diff --git a/tools/tests/Makefile b/tools/tests/Makefile
index 1319c3a9d88c..6a8844673abc 100644
--- a/tools/tests/Makefile
+++ b/tools/tests/Makefile
@@ -5,6 +5,7 @@ SUBDIRS-y :=
 SUBDIRS-y += resource
 SUBDIRS-$(CONFIG_X86) += cpu-policy
 SUBDIRS-$(CONFIG_X86) += tsx
+SUBDIRS-$(CONFIG_X86) += x86-decode-lite
 ifneq ($(clang),y)
 SUBDIRS-$(CONFIG_X86) += x86_emulator
 endif
diff --git a/tools/tests/x86-decode-lite/.gitignore b/tools/tests/x86-decode-lite/.gitignore
new file mode 100644
index 000000000000..e726b493c993
--- /dev/null
+++ b/tools/tests/x86-decode-lite/.gitignore
@@ -0,0 +1 @@
+test-x86-decode-lite
diff --git a/tools/tests/x86-decode-lite/Makefile b/tools/tests/x86-decode-lite/Makefile
new file mode 100644
index 000000000000..6e8ef21e1c29
--- /dev/null
+++ b/tools/tests/x86-decode-lite/Makefile
@@ -0,0 +1,45 @@
+XEN_ROOT = $(CURDIR)/../../..
+include $(XEN_ROOT)/tools/Rules.mk
+
+TARGET := test-x86-decode-lite
+
+.PHONY: all
+all: $(TARGET)
+
+.PHONY: run
+run: $(TARGET)
+	./$<
+
+.PHONY: clean
+clean:
+	$(RM) -- *.o $(TARGET) $(DEPS_RM)
+
+.PHONY: distclean
+distclean: clean
+	$(RM) -- *~
+
+.PHONY: install
+install: all
+	$(INSTALL_DIR) $(DESTDIR)$(LIBEXEC_BIN)
+	$(INSTALL_PROG) $(TARGET) $(DESTDIR)$(LIBEXEC_BIN)
+
+.PHONY: uninstall
+uninstall:
+	$(RM) -- $(DESTDIR)$(LIBEXEC_BIN)/$(TARGET)
+
+.PHONY: uninstall
+uninstall:
+
+vpath %.c ../../../xen/arch/x86/x86_emulate
+
+CFLAGS += $(CFLAGS_xeninclude) -I. -I../../../xen/arch/x86/
+CFLAGS += $(APPEND_CFLAGS)
+
+LDFLAGS += $(APPEND_LDFLAGS)
+
+%.o: Makefile
+
+$(TARGET): main.o insns.o decode-lite.o
+	$(CC) -o $@ $^ $(LDFLAGS)
+
+-include $(DEPS_INCLUDE)
diff --git a/tools/tests/x86-decode-lite/insns.S b/tools/tests/x86-decode-lite/insns.S
new file mode 100644
index 000000000000..a0f938d76905
--- /dev/null
+++ b/tools/tests/x86-decode-lite/insns.S
@@ -0,0 +1,703 @@
+#include "macro-magic.h"
+
+        .code64
+
+#ifndef __clang__
+        .allow_index_reg
+#endif
+        .text
+
+DECL(tests_rel0)
+modrm:
+        /* Mod=0, Reg=0, RM {0..f} */
+        _ add %al, (%rax)
+        _ add %al, (%rcx)
+        _ add %al, (%rdx)
+        _ add %al, (%rbx)
+        _ add %al, (%rsp) /* SIB */
+        /*add %al, (%rbp)    RIP --> tests_rel4 */
+        _ add %al, (%rsi)
+        _ add %al, (%rdi)
+        _ add %al, (%r8)
+        _ add %al, (%r9)
+        _ add %al, (%r10)
+        _ add %al, (%r11)
+        _ add %al, (%r12) /* SIB */
+        /*add %al, (%r13)    RIP --> tests_rel4 */
+        _ add %al, (%r14)
+        _ add %al, (%r15)
+
+        /* Mod=1, Reg=0, RM {0..f} */
+        _ add %al, 0x01(%rax)
+        _ add %al, 0x01(%rcx)
+        _ add %al, 0x01(%rdx)
+        _ add %al, 0x01(%rbx)
+        _ add %al, 0x01(%rsp) /* SIB */
+        _ add %al, 0x01(%rbp)
+        _ add %al, 0x01(%rsi)
+        _ add %al, 0x01(%rdi)
+        _ add %al, 0x01(%r8)
+        _ add %al, 0x01(%r9)
+        _ add %al, 0x01(%r10)
+        _ add %al, 0x01(%r11)
+        _ add %al, 0x01(%r12) /* SIB */
+        _ add %al, 0x01(%r13)
+        _ add %al, 0x01(%r14)
+        _ add %al, 0x01(%r15)
+
+        /* Mod=2, Reg=0, RM {0..f} */
+        _ add %al, 0x7f000001(%rax)
+        _ add %al, 0x7f000001(%rcx)
+        _ add %al, 0x7f000001(%rdx)
+        _ add %al, 0x7f000001(%rbx)
+        _ add %al, 0x7f000001(%rsp) /* SIB */
