrcImm | Mov, ByteOp | DstReg | SrcImm | Mov,
@@ -204,13 +211,13 @@ static u32 opcode_table[256] = {
 	0, 0, 0, 0, 0, 0, 0, 0,
 	/* 0xE0 - 0xE7 */
 	0, 0, 0, 0,
-	ByteOp | SrcImmUByte, SrcImmUByte,
-	ByteOp | SrcImmUByte, SrcImmUByte,
+	ByteOp | SrcImmUByte | DstAcc, SrcImmUByte | DstAcc,
+	ByteOp | SrcImmUByte | DstAcc, SrcImmUByte | DstAcc,
 	/* 0xE8 - 0xEF */
 	SrcImm | Stack, SrcImm | ImplicitOps,
 	SrcImmU | Src2Imm16 | No64, SrcImmByte | ImplicitOps,
-	SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
-	SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
+	SrcNone | ByteOp | DstAcc, SrcNone | DstAcc,
+	SrcNone | ByteOp | DstAcc, SrcNone | DstAcc,
 	/* 0xF0 - 0xF7 */
 	0, 0, 0, 0,
 	ImplicitOps | Priv, ImplicitOps, Group | Group3_Byte, Group | Group3,
@@ -343,7 +350,8 @@ static u32 group_table[] = {
 	[Group5*8] =
 	DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM,
 	SrcMem | ModRM | Stack, 0,
-	SrcMem | ModRM | Stack, 0, SrcMem | ModRM | Stack, 0,
+	SrcMem | ModRM | Stack, SrcMem | ModRM | Src2Mem16 | ImplicitOps,
+	SrcMem | ModRM | Stack, 0,
 	[Group7*8] =
 	0, 0, ModRM | SrcMem | Priv, ModRM | SrcMem | Priv,
 	SrcNone | ModRM | DstMem | Mov, 0,
@@ -353,14 +361,14 @@ static u32 group_table[] = {
 	DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM | Lock,
 	DstMem | SrcImmByte | ModRM | Lock, DstMem | SrcImmByte | ModRM | Lock,
 	[Group9*8] =
-	0, ImplicitOps | ModRM | Lock, 0, 0, 0, 0, 0, 0,
+	0, DstMem64 | ModRM | Lock, 0, 0, 0, 0, 0, 0,
 };
 
 static u32 group2_table[] = {
 	[Group7*8] =
-	SrcNone | ModRM | Priv, 0, 0, SrcNone | ModRM,
+	SrcNone | ModRM | Priv, 0, 0, SrcNone | ModRM | Priv,
 	SrcNone | ModRM | DstMem | Mov, 0,
-	SrcMem16 | ModRM | Mov, 0,
+	SrcMem16 | ModRM | Mov | Priv, 0,
 	[Group9*8] =
 	0, 0, 0, 0, 0, 0, 0, 0,
 };
@@ -562,7 +570,7 @@ static u32 group2_table[] = {
 #define insn_fetch(_type, _size, _eip)                                  \
 ({	unsigned long _x;						\
 	rc = do_insn_fetch(ctxt, ops, (_eip), &_x, (_size));		\
-	if (rc != 0)							\
+	if (rc != X86EMUL_CONTINUE)					\
 		goto done;						\
 	(_eip) += (_size);						\
 	(_type)_x;							\
@@ -638,40 +646,40 @@ static unsigned long ss_base(struct x86_emulate_ctxt *ctxt)
 
 static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
 			      struct x86_emulate_ops *ops,
-			      unsigned long linear, u8 *dest)
+			      unsigned long eip, u8 *dest)
 {
 	struct fetch_cache *fc = &ctxt->decode.fetch;
 	int rc;
-	int size;
+	int size, cur_size;
 
-	if (linear < fc->start || linear >= fc->end) {
-		size = min(15UL, PAGE_SIZE - offset_in_page(linear));
-		rc = ops->fetch(linear, fc->data, size, ctxt->vcpu, NULL);
-		if (rc)
+	if (eip == fc->end) {
+		cur_size = fc->end - fc->start;
+		size = min(15UL - cur_size, PAGE_SIZE - offset_in_page(eip));
+		rc = ops->fetch(ctxt->cs_base + eip, fc->data + cur_size,
+				size, ctxt->vcpu, NULL);
+		if (rc != X86EMUL_CONTINUE)
 			return rc;
-		fc->start = linear;
-		fc->end = linear + size;
+		fc->end += size;
 	}
-	*dest = fc->data[linear - fc->start];
-	return 0;
+	*dest = fc->data[eip - fc->start];
+	return X86EMUL_CONTINUE;
 }
 
 static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
 			 struct x86_emulate_ops *ops,
 			 unsigned long eip, void *dest, unsigned size)
 {
-	int rc = 0;
+	int rc;
 
 	/* x86 instructions are limited to 15 bytes. */
-	if (eip + size - ctxt->decode.eip_orig > 15)
+	if (eip + size - ctxt->eip > 15)
 		return X86EMUL_UNHANDLEABLE;
-	eip += ctxt->cs_base;
 	while (size--) {
 		rc = do_fetch_insn_byte(ctxt, ops, eip++, dest++);
-		if (rc)
+		if (rc != X86EMUL_CONTINUE)
 			return rc;
 	}
-	return 0;
+	return X86EMUL_CONTINUE;
 }
 
 /*
@@ -702,7 +710,7 @@ static int read_descriptor(struct x86_emulate_ctxt *ctxt,
 	*address = 0;
 	rc = ops->read_std((unsigned long)ptr, (unsigned long *)size, 2,
 			   ctxt->vcpu, NULL);
-	if (rc)
+	if (rc != X86EMUL_CONTINUE)
 		return rc;
 	rc = ops->read_std((unsigned long)ptr + 2, address, op_bytes,
 			   ctxt->vcpu, NULL);
@@ -782,7 +790,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
 	struct decode_cache *c = &ctxt->decode;
 	u8 sib;
 	int index_reg = 0, base_reg = 0, scale;
-	int rc = 0;
+	int rc = X86EMUL_CONTINUE;
 
 	if (c->rex_prefix) {
 		c->modrm_reg = (c->rex_prefix & 4) << 1;	/* REX.R */
@@ -895,7 +903,7 @@ static int decode_abs(struct x86_emulate_ctxt *ctxt,
 		      struct x86_emulate_ops *ops)
 {
 	struct decode_cache *c = &ctxt->decode;
-	int rc = 0;
+	int rc = X86EMUL_CONTINUE;
 
 	switch (c->ad_bytes) {
 	case 2:
@@ -916,14 +924,18 @@ int
 x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 {
 	struct decode_cache *c = &ctxt->decode;
-	int rc = 0;
+	int rc = X86EMUL_CONTINUE;
 	int mode = ctxt->mode;
 	int def_op_bytes, def_ad_bytes, group;
 
-	/* Shadow copy of register state. Committed on successful emulation. */
 
+	/* we cannot decode insn before we complete previous rep insn */
+	WARN_ON(ctxt->restart);
+
+	/* Shadow copy of register state. Committed on successful emulation. */
 	memset(c, 0, sizeof(struct decode_cache));
-	c->eip = c->eip_orig = kvm_rip_read(ctxt->vcpu);
+	c->eip = ctxt->eip;
+	c->fetch.start = c->fetch.end = c->eip;
 	ctxt->cs_base = seg_base(ctxt, VCPU_SREG_CS);
 	memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs);
 
@@ -1015,11 +1027,6 @@ done_prefixes:
 		}
 	}
 
-	if (mode == X86EMUL_MODE_PROT64 && (c->d & No64)) {
-		kvm_report_emulation_failure(ctxt->vcpu, "invalid x86/64 instruction");
-		return -1;
-	}
-
 	if (c->d & Group) {
 		group = c->d & GroupMask;
 		c->modrm = insn_fetch(u8, 1, c->eip);
@@ -1046,7 +1053,7 @@ done_prefixes:
 		rc = decode_modrm(ctxt, ops);
 	else if (c->d & MemAbs)
 		rc = decode_abs(ctxt, ops);
-	if (rc)
+	if (rc != X86EMUL_CONTINUE)
 		goto done;
 
 	if (!c->has_seg_override)
@@ -1057,6 +1064,10 @@ 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 +1102,8 @@ 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:
@@ -1139,6 +1152,14 @@ done_prefixes:
 		c->src.bytes = 1;
 		c->src.val = 1;
 		break;
+	case SrcSI:
+		c->src.type = OP_MEM;
+		c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
+		c->src.ptr = (unsigned long *)
+			register_address(c,  seg_override_base(ctxt, c),
+					 c->regs[VCPU_REGS_RSI]);
+		c->src.val = 0;
+		break;
 	}
 
 	/*
@@ -1168,6 +1189,12 @@ done_prefixes:
 		c->src2.bytes = 1;
 		c->src2.val = 1;
 		break;
+	case Src2Mem16:
+		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;
 	}
 
