hw: move target-independent files to subdirectories

This patch tackles all files that are compiled once, moving
them to subdirectories of hw/.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 976 insertions, 0 deletions

diff --git a/hw/xen/Makefile.objs b/hw/xen/Makefile.objs
index e69de29bb..4b209a7b9 100644
--- a/hw/xen/Makefile.objs
+++ b/hw/xen/Makefile.objs
@@ -0,0 +1,2 @@
+# xen backend driver support
+common-obj-$(CONFIG_XEN_BACKEND) += xen_backend.o xen_devconfig.o
diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c
new file mode 100644
index 000000000..2a8c9f5d1
--- /dev/null
+++ b/hw/xen/xen_backend.c
@@ -0,0 +1,800 @@
+/*
+ *  xen backend driver infrastructure
+ *  (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; under version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Contributions after 2012-01-13 are licensed under the terms of the
+ *  GNU GPL, version 2 or (at your option) any later version.
+ */
+
+/*
+ * TODO: add some xenbus / xenstore concepts overview here.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/signal.h>
+
+#include "hw/hw.h"
+#include "char/char.h"
+#include "qemu/log.h"
+#include "hw/xen/xen_backend.h"
+
+#include <xen/grant_table.h>
+
+/* ------------------------------------------------------------- */
+
+/* public */
+XenXC xen_xc = XC_HANDLER_INITIAL_VALUE;
+XenGnttab xen_xcg = XC_HANDLER_INITIAL_VALUE;
+struct xs_handle *xenstore = NULL;
+const char *xen_protocol;
+
+/* private */
+static QTAILQ_HEAD(XenDeviceHead, XenDevice) xendevs = QTAILQ_HEAD_INITIALIZER(xendevs);
+static int debug = 0;
+
+/* ------------------------------------------------------------- */
+
+int xenstore_write_str(const char *base, const char *node, const char *val)
+{
+    char abspath[XEN_BUFSIZE];
+
+    snprintf(abspath, sizeof(abspath), "%s/%s", base, node);
+    if (!xs_write(xenstore, 0, abspath, val, strlen(val))) {
+        return -1;
+    }
+    return 0;
+}
+
+char *xenstore_read_str(const char *base, const char *node)
+{
+    char abspath[XEN_BUFSIZE];
+    unsigned int len;
+    char *str, *ret = NULL;
+
+    snprintf(abspath, sizeof(abspath), "%s/%s", base, node);
+    str = xs_read(xenstore, 0, abspath, &len);
+    if (str != NULL) {
+        /* move to qemu-allocated memory to make sure
+         * callers can savely g_free() stuff. */
+        ret = g_strdup(str);
+        free(str);
+    }
+    return ret;
+}
+
+int xenstore_write_int(const char *base, const char *node, int ival)
+{
+    char val[12];
+
+    snprintf(val, sizeof(val), "%d", ival);
+    return xenstore_write_str(base, node, val);
+}
+
+int xenstore_write_int64(const char *base, const char *node, int64_t ival)
+{
+    char val[21];
+
+    snprintf(val, sizeof(val), "%"PRId64, ival);
+    return xenstore_write_str(base, node, val);
+}
+
+int xenstore_read_int(const char *base, const char *node, int *ival)
+{
+    char *val;
+    int rc = -1;
+
+    val = xenstore_read_str(base, node);
+    if (val && 1 == sscanf(val, "%d", ival)) {
+        rc = 0;
+    }
+    g_free(val);
+    return rc;
+}
+
+int xenstore_write_be_str(struct XenDevice *xendev, const char *node, const char *val)
+{
+    return xenstore_write_str(xendev->be, node, val);
+}
+
+int xenstore_write_be_int(struct XenDevice *xendev, const char *node, int ival)
+{
+    return xenstore_write_int(xendev->be, node, ival);
+}
+
+int xenstore_write_be_int64(struct XenDevice *xendev, const char *node, int64_t ival)
+{
+    return xenstore_write_int64(xendev->be, node, ival);
+}
+
+char *xenstore_read_be_str(struct XenDevice *xendev, const char *node)
+{
+    return xenstore_read_str(xendev->be, node);
+}
+
+int xenstore_read_be_int(struct XenDevice *xendev, const char *node, int *ival)