+        _ add %al, 0x7f000001(%rbp)
+        _ add %al, 0x7f000001(%rsi)
+        _ add %al, 0x7f000001(%rdi)
+        _ add %al, 0x7f000001(%r8)
+        _ add %al, 0x7f000001(%r9)
+        _ add %al, 0x7f000001(%r10)
+        _ add %al, 0x7f000001(%r11)
+        _ add %al, 0x7f000001(%r12) /* SIB */
+        _ add %al, 0x7f000001(%r13)
+        _ add %al, 0x7f000001(%r14)
+        _ add %al, 0x7f000001(%r15)
+
+        /* Mod=3, Reg=0, RM {0..f} */
+        _ add %al, %al
+        _ add %al, %cl
+        _ add %al, %dl
+        _ add %al, %bl
+        _ add %al, %ah
+        _ add %al, %ch
+        _ add %al, %dh
+        _ add %al, %dl
+        _ add %al, %r8b
+        _ add %al, %r9b
+        _ add %al, %r10b
+        _ add %al, %r11b
+        _ add %al, %r12b
+        _ add %al, %r13b
+        _ add %al, %r14b
+        _ add %al, %r15b
+
+sib:
+        /* Mod=0, Reg=0, RM=4, SIB S=3, I=0, B {0..f} */
+        _ add %al, (%rax, %rax, 8)
+        _ add %al, (%rcx, %rax, 8)
+        _ add %al, (%rdx, %rax, 8)
+        _ add %al, (%rbx, %rax, 8)
+        _ add %al, (%rsp, %rax, 8)
+        _ add %al, (    , %rax, 8) /* "none", %rbp encoded with mod=1/2 */
+        _ add %al, (%rsi, %rax, 8)
+        _ add %al, (%rdi, %rax, 8)
+        _ add %al, (%r8,  %rax, 8)
+        _ add %al, (%r9,  %rax, 8)
+        _ add %al, (%r10, %rax, 8)
+        _ add %al, (%r11, %rax, 8)
+        _ add %al, (%r12, %rax, 8)
+        _ rex.b add %al,(,%rax, 8) /* "none", %r13 encoded with mod=1/2 */
+        _ add %al, (%r14, %rax, 8)
+        _ add %al, (%r15, %rax, 8)
+
+        /* Mod=1, Reg=0, RM=4, SIB S=3, I=0, B {0..f} */
+        _ add %al, 0x01(%rax, %rax, 8)
+        _ add %al, 0x01(%rcx, %rax, 8)
+        _ add %al, 0x01(%rdx, %rax, 8)
+        _ add %al, 0x01(%rbx, %rax, 8)
+        _ add %al, 0x01(%rsp, %rax, 8)
+        _ add %al, 0x01(%rbp, %rax, 8)
+        _ add %al, 0x01(%rsi, %rax, 8)
+        _ add %al, 0x01(%rdi, %rax, 8)
+        _ add %al, 0x01(%r8,  %rax, 8)
+        _ add %al, 0x01(%r9,  %rax, 8)
+        _ add %al, 0x01(%r10, %rax, 8)
+        _ add %al, 0x01(%r11, %rax, 8)
+        _ add %al, 0x01(%r12, %rax, 8)
+        _ add %al, 0x01(%r13, %rax, 8)
+        _ add %al, 0x01(%r14, %rax, 8)
+        _ add %al, 0x01(%r15, %rax, 8)
+
+        /* Mod=2, Reg=0, RM=4, SIB S=3, I=0, B {0..f} */
+        _ add %al, 0x7f000001(%rax, %rax, 8)
+        _ add %al, 0x7f000001(%rcx, %rax, 8)
+        _ add %al, 0x7f000001(%rdx, %rax, 8)
+        _ add %al, 0x7f000001(%rbx, %rax, 8)
+        _ add %al, 0x7f000001(%rsp, %rax, 8)
+        _ add %al, 0x7f000001(%rbp, %rax, 8)
+        _ add %al, 0x7f000001(%rsi, %rax, 8)
+        _ add %al, 0x7f000001(%rdi, %rax, 8)
+        _ add %al, 0x7f000001(%r8,  %rax, 8)
+        _ add %al, 0x7f000001(%r9,  %rax, 8)
+        _ add %al, 0x7f000001(%r10, %rax, 8)
+        _ add %al, 0x7f000001(%r11, %rax, 8)
+        _ add %al, 0x7f000001(%r12, %rax, 8)
+        _ add %al, 0x7f000001(%r13, %rax, 8)
+        _ add %al, 0x7f000001(%r14, %rax, 8)
+        _ add %al, 0x7f000001(%r15, %rax, 8)
+
+        /* Mod=0, Reg=0, RM=4, SIB S=3, I=4, B {0..f} */
+        _ add %al, (%rax, %riz, 8)
+        _ add %al, (%rcx, %riz, 8)
+        _ add %al, (%rdx, %riz, 8)
+        _ add %al, (%rbx, %riz, 8)
+        _ add %al, (%rsp, %riz, 8)
