pkg/ifuzz/iset: rename ifuzzimpl to iset

ifuzzimpl is too lenghty and too clumsy on my taste
(nm/vmimpl worked better b/c it's shorter and used less).
I've tried to come up with something shorter and nicer.
We could use "insn" as a common name for "instruction" in ifuzz,
but it's a commonly used name already so would cause lots of conflicts.
"iset" is somewhat descriptive, short and nice.

10 files changed, 127 insertions, 126 deletions

diff --git a/pkg/ifuzz/ifuzz.go b/pkg/ifuzz/ifuzz.go
index 45082834d..01137b6ea 100644
--- a/pkg/ifuzz/ifuzz.go
+++ b/pkg/ifuzz/ifuzz.go
@@ -6,24 +6,24 @@ package ifuzz
 import (
 	"math/rand"
 
-	"github.com/google/syzkaller/pkg/ifuzz/ifuzzimpl"
+	"github.com/google/syzkaller/pkg/ifuzz/iset"
 	_ "github.com/google/syzkaller/pkg/ifuzz/powerpc/generated" // pull in generated instruction descriptions
 	_ "github.com/google/syzkaller/pkg/ifuzz/x86/generated"     // pull in generated instruction descriptions
 )
 
 type (
-	Config    = ifuzzimpl.Config
-	MemRegion = ifuzzimpl.MemRegion
-	Mode      = ifuzzimpl.Mode
+	Config    = iset.Config
+	MemRegion = iset.MemRegion
+	Mode      = iset.Mode
 )
 
 const (
-	ArchX86     = ifuzzimpl.ArchX86
-	ArchPowerPC = ifuzzimpl.ArchPowerPC
-	ModeLong64  = ifuzzimpl.ModeLong64
-	ModeProt32  = ifuzzimpl.ModeProt32
-	ModeProt16  = ifuzzimpl.ModeProt16
-	ModeReal16  = ifuzzimpl.ModeReal16
+	ArchX86     = iset.ArchX86
+	ArchPowerPC = iset.ArchPowerPC
+	ModeLong64  = iset.ModeLong64
+	ModeProt32  = iset.ModeProt32
+	ModeProt16  = iset.ModeProt16
+	ModeReal16  = iset.ModeReal16
 )
 
 func Generate(cfg *Config, r *rand.Rand) []byte {
@@ -99,21 +99,21 @@ func Mutate(cfg *Config, r *rand.Rand, text []byte) []byte {
 	return text
 }
 
-func randInsn(cfg *Config, r *rand.Rand) ifuzzimpl.Insn {
-	insnset := ifuzzimpl.Arches[cfg.Arch]
-	var insns []ifuzzimpl.Insn
+func randInsn(cfg *Config, r *rand.Rand) iset.Insn {
+	insnset := iset.Arches[cfg.Arch]
+	var insns []iset.Insn
 	if cfg.Priv && cfg.Exec {
-		insns = insnset.GetInsns(cfg.Mode, ifuzzimpl.Type(r.Intn(3)))
+		insns = insnset.GetInsns(cfg.Mode, iset.Type(r.Intn(3)))
 	} else if cfg.Priv {
-		insns = insnset.GetInsns(cfg.Mode, ifuzzimpl.Type(r.Intn(2)))
+		insns = insnset.GetInsns(cfg.Mode, iset.Type(r.Intn(2)))
 	} else {
-		insns = insnset.GetInsns(cfg.Mode, ifuzzimpl.TypeUser)
+		insns = insnset.GetInsns(cfg.Mode, iset.TypeUser)
 	}
 	return insns[r.Intn(len(insns))]
 }
 
 func split(cfg *Config, text []byte) [][]byte {
-	insnset := ifuzzimpl.Arches[cfg.Arch]
+	insnset := iset.Arches[cfg.Arch]
 	text = append([]byte{}, text...)
 	var insns [][]byte
 	var bad []byte
diff --git a/pkg/ifuzz/ifuzz_test.go b/pkg/ifuzz/ifuzz_test.go
index edee05c9a..eee8afe00 100644
--- a/pkg/ifuzz/ifuzz_test.go
+++ b/pkg/ifuzz/ifuzz_test.go
@@ -10,7 +10,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/google/syzkaller/pkg/ifuzz/ifuzzimpl"
+	"github.com/google/syzkaller/pkg/ifuzz/iset"
 )
 
 var allArches = []string{ArchX86, ArchPowerPC}
@@ -24,8 +24,8 @@ func TestMode(t *testing.T) {
 }
 