+{
+    return xenstore_read_int(xendev->be, node, ival);
+}
+
+char *xenstore_read_fe_str(struct XenDevice *xendev, const char *node)
+{
+    return xenstore_read_str(xendev->fe, node);
+}
+
+int xenstore_read_fe_int(struct XenDevice *xendev, const char *node, int *ival)
+{
+    return xenstore_read_int(xendev->fe, node, ival);
+}
+
+/* ------------------------------------------------------------- */
+
+const char *xenbus_strstate(enum xenbus_state state)
+{
+    static const char *const name[] = {
+        [ XenbusStateUnknown      ] = "Unknown",
+        [ XenbusStateInitialising ] = "Initialising",
+        [ XenbusStateInitWait     ] = "InitWait",
+        [ XenbusStateInitialised  ] = "Initialised",
+        [ XenbusStateConnected    ] = "Connected",
+        [ XenbusStateClosing      ] = "Closing",
+        [ XenbusStateClosed       ] = "Closed",
+    };
+    return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID";
+}
+
+int xen_be_set_state(struct XenDevice *xendev, enum xenbus_state state)
+{
+    int rc;
+
+    rc = xenstore_write_be_int(xendev, "state", state);
+    if (rc < 0) {
+        return rc;
+    }
+    xen_be_printf(xendev, 1, "backend state: %s -> %s\n",
+                  xenbus_strstate(xendev->be_state), xenbus_strstate(state));
+    xendev->be_state = state;
+    return 0;
+}
+
+/* ------------------------------------------------------------- */
+
+struct XenDevice *xen_be_find_xendev(const char *type, int dom, int dev)
+{
+    struct XenDevice *xendev;
+
+    QTAILQ_FOREACH(xendev, &xendevs, next) {
+        if (xendev->dom != dom) {
+            continue;
+        }
+        if (xendev->dev != dev) {
+            continue;
+        }
+        if (strcmp(xendev->type, type) != 0) {
+            continue;
+        }
+        return xendev;
+    }
+    return NULL;
+}
+
+/*
+ * get xen backend device, allocate a new one if it doesn't exist.
+ */
+static struct XenDevice *xen_be_get_xendev(const char *type, int dom, int dev,
+                                           struct XenDevOps *ops)
+{
+    struct XenDevice *xendev;
+    char *dom0;
+
+    xendev = xen_be_find_xendev(type, dom, dev);
+    if (xendev) {
+        return xendev;
+    }
+
+    /* init new xendev */
+    xendev = g_malloc0(ops->size);
+    xendev->type  = type;
+    xendev->dom   = dom;
+    xendev->dev   = dev;
+    xendev->ops   = ops;
+
+    dom0 = xs_get_domain_path(xenstore, 0);
+    snprintf(xendev->be, sizeof(xendev->be), "%s/backend/%s/%d/%d",
+             dom0, xendev->type, xendev->dom, xendev->dev);
+    snprintf(xendev->name, sizeof(xendev->name), "%s-%d",
+             xendev->type, xendev->dev);
+    free(dom0);
+
+    xendev->debug      = debug;
+    xendev->local_port = -1;
+
+    xendev->evtchndev = xen_xc_evtchn_open(NULL, 0);
+    if (xendev->evtchndev == XC_HANDLER_INITIAL_VALUE) {
+        xen_be_printf(NULL, 0, "can't open evtchn device\n");
+        g_free(xendev);
+        return NULL;
+    }
+    fcntl(xc_evtchn_fd(xendev->evtchndev), F_SETFD, FD_CLOEXEC);
+
+    if (ops->flags & DEVOPS_FLAG_NEED_GNTDEV) {
+        xendev->gnttabdev = xen_xc_gnttab_open(NULL, 0);
+        if (xendev->gnttabdev == XC_HANDLER_INITIAL_VALUE) {
+            xen_be_printf(NULL, 0, "can't open gnttab device\n");
+            xc_evtchn_close(xendev->evtchndev);
+            g_free(xendev);
+            return NULL;
+        }
+    } else {
+        xendev->gnttabdev = XC_HANDLER_INITIAL_VALUE;
+    }
+
+    QTAILQ_INSERT_TAIL(&xendevs, xendev, next);
+
+    if (xendev->ops->alloc) {
+        xendev->ops->alloc(xendev);
+    }
+
+    return xendev;
+}
+
+/*
+ * release xen backend device.