+        _ add %al, (    , %riz, 8) /* %rbp encoded with mod=1/2 */
+        _ add %al, (%rsi, %riz, 8)
+        _ add %al, (%rdi, %riz, 8)
+        _ add %al, (%r8,  %riz, 8)
+        _ add %al, (%r9,  %riz, 8)
+        _ add %al, (%r10, %riz, 8)
+        _ add %al, (%r11, %riz, 8)
+        _ add %al, (%r12, %riz, 8)
+        _ rex.b add %al,(,%riz, 8) /* %r13 encoded with mod=1/2 */
+        _ add %al, (%r14, %riz, 8)
+        _ add %al, (%r15, %riz, 8)
+
+        /* Mod=1, Reg=0, RM=4, SIB S=3, I=4, B {0..f} */
+        _ add %al, 0x01(%rax, %riz, 8)
+        _ add %al, 0x01(%rcx, %riz, 8)
+        _ add %al, 0x01(%rdx, %riz, 8)
+        _ add %al, 0x01(%rbx, %riz, 8)
+        _ add %al, 0x01(%rsp, %riz, 8)
+        _ add %al, 0x01(%rbp, %riz, 8)
+        _ add %al, 0x01(%rsi, %riz, 8)
+        _ add %al, 0x01(%rdi, %riz, 8)
+        _ add %al, 0x01(%r8,  %riz, 8)
+        _ add %al, 0x01(%r9,  %riz, 8)
+        _ add %al, 0x01(%r10, %riz, 8)
+        _ add %al, 0x01(%r11, %riz, 8)
+        _ add %al, 0x01(%r12, %riz, 8)
+        _ add %al, 0x01(%r13, %riz, 8)
+        _ add %al, 0x01(%r14, %riz, 8)
+        _ add %al, 0x01(%r15, %riz, 8)
+
+        /* Mod=2, Reg=0, RM=4, SIB S=3, I=4, B {0..f} */
+        _ add %al, 0x7f000001(%rax, %riz, 8)
+        _ add %al, 0x7f000001(%rcx, %riz, 8)
+        _ add %al, 0x7f000001(%rdx, %riz, 8)
+        _ add %al, 0x7f000001(%rbx, %riz, 8)
+        _ add %al, 0x7f000001(%rsp, %riz, 8)
+        _ add %al, 0x7f000001(%rbp, %riz, 8)
+        _ add %al, 0x7f000001(%rsi, %riz, 8)
+        _ add %al, 0x7f000001(%rdi, %riz, 8)
+        _ add %al, 0x7f000001(%r8,  %riz, 8)
+        _ add %al, 0x7f000001(%r9,  %riz, 8)
+        _ add %al, 0x7f000001(%r10, %riz, 8)
+        _ add %al, 0x7f000001(%r11, %riz, 8)
+        _ add %al, 0x7f000001(%r12, %riz, 8)
+        _ add %al, 0x7f000001(%r13, %riz, 8)
+        _ add %al, 0x7f000001(%r14, %riz, 8)
+        _ add %al, 0x7f000001(%r15, %riz, 8)
+
+        .macro alu_ops op
+        _ \op %al, (%rax)
+        _ \op %eax, (%rax)
+        _ \op (%rax), %al
+        _ \op (%rax), %eax
+        _ \op $1, %al
+        _ \op $0x7f000001, %eax
+
+        /* Vary osize on imm fields */
+        _ data16 \op $1, %al
+        _ rex.w \op $1, %al
+        _ data16 rex.w \op $1, %al
+
+        _ \op $0x7f01, %ax
+        _ \op $0x7f000001, %rax
+        _ data16 \op $0x7f000001, %rax
+        .endm
+
+onebyte_row_0x:
+        alu_ops add
+        alu_ops or
+
+onebyte_row_1x:
+        alu_ops adc
+        alu_ops sbb
+
+onebyte_row_2x:
+        alu_ops and
+        .code32
+        _ es nop
+        .code64
+        alu_ops sub
+        _ cs nop
+
+onebyte_row_3x:
+        alu_ops xor
+        .code32
+        _ ss nop
+        .code64
+        alu_ops cmp
+        _ ds nop
+
+/* onebyte_row_4x --> rex prefixes */
+
+onebyte_row_5x:
+        _ push %rax
+        _ push %rcx
+        _ push %rdx
+        _ push %rbx
+        _ push %rsp
+        _ push %rbp
+        _ push %rsi
+        _ push %rdi
+        _ pop %rax
+        _ pop %rcx
+        _ pop %rdx
+        _ pop %rbx
+        _ pop %rsp
+        _ pop %rbp
+        _ pop %rsi
+        _ pop %rdi
+
+onebyte_row_6x:
+        /*pusha,popa,bound --> not supported */
+        _ movsxd (%rax), %eax
+        _ movslq (%rax), %rax
+        _ fs nop
