diff --git a/.gitignore b/.gitignore
index a2f34a1..d507243 100644
--- a/.gitignore
+++ b/.gitignore
@@ -145,6 +145,7 @@ tools/flask/utils/flask-loadpolicy
 tools/flask/utils/flask-setenforce
 tools/flask/utils/flask-set-bool
 tools/flask/utils/flask-label-pci
+tools/fuzz/x86_instruction_emulator/x86_emulate*
 tools/helpers/_paths.h
 tools/helpers/init-xenstore-domain
 tools/helpers/xen-init-dom0
diff --git a/tools/fuzz/x86_instruction_emulator/Makefile b/tools/fuzz/x86_instruction_emulator/Makefile
new file mode 100644
index 0000000..374c84a
--- /dev/null
+++ b/tools/fuzz/x86_instruction_emulator/Makefile
@@ -0,0 +1,33 @@
+XEN_ROOT=$(CURDIR)/../../..
+include $(XEN_ROOT)/tools/Rules.mk
+
+x86-instruction-emulator-fuzzer-all: x86-insn-emulator.a x86-insn-emulator-fuzzer.o
+
+x86_emulate/x86_emulate.c x86_emulate/x86_emulate.h:
+	[ -L x86_emulate ] || ln -sf $(XEN_ROOT)/xen/arch/x86/x86_emulate .
+
+x86_emulate.c:
+	[ -L x86_emulate.c ] || ln -sf $(XEN_ROOT)/tools/tests/x86_emulator/x86_emulate.c
+
+x86_emulate.h:
+	[ -L x86_emulate.h ] || ln -sf $(XEN_ROOT)/tools/tests/x86_emulator/x86_emulate.h
+
+CFLAGS += $(CFLAGS_xeninclude)
+
+x86_emulate.o: x86_emulate.c x86_emulate.h x86_emulate/x86_emulate.c x86_emulate/x86_emulate.h
+
+x86-insn-emulator.a: x86_emulate.o
+	$(AR) rc $@ $^
+
+x86-insn-emulator-fuzzer.o: x86-insn-emulator-fuzzer.c
+
+# Common targets
+.PHONY: all
+all: x86-instruction-emulator-fuzzer-all
+
+.PHONY: distclean
+distclean: clean
+
+.PHONY: clean
+clean:
+	rm -f *.a *.o
diff --git a/tools/fuzz/x86_instruction_emulator/x86-insn-emulator-fuzzer.c b/tools/fuzz/x86_instruction_emulator/x86-insn-emulator-fuzzer.c
new file mode 100644
index 0000000..01ee7a4
--- /dev/null
+++ b/tools/fuzz/x86_instruction_emulator/x86-insn-emulator-fuzzer.c
@@ -0,0 +1,335 @@
+#include <errno.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <xen/xen.h>
+#include <unistd.h>
+#include <assert.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#define __packed __attribute__((packed))
+#define ASSERT assert
+
+#include "x86_emulate/x86_emulate.h"
+
+/* EFLAGS bit definitions. */
+#define EFLG_OF (1<<11)
+#define EFLG_DF (1<<10)
+#define EFLG_SF (1<<7)
+#define EFLG_ZF (1<<6)
+#define EFLG_AF (1<<4)
+#define EFLG_PF (1<<2)
+#define EFLG_CF (1<<0)
+
+static unsigned char data[4096];
+static unsigned int data_index = 0;
+static unsigned int data_max;
+
+int data_read(const char *why, void *dst, unsigned int bytes) {
+
+    if ( data_index + bytes > data_max )
+        return X86EMUL_EXCEPTION;
+
+    memcpy(dst,  data+data_index, bytes);
+    data_index += bytes;
+
+    return X86EMUL_OKAY;
+}
+
+static int emul_read(
+    unsigned int seg,
+    unsigned long offset,
+    void *p_data,
+    unsigned int bytes,
+    struct x86_emulate_ctxt *ctxt)
+{
+    return data_read("read", p_data, bytes);
+}
+
+static int emul_fetch(
+    unsigned int seg,
+    unsigned long offset,
+    void *p_data,
+    unsigned int bytes,
+    struct x86_emulate_ctxt *ctxt)
+{
+    return data_read("fetch", p_data, bytes);
+}
+
+static int emul_write(
+    unsigned int seg,
+    unsigned long offset,
+    void *p_data,
+    unsigned int bytes,
+    struct x86_emulate_ctxt *ctxt)
+{
+    return X86EMUL_OKAY;
+}
+
+static int emul_cmpxchg(
+    unsigned int seg,
+    unsigned long offset,
+    void *old,