+ */
+static struct XenDevice *xen_be_del_xendev(int dom, int dev)
+{
+    struct XenDevice *xendev, *xnext;
+
+    /*
+     * This is pretty much like QTAILQ_FOREACH(xendev, &xendevs, next) but
+     * we save the next pointer in xnext because we might free xendev.
+     */
+    xnext = xendevs.tqh_first;
+    while (xnext) {
+        xendev = xnext;
+        xnext = xendev->next.tqe_next;
+
+        if (xendev->dom != dom) {
+            continue;
+        }
+        if (xendev->dev != dev && dev != -1) {
+            continue;
+        }
+
+        if (xendev->ops->free) {
+            xendev->ops->free(xendev);
+        }
+
+        if (xendev->fe) {
+            char token[XEN_BUFSIZE];
+            snprintf(token, sizeof(token), "fe:%p", xendev);
+            xs_unwatch(xenstore, xendev->fe, token);
+            g_free(xendev->fe);
+        }
+
+        if (xendev->evtchndev != XC_HANDLER_INITIAL_VALUE) {
+            xc_evtchn_close(xendev->evtchndev);
+        }
+        if (xendev->gnttabdev != XC_HANDLER_INITIAL_VALUE) {
+            xc_gnttab_close(xendev->gnttabdev);
+        }
+
+        QTAILQ_REMOVE(&xendevs, xendev, next);
+        g_free(xendev);
+    }
+    return NULL;
+}
+
+/*
+ * Sync internal data structures on xenstore updates.
+ * Node specifies the changed field.  node = NULL means
+ * update all fields (used for initialization).
+ */
+static void xen_be_backend_changed(struct XenDevice *xendev, const char *node)
+{
+    if (node == NULL  ||  strcmp(node, "online") == 0) {
+        if (xenstore_read_be_int(xendev, "online", &xendev->online) == -1) {
+            xendev->online = 0;
+        }
+    }
+
+    if (node) {
+        xen_be_printf(xendev, 2, "backend update: %s\n", node);
+        if (xendev->ops->backend_changed) {
+            xendev->ops->backend_changed(xendev, node);
+        }
+    }
+}
+
+static void xen_be_frontend_changed(struct XenDevice *xendev, const char *node)
+{
+    int fe_state;
+
+    if (node == NULL  ||  strcmp(node, "state") == 0) {
+        if (xenstore_read_fe_int(xendev, "state", &fe_state) == -1) {
+            fe_state = XenbusStateUnknown;
+        }
+        if (xendev->fe_state != fe_state) {
+            xen_be_printf(xendev, 1, "frontend state: %s -> %s\n",
+                          xenbus_strstate(xendev->fe_state),
+                          xenbus_strstate(fe_state));
+        }
+        xendev->fe_state = fe_state;
+    }
+    if (node == NULL  ||  strcmp(node, "protocol") == 0) {
+        g_free(xendev->protocol);
+        xendev->protocol = xenstore_read_fe_str(xendev, "protocol");
+        if (xendev->protocol) {
+            xen_be_printf(xendev, 1, "frontend protocol: %s\n", xendev->protocol);
+        }
+    }
+
+    if (node) {
+        xen_be_printf(xendev, 2, "frontend update: %s\n", node);
+        if (xendev->ops->frontend_changed) {
+            xendev->ops->frontend_changed(xendev, node);
+        }
+    }
+}
+
+/* ------------------------------------------------------------- */
+/* Check for possible state transitions and perform them.        */
+
+/*
+ * Initial xendev setup.  Read frontend path, register watch for it.
+ * Should succeed once xend finished setting up the backend device.
+ *
+ * Also sets initial state (-> Initializing) when done.  Which
+ * only affects the xendev->be_state variable as xenbus should
+ * already be put into that state by xend.
