Archipelago » qemu

/*

 * Copyright (C) 2010       Citrix Ltd.

 *

 * This work is licensed under the terms of the GNU GPL, version 2.  See

 * the COPYING file in the top-level directory.

 *

 * Contributions after 2012-01-13 are licensed under the terms of the

 * GNU GPL, version 2 or (at your option) any later version.

 */

#include <sys/mman.h>

#include "hw/pci/pci.h"

#include "hw/pc.h"

#include "hw/xen_common.h"

#include "hw/xen_backend.h"

#include "qmp-commands.h"

#include "qemu/range.h"

#include "xen-mapcache.h"

#include "trace.h"

#include "exec/address-spaces.h"

#include <xen/hvm/ioreq.h>

#include <xen/hvm/params.h>

#include <xen/hvm/e820.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

static MemoryRegion ram_memory, ram_640k, ram_lo, ram_hi;

static MemoryRegion *framebuffer;

static bool xen_in_migration;

/* Compatibility with older version */

#if __XEN_LATEST_INTERFACE_VERSION__ < 0x0003020a

static inline uint32_t xen_vcpu_eport(shared_iopage_t *shared_page, int i)

{

    return shared_page->vcpu_iodata[i].vp_eport;

}

static inline ioreq_t *xen_vcpu_ioreq(shared_iopage_t *shared_page, int vcpu)

{

    return &shared_page->vcpu_iodata[vcpu].vp_ioreq;

}

#  define FMT_ioreq_size PRIx64

#else

static inline uint32_t xen_vcpu_eport(shared_iopage_t *shared_page, int i)

{

    return shared_page->vcpu_ioreq[i].vp_eport;

}

static inline ioreq_t *xen_vcpu_ioreq(shared_iopage_t *shared_page, int vcpu)

{

    return &shared_page->vcpu_ioreq[vcpu];

}

#  define FMT_ioreq_size "u"

#endif

#ifndef HVM_PARAM_BUFIOREQ_EVTCHN

#define HVM_PARAM_BUFIOREQ_EVTCHN 26

#endif

#define BUFFER_IO_MAX_DELAY  100

typedef struct XenPhysmap {

    hwaddr start_addr;

    ram_addr_t size;

    char *name;

    hwaddr phys_offset;

    QLIST_ENTRY(XenPhysmap) list;

} XenPhysmap;

typedef struct XenIOState {

    shared_iopage_t *shared_page;

    buffered_iopage_t *buffered_io_page;

    QEMUTimer *buffered_io_timer;

    /* the evtchn port for polling the notification, */

    evtchn_port_t *ioreq_local_port;

    /* evtchn local port for buffered io */

    evtchn_port_t bufioreq_local_port;

    /* the evtchn fd for polling */

    XenEvtchn xce_handle;

    /* which vcpu we are serving */

    int send_vcpu;

    struct xs_handle *xenstore;

    MemoryListener memory_listener;

    QLIST_HEAD(, XenPhysmap) physmap;

    hwaddr free_phys_offset;

    const XenPhysmap *log_for_dirtybit;

    Notifier exit;

    Notifier suspend;

} XenIOState;

/* Xen specific function for piix pci */

int xen_pci_slot_get_pirq(PCIDevice *pci_dev, int irq_num)

{

    return irq_num + ((pci_dev->devfn >> 3) << 2);

}

void xen_piix3_set_irq(void *opaque, int irq_num, int level)

{

    xc_hvm_set_pci_intx_level(xen_xc, xen_domid, 0, 0, irq_num >> 2,

                              irq_num & 3, level);

}

void xen_piix_pci_write_config_client(uint32_t address, uint32_t val, int len)

{

    int i;

    /* Scan for updates to PCI link routes (0x60-0x63). */

    for (i = 0; i < len; i++) {

        uint8_t v = (val >> (8 * i)) & 0xff;

        if (v & 0x80) {

            v = 0;

        }

        v &= 0xf;

        if (((address + i) >= 0x60) && ((address + i) <= 0x63)) {

            xc_hvm_set_pci_link_route(xen_xc, xen_domid, address + i - 0x60, v);

        }

    }

}

void xen_hvm_inject_msi(uint64_t addr, uint32_t data)

{

    xen_xc_hvm_inject_msi(xen_xc, xen_domid, addr, data);