 	/* Decode and fetch the destination operand: register or memory. */
@@ -1180,6 +1207,7 @@ done_prefixes:
 			 c->twobyte && (c->b == 0xb6 || c->b == 0xb7));
 		break;
 	case DstMem:
+	case DstMem64:
 		if ((c->d & ModRM) && c->modrm_mod == 3) {
 			c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
 			c->dst.type = OP_REG;
@@ -1188,12 +1216,24 @@ done_prefixes:
 			break;
 		}
 		c->dst.type = OP_MEM;
+		c->dst.ptr = (unsigned long *)c->modrm_ea;
+		if ((c->d & DstMask) == DstMem64)
+			c->dst.bytes = 8;
+		else
+			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;
-		c->dst.bytes = c->op_bytes;
+		c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
 		c->dst.ptr = &c->regs[VCPU_REGS_RAX];
-		switch (c->op_bytes) {
+		switch (c->dst.bytes) {
 			case 1:
 				c->dst.val = *(u8 *)c->dst.ptr;
 				break;
@@ -1203,18 +1243,248 @@ done_prefixes:
 			case 4:
 				c->dst.val = *(u32 *)c->dst.ptr;
 				break;
+			case 8:
+				c->dst.val = *(u64 *)c->dst.ptr;
+				break;
 		}
 		c->dst.orig_val = c->dst.val;
 		break;
+	case DstDI:
+		c->dst.type = OP_MEM;
+		c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
+		c->dst.ptr = (unsigned long *)
+			register_address(c, es_base(ctxt),
+					 c->regs[VCPU_REGS_RDI]);
+		c->dst.val = 0;
+		break;
 	}
 
-	if (c->rip_relative)
-		c->modrm_ea += c->eip;
-
 done:
 	return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
 }
 
+static int pio_in_emulated(struct x86_emulate_ctxt *ctxt,
+			   struct x86_emulate_ops *ops,
+			   unsigned int size, unsigned short port,
+			   void *dest)
+{
+	struct read_cache *rc = &ctxt->decode.io_read;
+
+	if (rc->pos == rc->end) { /* refill pio read ahead */
+		struct decode_cache *c = &ctxt->decode;
+		unsigned int in_page, n;
+		unsigned int count = c->rep_prefix ?
+			address_mask(c, c->regs[VCPU_REGS_RCX]) : 1;
+		in_page = (ctxt->eflags & EFLG_DF) ?
+			offset_in_page(c->regs[VCPU_REGS_RDI]) :
+			PAGE_SIZE - offset_in_page(c->regs[VCPU_REGS_RDI]);
+		n = min(min(in_page, (unsigned int)sizeof(rc->data)) / size,
+			count);
+		if (n == 0)
+			n = 1;
+		rc->pos = rc->end = 0;
+		if (!ops->pio_in_emulated(size, port, rc->data, n, ctxt->vcpu))
+			return 0;
+		rc->end = n * size;
+	}
+
+	memcpy(dest, rc->data + rc->pos, size);
+	rc->pos += size;
+	return 1;
+}
+
+static u32 desc_limit_scaled(struct desc_struct *desc)
+{
+	u32 limit = get_desc_limit(desc);
+
+	return desc->g ? (limit << 12) | 0xfff : limit;
+}
+
+static void get_descriptor_table_ptr(struct x86_emulate_ctxt *ctxt,
+				     struct x86_emulate_ops *ops,
+				     u16 selector, struct desc_ptr *dt)
+{
+	if (selector & 1 << 2) {
+		struct desc_struct desc;
+		memset (dt, 0, sizeof *dt);
+		if (!ops->get_cached_descriptor(&desc, VCPU_SREG_LDTR, ctxt->vcpu))
+			return;
+
+		dt->size = desc_limit_scaled(&desc); /* what if limit > 65535? */
+		dt->address = get_desc_base(&desc);
+	} else
+		ops->get_gdt(dt, ctxt->vcpu);
+}
+
+/* allowed just for 8 bytes segments */
+static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt,
+				   struct x86_emulate_ops *ops,
+				   u16 selector, struct desc_struct *desc)
+{
+	struct desc_ptr dt;
+	u16 index = selector >> 3;
+	int ret;
+	u32 err;
+	ulong addr;
+
+	get_descriptor_table_ptr(ctxt, ops, selector, &dt);
+
+	if (dt.size < index * 8 + 7) {
+		kvm_inject_gp(ctxt->vcpu, selector & 0xfffc);
+		return X86EMUL_PROPAGATE_FAULT;
+	}
+	addr = dt.address + index * 8;
+	ret = ops->read_std(addr, desc, sizeof *desc, ctxt->vcpu,  &err);
+	if (ret == X86EMUL_PROPAGATE_FAULT)
+		kvm_inject_page_fault(ctxt->vcpu, addr, err);
+
+       return ret;
+}
+
+/* allowed just for 8 bytes segments */
+static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
+				    struct x86_emulate_ops *ops,
+				    u16 selector, struct desc_struct *desc)
+{
+	struct desc_ptr dt;
+	u16 index = selector >> 3;
+	u32 err;
+	ulong addr;
+	int ret;
+
+	get_descriptor_table_ptr(ctxt, ops, selector, &dt);
+
+	if (dt.size < index * 8 + 7) {
+		kvm_inject_gp(ctxt->vcpu, selector & 0xfffc);
+		return X86EMUL_PROPAGATE_FAULT;
+	}
+
+	addr = dt.address + index * 8;
+	ret = ops->write_std(addr, desc, sizeof *desc, ctxt->vcpu, &err);
+	if (ret == X86EMUL_PROPAGATE_FAULT)
+		kvm_inject_page_fault(ctxt->vcpu, addr, err);
+
+	return ret;
+}
+
+static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
+				   struct x86_emulate_ops *ops,
+				   u16 selector, int seg)
+{
+	struct desc_struct seg_desc;
+	u8 dpl, rpl, cpl;
+	unsigned err_vec = GP_VECTOR;
+	u32 err_code = 0;
+	bool null_selector = !(selector & ~0x3); /* 0000-0003 are null */
+	int ret;
+
+	memset(&seg_desc, 0, sizeof seg_desc);
+
+	if ((seg <= VCPU_SREG_GS && ctxt->mode == X86EMUL_MODE_VM86)
+	    || ctxt->mode == X86EMUL_MODE_REAL) {
+		/* set real mode segment descriptor */
+		set_desc_base(&seg_desc, selector << 4);
+		set_desc_limit(&seg_desc, 0xffff);
+		seg_desc.type = 3;
+		seg_desc.p = 1;
+		seg_desc.s = 1;
+		goto load;
+	}
+
+	/* NULL selector is not valid for TR, CS and SS */
+	if ((seg == VCPU_SREG_CS || seg == VCPU_SREG_SS || seg == VCPU_SREG_TR)
+	    && null_selector)
+		goto exception;
+
+	/* TR should be in GDT only */
+	if (seg == VCPU_SREG_TR && (selector & (1 << 2)))
+		goto exception;
+
+	if (null_selector) /* for NULL selector skip all following checks */
+		goto load;
+
+	ret = read_segment_descriptor(ctxt, ops, selector, &seg_desc);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+
+	err_code = selector & 0xfffc;
+	err_vec = GP_VECTOR;
+
+	/* can't load system descriptor into segment selecor */
+	if (seg <= VCPU_SREG_GS && !seg_desc.s)
+		goto exception;
+
+	if (!seg_desc.p) {
+		err_vec = (seg == VCPU_SREG_SS) ? SS_VECTOR : NP_VECTOR;
+		goto exception;
+	}
+
+	rpl = selector & 3;
+	dpl = seg_desc.dpl;
+	cpl = ops->cpl(ctxt->vcpu);
+
+	switch (seg) {
+	case VCPU_SREG_SS:
+		/*
+		 * segment is not a writable data segment or segment
+		 * selector's RPL != CPL or segment selector's RPL != CPL
+		 */
+		if (rpl != cpl || (seg_desc.type & 0xa) != 0x2 || dpl != cpl)
+			goto exception;
+		break;
+	case VCPU_SREG_CS:
+		if (!(seg_desc.type & 8))
+			goto exception;
+
+		if (seg_desc.type & 4) {
+			/* conforming */
+			if (dpl > cpl)
+				goto exception;
+		} else {
+			/* nonconforming */
+			if (rpl > cpl || dpl != cpl)
+				goto exception;
+		}
+		/* CS(RPL) <- CPL */
+		selector = (selector & 0xfffc) | cpl;
+		break;
+	case VCPU_SREG_TR:
+		if (seg_desc.s || (seg_desc.type != 1 && seg_desc.type != 9))
+			goto exception;
+		break;
+	case VCPU_SREG_LDTR:
+		if (seg_desc.s || seg_desc.type != 2)
+			goto exception;
+		break;
+	default: /*  DS, ES, FS, or GS */
+		/*
+		 * segment is not a data or readable code segment or
+		 * ((segment is a data or nonconforming code segment)
+		 * and (both RPL and CPL > DPL))
+		 */
+		if ((seg_desc.type & 0xa) == 0x8 ||
+		    (((seg_desc.type & 0xc) != 0xc) &&
+		     (rpl > dpl && cpl > dpl)))
+			goto exception;
+		break;
+	}
+
+	if (seg_desc.s) {
+		/* mark segment as accessed */
+		seg_desc.type |= 1;
+		ret = write_segment_descriptor(ctxt, ops, selector, &seg_desc);
+		if (ret != X86EMUL_CONTINUE)
+			return ret;
+	}
+load:
+	ops->set_segment_selector(selector, seg, ctxt->vcpu);
+	ops->set_cached_descriptor(&seg_desc, seg, ctxt->vcpu);
+	return X86EMUL_CONTINUE;
+exception:
+	kvm_queue_exception_e(ctxt->vcpu, err_vec, err_code);
+	return X86EMUL_PROPAGATE_FAULT;
+}
+
 static inline void emulate_push(struct x86_emulate_ctxt *ctxt)
 {
 	struct decode_cache *c = &ctxt->decode;
@@ -1251,7 +1521,7 @@ static int emulate_popf(struct x86_emulate_ctxt *ctxt,
 	int rc;
 	unsigned long val, change_mask;
 	int iopl = (ctxt->eflags & X86_EFLAGS_IOPL) >> IOPL_SHIFT;
-	int cpl = kvm_x86_ops->get_cpl(ctxt->vcpu);
+	int cpl = ops->cpl(ctxt->vcpu);
 