+ */
+static int xen_be_try_setup(struct XenDevice *xendev)
+{
+    char token[XEN_BUFSIZE];
+    int be_state;
+
+    if (xenstore_read_be_int(xendev, "state", &be_state) == -1) {
+        xen_be_printf(xendev, 0, "reading backend state failed\n");
+        return -1;
+    }
+
+    if (be_state != XenbusStateInitialising) {
+        xen_be_printf(xendev, 0, "initial backend state is wrong (%s)\n",
+                      xenbus_strstate(be_state));
+        return -1;
+    }
+
+    xendev->fe = xenstore_read_be_str(xendev, "frontend");
+    if (xendev->fe == NULL) {
+        xen_be_printf(xendev, 0, "reading frontend path failed\n");
+        return -1;
+    }
+
+    /* setup frontend watch */
+    snprintf(token, sizeof(token), "fe:%p", xendev);
+    if (!xs_watch(xenstore, xendev->fe, token)) {
+        xen_be_printf(xendev, 0, "watching frontend path (%s) failed\n",
+                      xendev->fe);
+        return -1;
+    }
+    xen_be_set_state(xendev, XenbusStateInitialising);
+
+    xen_be_backend_changed(xendev, NULL);
+    xen_be_frontend_changed(xendev, NULL);
+    return 0;
+}
+
+/*
+ * Try initialize xendev.  Prepare everything the backend can do
+ * without synchronizing with the frontend.  Fakes hotplug-status.  No
+ * hotplug involved here because this is about userspace drivers, thus
+ * there are kernel backend devices which could invoke hotplug.
+ *
+ * Goes to InitWait on success.
+ */
+static int xen_be_try_init(struct XenDevice *xendev)
+{
+    int rc = 0;
+
+    if (!xendev->online) {
+        xen_be_printf(xendev, 1, "not online\n");
+        return -1;
+    }
+
+    if (xendev->ops->init) {
+        rc = xendev->ops->init(xendev);
+    }
+    if (rc != 0) {
+        xen_be_printf(xendev, 1, "init() failed\n");
+        return rc;
+    }
+
+    xenstore_write_be_str(xendev, "hotplug-status", "connected");
+    xen_be_set_state(xendev, XenbusStateInitWait);
+    return 0;
+}
+
+/*
+ * Try to initialise xendev.  Depends on the frontend being ready
+ * for it (shared ring and evtchn info in xenstore, state being
+ * Initialised or Connected).
+ *
+ * Goes to Connected on success.
+ */
+static int xen_be_try_initialise(struct XenDevice *xendev)
+{
+    int rc = 0;
+
+    if (xendev->fe_state != XenbusStateInitialised  &&
+        xendev->fe_state != XenbusStateConnected) {
+        if (xendev->ops->flags & DEVOPS_FLAG_IGNORE_STATE) {
+            xen_be_printf(xendev, 2, "frontend not ready, ignoring\n");
+        } else {
+            xen_be_printf(xendev, 2, "frontend not ready (yet)\n");
+            return -1;
+        }
+    }
+
+    if (xendev->ops->initialise) {
+        rc = xendev->ops->initialise(xendev);
+    }
+    if (rc != 0) {
+        xen_be_printf(xendev, 0, "initialise() failed\n");
+        return rc;
+    }
+
+    xen_be_set_state(xendev, XenbusStateConnected);
+    return 0;
+}
+
+/*
+ * Try to let xendev know that it is connected.  Depends on the
+ * frontend being Connected.  Note that this may be called more
+ * than once since the backend state is not modified.
+ */
+static void xen_be_try_connected(struct XenDevice *xendev)
+{
+    if (!xendev->ops->connected) {
+        return;
+    }
+
+    if (xendev->fe_state != XenbusStateConnected) {
+        if (xendev->ops->flags & DEVOPS_FLAG_IGNORE_STATE) {
+            xen_be_printf(xendev, 2, "frontend not ready, ignoring\n");
+        } else {
+            xen_be_printf(xendev, 2, "frontend not ready (yet)\n");
+            return;
+        }
+    }
+
+    xendev->ops->connected(xendev);
+}
+
+/*
+ * Teardown connection.
+ *
+ * Goes to Closed when done.