}

static void xen_suspend_notifier(Notifier *notifier, void *data)

{

    xc_set_hvm_param(xen_xc, xen_domid, HVM_PARAM_ACPI_S_STATE, 3);

}

/* Xen Interrupt Controller */

static void xen_set_irq(void *opaque, int irq, int level)

{

    xc_hvm_set_isa_irq_level(xen_xc, xen_domid, irq, level);

}

qemu_irq *xen_interrupt_controller_init(void)

{

    return qemu_allocate_irqs(xen_set_irq, NULL, 16);

}

/* Memory Ops */

static void xen_ram_init(ram_addr_t ram_size)

{

    MemoryRegion *sysmem = get_system_memory();

    ram_addr_t below_4g_mem_size, above_4g_mem_size = 0;

    ram_addr_t block_len;

    block_len = ram_size;

    if (ram_size >= HVM_BELOW_4G_RAM_END) {

        /* Xen does not allocate the memory continuously, and keep a hole at

         * HVM_BELOW_4G_MMIO_START of HVM_BELOW_4G_MMIO_LENGTH

         */

        block_len += HVM_BELOW_4G_MMIO_LENGTH;

    }

    memory_region_init_ram(&ram_memory, "xen.ram", block_len);

    vmstate_register_ram_global(&ram_memory);

    if (ram_size >= HVM_BELOW_4G_RAM_END) {

        above_4g_mem_size = ram_size - HVM_BELOW_4G_RAM_END;

        below_4g_mem_size = HVM_BELOW_4G_RAM_END;

    } else {

        below_4g_mem_size = ram_size;

    }

    memory_region_init_alias(&ram_640k, "xen.ram.640k",

                             &ram_memory, 0, 0xa0000);

    memory_region_add_subregion(sysmem, 0, &ram_640k);

    /* Skip of the VGA IO memory space, it will be registered later by the VGA

     * emulated device.

     *

     * The area between 0xc0000 and 0x100000 will be used by SeaBIOS to load

     * the Options ROM, so it is registered here as RAM.

     */

    memory_region_init_alias(&ram_lo, "xen.ram.lo",

                             &ram_memory, 0xc0000, below_4g_mem_size - 0xc0000);

    memory_region_add_subregion(sysmem, 0xc0000, &ram_lo);

    if (above_4g_mem_size > 0) {

        memory_region_init_alias(&ram_hi, "xen.ram.hi",

                                 &ram_memory, 0x100000000ULL,

                                 above_4g_mem_size);

        memory_region_add_subregion(sysmem, 0x100000000ULL, &ram_hi);

    }

}

void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size, MemoryRegion *mr)

{

    unsigned long nr_pfn;

    xen_pfn_t *pfn_list;

    int i;

    if (runstate_check(RUN_STATE_INMIGRATE)) {

        /* RAM already populated in Xen */

        fprintf(stderr, "%s: do not alloc "RAM_ADDR_FMT

                " bytes of ram at "RAM_ADDR_FMT" when runstate is INMIGRATE\n",

                __func__, size, ram_addr); 

        return;

    }

    if (mr == &ram_memory) {

        return;

    }

    trace_xen_ram_alloc(ram_addr, size);

    nr_pfn = size >> TARGET_PAGE_BITS;

    pfn_list = g_malloc(sizeof (*pfn_list) * nr_pfn);

    for (i = 0; i < nr_pfn; i++) {

        pfn_list[i] = (ram_addr >> TARGET_PAGE_BITS) + i;

    }

    if (xc_domain_populate_physmap_exact(xen_xc, xen_domid, nr_pfn, 0, 0, pfn_list)) {

        hw_error("xen: failed to populate ram at " RAM_ADDR_FMT, ram_addr);

    }

    g_free(pfn_list);

}

static XenPhysmap *get_physmapping(XenIOState *state,

                                   hwaddr start_addr, ram_addr_t size)

{

    XenPhysmap *physmap = NULL;

    start_addr &= TARGET_PAGE_MASK;

    QLIST_FOREACH(physmap, &state->physmap, list) {

        if (range_covers_byte(physmap->start_addr, physmap->size, start_addr)) {

            return physmap;

        }

    }

    return NULL;