 	rc = emulate_pop(ctxt, ops, &val, len);
 	if (rc != X86EMUL_CONTINUE)
@@ -1306,10 +1576,10 @@ static int emulate_pop_sreg(struct x86_emulate_ctxt *ctxt,
 	int rc;
 
 	rc = emulate_pop(ctxt, ops, &selector, c->op_bytes);
-	if (rc != 0)
+	if (rc != X86EMUL_CONTINUE)
 		return rc;
 
-	rc = kvm_load_segment_descriptor(ctxt->vcpu, (u16)selector, seg);
+	rc = load_segment_descriptor(ctxt, ops, (u16)selector, seg);
 	return rc;
 }
 
@@ -1332,7 +1602,7 @@ static int emulate_popa(struct x86_emulate_ctxt *ctxt,
 			struct x86_emulate_ops *ops)
 {
 	struct decode_cache *c = &ctxt->decode;
-	int rc = 0;
+	int rc = X86EMUL_CONTINUE;
 	int reg = VCPU_REGS_RDI;
 
 	while (reg >= VCPU_REGS_RAX) {
@@ -1343,7 +1613,7 @@ static int emulate_popa(struct x86_emulate_ctxt *ctxt,
 		}
 
 		rc = emulate_pop(ctxt, ops, &c->regs[reg], c->op_bytes);
-		if (rc != 0)
+		if (rc != X86EMUL_CONTINUE)
 			break;
 		--reg;
 	}
@@ -1354,12 +1624,8 @@ static inline int emulate_grp1a(struct x86_emulate_ctxt *ctxt,
 				struct x86_emulate_ops *ops)
 {
 	struct decode_cache *c = &ctxt->decode;
-	int rc;
 
-	rc = emulate_pop(ctxt, ops, &c->dst.val, c->dst.bytes);
-	if (rc != 0)
-		return rc;
-	return 0;
+	return emulate_pop(ctxt, ops, &c->dst.val, c->dst.bytes);
 }
 
 static inline void emulate_grp2(struct x86_emulate_ctxt *ctxt)
@@ -1395,7 +1661,6 @@ static inline int emulate_grp3(struct x86_emulate_ctxt *ctxt,
 			       struct x86_emulate_ops *ops)
 {
 	struct decode_cache *c = &ctxt->decode;
-	int rc = 0;
 
 	switch (c->modrm_reg) {
 	case 0 ... 1:	/* test */
@@ -1408,11 +1673,9 @@ static inline int emulate_grp3(struct x86_emulate_ctxt *ctxt,
 		emulate_1op("neg", c->dst, ctxt->eflags);
 		break;
 	default:
-		DPRINTF("Cannot emulate %02x\n", c->b);
-		rc = X86EMUL_UNHANDLEABLE;
-		break;
+		return 0;
 	}
-	return rc;
+	return 1;
 }
 
 static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt,
@@ -1442,20 +1705,14 @@ static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt,
 		emulate_push(ctxt);
 		break;
 	}
-	return 0;
+	return X86EMUL_CONTINUE;
 }
 
 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);
-	if (rc != X86EMUL_CONTINUE)
-		return rc;
+	u64 old = c->dst.orig_val;
 
 	if (((u32) (old >> 0) != (u32) c->regs[VCPU_REGS_RAX]) ||
 	    ((u32) (old >> 32) != (u32) c->regs[VCPU_REGS_RDX])) {
@@ -1463,17 +1720,13 @@ static inline int emulate_grp9(struct x86_emulate_ctxt *ctxt,
 		c->regs[VCPU_REGS_RAX] = (u32) (old >> 0);
 		c->regs[VCPU_REGS_RDX] = (u32) (old >> 32);
 		ctxt->eflags &= ~EFLG_ZF;
-
 	} else {
-		new = ((u64)c->regs[VCPU_REGS_RCX] << 32) |
+		c->dst.val = ((u64)c->regs[VCPU_REGS_RCX] << 32) |
 		       (u32) c->regs[VCPU_REGS_RBX];
 
-		rc = ops->cmpxchg_emulated(memop, &old, &new, 8, ctxt->vcpu);
-		if (rc != X86EMUL_CONTINUE)
-			return rc;
 		ctxt->eflags |= EFLG_ZF;
 	}
-	return 0;
+	return X86EMUL_CONTINUE;
 }
 
 static int emulate_ret_far(struct x86_emulate_ctxt *ctxt,
@@ -1484,14 +1737,14 @@ static int emulate_ret_far(struct x86_emulate_ctxt *ctxt,
 	unsigned long cs;
 
 	rc = emulate_pop(ctxt, ops, &c->eip, c->op_bytes);
-	if (rc)
+	if (rc != X86EMUL_CONTINUE)
 		return rc;
 	if (c->op_bytes == 4)
 		c->eip = (u32)c->eip;
 	rc = emulate_pop(ctxt, ops, &cs, c->op_bytes);
-	if (rc)
+	if (rc != X86EMUL_CONTINUE)
 		return rc;
-	rc = kvm_load_segment_descriptor(ctxt->vcpu, (u16)cs, VCPU_SREG_CS);
+	rc = load_segment_descriptor(ctxt, ops, (u16)cs, VCPU_SREG_CS);
 	return rc;
 }
 
@@ -1544,7 +1797,7 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
 	default:
 		break;
 	}
-	return 0;
+	return X86EMUL_CONTINUE;
 }
 
 static void toggle_interruptibility(struct x86_emulate_ctxt *ctxt, u32 mask)
@@ -1598,8 +1851,11 @@ emulate_syscall(struct x86_emulate_ctxt *ctxt)
 	u64 msr_data;
 
 	/* syscall is not available in real mode */
-	if (ctxt->mode == X86EMUL_MODE_REAL || ctxt->mode == X86EMUL_MODE_VM86)
-		return X86EMUL_UNHANDLEABLE;
+	if (ctxt->mode == X86EMUL_MODE_REAL ||
+	    ctxt->mode == X86EMUL_MODE_VM86) {
+		kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+		return X86EMUL_PROPAGATE_FAULT;
+	}
 
 	setup_syscalls_segments(ctxt, &cs, &ss);
 
@@ -1649,14 +1905,16 @@ emulate_sysenter(struct x86_emulate_ctxt *ctxt)
 	/* inject #GP if in real mode */
 	if (ctxt->mode == X86EMUL_MODE_REAL) {
 		kvm_inject_gp(ctxt->vcpu, 0);
-		return X86EMUL_UNHANDLEABLE;
+		return X86EMUL_PROPAGATE_FAULT;
 	}
 
 	/* XXX sysenter/sysexit have not been tested in 64bit mode.
 	* Therefore, we inject an #UD.
 	*/
-	if (ctxt->mode == X86EMUL_MODE_PROT64)
-		return X86EMUL_UNHANDLEABLE;
+	if (ctxt->mode == X86EMUL_MODE_PROT64) {
+		kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+		return X86EMUL_PROPAGATE_FAULT;
+	}
 
 	setup_syscalls_segments(ctxt, &cs, &ss);
 
@@ -1711,7 +1969,7 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt)
 	if (ctxt->mode == X86EMUL_MODE_REAL ||
 	    ctxt->mode == X86EMUL_MODE_VM86) {
 		kvm_inject_gp(ctxt->vcpu, 0);
-		return X86EMUL_UNHANDLEABLE;
+		return X86EMUL_PROPAGATE_FAULT;
 	}
 
 	setup_syscalls_segments(ctxt, &cs, &ss);
@@ -1756,7 +2014,8 @@ emulate_sysexit(struct x86_emulate_ctxt *ctxt)
 	return X86EMUL_CONTINUE;
 }
 
