diff --git a/hw/xen_common.h b/hw/xen_common.h
index dd54063..96cfad7 100644
--- a/hw/xen_common.h
+++ b/hw/xen_common.h
@@ -53,5 +53,6 @@ typedef xc_interface *qemu_xc_interface;
 #endif
 
 qemu_irq *i8259_xen_init(void);
+void destroy_hvm_domain(void);
 
 #endif /* QEMU_HW_XEN_COMMON_H */
diff --git a/xen-all.c b/xen-all.c
index 4e0b061..13672f0 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -8,12 +8,38 @@
 
 #include "config.h"
 
+#include <sys/mman.h>
+
 #include "hw/pci.h"
 #include "hw/xen_common.h"
 #include "hw/xen_backend.h"
 
 #include "xen_mapcache.h"
 
+#include <xen/hvm/ioreq.h>
+
+//#define DEBUG_XEN
+
+#ifdef DEBUG_XEN
+#define DPRINTF(fmt, ...) \
+    do { fprintf(stderr, "xen: " fmt, ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...) \
+    do { } while (0)
+#endif
+
+shared_iopage_t *shared_page = NULL;
+#define BUFFER_IO_MAX_DELAY  100
+buffered_iopage_t *buffered_io_page = NULL;
+QEMUTimer *buffered_io_timer;
+/* the evtchn port for polling the notification, */
+evtchn_port_t *ioreq_local_port;
+/* the evtchn fd for polling */
+int xce_handle = -1;
+/* which vcpu we are serving */
+int send_vcpu = 0;
+long time_offset = 0;
+
 /* Xen specific function for piix pci */
 
 int xen_pci_slot_get_pirq(PCIDevice *pci_dev, int irq_num)
@@ -111,19 +137,374 @@ void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size)
 }
 