 func testMode(t *testing.T, arch string) {
-	all := make(map[ifuzzimpl.Insn]bool)
-	for mode := ifuzzimpl.Mode(0); mode < ifuzzimpl.ModeLast; mode++ {
+	all := make(map[iset.Insn]bool)
+	for mode := iset.Mode(0); mode < iset.ModeLast; mode++ {
 		for priv := 0; priv < 2; priv++ {
 			for exec := 0; exec < 2; exec++ {
 				insns := allInsns(arch, mode, priv != 0, exec != 0)
@@ -48,7 +48,7 @@ func TestDecode(t *testing.T) {
 }
 
 func testDecode(t *testing.T, arch string) {
-	insnset := ifuzzimpl.Arches[arch]
+	insnset := iset.Arches[arch]
 	xedEnabled := false
 	if _, err := insnset.DecodeExt(0, nil); err == nil {
 		xedEnabled = true
@@ -61,8 +61,8 @@ func testDecode(t *testing.T, arch string) {
 	r := rand.New(rand.NewSource(seed))
 
 	for repeat := 0; repeat < 10; repeat++ {
-		for mode := ifuzzimpl.Mode(0); mode < ifuzzimpl.ModeLast; mode++ {
-			cfg := &ifuzzimpl.Config{
+		for mode := iset.Mode(0); mode < iset.ModeLast; mode++ {
+			cfg := &iset.Config{
 				Mode: mode,
 				Priv: true,
 				Exec: true,
@@ -122,13 +122,13 @@ func testDecode(t *testing.T, arch string) {
 	}
 }
 
-func allInsns(arch string, mode ifuzzimpl.Mode, priv, exec bool) []ifuzzimpl.Insn {
-	insnset := ifuzzimpl.Arches[arch]
-	insns := insnset.GetInsns(mode, ifuzzimpl.TypeUser)
+func allInsns(arch string, mode iset.Mode, priv, exec bool) []iset.Insn {
+	insnset := iset.Arches[arch]
+	insns := insnset.GetInsns(mode, iset.TypeUser)
 	if priv {
-		insns = append(insns, insnset.GetInsns(mode, ifuzzimpl.TypePriv)...)
+		insns = append(insns, insnset.GetInsns(mode, iset.TypePriv)...)
 		if exec {
-			insns = append(insns, insnset.GetInsns(mode, ifuzzimpl.TypeExec)...)
+			insns = append(insns, insnset.GetInsns(mode, iset.TypeExec)...)
 		}
 	}
 	return insns
diff --git a/pkg/ifuzz/ifuzzimpl/ifuzzimpl.go b/pkg/ifuzz/iset/iset.go
index 32f285250..46c42537d 100644
--- a/pkg/ifuzz/ifuzzimpl/ifuzzimpl.go
+++ b/pkg/ifuzz/iset/iset.go
@@ -1,7 +1,8 @@
 // Copyright 2017 syzkaller project authors. All rights reserved.
 // Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
 
-package ifuzzimpl
+// Package iset ("instruction set") provides base and helper types for ifuzz arch implementations.
+package iset
 
 import (
 	"math/rand"
diff --git a/pkg/ifuzz/powerpc/powerpc.go b/pkg/ifuzz/powerpc/powerpc.go
index a78e0a251..bee20850d 100644
--- a/pkg/ifuzz/powerpc/powerpc.go
+++ b/pkg/ifuzz/powerpc/powerpc.go
@@ -18,7 +18,7 @@ import (
 	"fmt"
 	"math/rand"
 
-	"github.com/google/syzkaller/pkg/ifuzz/ifuzzimpl"
+	"github.com/google/syzkaller/pkg/ifuzz/iset"
 )
 
 type InsnBits struct {
@@ -35,20 +35,20 @@ type Insn struct {
 	Opcode uint32
 	Mask   uint32
 
-	generator func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte
+	generator func(cfg *iset.Config, r *rand.Rand) []byte
 }
 
 type InsnSet struct {
 	Insns     []*Insn
-	modeInsns ifuzzimpl.ModeInsns
+	modeInsns iset.ModeInsns
 	insnMap   map[string]*Insn
 }
 
-func (insnset *InsnSet) GetInsns(mode ifuzzimpl.Mode, typ ifuzzimpl.Type) []ifuzzimpl.Insn {
+func (insnset *InsnSet) GetInsns(mode iset.Mode, typ iset.Type) []iset.Insn {
 	return insnset.modeInsns[mode][typ]
 }
 