+    void *new,
+    unsigned int bytes,
+    struct x86_emulate_ctxt *ctxt)
+{
+    return X86EMUL_OKAY;
+}
+
+static int emul_cpuid(
+    unsigned int *eax,
+    unsigned int *ebx,
+    unsigned int *ecx,
+    unsigned int *edx,
+    struct x86_emulate_ctxt *ctxt)
+{
+    unsigned int leaf = *eax;
+
+    asm ("cpuid" : "+a" (*eax), "+c" (*ecx), "=d" (*edx), "=b" (*ebx));
+
+    /* The emulator doesn't itself use MOVBE, so we can always run the test. */
+    if ( leaf == 1 )
+        *ecx |= 1U << 22;
+
+    return X86EMUL_OKAY;
+}
+
+#define cache_line_size() ({ \
+    unsigned int eax = 1, ebx, ecx = 0, edx; \
+    emul_cpuid(&eax, &ebx, &ecx, &edx, NULL); \
+    edx & (1U << 19) ? (ebx >> 5) & 0x7f8 : 0; \
+})
+
+#define cpu_has_mmx ({ \
+    unsigned int eax = 1, ecx = 0, edx; \
+    emul_cpuid(&eax, &ecx, &ecx, &edx, NULL); \
+    (edx & (1U << 23)) != 0; \
+})
+
+#define cpu_has_sse ({ \
+    unsigned int eax = 1, ecx = 0, edx; \
+    emul_cpuid(&eax, &ecx, &ecx, &edx, NULL); \
+    (edx & (1U << 25)) != 0; \
+})
+
+#define cpu_has_sse2 ({ \
+    unsigned int eax = 1, ecx = 0, edx; \
+    emul_cpuid(&eax, &ecx, &ecx, &edx, NULL); \
+    (edx & (1U << 26)) != 0; \
+})
+
+#define cpu_has_xsave ({ \
+    unsigned int eax = 1, ecx = 0; \
+    emul_cpuid(&eax, &eax, &ecx, &eax, NULL); \
+    /* Intentionally checking OSXSAVE here. */ \
+    (ecx & (1U << 27)) != 0; \
+})
+
+static inline uint64_t xgetbv(uint32_t xcr)
+{
+    uint32_t lo, hi;
+
+    asm ( ".byte 0x0f, 0x01, 0xd0" : "=a" (lo), "=d" (hi) : "c" (xcr) );
+
+    return ((uint64_t)hi << 32) | lo;
+}
+
+#define cpu_has_avx ({ \
+    unsigned int eax = 1, ecx = 0; \
+    emul_cpuid(&eax, &eax, &ecx, &eax, NULL); \
+    if ( !(ecx & (1U << 27)) || ((xgetbv(0) & 6) != 6) ) \
+        ecx = 0; \
+    (ecx & (1U << 28)) != 0; \
+})
+
+#define cpu_has_avx2 ({ \
+    unsigned int eax = 1, ebx, ecx = 0; \
+    emul_cpuid(&eax, &ebx, &ecx, &eax, NULL); \
+    if ( !(ecx & (1U << 27)) || ((xgetbv(0) & 6) != 6) ) \
+        ebx = 0; \
+    else { \
+        eax = 7, ecx = 0; \
+        cpuid(&eax, &ebx, &ecx, &eax, NULL); \
+    } \
+    (ebx & (1U << 5)) != 0; \
+})
+
+static int emul_read_cr(
+    unsigned int reg,
+    unsigned long *val,
+    struct x86_emulate_ctxt *ctxt)
+{
+    /* Fake just enough state for the emulator's _get_fpu() to be happy. */
+    switch ( reg )
+    {
+    case 0:
+        *val = 0x00000001; /* PE */
+        return X86EMUL_OKAY;
+
+    case 4:
+        /* OSFXSR, OSXMMEXCPT, and maybe OSXSAVE */
+        *val = 0x00000600 | (cpu_has_xsave ? 0x00040000 : 0);
+        return X86EMUL_OKAY;
+    }
+
+    return X86EMUL_UNHANDLEABLE;
+}
+
+int emul_get_fpu(
+    void (*exception_callback)(void *, struct cpu_user_regs *),
+    void *exception_callback_arg,
+    enum x86_emulate_fpu_type type,
+    struct x86_emulate_ctxt *ctxt)
+{
+    switch ( type )
+    {
+    case X86EMUL_FPU_fpu:
+        break;
+    case X86EMUL_FPU_mmx:
+        if ( cpu_has_mmx )
+            break;
+    case X86EMUL_FPU_xmm:
+        if ( cpu_has_sse )
+            break;
+    case X86EMUL_FPU_ymm:
+        if ( cpu_has_avx )
+            break;
+    default:
+        return X86EMUL_UNHANDLEABLE;
+    }
+    return X86EMUL_OKAY;
+}
+
+struct x86_emulate_ops emulops = {
+    .read       = emul_read,