+ */
+static void xen_be_disconnect(struct XenDevice *xendev, enum xenbus_state state)
+{
+    if (xendev->be_state != XenbusStateClosing &&
+        xendev->be_state != XenbusStateClosed  &&
+        xendev->ops->disconnect) {
+        xendev->ops->disconnect(xendev);
+    }
+    if (xendev->be_state != state) {
+        xen_be_set_state(xendev, state);
+    }
+}
+
+/*
+ * Try to reset xendev, for reconnection by another frontend instance.
+ */
+static int xen_be_try_reset(struct XenDevice *xendev)
+{
+    if (xendev->fe_state != XenbusStateInitialising) {
+        return -1;
+    }
+
+    xen_be_printf(xendev, 1, "device reset (for re-connect)\n");
+    xen_be_set_state(xendev, XenbusStateInitialising);
+    return 0;
+}
+
+/*
+ * state change dispatcher function
+ */
+void xen_be_check_state(struct XenDevice *xendev)
+{
+    int rc = 0;
+
+    /* frontend may request shutdown from almost anywhere */
+    if (xendev->fe_state == XenbusStateClosing ||
+        xendev->fe_state == XenbusStateClosed) {
+        xen_be_disconnect(xendev, xendev->fe_state);
+        return;
+    }
+
+    /* check for possible backend state transitions */
+    for (;;) {
+        switch (xendev->be_state) {
+        case XenbusStateUnknown:
+            rc = xen_be_try_setup(xendev);
+            break;
+        case XenbusStateInitialising:
+            rc = xen_be_try_init(xendev);
+            break;
+        case XenbusStateInitWait:
+            rc = xen_be_try_initialise(xendev);
+            break;
+        case XenbusStateConnected:
+            /* xendev->be_state doesn't change */
+            xen_be_try_connected(xendev);
+            rc = -1;
+            break;
+        case XenbusStateClosed:
+            rc = xen_be_try_reset(xendev);
+            break;
+        default:
+            rc = -1;
+        }
+        if (rc != 0) {
+            break;
+        }
+    }
+}
+
+/* ------------------------------------------------------------- */
+
+static int xenstore_scan(const char *type, int dom, struct XenDevOps *ops)
+{
+    struct XenDevice *xendev;
+    char path[XEN_BUFSIZE], token[XEN_BUFSIZE];
+    char **dev = NULL, *dom0;
+    unsigned int cdev, j;
+
+    /* setup watch */
+    dom0 = xs_get_domain_path(xenstore, 0);
+    snprintf(token, sizeof(token), "be:%p:%d:%p", type, dom, ops);
+    snprintf(path, sizeof(path), "%s/backend/%s/%d", dom0, type, dom);
+    free(dom0);
+    if (!xs_watch(xenstore, path, token)) {
+        xen_be_printf(NULL, 0, "xen be: watching backend path (%s) failed\n", path);
+        return -1;
+    }
+
+    /* look for backends */
+    dev = xs_directory(xenstore, 0, path, &cdev);
+    if (!dev) {
+        return 0;
+    }
+    for (j = 0; j < cdev; j++) {
+        xendev = xen_be_get_xendev(type, dom, atoi(dev[j]), ops);
+        if (xendev == NULL) {
+            continue;
+        }
+        xen_be_check_state(xendev);
+    }
+    free(dev);
+    return 0;
+}
+
+static void xenstore_update_be(char *watch, char *type, int dom,
+                               struct XenDevOps *ops)
+{
+    struct XenDevice *xendev;
+    char path[XEN_BUFSIZE], *dom0, *bepath;
+    unsigned int len, dev;
+
+    dom0 = xs_get_domain_path(xenstore, 0);
+    len = snprintf(path, sizeof(path), "%s/backend/%s/%d", dom0, type, dom);
+    free(dom0);
+    if (strncmp(path, watch, len) != 0) {
+        return;
+    }
+    if (sscanf(watch+len, "/%u/%255s", &dev, path) != 2) {
+        strcpy(path, "");
+        if (sscanf(watch+len, "/%u", &dev) != 1) {
+            dev = -1;
+        }
+    }
+    if (dev == -1) {
+        return;
+    }
+
+    xendev = xen_be_get_xendev(type, dom, dev, ops);
+    if (xendev != NULL) {