-func (insnset *InsnSet) Decode(mode ifuzzimpl.Mode, text []byte) (int, error) {
+func (insnset *InsnSet) Decode(mode iset.Mode, text []byte) (int, error) {
 	if len(text) < 4 {
 		return 0, errors.New("must be at least 4 bytes")
 	}
@@ -61,7 +61,7 @@ func (insnset *InsnSet) Decode(mode ifuzzimpl.Mode, text []byte) (int, error) {
 	return 0, fmt.Errorf("unrecognised instruction %08x", insn32)
 }
 
-func (insnset *InsnSet) DecodeExt(mode ifuzzimpl.Mode, text []byte) (int, error) {
+func (insnset *InsnSet) DecodeExt(mode iset.Mode, text []byte) (int, error) {
 	return 0, fmt.Errorf("no external decoder")
 }
 
@@ -85,7 +85,7 @@ func (insn *Insn) EncodeParam(v map[string]uint, r *rand.Rand) []byte {
 	return ret
 }
 
-func (insn Insn) Encode(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+func (insn Insn) Encode(cfg *iset.Config, r *rand.Rand) []byte {
 	if insn.Pseudo {
 		return insn.generator(cfg, r)
 	}
@@ -108,16 +108,16 @@ func Register(insns []*Insn) {
 	for _, insn := range insnset.Insns {
 		insnset.modeInsns.Add(insn)
 	}
-	ifuzzimpl.Arches[ifuzzimpl.ArchPowerPC] = insnset
+	iset.Arches[iset.ArchPowerPC] = insnset
 }
 
-func (insn *Insn) Info() (string, ifuzzimpl.Mode, bool, bool) {
+func (insn *Insn) Info() (string, iset.Mode, bool, bool) {
 	return insn.Name, insn.mode(), insn.Pseudo, insn.Priv
 }
 
-func (insn Insn) mode() ifuzzimpl.Mode {
+func (insn Insn) mode() iset.Mode {
 	if insn.M64 {
-		return (1 << ifuzzimpl.ModeLong64)
+		return (1 << iset.ModeLong64)
 	}
-	return (1 << ifuzzimpl.ModeLong64) | (1 << ifuzzimpl.ModeProt32)
+	return (1 << iset.ModeLong64) | (1 << iset.ModeProt32)
 }
diff --git a/pkg/ifuzz/powerpc/pseudo.go b/pkg/ifuzz/powerpc/pseudo.go
index 495e0f935..f300eec0f 100644
--- a/pkg/ifuzz/powerpc/pseudo.go
+++ b/pkg/ifuzz/powerpc/pseudo.go
@@ -6,7 +6,7 @@ package powerpc
 import (
 	"math/rand"
 
-	"github.com/google/syzkaller/pkg/ifuzz/ifuzzimpl"
+	"github.com/google/syzkaller/pkg/ifuzz/iset"
 )
 
 // nolint:dupl
@@ -15,7 +15,7 @@ func (insnset *InsnSet) initPseudo() {
 		Name:   "PSEUDO_hypercall",
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(insnset, cfg, r)
 			gen.sc(1)
 			return gen.text
@@ -25,7 +25,7 @@ func (insnset *InsnSet) initPseudo() {
 		Name:   "PSEUDO_syscall",
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(insnset, cfg, r)
 			gen.sc(0)
 			return gen.text
@@ -35,7 +35,7 @@ func (insnset *InsnSet) initPseudo() {
 		Name:   "PSEUDO_ultracall",
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(insnset, cfg, r)
 			gen.sc(2)
 			return gen.text
@@ -45,12 +45,12 @@ func (insnset *InsnSet) initPseudo() {
 
 type generator struct {
 	imap map[string]*Insn
-	mode ifuzzimpl.Mode
+	mode iset.Mode
 	r    *rand.Rand
 	text []byte
 }
 
-func makeGen(insnset *InsnSet, cfg *ifuzzimpl.Config, r *rand.Rand) *generator {
+func makeGen(insnset *InsnSet, cfg *iset.Config, r *rand.Rand) *generator {
 	return &generator{
 		imap: insnset.insnMap,
 		mode: cfg.Mode,
diff --git a/pkg/ifuzz/x86/decode.go b/pkg/ifuzz/x86/decode.go
index a40643a6b..1306f40db 100644
--- a/pkg/ifuzz/x86/decode.go
+++ b/pkg/ifuzz/x86/decode.go
@@ -6,26 +6,26 @@ package x86
 import (
 	"fmt"
 