 
+/* VCPU Operations, MMIO, IO ring ... */
+
+/* get the ioreq packets from share mem */
+static ioreq_t *cpu_get_ioreq_from_shared_memory(int vcpu)
+{
+    ioreq_t *req = &shared_page->vcpu_ioreq[vcpu];
+
+    if (req->state != STATE_IOREQ_READY) {
+        DPRINTF("I/O request not ready: "
+                "%x, ptr: %x, port: %"PRIx64", "
+                "data: %"PRIx64", count: %u, size: %u\n",
+                req->state, req->data_is_ptr, req->addr,
+                req->data, req->count, req->size);
+        return NULL;
+    }
+
+    xen_rmb(); /* see IOREQ_READY /then/ read contents of ioreq */
+
+    req->state = STATE_IOREQ_INPROCESS;
+    return req;
+}
+
+/* use poll to get the port notification */
+/* ioreq_vec--out,the */
+/* retval--the number of ioreq packet */
+static ioreq_t *cpu_get_ioreq(void)
+{
+    int i;
+    evtchn_port_t port;
+
+    port = xc_evtchn_pending(xce_handle);
+    if (port != -1) {
+        for ( i = 0; i < smp_cpus; i++ )
+            if ( ioreq_local_port[i] == port )
+                break;
+
+        if ( i == smp_cpus ) {
+            hw_error("Fatal error while trying to get io event!\n");
+        }
+
+        /* unmask the wanted port again */
+        xc_evtchn_unmask(xce_handle, port);
+
+        /* get the io packet from shared memory */
+        send_vcpu = i;
+        return cpu_get_ioreq_from_shared_memory(i);
+    }
+
+    /* read error or read nothing */
+    return NULL;
+}
+
+static uint32_t do_inp(CPUState *env, pio_addr_t addr, unsigned long size)
+{
+    switch(size) {
+        case 1:
+            return cpu_inb(addr);
+        case 2:
+            return cpu_inw(addr);
+        case 4:
+            return cpu_inl(addr);
+        default:
+            hw_error("inp: bad size: %04"FMT_pioaddr" %lx", addr, size);
+    }
+}
+
+static void do_outp(CPUState *env, pio_addr_t addr,
+        unsigned long size, uint32_t val)
+{
+    switch(size) {
+        case 1:
+            return cpu_outb(addr, val);
+        case 2:
+            return cpu_outw(addr, val);
+        case 4:
+            return cpu_outl(addr, val);
+        default:
+            hw_error("outp: bad size: %04"FMT_pioaddr" %lx", addr, size);
+    }
+}
+
+static void cpu_ioreq_pio(CPUState *env, ioreq_t *req)
+{
+    int i, sign;
+
+    sign = req->df ? -1 : 1;
+
+    if (req->dir == IOREQ_READ) {
+        if (!req->data_is_ptr) {
+            req->data = do_inp(env, req->addr, req->size);
+        } else {
+            uint32_t tmp;
+
+            for (i = 0; i < req->count; i++) {
+                tmp = do_inp(env, req->addr, req->size);
+                cpu_physical_memory_write(req->data + (sign * i * req->size),
+                        (uint8_t*) &tmp, req->size);
+            }
+        }
+    } else if (req->dir == IOREQ_WRITE) {
+        if (!req->data_is_ptr) {
+            do_outp(env, req->addr, req->size, req->data);
+        } else {
+            for (i = 0; i < req->count; i++) {
+                uint32_t tmp = 0;
+
+                cpu_physical_memory_read(req->data + (sign * i * req->size),
+                        (uint8_t*) &tmp, req->size);
+                do_outp(env, req->addr, req->size, tmp);
+            }
+        }
+    }
+}
+
+static void cpu_ioreq_move(CPUState *env, ioreq_t *req)
+{
+    int i, sign;
+
+    sign = req->df ? -1 : 1;
+
+    if (!req->data_is_ptr) {
+        if (req->dir == IOREQ_READ) {
+            for (i = 0; i < req->count; i++) {
+                cpu_physical_memory_read(req->addr + (sign * i * req->size),
+                        (uint8_t*) &req->data, req->size);
+            }
+        } else if (req->dir == IOREQ_WRITE) {
+            for (i = 0; i < req->count; i++) {
+                cpu_physical_memory_write(req->addr + (sign * i * req->size),
+                        (uint8_t*) &req->data, req->size);
+            }
+        }
+    } else {
+        target_ulong tmp;
+
+        if (req->dir == IOREQ_READ) {
+            for (i = 0; i < req->count; i++) {
+                cpu_physical_memory_read(req->addr + (sign * i * req->size),
+                        (uint8_t*) &tmp, req->size);
+                cpu_physical_memory_write(req->data + (sign * i * req->size),
+                        (uint8_t*) &tmp, req->size);
+            }
+        } else if (req->dir == IOREQ_WRITE) {
+            for (i = 0; i < req->count; i++) {
+                cpu_physical_memory_read(req->data + (sign * i * req->size),
+                        (uint8_t*) &tmp, req->size);
+                cpu_physical_memory_write(req->addr + (sign * i * req->size),
+                        (uint8_t*) &tmp, req->size);
+            }
+        }
+    }
+}
+
+static void cpu_ioreq_timeoffset(CPUState *env, ioreq_t *req)
+{
+    /* char b[64]; */
+
+    time_offset += (unsigned long)req->data;
+
+    //DPRINTF("Time offset set %ld, added offset %"PRId64"\n",
+            //time_offset, req->data);
+    /* snprintf(b, 64, "%ld", time_offset); */
+    /* xenstore_vm_write(xen_domid, "rtc/timeoffset", b); */
+}
+
+static void handle_ioreq(CPUState *env, ioreq_t *req)
+{
+    if (!req->data_is_ptr && (req->dir == IOREQ_WRITE) &&
+            (req->size < sizeof(target_ulong)))
+        req->data &= ((target_ulong)1 << (8 * req->size)) - 1;
+
+    switch (req->type) {
+        case IOREQ_TYPE_PIO:
+            cpu_ioreq_pio(env, req);
+            break;
+        case IOREQ_TYPE_COPY:
+            cpu_ioreq_move(env, req);
+            break;
+        case IOREQ_TYPE_TIMEOFFSET:
+            cpu_ioreq_timeoffset(env, req);
+            break;
+        case IOREQ_TYPE_INVALIDATE:
+            qemu_invalidate_map_cache();
+            break;
+        default:
+            hw_error("Invalid ioreq type 0x%x\n", req->type);
+    }
+}
+
+static void handle_buffered_iopage(CPUState *env)
+{
+    buf_ioreq_t *buf_req = NULL;
+    ioreq_t req;
+    int qw;
+
+    if (!buffered_io_page)
+        return;
+
+    while (buffered_io_page->read_pointer !=
+            buffered_io_page->write_pointer) {
+        buf_req = &buffered_io_page->buf_ioreq[
+            buffered_io_page->read_pointer % IOREQ_BUFFER_SLOT_NUM];
+        req.size = 1UL << buf_req->size;
+        req.count = 1;
+        req.addr = buf_req->addr;
+        req.data = buf_req->data;
+        req.state = STATE_IOREQ_READY;
+        req.dir = buf_req->dir;
+        req.df = 1;
+        req.type = buf_req->type;
+        req.data_is_ptr = 0;
+        qw = (req.size == 8);
+        if (qw) {
+            buf_req = &buffered_io_page->buf_ioreq[
+                (buffered_io_page->read_pointer+1) % IOREQ_BUFFER_SLOT_NUM];
+            req.data |= ((uint64_t)buf_req->data) << 32;
+        }
+
+        handle_ioreq(env, &req);
+
+        xen_mb();
+        buffered_io_page->read_pointer += qw ? 2 : 1;
+    }
+}
+
+static void handle_buffered_io(void *opaque)
+{
+    CPUState *env = opaque;
+
+    handle_buffered_iopage(env);
+    qemu_mod_timer(buffered_io_timer, BUFFER_IO_MAX_DELAY +
+                   qemu_get_clock(rt_clock));
+}
+
+static void cpu_handle_ioreq(void *opaque)
+{
+    CPUState *env = opaque;
+    ioreq_t *req = cpu_get_ioreq();
+
+    handle_buffered_iopage(env);
+    if (req) {
+        handle_ioreq(env, req);
+
+        if (req->state != STATE_IOREQ_INPROCESS) {
+            fprintf(stderr, "Badness in I/O request ... not in service?!: "
+                    "%x, ptr: %x, port: %"PRIx64", "
+                    "data: %"PRIx64", count: %u, size: %u\n",
+                    req->state, req->data_is_ptr, req->addr,
+                    req->data, req->count, req->size);
+            destroy_hvm_domain();
+            return;
+        }
+
+        xen_wmb(); /* Update ioreq contents /then/ update state. */
+
+        /*
+         * We do this before we send the response so that the tools
+         * have the opportunity to pick up on the reset before the
+         * guest resumes and does a hlt with interrupts disabled which
+         * causes Xen to powerdown the domain.
+         */
+        if (vm_running) {
+            if (qemu_shutdown_requested_get()) {
+                destroy_hvm_domain();
+            }
+            if (qemu_reset_requested_get()) {
+                qemu_system_reset();
+            }
+        }
+
+        req->state = STATE_IORESP_READY;
+        xc_evtchn_notify(xce_handle, ioreq_local_port[send_vcpu]);
+    }
+}
+
+static void xen_main_loop_prepare(void)
+{
+    CPUState *env = cpu_single_env;
+
+    int evtchn_fd = xce_handle == -1 ? -1 : xc_evtchn_fd(xce_handle);
+
+    buffered_io_timer = qemu_new_timer(rt_clock, handle_buffered_io,
+                                       cpu_single_env);
+    qemu_mod_timer(buffered_io_timer, qemu_get_clock(rt_clock));
+
+    if (evtchn_fd != -1)
+        qemu_set_fd_handler(evtchn_fd, cpu_handle_ioreq, NULL, env);
+}
+
+
 /* Initialise Xen */
 