+        _ gs nop
+        _ data16 nop
+        /* addr32 --> not supported */
+        _ pushq $0x7f000001
+        _ pushw $0x7f01
+        _ rex.w pushq $0x7f000001
+        _ imul $0x7f01, %ax, %ax
+        _ imul $0x7f000001, %eax, %eax
+        _ imul $0x7f000001, %rax, %rax
+        _ pushq $0
+        _ pushw $0
+        _ rex.w pushq $0
+        _ imul $0, %ax, %ax
+        _ imul $0, %eax, %eax
+        _ imul $0, %rax, %rax
+        _ insb
+        _ insw
+        _ insl
+        _ outsb
+        _ outsw
+        _ outsl
+
+/* onebyte_row_7x: --> Jcc disp8 */
+
+onebyte_row_8x:
+        _ add $0, %cl /* Grp1 */
+        _ data16 add $0, %cl
+        _ rex.w add $0, %cl
+        _ add $0x7f01, %cx
+        _ add $0x7f000001, %ecx
+        _ add $0x7f000001, %rcx
+        _ add $0, %cx
+        _ add $0, %ecx
+        _ add $0, %rcx
+        _ test %cl, %cl
+        _ test %ecx, %ecx
+        _ xchg %cl, %cl
+        _ xchg %ecx, %ecx
+        _ mov %cl, (%rax)
+        _ mov %ecx, (%rax)
+        _ mov (%rax), %cl
+        _ mov (%rax), %ecx
+        _ mov %cs, (%rax)
+        _ lea (%rax), %eax
+        _ mov (%rax), %cs
+        /*pop mem --> Grp1a, Not supported (XOP prefix adjacent) */
+
+onebyte_row_9x:
+        _ nop
+        _ pause
+        _ xchg %ax, %ax
+        _ xchg %eax, %eax
+        _ xchg %rax, %rax
+        _ rex.w xchg %rax, %rax
+        _ cltq
+        _ cqto
+        _ wait
+        _ pushf
+        _ popf
+        _ sahf
+        _ lahf
+
+onebyte_row_ax:
+        _ mov 0x8000000000000001, %al
+        _ mov 0x8000000000000001, %ax
+        _ mov 0x8000000000000001, %eax
+        _ mov 0x8000000000000001, %rax
+        _ mov %al,  0x8000000000000001
+        _ mov %ax,  0x8000000000000001
+        _ mov %eax, 0x8000000000000001
+        _ mov %rax, 0x8000000000000001
+        _ movsb
+        _ movsl
+        _ cmpsb
+        _ cmpsl
+        _ test $0, %al
+        _ test $0x80000001, %eax
+        _ test $0x7f000001, %rax
+        _ stosb
+        _ stosl
+        _ lodsb
+        _ lodsl
+        _ scasb
+        _ scasl
+
+onebyte_row_bx:
+        _ mov $0, %al
+        _ mov $0, %cl
+        _ mov $0x7f01, %ax
+        _ mov $0x7f01, %cx
+        _ mov $0x7f000001, %eax
+        _ mov $0x7f000001, %ecx
+        _ mov $0x7f00000000000001, %rax
+        _ mov $0x7f00000000000001, %rcx
+
+onebyte_row_cx:
+        _ rol $0, %al /* Grp2 */
+        _ rol $0, %ax
+        _ rol $0, %eax
+        _ rol $0, %rax
+        /*ret $0 --> not supported */
+        _ ret
+        /*les,lds --> not supported */
+        _ movb $0, (%rax) /* Grp11 */
+        _ movw $0, (%rax)
+        _ movl $0, (%rax)
+        _ movq $0, (%rax)
+        /*xbegin (Grp11) --> disp32 */
+        /*enter,leave,lretq $0 --> not supported */
+        _ lretq
+        _ int3
+        _ int $0
+        /*into,iret --> not supported */
+
+onebyte_row_dx:
+        _ rol $1, %al /* Grp2 */
+        _ rol $1, %ax
+        _ rol $1, %eax
+        _ rol $1, %rax
+        _ rol %cl, %al
+        _ rol %cl, %ax
+        _ rol %cl, %eax
+        _ rol %cl, %rax
+        /*aam,aad,setalc,xlat,d8...df --> not supported */
+
+onebyte_row_ex:
+        /*loop{ne,e,},jrcxz --> not supported */
+        _ in $0, %al
+        _ in $0, %eax
+        _ out %al,  $0