-static bool emulator_bad_iopl(struct x86_emulate_ctxt *ctxt)
+static bool emulator_bad_iopl(struct x86_emulate_ctxt *ctxt,
+			      struct x86_emulate_ops *ops)
 {
 	int iopl;
 	if (ctxt->mode == X86EMUL_MODE_REAL)
@@ -1764,7 +2023,7 @@ static bool emulator_bad_iopl(struct x86_emulate_ctxt *ctxt)
 	if (ctxt->mode == X86EMUL_MODE_VM86)
 		return true;
 	iopl = (ctxt->eflags & X86_EFLAGS_IOPL) >> IOPL_SHIFT;
-	return kvm_x86_ops->get_cpl(ctxt->vcpu) > iopl;
+	return ops->cpl(ctxt->vcpu) > iopl;
 }
 
 static bool emulator_io_port_access_allowed(struct x86_emulate_ctxt *ctxt,
@@ -1801,22 +2060,419 @@ static bool emulator_io_permited(struct x86_emulate_ctxt *ctxt,
 				 struct x86_emulate_ops *ops,
 				 u16 port, u16 len)
 {
-	if (emulator_bad_iopl(ctxt))
+	if (emulator_bad_iopl(ctxt, ops))
 		if (!emulator_io_port_access_allowed(ctxt, ops, port, len))
 			return false;
 	return true;
 }
 