+    .insn_fetch = emul_fetch,
+    .write      = emul_write,
+    .cmpxchg    = emul_cmpxchg,
+    .cpuid      = emul_cpuid,
+    .read_cr    = emul_read_cr,
+    .get_fpu    = emul_get_fpu,
+};
+
+bool make_stack_executable(void) {
+    unsigned long sp;
+    bool stack_exec;
+
+    /*
+     * Mark the entire stack executable so that the stub executions
+     * don't fault
+     */
+#define MMAP_SZ 16384
+
+#ifdef __x86_64__
+    asm ("movq %%rsp, %0" : "=g" (sp));
+#else
+    asm ("movl %%esp, %0" : "=g" (sp));
+#endif
+
+    stack_exec = mprotect((void *)(sp & -0x1000L) - (MMAP_SZ - 0x1000),
+                          MMAP_SZ, PROT_READ|PROT_WRITE|PROT_EXEC) == 0;
+    if ( !stack_exec )
+        printf("Warning: Stack could not be made executable (%d).\n", errno);
+
+    return stack_exec;
+}
+
+#define CANONICALIZE(x)   \
+    do {                                               \
+        uint64_t _y = (x);                             \
+        if ( _y & (1ULL<<47) ) {                       \
+            _y |= (~0ULL)<<48;                          \
+        } else {                                        \
+            _y &= (1ULL<<48)-1;                         \
+        }                                               \
+        printf("Canonicalized %" PRIx64 " to %" PRIx64 "\n", x, _y);    \
+        (x) = _y;                                       \
+    } while(0)
+
+#define ADDR_SIZE_SHIFT 60
+#define ADDR_SIZE_64 (2ULL<<ADDR_SIZE_SHIFT)
+#define ADDR_SIZE_32 (1ULL<<ADDR_SIZE_SHIFT)
+#define ADDR_SIZE_16 (0)
+
+int LLVMFuzzerTestOneInput(const uint8_t *data_p, size_t size) {
+    struct cpu_user_regs regs = {};
+    struct x86_emulate_ctxt ctxt =
+        {
+            .regs = &regs,
+            .addr_size = 8 * sizeof(void *),
+            .sp_size = 8 * sizeof(void *),
+        };
+
+    int nr = 0;
+    int rc;
+    unsigned x;
+    const uint8_t *p = data_p;
+
+    make_stack_executable();
+
+    memset(data, 0, sizeof(data));
+
+    nr = size < sizeof(regs) ? size : sizeof(regs);
+
+    memcpy(&regs, p, nr);
+    p += sizeof(regs);
+    nr += sizeof(regs);
+
+    if (nr <= size) {
+        memcpy(data, p, size - nr);
+        data_max = size - nr;
+    }
+
+    ctxt.force_writeback = 0;
+
+    /* Zero 'private' entries */
+    regs.error_code = 0;
+    regs.entry_vector = 0;
+
+    /* Use the upper bits of regs.eip to determine addr_size */
+    x = (regs.rip >> ADDR_SIZE_SHIFT) & 0x3;
+    if (x == 3)
+        x = 2;
+    ctxt.addr_size = 16 << x;
+    printf("addr_size: %d\n", ctxt.addr_size);
+
+    /* Use the upper bit of regs.rsp to determine sp_size (if appropriate) */
+    if ( ctxt.addr_size == 64) {
+        ctxt.sp_size = 64;
+    } else {
+        /* If addr_size isn't 64-bits, sp_size can only be 16 or 32 bits */
+        x = (regs.rsp >> ADDR_SIZE_SHIFT) & 0x1;
+        ctxt.sp_size = 16 << x;
+    }
+    printf("sp_size: %d\n", ctxt.sp_size);
+    CANONICALIZE(regs.rip);
+    CANONICALIZE(regs.rsp);
+    CANONICALIZE(regs.rbp);
+
+    /* Zero all segments for now */
+    regs.cs = regs.ss = regs.es = regs.ds = regs.fs = regs.gs = 0;
+
+    do {
+        rc = x86_emulate(&ctxt, &emulops);
+        printf("Emulation result: %d\n", rc);
+    } while (rc == X86EMUL_OKAY);
+
+    return 0;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