}

static hwaddr xen_phys_offset_to_gaddr(hwaddr start_addr,

                                                   ram_addr_t size, void *opaque)

{

    hwaddr addr = start_addr & TARGET_PAGE_MASK;

    XenIOState *xen_io_state = opaque;

    XenPhysmap *physmap = NULL;

    QLIST_FOREACH(physmap, &xen_io_state->physmap, list) {

        if (range_covers_byte(physmap->phys_offset, physmap->size, addr)) {

            return physmap->start_addr;

        }

    }

    return start_addr;

}

#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 340

static int xen_add_to_physmap(XenIOState *state,

                              hwaddr start_addr,

                              ram_addr_t size,

                              MemoryRegion *mr,

                              hwaddr offset_within_region)

{

    unsigned long i = 0;

    int rc = 0;

    XenPhysmap *physmap = NULL;

    hwaddr pfn, start_gpfn;

    hwaddr phys_offset = memory_region_get_ram_addr(mr);

    char path[80], value[17];

    if (get_physmapping(state, start_addr, size)) {

        return 0;

    }

    if (size <= 0) {

        return -1;

    }

    /* Xen can only handle a single dirty log region for now and we want

     * the linear framebuffer to be that region.

     * Avoid tracking any regions that is not videoram and avoid tracking

     * the legacy vga region. */

    if (mr == framebuffer && start_addr > 0xbffff) {

        goto go_physmap;

    }

    return -1;

go_physmap:

    DPRINTF("mapping vram to %llx - %llx\n", start_addr, start_addr + size);

    pfn = phys_offset >> TARGET_PAGE_BITS;

    start_gpfn = start_addr >> TARGET_PAGE_BITS;

    for (i = 0; i < size >> TARGET_PAGE_BITS; i++) {

        unsigned long idx = pfn + i;

        xen_pfn_t gpfn = start_gpfn + i;

        rc = xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);

        if (rc) {

            DPRINTF("add_to_physmap MFN %"PRI_xen_pfn" to PFN %"

                    PRI_xen_pfn" failed: %d\n", idx, gpfn, rc);

            return -rc;

        }

    }

    physmap = g_malloc(sizeof (XenPhysmap));

    physmap->start_addr = start_addr;

    physmap->size = size;

    physmap->name = (char *)mr->name;

    physmap->phys_offset = phys_offset;

    QLIST_INSERT_HEAD(&state->physmap, physmap, list);

    xc_domain_pin_memory_cacheattr(xen_xc, xen_domid,

                                   start_addr >> TARGET_PAGE_BITS,

                                   (start_addr + size) >> TARGET_PAGE_BITS,

                                   XEN_DOMCTL_MEM_CACHEATTR_WB);

    snprintf(path, sizeof(path),

            "/local/domain/0/device-model/%d/physmap/%"PRIx64"/start_addr",

            xen_domid, (uint64_t)phys_offset);

    snprintf(value, sizeof(value), "%"PRIx64, (uint64_t)start_addr);

    if (!xs_write(state->xenstore, 0, path, value, strlen(value))) {

        return -1;

    }

    snprintf(path, sizeof(path),

            "/local/domain/0/device-model/%d/physmap/%"PRIx64"/size",

            xen_domid, (uint64_t)phys_offset);

    snprintf(value, sizeof(value), "%"PRIx64, (uint64_t)size);

    if (!xs_write(state->xenstore, 0, path, value, strlen(value))) {

        return -1;

    }

    if (mr->name) {

        snprintf(path, sizeof(path),

                "/local/domain/0/device-model/%d/physmap/%"PRIx64"/name",

                xen_domid, (uint64_t)phys_offset);

        if (!xs_write(state->xenstore, 0, path, mr->name, strlen(mr->name))) {

            return -1;

        }

    }

    return 0;

}

static int xen_remove_from_physmap(XenIOState *state,

                                   hwaddr start_addr,

                                   ram_addr_t size)

{

    unsigned long i = 0;

    int rc = 0;

    XenPhysmap *physmap = NULL;

    hwaddr phys_offset = 0;

    physmap = get_physmapping(state, start_addr, size);

    if (physmap == NULL) {

        return -1;

    }

    phys_offset = physmap->phys_offset;

    size = physmap->size;