+static u32 get_cached_descriptor_base(struct x86_emulate_ctxt *ctxt,
+				      struct x86_emulate_ops *ops,
+				      int seg)
+{
+	struct desc_struct desc;
+	if (ops->get_cached_descriptor(&desc, seg, ctxt->vcpu))
+		return get_desc_base(&desc);
+	else
+		return ~0;
+}
+
+static void save_state_to_tss16(struct x86_emulate_ctxt *ctxt,
+				struct x86_emulate_ops *ops,
+				struct tss_segment_16 *tss)
+{
+	struct decode_cache *c = &ctxt->decode;
+
+	tss->ip = c->eip;
+	tss->flag = ctxt->eflags;
+	tss->ax = c->regs[VCPU_REGS_RAX];
+	tss->cx = c->regs[VCPU_REGS_RCX];
+	tss->dx = c->regs[VCPU_REGS_RDX];
+	tss->bx = c->regs[VCPU_REGS_RBX];
+	tss->sp = c->regs[VCPU_REGS_RSP];
+	tss->bp = c->regs[VCPU_REGS_RBP];
+	tss->si = c->regs[VCPU_REGS_RSI];
+	tss->di = c->regs[VCPU_REGS_RDI];
+
+	tss->es = ops->get_segment_selector(VCPU_SREG_ES, ctxt->vcpu);
+	tss->cs = ops->get_segment_selector(VCPU_SREG_CS, ctxt->vcpu);
+	tss->ss = ops->get_segment_selector(VCPU_SREG_SS, ctxt->vcpu);
+	tss->ds = ops->get_segment_selector(VCPU_SREG_DS, ctxt->vcpu);
+	tss->ldt = ops->get_segment_selector(VCPU_SREG_LDTR, ctxt->vcpu);
+}
+
+static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt,
+				 struct x86_emulate_ops *ops,
+				 struct tss_segment_16 *tss)
+{
+	struct decode_cache *c = &ctxt->decode;
+	int ret;
+
+	c->eip = tss->ip;
+	ctxt->eflags = tss->flag | 2;
+	c->regs[VCPU_REGS_RAX] = tss->ax;
+	c->regs[VCPU_REGS_RCX] = tss->cx;
+	c->regs[VCPU_REGS_RDX] = tss->dx;
+	c->regs[VCPU_REGS_RBX] = tss->bx;
+	c->regs[VCPU_REGS_RSP] = tss->sp;
+	c->regs[VCPU_REGS_RBP] = tss->bp;
+	c->regs[VCPU_REGS_RSI] = tss->si;
+	c->regs[VCPU_REGS_RDI] = tss->di;
+
+	/*
+	 * SDM says that segment selectors are loaded before segment
+	 * descriptors
+	 */
+	ops->set_segment_selector(tss->ldt, VCPU_SREG_LDTR, ctxt->vcpu);
+	ops->set_segment_selector(tss->es, VCPU_SREG_ES, ctxt->vcpu);
+	ops->set_segment_selector(tss->cs, VCPU_SREG_CS, ctxt->vcpu);
+	ops->set_segment_selector(tss->ss, VCPU_SREG_SS, ctxt->vcpu);
+	ops->set_segment_selector(tss->ds, VCPU_SREG_DS, ctxt->vcpu);
+
+	/*
+	 * Now load segment descriptors. If fault happenes at this stage
+	 * it is handled in a context of new task
+	 */
+	ret = load_segment_descriptor(ctxt, ops, tss->ldt, VCPU_SREG_LDTR);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+	ret = load_segment_descriptor(ctxt, ops, tss->es, VCPU_SREG_ES);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+	ret = load_segment_descriptor(ctxt, ops, tss->cs, VCPU_SREG_CS);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+	ret = load_segment_descriptor(ctxt, ops, tss->ss, VCPU_SREG_SS);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+	ret = load_segment_descriptor(ctxt, ops, tss->ds, VCPU_SREG_DS);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+
+	return X86EMUL_CONTINUE;
+}
+
+static int task_switch_16(struct x86_emulate_ctxt *ctxt,
+			  struct x86_emulate_ops *ops,
+			  u16 tss_selector, u16 old_tss_sel,
+			  ulong old_tss_base, struct desc_struct *new_desc)
+{
+	struct tss_segment_16 tss_seg;
+	int ret;
+	u32 err, new_tss_base = get_desc_base(new_desc);
+
+	ret = ops->read_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
+			    &err);
+	if (ret == X86EMUL_PROPAGATE_FAULT) {
+		/* FIXME: need to provide precise fault address */
+		kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+		return ret;
+	}
+
+	save_state_to_tss16(ctxt, ops, &tss_seg);
+
+	ret = ops->write_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
+			     &err);
+	if (ret == X86EMUL_PROPAGATE_FAULT) {
+		/* FIXME: need to provide precise fault address */
+		kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+		return ret;
+	}
+
+	ret = ops->read_std(new_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
+			    &err);
+	if (ret == X86EMUL_PROPAGATE_FAULT) {
+		/* FIXME: need to provide precise fault address */
+		kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+		return ret;
+	}
+
+	if (old_tss_sel != 0xffff) {
+		tss_seg.prev_task_link = old_tss_sel;
+
+		ret = ops->write_std(new_tss_base,
+				     &tss_seg.prev_task_link,
+				     sizeof tss_seg.prev_task_link,
+				     ctxt->vcpu, &err);
+		if (ret == X86EMUL_PROPAGATE_FAULT) {
+			/* FIXME: need to provide precise fault address */
+			kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+			return ret;
+		}
+	}
+
+	return load_state_from_tss16(ctxt, ops, &tss_seg);
+}
+
+static void save_state_to_tss32(struct x86_emulate_ctxt *ctxt,
+				struct x86_emulate_ops *ops,
+				struct tss_segment_32 *tss)
+{
+	struct decode_cache *c = &ctxt->decode;
+
+	tss->cr3 = ops->get_cr(3, ctxt->vcpu);
+	tss->eip = c->eip;
+	tss->eflags = ctxt->eflags;
+	tss->eax = c->regs[VCPU_REGS_RAX];
+	tss->ecx = c->regs[VCPU_REGS_RCX];
+	tss->edx = c->regs[VCPU_REGS_RDX];
+	tss->ebx = c->regs[VCPU_REGS_RBX];
+	tss->esp = c->regs[VCPU_REGS_RSP];
+	tss->ebp = c->regs[VCPU_REGS_RBP];
+	tss->esi = c->regs[VCPU_REGS_RSI];
+	tss->edi = c->regs[VCPU_REGS_RDI];
+
+	tss->es = ops->get_segment_selector(VCPU_SREG_ES, ctxt->vcpu);
+	tss->cs = ops->get_segment_selector(VCPU_SREG_CS, ctxt->vcpu);
+	tss->ss = ops->get_segment_selector(VCPU_SREG_SS, ctxt->vcpu);
+	tss->ds = ops->get_segment_selector(VCPU_SREG_DS, ctxt->vcpu);
+	tss->fs = ops->get_segment_selector(VCPU_SREG_FS, ctxt->vcpu);
+	tss->gs = ops->get_segment_selector(VCPU_SREG_GS, ctxt->vcpu);
+	tss->ldt_selector = ops->get_segment_selector(VCPU_SREG_LDTR, ctxt->vcpu);
+}
+
+static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
+				 struct x86_emulate_ops *ops,
+				 struct tss_segment_32 *tss)
+{
+	struct decode_cache *c = &ctxt->decode;
+	int ret;
+
+	ops->set_cr(3, tss->cr3, ctxt->vcpu);
+	c->eip = tss->eip;
+	ctxt->eflags = tss->eflags | 2;
+	c->regs[VCPU_REGS_RAX] = tss->eax;
+	c->regs[VCPU_REGS_RCX] = tss->ecx;
+	c->regs[VCPU_REGS_RDX] = tss->edx;
+	c->regs[VCPU_REGS_RBX] = tss->ebx;
+	c->regs[VCPU_REGS_RSP] = tss->esp;
+	c->regs[VCPU_REGS_RBP] = tss->ebp;
+	c->regs[VCPU_REGS_RSI] = tss->esi;
+	c->regs[VCPU_REGS_RDI] = tss->edi;
+
+	/*
+	 * SDM says that segment selectors are loaded before segment
+	 * descriptors
+	 */
+	ops->set_segment_selector(tss->ldt_selector, VCPU_SREG_LDTR, ctxt->vcpu);
+	ops->set_segment_selector(tss->es, VCPU_SREG_ES, ctxt->vcpu);
+	ops->set_segment_selector(tss->cs, VCPU_SREG_CS, ctxt->vcpu);
+	ops->set_segment_selector(tss->ss, VCPU_SREG_SS, ctxt->vcpu);
+	ops->set_segment_selector(tss->ds, VCPU_SREG_DS, ctxt->vcpu);
+	ops->set_segment_selector(tss->fs, VCPU_SREG_FS, ctxt->vcpu);
+	ops->set_segment_selector(tss->gs, VCPU_SREG_GS, ctxt->vcpu);
+
+	/*
+	 * Now load segment descriptors. If fault happenes at this stage
+	 * it is handled in a context of new task
+	 */
+	ret = load_segment_descriptor(ctxt, ops, tss->ldt_selector, VCPU_SREG_LDTR);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+	ret = load_segment_descriptor(ctxt, ops, tss->es, VCPU_SREG_ES);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+	ret = load_segment_descriptor(ctxt, ops, tss->cs, VCPU_SREG_CS);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+	ret = load_segment_descriptor(ctxt, ops, tss->ss, VCPU_SREG_SS);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+	ret = load_segment_descriptor(ctxt, ops, tss->ds, VCPU_SREG_DS);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+	ret = load_segment_descriptor(ctxt, ops, tss->fs, VCPU_SREG_FS);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+	ret = load_segment_descriptor(ctxt, ops, tss->gs, VCPU_SREG_GS);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+
+	return X86EMUL_CONTINUE;
+}
+
+static int task_switch_32(struct x86_emulate_ctxt *ctxt,
+			  struct x86_emulate_ops *ops,
+			  u16 tss_selector, u16 old_tss_sel,
+			  ulong old_tss_base, struct desc_struct *new_desc)
+{
+	struct tss_segment_32 tss_seg;
+	int ret;
+	u32 err, new_tss_base = get_desc_base(new_desc);
+
+	ret = ops->read_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
+			    &err);
+	if (ret == X86EMUL_PROPAGATE_FAULT) {
+		/* FIXME: need to provide precise fault address */
+		kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+		return ret;
+	}
+
+	save_state_to_tss32(ctxt, ops, &tss_seg);
+
+	ret = ops->write_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
+			     &err);
+	if (ret == X86EMUL_PROPAGATE_FAULT) {
+		/* FIXME: need to provide precise fault address */
+		kvm_inject_page_fault(ctxt->vcpu, old_tss_base, err);
+		return ret;
+	}
+
+	ret = ops->read_std(new_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
+			    &err);
+	if (ret == X86EMUL_PROPAGATE_FAULT) {
+		/* FIXME: need to provide precise fault address */
+		kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+		return ret;
+	}
+
+	if (old_tss_sel != 0xffff) {
+		tss_seg.prev_task_link = old_tss_sel;
+
+		ret = ops->write_std(new_tss_base,
+				     &tss_seg.prev_task_link,
+				     sizeof tss_seg.prev_task_link,
+				     ctxt->vcpu, &err);
+		if (ret == X86EMUL_PROPAGATE_FAULT) {
+			/* FIXME: need to provide precise fault address */
+			kvm_inject_page_fault(ctxt->vcpu, new_tss_base, err);
+			return ret;
+		}
+	}
+
+	return load_state_from_tss32(ctxt, ops, &tss_seg);
+}
+
+static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
+				   struct x86_emulate_ops *ops,
+				   u16 tss_selector, int reason,
+				   bool has_error_code, u32 error_code)
+{
+	struct desc_struct curr_tss_desc, next_tss_desc;
+	int ret;
+	u16 old_tss_sel = ops->get_segment_selector(VCPU_SREG_TR, ctxt->vcpu);
+	ulong old_tss_base =
+		get_cached_descriptor_base(ctxt, ops, VCPU_SREG_TR);
+	u32 desc_limit;
+
+	/* FIXME: old_tss_base == ~0 ? */
+
+	ret = read_segment_descriptor(ctxt, ops, tss_selector, &next_tss_desc);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+	ret = read_segment_descriptor(ctxt, ops, old_tss_sel, &curr_tss_desc);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+
+	/* FIXME: check that next_tss_desc is tss */
+
+	if (reason != TASK_SWITCH_IRET) {
+		if ((tss_selector & 3) > next_tss_desc.dpl ||
+		    ops->cpl(ctxt->vcpu) > next_tss_desc.dpl) {
+			kvm_inject_gp(ctxt->vcpu, 0);
+			return X86EMUL_PROPAGATE_FAULT;
+		}
+	}
+
+	desc_limit = desc_limit_scaled(&next_tss_desc);
+	if (!next_tss_desc.p ||
+	    ((desc_limit < 0x67 && (next_tss_desc.type & 8)) ||
+	     desc_limit < 0x2b)) {
+		kvm_queue_exception_e(ctxt->vcpu, TS_VECTOR,
+				      tss_selector & 0xfffc);
+		return X86EMUL_PROPAGATE_FAULT;
+	}
+
+	if (reason == TASK_SWITCH_IRET || reason == TASK_SWITCH_JMP) {
+		curr_tss_desc.type &= ~(1 << 1); /* clear busy flag */
+		write_segment_descriptor(ctxt, ops, old_tss_sel,
+					 &curr_tss_desc);
+	}
+
+	if (reason == TASK_SWITCH_IRET)
+		ctxt->eflags = ctxt->eflags & ~X86_EFLAGS_NT;
+
+	/* set back link to prev task only if NT bit is set in eflags
+	   note that old_tss_sel is not used afetr this point */
+	if (reason != TASK_SWITCH_CALL && reason != TASK_SWITCH_GATE)
+		old_tss_sel = 0xffff;
+
+	if (next_tss_desc.type & 8)
+		ret = task_switch_32(ctxt, ops, tss_selector, old_tss_sel,
+				     old_tss_base, &next_tss_desc);
+	else
+		ret = task_switch_16(ctxt, ops, tss_selector, old_tss_sel,
+				     old_tss_base, &next_tss_desc);
+	if (ret != X86EMUL_CONTINUE)
+		return ret;
+
+	if (reason == TASK_SWITCH_CALL || reason == TASK_SWITCH_GATE)
+		ctxt->eflags = ctxt->eflags | X86_EFLAGS_NT;
+
+	if (reason != TASK_SWITCH_IRET) {
+		next_tss_desc.type |= (1 << 1); /* set busy flag */
+		write_segment_descriptor(ctxt, ops, tss_selector,
+					 &next_tss_desc);
+	}
+
+	ops->set_cr(0,  ops->get_cr(0, ctxt->vcpu) | X86_CR0_TS, ctxt->vcpu);
+	ops->set_cached_descriptor(&next_tss_desc, VCPU_SREG_TR, ctxt->vcpu);
+	ops->set_segment_selector(tss_selector, VCPU_SREG_TR, ctxt->vcpu);
+
+	if (has_error_code) {
+		struct decode_cache *c = &ctxt->decode;
+
+		c->op_bytes = c->ad_bytes = (next_tss_desc.type & 8) ? 4 : 2;
+		c->lock_prefix = 0;
+		c->src.val = (unsigned long) error_code;
+		emulate_push(ctxt);
+	}
+
+	return ret;
+}
+
+int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
+			 struct x86_emulate_ops *ops,
+			 u16 tss_selector, int reason,
+			 bool has_error_code, u32 error_code)
+{
+	struct decode_cache *c = &ctxt->decode;
+	int rc;
+
+	memset(c, 0, sizeof(struct decode_cache));
+	c->eip = ctxt->eip;
+	memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs);
+	c->dst.type = OP_NONE;
+
+	rc = emulator_do_task_switch(ctxt, ops, tss_selector, reason,
+				     has_error_code, error_code);
+
+	if (rc == X86EMUL_CONTINUE) {
+		memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs);
+		kvm_rip_write(ctxt->vcpu, c->eip);
+		rc = writeback(ctxt, ops);
+	}
+
+	return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
+}
+
+static void string_addr_inc(struct x86_emulate_ctxt *ctxt, unsigned long base,
+			    int reg, struct operand *op)
+{
+	struct decode_cache *c = &ctxt->decode;
+	int df = (ctxt->eflags & EFLG_DF) ? -1 : 1;
+
+	register_address_increment(c, &c->regs[reg], df * op->bytes);
+	op->ptr = (unsigned long *)register_address(c,  base, c->regs[reg]);
+}
+
 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;
-	unsigned int port;
-	int io_dir_in;
-	int rc = 0;
+	int rc = X86EMUL_CONTINUE;
+	int saved_dst_type = c->dst.type;
 
 	ctxt->interruptibility = 0;
 