+        _ out %eax, $0
+        /*call,jmp --> disp32 */
+        /*ljmp --> not supported */
+        /*jmp --> disp8 */
+        _ in %dx, %al
+        _ in %dx, %eax
+        _ out %al,  %dx
+        _ out %eax, %dx
+
+onebyte_row_fx:
+        _ lock addb $0, (%rax)
+        n "icebp" .byte 0xf1 /* icebp */
+        _ repne nop
+        _ repe nop
+        _ hlt
+        _ cmc
+        _ test $0, %cl /* Grp3, /0 has extra Imm{8,} */
+        _ not %cl
+        _ test $0x7f01, %cx
+        _ not %cx
+        _ test $0x7f000001, %ecx
+        _ not %ecx
+        _ test $0x7f000001, %rcx
+        _ not %rcx
+        _ clc
+        _ stc
+        _ cli
+        _ sti
+        _ cld
+        _ std
+        _ inc %cl /* Grp4 */
+        _ dec %cl
+        _ inc %ecx /* Grp5 */
+        _ dec %ecx
+        _ call *(%rax)
+        _ lcall *(%rax)
+        _ jmp *(%rax)
+        _ ljmp *(%rax)
+        _ push (%rax)
+
+twobyte_row_0x:
+        _ sldt (%rax) /* Grp6 */
+        _ sgdt (%rax) /* Grp7 */
+        _ lar (%rax), %eax
+        _ lsl (%rax), %eax
+        _ clts
+        _ wbinvd
+        _ ud2a
+
+twobyte_row_1x:
+        _ prefetchnta (%rax) /* Grp16 (Hint Nop) */
+        _ nopl (%rax)
+
+twobyte_row_2x:
+        _ mov %cr0, %rax
+        _ mov %dr0, %rax
+        _ mov %rax, %cr0
+        _ mov %rax, %dr0
+
+twobyte_row_3x:
+        _ wrmsr
+        _ rdtsc
+        _ rdmsr
+        _ rdpmc
+
+twobyte_row_4x:
+        _ cmovo (%rax), %eax
+        _ cmovg (%rax), %eax
+
+/* twobyte_row_8x: --> Jcc disp32 */
+
+twobyte_row_9x:
+        _ seto (%rax)
+        _ setg (%rax)
+
+twobyte_row_ax:
+        _ push %fs
+        _ pop %fs
+        _ cpuid
+        _ bt %eax, (%rax)
+        _ shld $0, %ax, (%rax)
+        _ shld $0, %eax, (%rax)
+        _ shld $0, %rax, (%rax)
+        _ shld %cl, %ax, (%rax)
+        _ shld %cl, %eax, (%rax)
+        _ shld %cl, %rax, (%rax)
+        _ push %gs
+        _ pop %gs
+        /*rsm --> not supported */
+        _ bts %eax, (%rax)
+        _ shrd $0, %ax, (%rax)
+        _ shrd $0, %eax, (%rax)
+        _ shrd $0, %rax, (%rax)
+        _ shrd %cl, %ax, (%rax)
+        _ shrd %cl, %eax, (%rax)
+        _ shrd %cl, %rax, (%rax)
+        _ fxsave (%rax) /* Grp15 */
+        _ imul (%rax), %eax
+
+twobyte_row_bx:
+        _ cmpxchg %al, (%rax)
+        _ cmpxchg %eax, (%rax)
+        _ lss (%rax), %eax
+        _ btr %eax, (%rax)
+        _ lfs (%rax), %eax
+        _ lgs (%rax), %eax
+        _ movzbl (%rax), %eax
+        _ movzwl (%rax), %eax
+        _ popcnt (%rax), %eax
+        _ ud1 (%rax), %eax /* Grp10 */
+        _ bt $0, %ax /* Grp8 */
+        _ bt $0, %eax
+        _ bt $0, %rax
+        _ btc %eax, (%rax)
+        _ bsf (%rax), %eax
+        _ bsr (%rax), %eax
+        _ movsbl (%rax), %eax
+        _ movswl (%rax), %eax
+
+twobyte_row_cx:
+        _ xadd %al, (%rax)
+        _ xadd %eax, (%rax)
+        _ cmpxchg8b (%rax) /* Grp9 */
+        _ bswap %eax
+        _ bswap %edi
+
+END(tests_rel0)
+
+DECL(tests_rel1)
+disp8:
+1:
+        _ jo   1b
+        _ jno  1b
+        _ jb   1b
+        _ jae  1b
+        _ je   1b
+        _ jne  1b
+        _ jbe  1b
+        _ ja   1b
+        _ js   1b
+        _ jns  1b
+        _ jp   1b
+        _ jnp  1b
+        _ jl   1b
+        _ jge  1b
+        _ jle  1b