+static void xen_vm_change_state_handler(void *opaque, int running, int reason)
+{
+    if (running)
+        xen_main_loop_prepare();
+}
+
 int xen_init(int smp_cpus)
 {
+    int i, rc;
+    unsigned long ioreq_pfn;
+
     xen_xc = xc_interface_open(NULL, NULL, 0);
     if (xen_xc == NULL) {
         xen_be_printf(NULL, 0, "can't open xen interface\n");
         return -1;
     }
 
+    xce_handle = xc_evtchn_open();
+    if (xce_handle == -1) {
+        perror("open");
+        return -errno;
+    }
+
+    xc_get_hvm_param(xen_xc, xen_domid, HVM_PARAM_IOREQ_PFN, &ioreq_pfn);
+    DPRINTF("shared page at pfn %lx\n", ioreq_pfn);
+    shared_page = xc_map_foreign_range(xen_xc, xen_domid, XC_PAGE_SIZE,
+                                       PROT_READ|PROT_WRITE, ioreq_pfn);
+    if (shared_page == NULL) {
+        hw_error("map shared IO page returned error %d handle=%p", errno, xen_xc);
+    }
+
+    xc_get_hvm_param(xen_xc, xen_domid, HVM_PARAM_BUFIOREQ_PFN, &ioreq_pfn);
+    DPRINTF("buffered io page at pfn %lx\n", ioreq_pfn);
+    buffered_io_page = xc_map_foreign_range(xen_xc, xen_domid, XC_PAGE_SIZE,
+                                            PROT_READ|PROT_WRITE, ioreq_pfn);
+    if (buffered_io_page == NULL) {
+        hw_error("map buffered IO page returned error %d", errno);
+    }
+
+    ioreq_local_port = qemu_mallocz(smp_cpus * sizeof(evtchn_port_t));
+
+    /* FIXME: how about if we overflow the page here? */
+    for (i = 0; i < smp_cpus; i++) {
+        rc = xc_evtchn_bind_interdomain(xce_handle, xen_domid,
+                                        shared_page->vcpu_ioreq[i].vp_eport);
+        if (rc == -1) {
+            fprintf(stderr, "bind interdomain ioctl error %d\n", errno);
+            return -1;
+        }
+        ioreq_local_port[i] = rc;
+    }
+
     /* Init RAM management */
     qemu_map_cache_init();
     xen_ram_init(ram_size);
 
+    qemu_add_vm_change_state_handler(xen_vm_change_state_handler, NULL);
+
     return 0;
 }
+
+void destroy_hvm_domain(void)
+{
+    xc_interface *xc_handle;
+    int sts;
+
+    xc_handle = xc_interface_open(NULL, NULL, 0);
+    if (!xc_handle)
+        fprintf(stderr, "Cannot acquire xenctrl handle\n");
+    else {
+        sts = xc_domain_shutdown(xc_handle, xen_domid, SHUTDOWN_poweroff);
+        if (sts != 0)
+            fprintf(stderr, "? xc_domain_shutdown failed to issue poweroff, "
+                    "sts %d, errno %d\n", sts, errno);
+        else
+            fprintf(stderr, "Issued domain %d poweroff\n", xen_domid);
+        xc_interface_close(xc_handle);
+    }
+}