@@ -1826,26 +2482,30 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 	 */
 
 	memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs);
-	saved_eip = c->eip;
+
+	if (ctxt->mode == X86EMUL_MODE_PROT64 && (c->d & No64)) {
+		kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+		goto done;
+	}
 
 	/* LOCK prefix is allowed only with some instructions */
-	if (c->lock_prefix && !(c->d & Lock)) {
+	if (c->lock_prefix && (!(c->d & Lock) || c->dst.type != OP_MEM)) {
 		kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
 		goto done;
 	}
 
 	/* Privileged instruction can be executed only in CPL=0 */
-	if ((c->d & Priv) && kvm_x86_ops->get_cpl(ctxt->vcpu)) {
+	if ((c->d & Priv) && ops->cpl(ctxt->vcpu)) {
 		kvm_inject_gp(ctxt->vcpu, 0);
 		goto done;
 	}
 
-	if (((c->d & ModRM) && (c->modrm_mod != 3)) || (c->d & MemAbs))
-		memop = c->modrm_ea;
-
 	if (c->rep_prefix && (c->d & String)) {
+		ctxt->restart = true;
 		/* All REP prefixes have the same first termination condition */
-		if (c->regs[VCPU_REGS_RCX] == 0) {
+		if (address_mask(c, c->regs[VCPU_REGS_RCX]) == 0) {
+		string_done:
+			ctxt->restart = false;
 			kvm_rip_write(ctxt->vcpu, c->eip);
 			goto done;
 		}
@@ -1857,25 +2517,18 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 		 * 	- if REPNE/REPNZ and ZF = 1 then done
 		 */
 		if ((c->b == 0xa6) || (c->b == 0xa7) ||
-				(c->b == 0xae) || (c->b == 0xaf)) {
+		    (c->b == 0xae) || (c->b == 0xaf)) {
 			if ((c->rep_prefix == REPE_PREFIX) &&
-				((ctxt->eflags & EFLG_ZF) == 0)) {
-					kvm_rip_write(ctxt->vcpu, c->eip);
-					goto done;
-			}
+			    ((ctxt->eflags & EFLG_ZF) == 0))
+				goto string_done;
 			if ((c->rep_prefix == REPNE_PREFIX) &&
-				((ctxt->eflags & EFLG_ZF) == EFLG_ZF)) {
-				kvm_rip_write(ctxt->vcpu, c->eip);
-				goto done;
-			}
+			    ((ctxt->eflags & EFLG_ZF) == EFLG_ZF))
+				goto string_done;
 		}
-		c->regs[VCPU_REGS_RCX]--;
-		c->eip = kvm_rip_read(ctxt->vcpu);
+		c->eip = ctxt->eip;
 	}
 
 	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,
@@ -1885,29 +2538,25 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 		c->src.orig_val = c->src.val;
 	}
 
+	if (c->src2.type == OP_MEM) {
+		rc = ops->read_emulated((unsigned long)c->src2.ptr,
+					&c->src2.val,
+					c->src2.bytes,
+					ctxt->vcpu);
+		if (rc != X86EMUL_CONTINUE)
+			goto done;
+	}
+
 	if ((c->d & DstMask) == ImplicitOps)
 		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;
 
@@ -1926,7 +2575,7 @@ special_insn:
 		break;
 	case 0x07:		/* pop es */
 		rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_ES);
-		if (rc != 0)
+		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		break;
 	case 0x08 ... 0x0d:
@@ -1945,7 +2594,7 @@ special_insn:
 		break;
 	case 0x17:		/* pop ss */
 		rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_SS);
-		if (rc != 0)
+		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		break;
 	case 0x18 ... 0x1d:
@@ -1957,7 +2606,7 @@ special_insn:
 		break;
 	case 0x1f:		/* pop ds */
 		rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_DS);
-		if (rc != 0)
+		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		break;
 	case 0x20 ... 0x25:
@@ -1988,7 +2637,7 @@ special_insn:
 	case 0x58 ... 0x5f: /* pop reg */
 	pop_instruction:
 		rc = emulate_pop(ctxt, ops, &c->dst.val, c->op_bytes);
-		if (rc != 0)
+		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		break;
 	case 0x60:	/* pusha */
@@ -1996,7 +2645,7 @@ special_insn:
 		break;
 	case 0x61:	/* popa */
 		rc = emulate_popa(ctxt, ops);
-		if (rc != 0)
+		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		break;
 	case 0x63:		/* movsxd */
@@ -2010,47 +2659,29 @@ special_insn:
 		break;
 	case 0x6c:		/* insb */
 	case 0x6d:		/* insw/insd */
+		c->dst.bytes = min(c->dst.bytes, 4u);
 		if (!emulator_io_permited(ctxt, ops, c->regs[VCPU_REGS_RDX],
-					  (c->d & ByteOp) ? 1 : c->op_bytes)) {
+					  c->dst.bytes)) {
 			kvm_inject_gp(ctxt->vcpu, 0);
 			goto done;
 		}
-		if (kvm_emulate_pio_string(ctxt->vcpu,
-				1,
-				(c->d & ByteOp) ? 1 : c->op_bytes,
-				c->rep_prefix ?
-				address_mask(c, c->regs[VCPU_REGS_RCX]) : 1,
-				(ctxt->eflags & EFLG_DF),
-				register_address(c, es_base(ctxt),
-						 c->regs[VCPU_REGS_RDI]),
-				c->rep_prefix,
-				c->regs[VCPU_REGS_RDX]) == 0) {
-			c->eip = saved_eip;
-			return -1;
-		}
-		return 0;
+		if (!pio_in_emulated(ctxt, ops, c->dst.bytes,
+				     c->regs[VCPU_REGS_RDX], &c->dst.val))
+			goto done; /* IO is needed, skip writeback */
+		break;
 	case 0x6e:		/* outsb */
 	case 0x6f:		/* outsw/outsd */
+		c->src.bytes = min(c->src.bytes, 4u);
 		if (!emulator_io_permited(ctxt, ops, c->regs[VCPU_REGS_RDX],
-					  (c->d & ByteOp) ? 1 : c->op_bytes)) {
+					  c->src.bytes)) {
 			kvm_inject_gp(ctxt->vcpu, 0);
 			goto done;
 		}
-		if (kvm_emulate_pio_string(ctxt->vcpu,
-				0,
-				(c->d & ByteOp) ? 1 : c->op_bytes,
-				c->rep_prefix ?
-				address_mask(c, c->regs[VCPU_REGS_RCX]) : 1,
-				(ctxt->eflags & EFLG_DF),
-					 register_address(c,
-					  seg_override_base(ctxt, c),
-						 c->regs[VCPU_REGS_RSI]),
-				c->rep_prefix,
-				c->regs[VCPU_REGS_RDX]) == 0) {
-			c->eip = saved_eip;
-			return -1;
-		}
-		return 0;
+		ops->pio_out_emulated(c->src.bytes, c->regs[VCPU_REGS_RDX],
+				      &c->src.val, 1, ctxt->vcpu);
+
+		c->dst.type = OP_NONE; /* nothing to writeback */
+		break;
 	case 0x70 ... 0x7f: /* jcc (short) */
 		if (test_cc(c->b, ctxt->eflags))
 			jmp_rel(c, c->src.val);
@@ -2107,12 +2738,11 @@ special_insn:
 	case 0x8c: { /* mov r/m, sreg */
 		struct kvm_segment segreg;
 
-		if (c->modrm_reg <= 5)
+		if (c->modrm_reg <= VCPU_SREG_GS)
 			kvm_get_segment(ctxt->vcpu, &segreg, c->modrm_reg);
 		else {
-			printk(KERN_INFO "0x8c: Invalid segreg in modrm byte 0x%02x\n",
-			       c->modrm);
-			goto cannot_emulate;
+			kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+			goto done;
 		}
 		c->dst.val = segreg.selector;
 		break;
@@ -2132,16 +2762,16 @@ special_insn:
 		}
 
 		if (c->modrm_reg == VCPU_SREG_SS)
-			toggle_interruptibility(ctxt, X86_SHADOW_INT_MOV_SS);
+			toggle_interruptibility(ctxt, KVM_X86_SHADOW_INT_MOV_SS);
 