+        _ jg   1b
+        _ jmp  1b
+
+disp8_rex:
+        _ rex.w jo   1b
+        _ rex.w jno  1b
+        _ rex.w jb   1b
+        _ rex.w jae  1b
+        _ rex.w je   1b
+        _ rex.w jne  1b
+        _ rex.w jbe  1b
+        _ rex.w ja   1b
+        _ rex.w js   1b
+        _ rex.w jns  1b
+        _ rex.w jp   1b
+        _ rex.w jnp  1b
+        _ rex.w jl   1b
+        _ rex.w jge  1b
+        _ rex.w jle  1b
+        _ rex.w jg   1b
+        _ rex.w jmp  1b
+END(tests_rel1)
+
+DECL(tests_rel4)
+disp32:
+        _ call   other_section
+        _ jmp    other_section
+        _ jo     other_section
+        _ jno    other_section
+        _ jb     other_section
+        _ jae    other_section
+        _ je     other_section
+        _ jne    other_section
+        _ jbe    other_section
+        _ ja     other_section
+        _ js     other_section
+        _ jns    other_section
+        _ jp     other_section
+        _ jnp    other_section
+        _ jl     other_section
+        _ jge    other_section
+        _ jle    other_section
+        _ jg     other_section
+        _ xbegin other_section
+
+disp32_rex:
+        _ rex.w call   other_section
+        _ rex.w jmp    other_section
+        _ rex.w jo     other_section
+        _ rex.w jno    other_section
+        _ rex.w jb     other_section
+        _ rex.w jae    other_section
+        _ rex.w je     other_section
+        _ rex.w jne    other_section
+        _ rex.w jbe    other_section
+        _ rex.w ja     other_section
+        _ rex.w js     other_section
+        _ rex.w jns    other_section
+        _ rex.w jp     other_section
+        _ rex.w jnp    other_section
+        _ rex.w jl     other_section
+        _ rex.w jge    other_section
+        _ rex.w jle    other_section
+        _ rex.w jg     other_section
+        _ rex.w xbegin other_section
+
+riprel:
+        _ add %al, 0(%rip)
+        _ rex.b add %al, 0(%rip)
+
+        _ addb $1, 0(%rip)
+        _ rex.b addb $1, 0(%rip)
+
+        _ addl $0x7f000001, 0(%rip)
+        _ rex.b addl $0x7f000001, 0(%rip)
+END(tests_rel4)
+
+DECL(tests_unsup)
+
+unsup_prefix: /* Prefixes unimplemented for simplicity. */
+        _ vaddpd %zmm0, %zmm0, %zmm0 /* 0x62 EVEX */
+        _ addr32 nop                 /* 0x67 Address size override */
+        _ bextr $0, %eax, %eax       /* 0x8f XOP */
+        _ bextr %eax, %eax, %eax     /* 0xc4 VEX3 */
+        _ vaddpd %ymm0, %ymm0, %ymm0 /* 0xc5 VEX2 */
+        n "jmpabs 0" .byte 0xd5, 0x00, 0xa1, 0x01, 0, 0, 0, 0, 0, 0, 0x80 /* 0xd5 REX2 */
+        _ fadds (%rax)               /* 0xd8 ... 0xdf ESCAPE (x87) */
+        _ femms                      /* 0x0f,0x0e ... 0x0f 3DNOW */
+
+unsup_branch:
+1:
+        _ loopne 1b
+        _ loope  1b
+        _ loop   1b
+        _ jrcxz  1b
+
+opsize_branch: /* 66-prefixed branches are decoded differently by vendors */
+        _ data16 call   other_section
+        _ data16 jmp    other_section
+        _ data16 jo     other_section
+        _ data16 jno    other_section
+        _ data16 jb     other_section
+        _ data16 jae    other_section
+        _ data16 je     other_section
+        _ data16 jne    other_section
+        _ data16 jbe    other_section
+        _ data16 ja     other_section
+        _ data16 js     other_section