    DPRINTF("unmapping vram to %llx - %llx, from %llx\n",

            phys_offset, phys_offset + size, start_addr);

    size >>= TARGET_PAGE_BITS;

    start_addr >>= TARGET_PAGE_BITS;

    phys_offset >>= TARGET_PAGE_BITS;

    for (i = 0; i < size; i++) {

        unsigned long idx = start_addr + i;

        xen_pfn_t gpfn = phys_offset + i;

        rc = xc_domain_add_to_physmap(xen_xc, xen_domid, XENMAPSPACE_gmfn, idx, gpfn);

        if (rc) {

            fprintf(stderr, "add_to_physmap MFN %"PRI_xen_pfn" to PFN %"

                    PRI_xen_pfn" failed: %d\n", idx, gpfn, rc);

            return -rc;

        }

    }

    QLIST_REMOVE(physmap, list);

    if (state->log_for_dirtybit == physmap) {

        state->log_for_dirtybit = NULL;

    }

    free(physmap);

    return 0;

}

#else

static int xen_add_to_physmap(XenIOState *state,

                              hwaddr start_addr,

                              ram_addr_t size,

                              MemoryRegion *mr,

                              hwaddr offset_within_region)

{

    return -ENOSYS;

}

static int xen_remove_from_physmap(XenIOState *state,

                                   hwaddr start_addr,

                                   ram_addr_t size)

{

    return -ENOSYS;

}

#endif

static void xen_set_memory(struct MemoryListener *listener,

                           MemoryRegionSection *section,

                           bool add)

{

    XenIOState *state = container_of(listener, XenIOState, memory_listener);

    hwaddr start_addr = section->offset_within_address_space;

    ram_addr_t size = section->size;

    bool log_dirty = memory_region_is_logging(section->mr);

    hvmmem_type_t mem_type;

    if (!memory_region_is_ram(section->mr)) {

        return;

    }

    if (!(section->mr != &ram_memory

          && ( (log_dirty && add) || (!log_dirty && !add)))) {

        return;

    }

    trace_xen_client_set_memory(start_addr, size, log_dirty);

    start_addr &= TARGET_PAGE_MASK;

    size = TARGET_PAGE_ALIGN(size);

    if (add) {

        if (!memory_region_is_rom(section->mr)) {

            xen_add_to_physmap(state, start_addr, size,

                               section->mr, section->offset_within_region);

        } else {

            mem_type = HVMMEM_ram_ro;

            if (xc_hvm_set_mem_type(xen_xc, xen_domid, mem_type,

                                    start_addr >> TARGET_PAGE_BITS,

                                    size >> TARGET_PAGE_BITS)) {

                DPRINTF("xc_hvm_set_mem_type error, addr: "TARGET_FMT_plx"\n",

                        start_addr);

            }

        }

    } else {

        if (xen_remove_from_physmap(state, start_addr, size) < 0) {

            DPRINTF("physmapping does not exist at "TARGET_FMT_plx"\n", start_addr);

        }

    }

}

static void xen_region_add(MemoryListener *listener,

                           MemoryRegionSection *section)

{

    xen_set_memory(listener, section, true);

}

static void xen_region_del(MemoryListener *listener,

                           MemoryRegionSection *section)

{

    xen_set_memory(listener, section, false);

}

static void xen_sync_dirty_bitmap(XenIOState *state,

                                  hwaddr start_addr,

                                  ram_addr_t size)

{

    hwaddr npages = size >> TARGET_PAGE_BITS;

    const int width = sizeof(unsigned long) * 8;

    unsigned long bitmap[(npages + width - 1) / width];

    int rc, i, j;

    const XenPhysmap *physmap = NULL;

    physmap = get_physmapping(state, start_addr, size);

    if (physmap == NULL) {

        /* not handled */

        return;

    }

    if (state->log_for_dirtybit == NULL) {

        state->log_for_dirtybit = physmap;

    } else if (state->log_for_dirtybit != physmap) {

        /* Only one range for dirty bitmap can be tracked. */

        return;

    }

    rc = xc_hvm_track_dirty_vram(xen_xc, xen_domid,

                                 start_addr >> TARGET_PAGE_BITS, npages,

                                 bitmap);

    if (rc < 0) {

        if (rc != -ENODATA) {

            memory_region_set_dirty(framebuffer, 0, size);