-		rc = kvm_load_segment_descriptor(ctxt->vcpu, sel, c->modrm_reg);
+		rc = load_segment_descriptor(ctxt, ops, sel, c->modrm_reg);
 
 		c->dst.type = OP_NONE;  /* Disable writeback. */
 		break;
 	}
 	case 0x8f:		/* pop (sole member of Grp1a) */
 		rc = emulate_grp1a(ctxt, ops);
-		if (rc != 0)
+		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		break;
 	case 0x90: /* nop / xchg r8,rax */
@@ -2175,89 +2805,16 @@ special_insn:
 		c->dst.val = (unsigned long)c->regs[VCPU_REGS_RAX];
 		break;
 	case 0xa4 ... 0xa5:	/* movs */
-		c->dst.type = OP_MEM;
-		c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-		c->dst.ptr = (unsigned long *)register_address(c,
-						   es_base(ctxt),
-						   c->regs[VCPU_REGS_RDI]);
-		rc = ops->read_emulated(register_address(c,
-						seg_override_base(ctxt, c),
-						c->regs[VCPU_REGS_RSI]),
-					&c->dst.val,
-					c->dst.bytes, ctxt->vcpu);
-		if (rc != X86EMUL_CONTINUE)
-			goto done;
-		register_address_increment(c, &c->regs[VCPU_REGS_RSI],
-				       (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
-							   : c->dst.bytes);
-		register_address_increment(c, &c->regs[VCPU_REGS_RDI],
-				       (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
-							   : c->dst.bytes);
-		break;
+		goto mov;
 	case 0xa6 ... 0xa7:	/* cmps */
-		c->src.type = OP_NONE; /* Disable writeback. */
-		c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-		c->src.ptr = (unsigned long *)register_address(c,
-				       seg_override_base(ctxt, c),
-						   c->regs[VCPU_REGS_RSI]);
-		rc = ops->read_emulated((unsigned long)c->src.ptr,
-					&c->src.val,
-					c->src.bytes,
-					ctxt->vcpu);
-		if (rc != X86EMUL_CONTINUE)
-			goto done;
-
 		c->dst.type = OP_NONE; /* Disable writeback. */
-		c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-		c->dst.ptr = (unsigned long *)register_address(c,
-						   es_base(ctxt),
-						   c->regs[VCPU_REGS_RDI]);
-		rc = ops->read_emulated((unsigned long)c->dst.ptr,
-					&c->dst.val,
-					c->dst.bytes,
-					ctxt->vcpu);
-		if (rc != X86EMUL_CONTINUE)
-			goto done;
-
 		DPRINTF("cmps: mem1=0x%p mem2=0x%p\n", c->src.ptr, c->dst.ptr);
-
-		emulate_2op_SrcV("cmp", c->src, c->dst, ctxt->eflags);
-
-		register_address_increment(c, &c->regs[VCPU_REGS_RSI],
-				       (ctxt->eflags & EFLG_DF) ? -c->src.bytes
-								  : c->src.bytes);
-		register_address_increment(c, &c->regs[VCPU_REGS_RDI],
-				       (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
-								  : c->dst.bytes);
-
-		break;
+		goto cmp;
 	case 0xaa ... 0xab:	/* stos */
-		c->dst.type = OP_MEM;
-		c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-		c->dst.ptr = (unsigned long *)register_address(c,
-						   es_base(ctxt),
-						   c->regs[VCPU_REGS_RDI]);
 		c->dst.val = c->regs[VCPU_REGS_RAX];
-		register_address_increment(c, &c->regs[VCPU_REGS_RDI],
-				       (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
-							   : c->dst.bytes);
 		break;
 	case 0xac ... 0xad:	/* lods */
-		c->dst.type = OP_REG;
-		c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-		c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
-		rc = ops->read_emulated(register_address(c,
-						seg_override_base(ctxt, c),
-						c->regs[VCPU_REGS_RSI]),
-					&c->dst.val,
-					c->dst.bytes,
-					ctxt->vcpu);
-		if (rc != X86EMUL_CONTINUE)
-			goto done;
-		register_address_increment(c, &c->regs[VCPU_REGS_RSI],
-				       (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
-							   : c->dst.bytes);
-		break;
+		goto mov;
 	case 0xae ... 0xaf:	/* scas */
 		DPRINTF("Urk! I don't handle SCAS.\n");
 		goto cannot_emulate;
@@ -2277,7 +2834,7 @@ special_insn:
 		break;
 	case 0xcb:		/* ret far */
 		rc = emulate_ret_far(ctxt, ops);
-		if (rc)
+		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		break;
 	case 0xd0 ... 0xd1:	/* Grp2 */
@@ -2290,14 +2847,10 @@ special_insn:
 		break;
 	case 0xe4: 	/* inb */
 	case 0xe5: 	/* in */
-		port = c->src.val;
-		io_dir_in = 1;
-		goto do_io;
+		goto do_io_in;
 	case 0xe6: /* outb */
 	case 0xe7: /* out */
-		port = c->src.val;
-		io_dir_in = 0;
-		goto do_io;
+		goto do_io_out;
 	case 0xe8: /* call (near) */ {
 		long int rel = c->src.val;
 		c->src.val = (unsigned long) c->eip;
@@ -2308,8 +2861,9 @@ special_insn:
 	case 0xe9: /* jmp rel */
 		goto jmp;
 	case 0xea: /* jmp far */
-		if (kvm_load_segment_descriptor(ctxt->vcpu, c->src2.val,
-						VCPU_SREG_CS))
+	jump_far:
+		if (load_segment_descriptor(ctxt, ops, c->src2.val,
+					    VCPU_SREG_CS))
 			goto done;
 
 		c->eip = c->src.val;
@@ -2321,25 +2875,29 @@ special_insn:
 		break;
 	case 0xec: /* in al,dx */
 	case 0xed: /* in (e/r)ax,dx */
-		port = c->regs[VCPU_REGS_RDX];
-		io_dir_in = 1;
-		goto do_io;
+		c->src.val = c->regs[VCPU_REGS_RDX];
+	do_io_in:
+		c->dst.bytes = min(c->dst.bytes, 4u);
+		if (!emulator_io_permited(ctxt, ops, c->src.val, c->dst.bytes)) {
+			kvm_inject_gp(ctxt->vcpu, 0);
+			goto done;
+		}
+		if (!pio_in_emulated(ctxt, ops, c->dst.bytes, c->src.val,
+				     &c->dst.val))
+			goto done; /* IO is needed */
+		break;
 	case 0xee: /* out al,dx */
 	case 0xef: /* out (e/r)ax,dx */
-		port = c->regs[VCPU_REGS_RDX];
-		io_dir_in = 0;
-	do_io:
-		if (!emulator_io_permited(ctxt, ops, port,
-					  (c->d & ByteOp) ? 1 : c->op_bytes)) {
+		c->src.val = c->regs[VCPU_REGS_RDX];
+	do_io_out:
+		c->dst.bytes = min(c->dst.bytes, 4u);
+		if (!emulator_io_permited(ctxt, ops, c->src.val, c->dst.bytes)) {
 			kvm_inject_gp(ctxt->vcpu, 0);
 			goto done;
 		}
-		if (kvm_emulate_pio(ctxt->vcpu, io_dir_in,
-				   (c->d & ByteOp) ? 1 : c->op_bytes,
-				   port) != 0) {
-			c->eip = saved_eip;
-			goto cannot_emulate;
-		}
+		ops->pio_out_emulated(c->dst.bytes, c->src.val, &c->dst.val, 1,
+				      ctxt->vcpu);
+		c->dst.type = OP_NONE;	/* Disable writeback. */
 		break;
 	case 0xf4:              /* hlt */
 		ctxt->vcpu->arch.halt_request = 1;
@@ -2350,16 +2908,15 @@ special_insn:
 		c->dst.type = OP_NONE;	/* Disable writeback. */
 		break;
 	case 0xf6 ... 0xf7:	/* Grp3 */
-		rc = emulate_grp3(ctxt, ops);
-		if (rc != 0)
-			goto done;
+		if (!emulate_grp3(ctxt, ops))
+			goto cannot_emulate;
 		break;
 	case 0xf8: /* clc */
 		ctxt->eflags &= ~EFLG_CF;
 		c->dst.type = OP_NONE;	/* Disable writeback. */
 		break;
 	case 0xfa: /* cli */
-		if (emulator_bad_iopl(ctxt))
+		if (emulator_bad_iopl(ctxt, ops))
 			kvm_inject_gp(ctxt->vcpu, 0);
 		else {
 			ctxt->eflags &= ~X86_EFLAGS_IF;
@@ -2367,10 +2924,10 @@ special_insn:
 		}
 		break;
 	case 0xfb: /* sti */
-		if (emulator_bad_iopl(ctxt))
+		if (emulator_bad_iopl(ctxt, ops))
 			kvm_inject_gp(ctxt->vcpu, 0);
 		else {
-			toggle_interruptibility(ctxt, X86_SHADOW_INT_STI);
+			toggle_interruptibility(ctxt, KVM_X86_SHADOW_INT_STI);
 			ctxt->eflags |= X86_EFLAGS_IF;
 			c->dst.type = OP_NONE;	/* Disable writeback. */
 		}
@@ -2383,28 +2940,55 @@ special_insn:
 		ctxt->eflags |= EFLG_DF;
 		c->dst.type = OP_NONE;	/* Disable writeback. */
 		break;
-	case 0xfe ... 0xff:	/* Grp4/Grp5 */
+	case 0xfe: /* Grp4 */
+	grp45:
 		rc = emulate_grp45(ctxt, ops);
-		if (rc != 0)
+		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		break;
+	case 0xff: /* Grp5 */
+		if (c->modrm_reg == 5)
+			goto jump_far;
+		goto grp45;
 	}
 
 writeback:
 	rc = writeback(ctxt, ops);
-	if (rc != 0)
+	if (rc != X86EMUL_CONTINUE)
 		goto done;
 