-	"github.com/google/syzkaller/pkg/ifuzz/ifuzzimpl"
+	"github.com/google/syzkaller/pkg/ifuzz/iset"
 )
 
 // Decode decodes instruction length for the given mode.
 // It can have falsely decode incorrect instructions,
 // but should not fail to decode correct instructions.
 // nolint: gocyclo, nestif, gocognit, funlen
-func (insnset *InsnSet) Decode(mode ifuzzimpl.Mode, text []byte) (int, error) {
+func (insnset *InsnSet) Decode(mode iset.Mode, text []byte) (int, error) {
 	if len(text) == 0 {
 		return 0, fmt.Errorf("zero-length instruction")
 	}
 	prefixes := prefixes32
 	var operSize, immSize, dispSize, addrSize int
 	switch mode {
-	case ifuzzimpl.ModeLong64:
+	case iset.ModeLong64:
 		operSize, immSize, dispSize, addrSize = 4, 4, 4, 8
 		prefixes = prefixes64
-	case ifuzzimpl.ModeProt32:
+	case iset.ModeProt32:
 		operSize, immSize, dispSize, addrSize = 4, 4, 4, 4
-	case ifuzzimpl.ModeProt16, ifuzzimpl.ModeReal16:
+	case iset.ModeProt16, iset.ModeReal16:
 		operSize, immSize, dispSize, addrSize = 2, 2, 2, 2
 	default:
 		panic("bad mode")
@@ -36,7 +36,7 @@ func (insnset *InsnSet) Decode(mode ifuzzimpl.Mode, text []byte) (int, error) {
 	if len(text) > 1 {
 		// There are only 2 32-bit instructions that look like VEX-prefixed but are actually not: LDS, LES.
 		// They always reference memory (mod!=3), but all VEX instructions have "mod=3" where LDS/LES would have mod.
-		if (text[0] == 0xc4 || text[0] == 0xc5) && (mode == ifuzzimpl.ModeLong64 || text[1]&0xc0 == 0xc0) {
+		if (text[0] == 0xc4 || text[0] == 0xc5) && (mode == iset.ModeLong64 || text[1]&0xc0 == 0xc0) {
 			vex = true
 		}
 		// There is only one instruction that looks like XOP-prefixed but is actually not: POP.
@@ -208,7 +208,7 @@ nextInsn:
 	return 0, fmt.Errorf("unknown instruction")
 }
 
-var XedDecode func(mode ifuzzimpl.Mode, text []byte) (int, error)
+var XedDecode func(mode iset.Mode, text []byte) (int, error)
 
 var (
 	prefixes32 = map[byte]bool{
@@ -226,7 +226,7 @@ var (
 	}
 )
 
-func (insnset *InsnSet) DecodeExt(mode ifuzzimpl.Mode, text []byte) (int, error) {
+func (insnset *InsnSet) DecodeExt(mode iset.Mode, text []byte) (int, error) {
 	if XedDecode != nil && text != nil && len(text) > 0 {
 		return XedDecode(mode, text)
 	}
diff --git a/pkg/ifuzz/x86/encode.go b/pkg/ifuzz/x86/encode.go
index 9203d51c3..59b9a294a 100644
--- a/pkg/ifuzz/x86/encode.go
+++ b/pkg/ifuzz/x86/encode.go
@@ -10,11 +10,11 @@ package x86
 import (
 	"math/rand"
 
-	"github.com/google/syzkaller/pkg/ifuzz/ifuzzimpl"
+	"github.com/google/syzkaller/pkg/ifuzz/iset"
 )
 
 // nolint: gocyclo, nestif, gocognit, funlen
-func (insn *Insn) Encode(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+func (insn *Insn) Encode(cfg *iset.Config, r *rand.Rand) []byte {
 	if !cfg.IsCompatible(insn) {
 		panic("instruction is not suitable for this mode")
 	}
@@ -24,11 +24,11 @@ func (insn *Insn) Encode(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
 