            DPRINTF("xen: track_dirty_vram failed (0x" TARGET_FMT_plx

                    ", 0x" TARGET_FMT_plx "): %s\n",

                    start_addr, start_addr + size, strerror(-rc));

        }

        return;

    }

    for (i = 0; i < ARRAY_SIZE(bitmap); i++) {

        unsigned long map = bitmap[i];

        while (map != 0) {

            j = ffsl(map) - 1;

            map &= ~(1ul << j);

            memory_region_set_dirty(framebuffer,

                                    (i * width + j) * TARGET_PAGE_SIZE,

                                    TARGET_PAGE_SIZE);

        };

    }

}

static void xen_log_start(MemoryListener *listener,

                          MemoryRegionSection *section)

{

    XenIOState *state = container_of(listener, XenIOState, memory_listener);

    xen_sync_dirty_bitmap(state, section->offset_within_address_space,

                          section->size);

}

static void xen_log_stop(MemoryListener *listener, MemoryRegionSection *section)

{

    XenIOState *state = container_of(listener, XenIOState, memory_listener);

    state->log_for_dirtybit = NULL;

    /* Disable dirty bit tracking */

    xc_hvm_track_dirty_vram(xen_xc, xen_domid, 0, 0, NULL);

}

static void xen_log_sync(MemoryListener *listener, MemoryRegionSection *section)

{

    XenIOState *state = container_of(listener, XenIOState, memory_listener);

    xen_sync_dirty_bitmap(state, section->offset_within_address_space,

                          section->size);

}

static void xen_log_global_start(MemoryListener *listener)

{

    if (xen_enabled()) {

        xen_in_migration = true;

    }

}

static void xen_log_global_stop(MemoryListener *listener)

{

    xen_in_migration = false;

}

static MemoryListener xen_memory_listener = {

    .region_add = xen_region_add,

    .region_del = xen_region_del,

    .log_start = xen_log_start,

    .log_stop = xen_log_stop,

    .log_sync = xen_log_sync,

    .log_global_start = xen_log_global_start,

    .log_global_stop = xen_log_global_stop,

    .priority = 10,

};

void qmp_xen_set_global_dirty_log(bool enable, Error **errp)

{

    if (enable) {

        memory_global_dirty_log_start();

    } else {

        memory_global_dirty_log_stop();

    }

}

/* VCPU Operations, MMIO, IO ring ... */

static void xen_reset_vcpu(void *opaque)

{

    CPUArchState *env = opaque;

    env->halted = 1;

}

void xen_vcpu_init(void)

{

    CPUArchState *first_cpu;

    if ((first_cpu = qemu_get_cpu(0))) {

        qemu_register_reset(xen_reset_vcpu, first_cpu);

        xen_reset_vcpu(first_cpu);

    }

    /* if rtc_clock is left to default (host_clock), disable it */

    if (rtc_clock == host_clock) {

        qemu_clock_enable(rtc_clock, false);

    }

}

/* get the ioreq packets from share mem */

static ioreq_t *cpu_get_ioreq_from_shared_memory(XenIOState *state, int vcpu)

{

    ioreq_t *req = xen_vcpu_ioreq(state->shared_page, vcpu);

    if (req->state != STATE_IOREQ_READY) {

        DPRINTF("I/O request not ready: "

                "%x, ptr: %x, port: %"PRIx64", "

                "data: %"PRIx64", count: %" FMT_ioreq_size ", size: %" FMT_ioreq_size "\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(XenIOState *state)

{

    int i;

    evtchn_port_t port;

    port = xc_evtchn_pending(state->xce_handle);

    if (port == state->bufioreq_local_port) {

        qemu_mod_timer(state->buffered_io_timer,

                BUFFER_IO_MAX_DELAY + qemu_get_clock_ms(rt_clock));

        return NULL;

    }

    if (port != -1) {

        for (i = 0; i < smp_cpus; i++) {

            if (state->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(state->xce_handle, port);

        /* get the io packet from shared memory */

        state->send_vcpu = i;

        return cpu_get_ioreq_from_shared_memory(state, i);

    }

    /* read error or read nothing */

    return NULL;

}

static uint32_t do_inp(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(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(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(req->addr, req->size);