+        bepath = xs_read(xenstore, 0, xendev->be, &len);
+        if (bepath == NULL) {
+            xen_be_del_xendev(dom, dev);
+        } else {
+            free(bepath);
+            xen_be_backend_changed(xendev, path);
+            xen_be_check_state(xendev);
+        }
+    }
+}
+
+static void xenstore_update_fe(char *watch, struct XenDevice *xendev)
+{
+    char *node;
+    unsigned int len;
+
+    len = strlen(xendev->fe);
+    if (strncmp(xendev->fe, watch, len) != 0) {
+        return;
+    }
+    if (watch[len] != '/') {
+        return;
+    }
+    node = watch + len + 1;
+
+    xen_be_frontend_changed(xendev, node);
+    xen_be_check_state(xendev);
+}
+
+static void xenstore_update(void *unused)
+{
+    char **vec = NULL;
+    intptr_t type, ops, ptr;
+    unsigned int dom, count;
+
+    vec = xs_read_watch(xenstore, &count);
+    if (vec == NULL) {
+        goto cleanup;
+    }
+
+    if (sscanf(vec[XS_WATCH_TOKEN], "be:%" PRIxPTR ":%d:%" PRIxPTR,
+               &type, &dom, &ops) == 3) {
+        xenstore_update_be(vec[XS_WATCH_PATH], (void*)type, dom, (void*)ops);
+    }
+    if (sscanf(vec[XS_WATCH_TOKEN], "fe:%" PRIxPTR, &ptr) == 1) {
+        xenstore_update_fe(vec[XS_WATCH_PATH], (void*)ptr);
+    }
+
+cleanup:
+    free(vec);
+}
+
+static void xen_be_evtchn_event(void *opaque)
+{
+    struct XenDevice *xendev = opaque;
+    evtchn_port_t port;
+
+    port = xc_evtchn_pending(xendev->evtchndev);
+    if (port != xendev->local_port) {
+        xen_be_printf(xendev, 0, "xc_evtchn_pending returned %d (expected %d)\n",
+                      port, xendev->local_port);
+        return;
+    }
+    xc_evtchn_unmask(xendev->evtchndev, port);
+
+    if (xendev->ops->event) {
+        xendev->ops->event(xendev);
+    }
+}
+
+/* -------------------------------------------------------------------- */
+
+int xen_be_init(void)
+{
+    xenstore = xs_daemon_open();
+    if (!xenstore) {
+        xen_be_printf(NULL, 0, "can't connect to xenstored\n");
+        return -1;
+    }
+
+    if (qemu_set_fd_handler(xs_fileno(xenstore), xenstore_update, NULL, NULL) < 0) {
+        goto err;
+    }
+
+    if (xen_xc == XC_HANDLER_INITIAL_VALUE) {
+        /* Check if xen_init() have been called */
+        goto err;
+    }
+    return 0;
+
+err:
+    qemu_set_fd_handler(xs_fileno(xenstore), NULL, NULL, NULL);
+    xs_daemon_close(xenstore);
+    xenstore = NULL;
+
+    return -1;
+}
+
+int xen_be_register(const char *type, struct XenDevOps *ops)
+{
+    return xenstore_scan(type, xen_domid, ops);
+}
+
+int xen_be_bind_evtchn(struct XenDevice *xendev)
+{
+    if (xendev->local_port != -1) {
+        return 0;
+    }
+    xendev->local_port = xc_evtchn_bind_interdomain
+        (xendev->evtchndev, xendev->dom, xendev->remote_port);
+    if (xendev->local_port == -1) {
+        xen_be_printf(xendev, 0, "xc_evtchn_bind_interdomain failed\n");
+        return -1;
+    }
+    xen_be_printf(xendev, 2, "bind evtchn port %d\n", xendev->local_port);
+    qemu_set_fd_handler(xc_evtchn_fd(xendev->evtchndev),
+                        xen_be_evtchn_event, NULL, xendev);
+    return 0;
+}
+
+void xen_be_unbind_evtchn(struct XenDevice *xendev)
+{
+    if (xendev->local_port == -1) {
+        return;
+    }
+    qemu_set_fd_handler(xc_evtchn_fd(xendev->evtchndev), NULL, NULL, NULL);
+    xc_evtchn_unbind(xendev->evtchndev, xendev->local_port);
+    xen_be_printf(xendev, 2, "unbind evtchn port %d\n", xendev->local_port);
+    xendev->local_port = -1;
+}
+
+int xen_be_send_notify(struct XenDevice *xendev)
+{
+    return xc_evtchn_notify(xendev->evtchndev, xendev->local_port);
+}
+
+/*
+ * msg_level:
+ *  0 == errors (stderr + logfile).