+	/*
+	 * restore dst type in case the decoding will be reused
+	 * (happens for string instruction )
+	 */
+	c->dst.type = saved_dst_type;
+
+	if ((c->d & SrcMask) == SrcSI)
+		string_addr_inc(ctxt, seg_override_base(ctxt, c), VCPU_REGS_RSI,
+				&c->src);
+
+	if ((c->d & DstMask) == DstDI)
+		string_addr_inc(ctxt, es_base(ctxt), VCPU_REGS_RDI, &c->dst);
+
+	if (c->rep_prefix && (c->d & String)) {
+		struct read_cache *rc = &ctxt->decode.io_read;
+		register_address_increment(c, &c->regs[VCPU_REGS_RCX], -1);
+		/*
+		 * Re-enter guest when pio read ahead buffer is empty or,
+		 * if it is not used, after each 1024 iteration.
+		 */
+		if ((rc->end == 0 && !(c->regs[VCPU_REGS_RCX] & 0x3ff)) ||
+		    (rc->end != 0 && rc->end == rc->pos))
+			ctxt->restart = false;
+	}
+
 	/* Commit shadow register state. */
 	memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs);
 	kvm_rip_write(ctxt->vcpu, c->eip);
+	ops->set_rflags(ctxt->vcpu, ctxt->eflags);
 
 done:
-	if (rc == X86EMUL_UNHANDLEABLE) {
-		c->eip = saved_eip;
-		return -1;
-	}
-	return 0;
+	return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
 
 twobyte_insn:
 	switch (c->b) {
@@ -2418,18 +3002,18 @@ twobyte_insn:
 				goto cannot_emulate;
 
 			rc = kvm_fix_hypercall(ctxt->vcpu);
-			if (rc)
+			if (rc != X86EMUL_CONTINUE)
 				goto done;
 
 			/* Let the processor re-execute the fixed hypercall */
-			c->eip = kvm_rip_read(ctxt->vcpu);
+			c->eip = ctxt->eip;
 			/* Disable writeback. */
 			c->dst.type = OP_NONE;
 			break;
 		case 2: /* lgdt */
 			rc = read_descriptor(ctxt, ops, c->src.ptr,
 					     &size, &address, c->op_bytes);
-			if (rc)
+			if (rc != X86EMUL_CONTINUE)
 				goto done;
 			realmode_lgdt(ctxt->vcpu, size, address);
 			/* Disable writeback. */
@@ -2440,7 +3024,7 @@ twobyte_insn:
 				switch (c->modrm_rm) {
 				case 1:
 					rc = kvm_fix_hypercall(ctxt->vcpu);
-					if (rc)
+					if (rc != X86EMUL_CONTINUE)
 						goto done;
 					break;
 				default:
@@ -2450,7 +3034,7 @@ twobyte_insn:
 				rc = read_descriptor(ctxt, ops, c->src.ptr,
 						     &size, &address,
 						     c->op_bytes);
-				if (rc)
+				if (rc != X86EMUL_CONTINUE)
 					goto done;
 				realmode_lidt(ctxt->vcpu, size, address);
 			}
@@ -2459,15 +3043,18 @@ twobyte_insn:
 			break;
 		case 4: /* smsw */
 			c->dst.bytes = 2;
-			c->dst.val = realmode_get_cr(ctxt->vcpu, 0);
+			c->dst.val = ops->get_cr(0, ctxt->vcpu);
 			break;
 		case 6: /* lmsw */
-			realmode_lmsw(ctxt->vcpu, (u16)c->src.val,
-				      &ctxt->eflags);
+			ops->set_cr(0, (ops->get_cr(0, ctxt->vcpu) & ~0x0ful) |
+				    (c->src.val & 0x0f), ctxt->vcpu);
 			c->dst.type = OP_NONE;
 			break;
+		case 5: /* not defined */
+			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;
@@ -2493,54 +3080,54 @@ twobyte_insn:
 		c->dst.type = OP_NONE;
 		break;
 	case 0x20: /* mov cr, reg */
-		if (c->modrm_mod != 3)
-			goto cannot_emulate;
-		c->regs[c->modrm_rm] =
-				realmode_get_cr(ctxt->vcpu, c->modrm_reg);
+		switch (c->modrm_reg) {
+		case 1:
+		case 5 ... 7:
+		case 9 ... 15:
+			kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+			goto done;
+		}
+		c->regs[c->modrm_rm] = ops->get_cr(c->modrm_reg, ctxt->vcpu);
 		c->dst.type = OP_NONE;	/* no writeback */
 		break;
 	case 0x21: /* mov from dr to reg */
-		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;
+		if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
+		    (c->modrm_reg == 4 || c->modrm_reg == 5)) {
+			kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+			goto done;
+		}
+		emulator_get_dr(ctxt, c->modrm_reg, &c->regs[c->modrm_rm]);
 		c->dst.type = OP_NONE;	/* no writeback */
 		break;
 	case 0x22: /* mov reg, cr */
-		if (c->modrm_mod != 3)
-			goto cannot_emulate;
-		realmode_set_cr(ctxt->vcpu,
-				c->modrm_reg, c->modrm_val, &ctxt->eflags);
+		ops->set_cr(c->modrm_reg, c->modrm_val, ctxt->vcpu);
 		c->dst.type = OP_NONE;
 		break;
 	case 0x23: /* mov from reg to dr */
-		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;
+		if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
+		    (c->modrm_reg == 4 || c->modrm_reg == 5)) {
+			kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+			goto done;
+		}
+		emulator_set_dr(ctxt, c->modrm_reg, c->regs[c->modrm_rm]);
 		c->dst.type = OP_NONE;	/* no writeback */
 		break;
 	case 0x30:
 		/* wrmsr */
 		msr_data = (u32)c->regs[VCPU_REGS_RAX]
 			| ((u64)c->regs[VCPU_REGS_RDX] << 32);
-		rc = kvm_set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data);
-		if (rc) {
+		if (kvm_set_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], msr_data)) {
 			kvm_inject_gp(ctxt->vcpu, 0);
-			c->eip = kvm_rip_read(ctxt->vcpu);
+			goto done;
 		}
 		rc = X86EMUL_CONTINUE;
 		c->dst.type = OP_NONE;
 		break;
 	case 0x32:
 		/* rdmsr */
-		rc = kvm_get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], &msr_data);
-		if (rc) {
+		if (kvm_get_msr(ctxt->vcpu, c->regs[VCPU_REGS_RCX], &msr_data)) {
 			kvm_inject_gp(ctxt->vcpu, 0);
-			c->eip = kvm_rip_read(ctxt->vcpu);
+			goto done;
 		} else {
 			c->regs[VCPU_REGS_RAX] = (u32)msr_data;
 			c->regs[VCPU_REGS_RDX] = msr_data >> 32;
@@ -2577,7 +3164,7 @@ twobyte_insn:
 		break;
 	case 0xa1:	 /* pop fs */
 		rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_FS);
-		if (rc != 0)
+		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		break;
 	case 0xa3:
@@ -2596,7 +3183,7 @@ twobyte_insn:
 		break;
 	case 0xa9:	/* pop gs */
 		rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_GS);
-		if (rc != 0)
+		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		break;
 	case 0xab:
@@ -2668,16 +3255,14 @@ twobyte_insn:
 							(u64) c->src.val;
 		break;
 	case 0xc7:		/* Grp9 (cmpxchg8b) */
-		rc = emulate_grp9(ctxt, ops, memop);
-		if (rc != 0)
+		rc = emulate_grp9(ctxt, ops);
+		if (rc != X86EMUL_CONTINUE)
 			goto done;
-		c->dst.type = OP_NONE;
 		break;
 	}
 	goto writeback;
 
 cannot_emulate:
 	DPRINTF("Cannot emulate %02x\n", c->b);
-	c->eip = saved_eip;
 	return -1;
 }