+        _ data16 jns    other_section
+        _ data16 jp     other_section
+        _ data16 jnp    other_section
+        _ data16 jl     other_section
+        _ data16 jge    other_section
+        _ data16 jle    other_section
+        _ data16 jg     other_section
+        _ data16 xbegin other_section
+
+not_64bit: /* Not valid/encodable in 64bit mode */
+        .code32
+        _ push %es
+        _ pop %es
+        _ push %cs
+        _ push %ss
+        _ pop %ss
+        _ push %ds
+        _ pop %ds
+        _ daa
+        _ das
+        _ aaa
+        _ aas
+        _ pusha
+        _ popa
+        _ bound %eax, (%eax)
+        /*arpl %ax, %ax --> movsxd in 64bit mode */
+        /* Grp1 */
+        _ lcall $-1, $-1
+        _ les (%eax), %eax
+        _ lds (%eax), %eax
+        _ into
+        _ aam $0
+        _ aad $0 /* Also REX2, also not supported */
+        n "salc" .byte 0xd6
+        _ ljmp $-1, $-1
+        .code64
+
+unsup_insn: /* Instructions that would complicated decode, or shouldn't be used */
+        _ ret $0
+        _ enter $0, $0
+        _ leave
+        _ lretq $0
+        _ iretq
+        _ xlat
+        _ syscall
+        _ sysretl
+        _ invd
+        _ sysenter
+        _ sysexitl
+        _ rsm
+
+END(tests_unsup)
+
+        /* This is here to cause jmps to use their disp32 form. */
+        .section .text.other_section, "ax", @progbits
+other_section:
+        int3
+
+        /* Mark this file as not needing executable stacks. */
+        .section  .note.GNU-stack, "", @progbits
diff --git a/tools/tests/x86-decode-lite/macro-magic.h b/tools/tests/x86-decode-lite/macro-magic.h
new file mode 100644
index 000000000000..b6b59906c941
--- /dev/null
+++ b/tools/tests/x86-decode-lite/macro-magic.h
@@ -0,0 +1,52 @@
+#ifndef X86_DECODE_LITE_LINKAGE_H
+#define X86_DECODE_LITE_LINKAGE_H
+
+/* Start a 'struct test' array */
+.macro start_arr aname
+    .pushsection .data.rel.ro.\aname, "aw", @progbits
+    .globl \aname
+    .type \aname, STT_OBJECT
+\aname:
+    .popsection
+
+    /* Declare a macro wrapping \aname */
+    .macro pushsection_arr
+    .pushsection .data.rel.ro.\aname, "aw", @progbits
+    .endm
+.endm
+
+/* Macro 'n' to wrap the metadata of an instruction.  Name can be different. */
+.macro n name:req insn:vararg
+    /* Emit the instruction, with start & end markers. */
+.Ls\@: \insn
+.Le\@:
+
+    /* Emit \name as a string. */
+    .pushsection .rosdata.str1, "aMS", @progbits, 1
+.Ln\@: .asciz "\name"
+    .popsection
+
+    /* Emit an entry into the array. */
+    pushsection_arr
+    .quad .Ln\@, .Ls\@, .Le\@ - .Ls\@
+    .popsection
+.endm
+
+/* Macro '_' where the name is the instruction itself. */
+.macro _ insn:vararg
+    n "\insn" \insn
+.endm
+
+/* Finish a 'struct test' array */
+.macro finish_arr aname
+    pushsection_arr
+    .quad 0, 0, 0
+    .size \aname, . - \aname
+    .popsection
+    .purgem pushsection_arr
+.endm
+
+#define DECL(aname) start_arr aname
+#define END(aname) finish_arr aname
+
+#endif /* X86_DECODE_LITE_LINKAGE_H */
diff --git a/tools/tests/x86-decode-lite/main.c b/tools/tests/x86-decode-lite/main.c
new file mode 100644
index 000000000000..cdae7de8e90e
--- /dev/null
+++ b/tools/tests/x86-decode-lite/main.c
@@ -0,0 +1,111 @@
+/*
+ * Userspace test harness for x86_decode_lite().