+ *  1 == informative debug messages (logfile only).
+ *  2 == noisy debug messages (logfile only).
+ *  3 == will flood your log (logfile only).
+ */
+void xen_be_printf(struct XenDevice *xendev, int msg_level, const char *fmt, ...)
+{
+    va_list args;
+
+    if (xendev) {
+        if (msg_level > xendev->debug) {
+            return;
+        }
+        qemu_log("xen be: %s: ", xendev->name);
+        if (msg_level == 0) {
+            fprintf(stderr, "xen be: %s: ", xendev->name);
+        }
+    } else {
+        if (msg_level > debug) {
+            return;
+        }
+        qemu_log("xen be core: ");
+        if (msg_level == 0) {
+            fprintf(stderr, "xen be core: ");
+        }
+    }
+    va_start(args, fmt);
+    qemu_log_vprintf(fmt, args);
+    va_end(args);
+    if (msg_level == 0) {
+        va_start(args, fmt);
+        vfprintf(stderr, fmt, args);
+        va_end(args);
+    }
+    qemu_log_flush();
+}
diff --git a/hw/xen/xen_devconfig.c b/hw/xen/xen_devconfig.c
new file mode 100644
index 000000000..fa998eff0
--- /dev/null
+++ b/hw/xen/xen_devconfig.c
@@ -0,0 +1,174 @@
+#include "hw/xen/xen_backend.h"
+#include "sysemu/blockdev.h"
+
+/* ------------------------------------------------------------- */
+
+struct xs_dirs {
+    char *xs_dir;
+    QTAILQ_ENTRY(xs_dirs) list;
+};
+static QTAILQ_HEAD(xs_dirs_head, xs_dirs) xs_cleanup = QTAILQ_HEAD_INITIALIZER(xs_cleanup);
+
+static void xen_config_cleanup_dir(char *dir)
+{
+    struct xs_dirs *d;
+
+    d = g_malloc(sizeof(*d));
+    d->xs_dir = dir;
+    QTAILQ_INSERT_TAIL(&xs_cleanup, d, list);
+}
+
+void xen_config_cleanup(void)
+{
+    struct xs_dirs *d;
+
+    QTAILQ_FOREACH(d, &xs_cleanup, list) {
+	xs_rm(xenstore, 0, d->xs_dir);
+    }
+}
+
+/* ------------------------------------------------------------- */
+
+static int xen_config_dev_mkdir(char *dev, int p)
+{
+    struct xs_permissions perms[2] = {{
+            .id    = 0, /* set owner: dom0 */
+        },{
+            .id    = xen_domid,
+            .perms = p,
+        }};
+
+    if (!xs_mkdir(xenstore, 0, dev)) {
+	xen_be_printf(NULL, 0, "xs_mkdir %s: failed\n", dev);
+	return -1;
+    }
+    xen_config_cleanup_dir(g_strdup(dev));
+
+    if (!xs_set_permissions(xenstore, 0, dev, perms, 2)) {
+	xen_be_printf(NULL, 0, "xs_set_permissions %s: failed\n", dev);
+	return -1;
+    }
+    return 0;
+}
+
+static int xen_config_dev_dirs(const char *ftype, const char *btype, int vdev,
+			       char *fe, char *be, int len)
+{
+    char *dom;
+
+    dom = xs_get_domain_path(xenstore, xen_domid);
+    snprintf(fe, len, "%s/device/%s/%d", dom, ftype, vdev);
+    free(dom);
+
+    dom = xs_get_domain_path(xenstore, 0);
+    snprintf(be, len, "%s/backend/%s/%d/%d", dom, btype, xen_domid, vdev);
+    free(dom);
+
+    xen_config_dev_mkdir(fe, XS_PERM_READ | XS_PERM_WRITE);
+    xen_config_dev_mkdir(be, XS_PERM_READ);
+    return 0;
+}
+
+static int xen_config_dev_all(char *fe, char *be)
+{
+    /* frontend */
+    if (xen_protocol)
+        xenstore_write_str(fe, "protocol", xen_protocol);
+