        } else {

            uint32_t tmp;

            for (i = 0; i < req->count; i++) {

                tmp = do_inp(req->addr, req->size);

                cpu_physical_memory_write(

                        req->data + (sign * i * (int64_t)req->size),

                        (uint8_t *) &tmp, req->size);

            }

        }

    } else if (req->dir == IOREQ_WRITE) {

        if (!req->data_is_ptr) {

            do_outp(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 * (int64_t)req->size),

                        (uint8_t*) &tmp, req->size);

                do_outp(req->addr, req->size, tmp);

            }

        }

    }

}

static void cpu_ioreq_move(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 * (int64_t)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 * (int64_t)req->size),

                        (uint8_t *) &req->data, req->size);

            }

        }

    } else {

        uint64_t tmp;

        if (req->dir == IOREQ_READ) {

            for (i = 0; i < req->count; i++) {

                cpu_physical_memory_read(

                        req->addr + (sign * i * (int64_t)req->size),

                        (uint8_t*) &tmp, req->size);

                cpu_physical_memory_write(

                        req->data + (sign * i * (int64_t)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 * (int64_t)req->size),

                        (uint8_t*) &tmp, req->size);

                cpu_physical_memory_write(

                        req->addr + (sign * i * (int64_t)req->size),

                        (uint8_t*) &tmp, req->size);

            }

        }

    }

}

static void handle_ioreq(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(req);

            break;

        case IOREQ_TYPE_COPY:

            cpu_ioreq_move(req);

            break;

        case IOREQ_TYPE_TIMEOFFSET:

            break;

        case IOREQ_TYPE_INVALIDATE:

            xen_invalidate_map_cache();

            break;

        default:

            hw_error("Invalid ioreq type 0x%x\n", req->type);

    }

}

static int handle_buffered_iopage(XenIOState *state)

{

    buf_ioreq_t *buf_req = NULL;

    ioreq_t req;

    int qw;

    if (!state->buffered_io_page) {

        return 0;

    }

    memset(&req, 0x00, sizeof(req));

    while (state->buffered_io_page->read_pointer != state->buffered_io_page->write_pointer) {

        buf_req = &state->buffered_io_page->buf_ioreq[

            state->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 = &state->buffered_io_page->buf_ioreq[

                (state->buffered_io_page->read_pointer + 1) % IOREQ_BUFFER_SLOT_NUM];

            req.data |= ((uint64_t)buf_req->data) << 32;

        }

        handle_ioreq(&req);

        xen_mb();

        state->buffered_io_page->read_pointer += qw ? 2 : 1;

    }

    return req.count;

}

static void handle_buffered_io(void *opaque)

{

    XenIOState *state = opaque;

    if (handle_buffered_iopage(state)) {

        qemu_mod_timer(state->buffered_io_timer,

                BUFFER_IO_MAX_DELAY + qemu_get_clock_ms(rt_clock));

    } else {

        qemu_del_timer(state->buffered_io_timer);

        xc_evtchn_unmask(state->xce_handle, state->bufioreq_local_port);

    }

}

static void cpu_handle_ioreq(void *opaque)

{

    XenIOState *state = opaque;

    ioreq_t *req = cpu_get_ioreq(state);

    handle_buffered_iopage(state);

    if (req) {

        handle_ioreq(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: %" FMT_ioreq_size ", size: %" FMT_ioreq_size "\n",

                    req->state, req->data_is_ptr, req->addr,

                    req->data, req->count, req->size);

            destroy_hvm_domain(false);

            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 (runstate_is_running()) {

            if (qemu_shutdown_requested_get()) {

                destroy_hvm_domain(false);

            }

            if (qemu_reset_requested_get()) {

                qemu_system_reset(VMRESET_REPORT);

                destroy_hvm_domain(true);

            }

        }

        req->state = STATE_IORESP_READY;

        xc_evtchn_notify(state->xce_handle, state->ioreq_local_port[state->send_vcpu]);

    }

}

static int store_dev_info(int domid, CharDriverState *cs, const char *string)

{

    struct xs_handle *xs = NULL;

    char *path = NULL;

    char *newpath = NULL;

    char *pts = NULL;

    int ret = -1;

    /* Only continue if we're talking to a pty. */

    if (strncmp(cs->filename, "pty:", 4)) {

        return 0;