 	var operSize, immSize, dispSize, addrSize int
 	switch cfg.Mode {
-	case ifuzzimpl.ModeLong64:
+	case iset.ModeLong64:
 		operSize, immSize, dispSize, addrSize = 4, 4, 4, 8
-	case ifuzzimpl.ModeProt32:
+	case iset.ModeProt32:
 		operSize, immSize, dispSize, addrSize = 4, 4, 4, 4
-	case ifuzzimpl.ModeProt16, ifuzzimpl.ModeReal16:
+	case iset.ModeProt16, iset.ModeReal16:
 		operSize, immSize, dispSize, addrSize = 2, 2, 2, 2
 	default:
 		panic("bad mode")
@@ -54,7 +54,7 @@ func (insn *Insn) Encode(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
 			if !insn.No66Prefix {
 				prefixes = append(prefixes, 0x66) // operand size
 			}
-			if cfg.Mode == ifuzzimpl.ModeLong64 || !insn.Mem32 {
+			if cfg.Mode == iset.ModeLong64 || !insn.Mem32 {
 				prefixes = append(prefixes, 0x67) // address size
 			}
 			if !insn.NoRepPrefix {
@@ -71,7 +71,7 @@ func (insn *Insn) Encode(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
 
 		// REX
 		var rex byte
-		if cfg.Mode == ifuzzimpl.ModeLong64 && r.Intn(2) == 0 {
+		if cfg.Mode == iset.ModeLong64 && r.Intn(2) == 0 {
 			// bit 0 - B
 			// bit 1 - X
 			// bit 2 - R
@@ -119,7 +119,7 @@ func (insn *Insn) Encode(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
 		code = append(code, insn.Vex)
 		vexR = byte(1)
 		vexX = byte(1)
-		if cfg.Mode == ifuzzimpl.ModeLong64 {
+		if cfg.Mode == iset.ModeLong64 {
 			vexR = byte(r.Intn(2))
 			vexX = byte(r.Intn(2))
 		}
@@ -147,7 +147,7 @@ func (insn *Insn) Encode(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
 		code = append(code, vexR<<7|vexX<<6|vexB<<5|insn.VexMap)
 		code = append(code, W<<7|vvvv<<3|L<<2|pp)
 		// TODO: short encoding
-		if cfg.Mode != ifuzzimpl.ModeLong64 {
+		if cfg.Mode != iset.ModeLong64 {
 			vvvv |= 8
 		}
 	}
diff --git a/pkg/ifuzz/x86/gen/gen.go b/pkg/ifuzz/x86/gen/gen.go
index 3622ba248..284ea9033 100644
--- a/pkg/ifuzz/x86/gen/gen.go
+++ b/pkg/ifuzz/x86/gen/gen.go
@@ -13,7 +13,7 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/google/syzkaller/pkg/ifuzz/ifuzzimpl"
+	"github.com/google/syzkaller/pkg/ifuzz/iset"
 	"github.com/google/syzkaller/pkg/ifuzz/x86"
 	"github.com/google/syzkaller/pkg/serializer"
 )
@@ -102,7 +102,7 @@ func main() {
 			insn.Extension = vals[0]
 			switch insn.Extension {
 			case "FMA", "AVX2", "AVX", "F16C", "BMI2", "BMI", "XOP", "FMA4", "AVXAES", "BMI1", "AVX2GATHER":
-				insn.Mode = 1<<ifuzzimpl.ModeLong64 | 1<<ifuzzimpl.ModeProt32
+				insn.Mode = 1<<iset.ModeLong64 | 1<<iset.ModeProt32
 			}
 			insn.Avx2Gather = insn.Extension == "AVX2GATHER"
 		case "PATTERN":
@@ -201,7 +201,7 @@ func parsePattern(insn *x86.Insn, vals []string) error {
 		return errSkip("")
 	}
 	if insn.Mode == 0 {
-		insn.Mode = 1<<ifuzzimpl.ModeLast - 1
+		insn.Mode = 1<<iset.ModeLast - 1
 	}
 	insn.Mod = -100
 	insn.Reg = -100
@@ -314,7 +314,7 @@ func parsePattern(insn *x86.Insn, vals []string) error {
 		// VOP/VEX
 		case v == "XOPV":
 			insn.Vex = 0x8f
-			insn.Mode &^= 1 << ifuzzimpl.ModeReal16
+			insn.Mode &^= 1 << iset.ModeReal16
 		case v == "EVV":
 			insn.Vex = 0xc4
 		case v == "VV1":
@@ -355,13 +355,13 @@ func parsePattern(insn *x86.Insn, vals []string) error {
 