+    xenstore_write_int(fe, "state",           XenbusStateInitialising);
+    xenstore_write_int(fe, "backend-id",      0);
+    xenstore_write_str(fe, "backend",         be);
+
+    /* backend */
+    xenstore_write_str(be, "domain",          qemu_name ? qemu_name : "no-name");
+    xenstore_write_int(be, "online",          1);
+    xenstore_write_int(be, "state",           XenbusStateInitialising);
+    xenstore_write_int(be, "frontend-id",     xen_domid);
+    xenstore_write_str(be, "frontend",        fe);
+
+    return 0;
+}
+
+/* ------------------------------------------------------------- */
+
+int xen_config_dev_blk(DriveInfo *disk)
+{
+    char fe[256], be[256], device_name[32];
+    int vdev = 202 * 256 + 16 * disk->unit;
+    int cdrom = disk->media_cd;
+    const char *devtype = cdrom ? "cdrom" : "disk";
+    const char *mode    = cdrom ? "r"     : "w";
+    const char *filename = qemu_opt_get(disk->opts, "file");
+
+    snprintf(device_name, sizeof(device_name), "xvd%c", 'a' + disk->unit);
+    xen_be_printf(NULL, 1, "config disk %d [%s]: %s\n",
+                  disk->unit, device_name, filename);
+    xen_config_dev_dirs("vbd", "qdisk", vdev, fe, be, sizeof(fe));
+
+    /* frontend */
+    xenstore_write_int(fe, "virtual-device",  vdev);
+    xenstore_write_str(fe, "device-type",     devtype);
+
+    /* backend */
+    xenstore_write_str(be, "dev",             device_name);
+    xenstore_write_str(be, "type",            "file");
+    xenstore_write_str(be, "params",          filename);
+    xenstore_write_str(be, "mode",            mode);
+
+    /* common stuff */
+    return xen_config_dev_all(fe, be);
+}
+
+int xen_config_dev_nic(NICInfo *nic)
+{
+    char fe[256], be[256];
+    char mac[20];
+    int vlan_id = -1;
+
+    net_hub_id_for_client(nic->netdev, &vlan_id);
+    snprintf(mac, sizeof(mac), "%02x:%02x:%02x:%02x:%02x:%02x",
+             nic->macaddr.a[0], nic->macaddr.a[1], nic->macaddr.a[2],
+             nic->macaddr.a[3], nic->macaddr.a[4], nic->macaddr.a[5]);
+    xen_be_printf(NULL, 1, "config nic %d: mac=\"%s\"\n", vlan_id, mac);
+    xen_config_dev_dirs("vif", "qnic", vlan_id, fe, be, sizeof(fe));
+
+    /* frontend */
+    xenstore_write_int(fe, "handle",     vlan_id);
+    xenstore_write_str(fe, "mac",        mac);
+
+    /* backend */
+    xenstore_write_int(be, "handle",     vlan_id);
+    xenstore_write_str(be, "mac",        mac);
+
+    /* common stuff */
+    return xen_config_dev_all(fe, be);
+}
+
+int xen_config_dev_vfb(int vdev, const char *type)
+{
+    char fe[256], be[256];
+
+    xen_config_dev_dirs("vfb", "vfb", vdev, fe, be, sizeof(fe));
+
+    /* backend */
+    xenstore_write_str(be, "type",  type);
+
+    /* common stuff */
+    return xen_config_dev_all(fe, be);
+}
+
+int xen_config_dev_vkbd(int vdev)
+{
+    char fe[256], be[256];
+
+    xen_config_dev_dirs("vkbd", "vkbd", vdev, fe, be, sizeof(fe));
+    return xen_config_dev_all(fe, be);
+}
+
+int xen_config_dev_console(int vdev)
+{
+    char fe[256], be[256];
+
+    xen_config_dev_dirs("console", "console", vdev, fe, be, sizeof(fe));
+    return xen_config_dev_all(fe, be);
+}