+ */
+#include <stdio.h>
+
+#include "x86-emulate.h"
+
+static unsigned int nr_failures;
+#define fail(t, fmt, ...)                                       \
+({                                                              \
+    const unsigned char *insn = (t)->ip;                        \
+                                                                \
+    nr_failures++;                                              \
+                                                                \
+    (void)printf("  Fail '%s' [%02x", (t)->name, *insn);        \
+    for ( unsigned int i = 1; i < (t)->len; i++ )               \
+        printf(" %02x", insn[i]);                               \
+    printf("]\n");                                              \
+                                                                \
+    (void)printf(fmt, ##__VA_ARGS__);                           \
+})
+
+struct test {
+    const char *name;
+    void *ip;
+    unsigned long len;
+};
+
+extern const struct test
+/* Defined in insns.S, ends with sentinel */
+    tests_rel0[], /* No relocatable entry */
+    tests_rel1[], /* disp8 */
+    tests_rel4[], /* disp32 or RIP-relative */
+    tests_unsup[]; /* Unsupported instructions */
+
+static inline void run_tests(const struct test *tests, unsigned int rel_sz)
+{
+    printf("Test rel%u\n", rel_sz);
+
+    for ( unsigned int i = 0; tests[i].name; ++i )
+    {
+        const struct test *t = &tests[i];
+        x86_decode_lite_t r;
+
+        /*
+         * Don't end strictly at t->len.  This provides better diagnostics if
+         * too many bytes end up getting consumed.
+         */
+        r = x86_decode_lite(t->ip, t->ip + /* t->len */ 20);
+
+        if ( r.len == 0 )
+        {
+            fail(t, "    Failed to decode instruction\n");
+
+            if ( r.rel_sz != 0 || r.rel )
+                fail(t, "    Rel/sz despite no decode\n");
+
+            continue;
+        }
+
+        if ( r.len != t->len )
+        {
+            fail(t, "    Expected length %lu, got %u\n",
+                 t->len, r.len);
+            continue;
+        }
+
+        if ( r.rel_sz != rel_sz )
+        {
+            fail(t, "    Expected relocation size %u, got %u\n",
+                 rel_sz, r.rel_sz);
+            continue;
+        }
+
+        if ( r.rel_sz &&
+             (r.rel < t->ip ||
+              r.rel > t->ip + t->len ||
+              r.rel + r.rel_sz > t->ip + t->len) )
+        {
+            fail(t, "    Rel [%p,+%u) outside insn [%p,+%lu)\n",
+                 r.rel, r.rel_sz, t->ip, t->len);
+            continue;
+        }
+    }
+}
+
+static void run_tests_unsup(const struct test *tests)
+{
+    printf("Test unsup\n");
+
+    for ( unsigned int i = 0; tests[i].name; ++i )
+    {
+        const struct test *t = &tests[i];
+        x86_decode_lite_t r = x86_decode_lite(t->ip, t->ip + t->len);
+
+        if ( r.len )
+            fail(t, "    Got len %u\n", r.len);
+    }
+}
+
+int main(int argc, char **argv)
+{
+    printf("Tests for x86_decode_lite()\n");
+
+    run_tests(tests_rel0, 0);
+    run_tests(tests_rel1, 1);
+    run_tests(tests_rel4, 4);
+    run_tests_unsup(tests_unsup);
+
+    return !!nr_failures;
+}
diff --git a/tools/tests/x86-decode-lite/x86-emulate.h b/tools/tests/x86-decode-lite/x86-emulate.h
new file mode 100644
index 000000000000..558dab1b768e
--- /dev/null
+++ b/tools/tests/x86-decode-lite/x86-emulate.h
@@ -0,0 +1,27 @@
+#ifndef X86_EMULATE_H
+#define X86_EMULATE_H
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <xen/asm/x86-defns.h>
+#include <xen/asm/x86-vendors.h>
+
+#include <xen-tools/common-macros.h>
+
+#define ASSERT assert
+
+#define printk(...)
+
+#define likely
+#define unlikely
+#define cf_check
+#define init_or_livepatch
+#define init_or_livepatch_const
+
+#include "x86_emulate/x86_emulate.h"
+
+#endif /* X86_EMULATE_H */