 		// Modes.
 		case v == "mode64":
-			insn.Mode &= 1 << ifuzzimpl.ModeLong64
+			insn.Mode &= 1 << iset.ModeLong64
 		case v == "not64":
-			insn.Mode &^= 1 << ifuzzimpl.ModeLong64
+			insn.Mode &^= 1 << iset.ModeLong64
 		case v == "mode32":
-			insn.Mode &= 1 << ifuzzimpl.ModeProt32
+			insn.Mode &= 1 << iset.ModeProt32
 		case v == "mode16":
-			insn.Mode &= 1<<ifuzzimpl.ModeProt16 | 1<<ifuzzimpl.ModeReal16
+			insn.Mode &= 1<<iset.ModeProt16 | 1<<iset.ModeReal16
 		case v == "eamode64",
 			v == "eamode32",
 			v == "eamode16",
diff --git a/pkg/ifuzz/x86/pseudo.go b/pkg/ifuzz/x86/pseudo.go
index e11ace0cc..9e6f31204 100644
--- a/pkg/ifuzz/x86/pseudo.go
+++ b/pkg/ifuzz/x86/pseudo.go
@@ -6,16 +6,16 @@ package x86
 import (
 	"math/rand"
 
-	"github.com/google/syzkaller/pkg/ifuzz/ifuzzimpl"
+	"github.com/google/syzkaller/pkg/ifuzz/iset"
 )
 
 var pseudo = []*Insn{
 	{
 		Name:   "PSEUDO_RDMSR",
-		Mode:   1<<ifuzzimpl.ModeLast - 1,
+		Mode:   1<<iset.ModeLast - 1,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			msr := msrs[r.Intn(len(msrs))]
 			gen.mov32(regECX, msr)
@@ -25,10 +25,10 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_WRMSR",
-		Mode:   1<<ifuzzimpl.ModeLast - 1,
+		Mode:   1<<iset.ModeLast - 1,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			msr := msrs[r.Intn(len(msrs))]
 			v := generateInt(cfg, r, 8)
@@ -41,10 +41,10 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_PCI_READ",
-		Mode:   1<<ifuzzimpl.ModeLast - 1,
+		Mode:   1<<iset.ModeLast - 1,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			addr, port, size := pciAddrPort(r)
 			gen.out32(0xcf8, addr)
@@ -54,10 +54,10 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_PCI_WRITE",
-		Mode:   1<<ifuzzimpl.ModeLast - 1,
+		Mode:   1<<iset.ModeLast - 1,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			addr, port, size := pciAddrPort(r)
 			val := generateInt(cfg, r, 4)
@@ -68,10 +68,10 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_PORT_READ",
-		Mode:   1<<ifuzzimpl.ModeLast - 1,
+		Mode:   1<<iset.ModeLast - 1,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			port := ports[r.Intn(len(ports))]
 			gen.in(port, r.Intn(3))
@@ -80,10 +80,10 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_PORT_WRITE",
-		Mode:   1<<ifuzzimpl.ModeLast - 1,
+		Mode:   1<<iset.ModeLast - 1,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			port := ports[r.Intn(len(ports))]
 			val := generateInt(cfg, r, 4)
@@ -93,10 +93,10 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_XOR_CR",
-		Mode:   1<<ifuzzimpl.ModeLast - 1,
+		Mode:   1<<iset.ModeLast - 1,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			cr := controlRegisters[r.Intn(len(controlRegisters))]
 			var v uint32
@@ -114,10 +114,10 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_XOR_EFER",
-		Mode:   1<<ifuzzimpl.ModeLast - 1,
+		Mode:   1<<iset.ModeLast - 1,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			gen.mov32(regECX, eferMSR)
 			gen.byte(0x0f, 0x32) // rdmsr
@@ -129,16 +129,16 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_SET_BREAK",
-		Mode:   1<<ifuzzimpl.ModeLast - 1,
+		Mode:   1<<iset.ModeLast - 1,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			br := uint8(r.Intn(4))
 			loc := uint32(r.Intn(4))
 			typ := uint32(r.Intn(16))
 			addr := generateInt(cfg, r, 8)
-			if cfg.Mode == ifuzzimpl.ModeLong64 {
+			if cfg.Mode == iset.ModeLong64 {
 				gen.mov64(regRAX, addr)
 			} else {
 				gen.mov32(regEAX, uint32(addr))
@@ -152,13 +152,13 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_LOAD_SEG",
-		Mode:   1<<ifuzzimpl.ModeLast - 1,
+		Mode:   1<<iset.ModeLast - 1,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			sel := randSelector(r)
-			if cfg.Mode == ifuzzimpl.ModeReal16 {
+			if cfg.Mode == iset.ModeReal16 {
 				sel = uint16(generateInt(cfg, r, 8)) >> 4
 			}
 			reg := uint8(r.Intn(6))
@@ -169,14 +169,14 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_FAR_JMP",
-		Mode:   1<<ifuzzimpl.ModeLong64 | 1<<ifuzzimpl.ModeProt32 | 1<<ifuzzimpl.ModeProt16,
+		Mode:   1<<iset.ModeLong64 | 1<<iset.ModeProt32 | 1<<iset.ModeProt16,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			sel := randSelector(r)
 			off := generateInt(cfg, r, 4)
-			if cfg.Mode == ifuzzimpl.ModeLong64 {
+			if cfg.Mode == iset.ModeLong64 {
 				gen.mov32toSPaddr(uint32(sel), 0)
 				gen.mov32toSPaddr(uint32(off), 2)
 				if r.Intn(2) == 0 {
@@ -190,7 +190,7 @@ var pseudo = []*Insn{
 				} else {
 					gen.byte(0x9a) // lcall $imm16, $imm16/32
 				}
-				if cfg.Mode == ifuzzimpl.ModeProt16 {
+				if cfg.Mode == iset.ModeProt16 {
 					gen.imm16(uint16(off))
 				} else {
 					gen.imm32(uint32(off))
@@ -202,10 +202,10 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_LTR_LLDT",
-		Mode:   1<<ifuzzimpl.ModeLong64 | 1<<ifuzzimpl.ModeProt32 | 1<<ifuzzimpl.ModeProt16,
+		Mode:   1<<iset.ModeLong64 | 1<<iset.ModeProt32 | 1<<iset.ModeProt16,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			sel := randSelector(r)
 			gen.mov16(regAX, sel)
@@ -219,10 +219,10 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_LGIDT",
-		Mode:   1<<ifuzzimpl.ModeLong64 | 1<<ifuzzimpl.ModeProt32 | 1<<ifuzzimpl.ModeProt16,
+		Mode:   1<<iset.ModeLong64 | 1<<iset.ModeProt32 | 1<<iset.ModeProt16,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			limit := uint32(generateInt(cfg, r, 2))
 			base := uint32(generateInt(cfg, r, 4))
@@ -240,10 +240,10 @@ var pseudo = []*Insn{
 	},
 	{
 		Name:   "PSEUDO_HYPERCALL",
-		Mode:   1<<ifuzzimpl.ModeLong64 | 1<<ifuzzimpl.ModeProt32 | 1<<ifuzzimpl.ModeProt16,
+		Mode:   1<<iset.ModeLong64 | 1<<iset.ModeProt32 | 1<<iset.ModeProt16,
 		Priv:   true,
 		Pseudo: true,
-		generator: func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte {
+		generator: func(cfg *iset.Config, r *rand.Rand) []byte {
 			gen := makeGen(cfg, r)
 			switch r.Intn(2) {
 			case 0:
@@ -280,12 +280,12 @@ const (
 )
 
 type generator struct {
-	mode ifuzzimpl.Mode
+	mode iset.Mode
 	r    *rand.Rand
 	text []byte
 }
 
-func makeGen(cfg *ifuzzimpl.Config, r *rand.Rand) *generator {
+func makeGen(cfg *iset.Config, r *rand.Rand) *generator {
 	return &generator{
 		mode: cfg.Mode,
 		r:    r,
@@ -311,9 +311,9 @@ func (gen *generator) imm64(v uint64) {
 
 func (gen *generator) operand16() {
 	switch gen.mode {
-	case ifuzzimpl.ModeLong64, ifuzzimpl.ModeProt32:
+	case iset.ModeLong64, iset.ModeProt32:
 		gen.byte(0x66)
-	case ifuzzimpl.ModeProt16, ifuzzimpl.ModeReal16:
+	case iset.ModeProt16, iset.ModeReal16:
 	default:
 		panic("bad mode")
 	}
@@ -321,8 +321,8 @@ func (gen *generator) operand16() {
 
 func (gen *generator) operand32() {
 	switch gen.mode {
-	case ifuzzimpl.ModeLong64, ifuzzimpl.ModeProt32:
-	case ifuzzimpl.ModeProt16, ifuzzimpl.ModeReal16:
+	case iset.ModeLong64, iset.ModeProt32:
+	case iset.ModeProt16, iset.ModeReal16:
 		gen.byte(0x66)
 	default:
 		panic("bad mode")
@@ -331,8 +331,8 @@ func (gen *generator) operand32() {
 
 func (gen *generator) addr32() {
 	switch gen.mode {
-	case ifuzzimpl.ModeLong64, ifuzzimpl.ModeProt32:
-	case ifuzzimpl.ModeProt16, ifuzzimpl.ModeReal16:
+	case iset.ModeLong64, iset.ModeProt32:
+	case iset.ModeProt16, iset.ModeReal16:
 		gen.byte(0x67)
 	default:
 		panic("bad mode")
@@ -384,7 +384,7 @@ func (gen *generator) mov32(reg int, v uint32) {
 }
 
 func (gen *generator) mov64(reg int, v uint64) {
-	if gen.mode != ifuzzimpl.ModeLong64 {
+	if gen.mode != iset.ModeLong64 {
 		panic("bad mode")
 	}
 	gen.byte(0x48)
diff --git a/pkg/ifuzz/x86/x86.go b/pkg/ifuzz/x86/x86.go
index 51623aa2f..25d01fd36 100644
--- a/pkg/ifuzz/x86/x86.go
+++ b/pkg/ifuzz/x86/x86.go
@@ -9,16 +9,16 @@ package x86
 import (
 	"math/rand"
 
-	"github.com/google/syzkaller/pkg/ifuzz/ifuzzimpl"
+	"github.com/google/syzkaller/pkg/ifuzz/iset"
 )
 
 type Insn struct {
 	Name      string
 	Extension string
 
-	Mode   ifuzzimpl.Mode // bitmask of compatible modes
-	Priv   bool           // CPL=0
-	Pseudo bool           // pseudo instructions can consist of several real instructions
+	Mode   iset.Mode // bitmask of compatible modes
+	Priv   bool      // CPL=0
+	Pseudo bool      // pseudo instructions can consist of several real instructions
 
 	Opcode      []byte
 	Prefix      []byte
@@ -44,11 +44,11 @@ type Insn struct {
 	VexP       int8
 	Avx2Gather bool
 
-	generator func(cfg *ifuzzimpl.Config, r *rand.Rand) []byte // for pseudo instructions
+	generator func(cfg *iset.Config, r *rand.Rand) []byte // for pseudo instructions
 }
 
 type InsnSet struct {
-	modeInsns ifuzzimpl.ModeInsns
+	modeInsns iset.ModeInsns
 	Insns     []*Insn
 }
 
@@ -62,18 +62,18 @@ func Register(insns []*Insn) {
 	for _, insn := range insnset.Insns {
 		insnset.modeInsns.Add(insn)
 	}
-	ifuzzimpl.Arches[ifuzzimpl.ArchX86] = insnset
+	iset.Arches[iset.ArchX86] = insnset
 }
 
-func (insnset *InsnSet) GetInsns(mode ifuzzimpl.Mode, typ ifuzzimpl.Type) []ifuzzimpl.Insn {
+func (insnset *InsnSet) GetInsns(mode iset.Mode, typ iset.Type) []iset.Insn {
 	return insnset.modeInsns[mode][typ]
 }
 
-func (insn *Insn) Info() (string, ifuzzimpl.Mode, bool, bool) {
+func (insn *Insn) Info() (string, iset.Mode, bool, bool) {
 	return insn.Name, insn.Mode, insn.Pseudo, insn.Priv
 }
 
-func generateArg(cfg *ifuzzimpl.Config, r *rand.Rand, size int) []byte {
+func generateArg(cfg *iset.Config, r *rand.Rand, size int) []byte {
 	v := generateInt(cfg, r, size)
 	arg := make([]byte, size)
 	for i := 0; i < size; i++ {
@@ -83,7 +83,7 @@ func generateArg(cfg *ifuzzimpl.Config, r *rand.Rand, size int) []byte {
 	return arg
 }
 
-func generateInt(cfg *ifuzzimpl.Config, r *rand.Rand, size int) uint64 {
+func generateInt(cfg *iset.Config, r *rand.Rand, size int) uint64 {
 	if size != 1 && size != 2 && size != 4 && size != 8 {
 		panic("bad arg size")
 	}
@@ -98,7 +98,7 @@ func generateInt(cfg *ifuzzimpl.Config, r *rand.Rand, size int) uint64 {
 	case x < 30:
 		v = uint64(r.Int63())
 	case x < 40:
-		v = ifuzzimpl.SpecialNumbers[r.Intn(len(ifuzzimpl.SpecialNumbers))]
+		v = iset.SpecialNumbers[r.Intn(len(iset.SpecialNumbers))]
 		if r.Intn(5) == 0 {
 			v += uint64(r.Intn(33)) - 16
 		}