[PATCH v3 16/28] hw/xen: update Xen console to XenDevice model

David Woodhouse
2023-10-25T14:51:56Z

From: David Woodhouse <dwmw@amazon.co.uk>

This allows (non-primary) console devices to be created on the command
line and hotplugged.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
---
hw/char/trace-events | 8 +
hw/char/xen_console.c | 532 +++++++++++++++++++++++++++---------
hw/xen/xen-legacy-backend.c | 1 -
3 files changed, 411 insertions(+), 130 deletions(-)

diff --git a/hw/char/trace-events b/hw/char/trace-events
index babf4d35ea..7a398c82a5 100644
--- a/hw/char/trace-events
+++ b/hw/char/trace-events
@@ -105,3 +105,11 @@ cadence_uart_baudrate(unsigned baudrate) "baudrate %u"
# sh_serial.c
sh_serial_read(char *id, unsigned size, uint64_t offs, uint64_t val) " %s size %d offs 0x%02" PRIx64 " -> 0x%02" PRIx64
sh_serial_write(char *id, unsigned size, uint64_t offs, uint64_t val) "%s size %d offs 0x%02" PRIx64 " <- 0x%02" PRIx64
+
+# xen_console.c
+xen_console_connect(unsigned int idx, unsigned int ring_ref, unsigned int port, unsigned int limit) "idx %u ring_ref %u port %u limit %u"
+xen_console_disconnect(unsigned int idx) "idx %u"
+xen_console_unrealize(unsigned int idx) "idx %u"
+xen_console_realize(unsigned int idx, const char *chrdev) "idx %u chrdev %s"
+xen_console_device_create(unsigned int idx) "idx %u"
+xen_console_device_destroy(unsigned int idx) "idx %u"
diff --git a/hw/char/xen_console.c b/hw/char/xen_console.c
index 810dae3f44..4a419dc287 100644
--- a/hw/char/xen_console.c
+++ b/hw/char/xen_console.c
@@ -20,15 +20,20 @@
*/

#include "qemu/osdep.h"
+#include "qemu/cutils.h"
#include <sys/select.h>
#include <termios.h>

#include "qapi/error.h"
#include "sysemu/sysemu.h"
#include "chardev/char-fe.h"
-#include "hw/xen/xen-legacy-backend.h"
-
+#include "hw/xen/xen-backend.h"
+#include "hw/xen/xen-bus-helper.h"
+#include "hw/qdev-properties.h"
+#include "hw/qdev-properties-system.h"
#include "hw/xen/interface/io/console.h"
+#include "hw/xen/interface/io/xs_wire.h"
+#include "trace.h"

struct buffer {
uint8_t *data;
@@ -39,16 +44,22 @@ struct buffer {
};

struct XenConsole {
- struct XenLegacyDevice xendev; /* must be first */
+ struct XenDevice xendev; /* must be first */
+ XenEventChannel *event_channel;
+ int dev;
struct buffer buffer;
- char console[XEN_BUFSIZE];
- int ring_ref;
+ char *fe_path;
+ unsigned int ring_ref;
void *sring;
CharBackend chr;
int backlog;
};
+typedef struct XenConsole XenConsole;
+
+#define TYPE_XEN_CONSOLE_DEVICE "xen-console"
+OBJECT_DECLARE_SIMPLE_TYPE(XenConsole, XEN_CONSOLE_DEVICE)

-static void buffer_append(struct XenConsole *con)
+static bool buffer_append(XenConsole *con)
{
struct buffer *buffer = &con->buffer;
XENCONS_RING_IDX cons, prod, size;
@@ -60,7 +71,7 @@ static void buffer_append(struct XenConsole *con)

size = prod - cons;
if ((size == 0) || (size > sizeof(intf->out)))
- return;
+ return false;

if ((buffer->capacity - buffer->size) < size) {
buffer->capacity += (size + 1024);
@@ -73,7 +84,7 @@ static void buffer_append(struct XenConsole *con)

xen_mb();
intf->out_cons = cons;
- xen_pv_send_notify(&con->xendev);
+ xen_device_notify_event_channel(XEN_DEVICE(con), con->event_channel, NULL);

if (buffer->max_capacity &&
buffer->size > buffer->max_capacity) {
@@ -89,6 +100,7 @@ static void buffer_append(struct XenConsole *con)
if (buffer->consumed > buffer->max_capacity - over)
buffer->consumed = buffer->max_capacity - over;
}
+ return true;
}

static void buffer_advance(struct buffer *buffer, size_t len)
@@ -100,7 +112,7 @@ static void buffer_advance(struct buffer *buffer, size_t len)
}
}

-static int ring_free_bytes(struct XenConsole *con)
+static int ring_free_bytes(XenConsole *con)
{
struct xencons_interface *intf = con->sring;
XENCONS_RING_IDX cons, prod, space;
@@ -118,13 +130,13 @@ static int ring_free_bytes(struct XenConsole *con)

static int xencons_can_receive(void *opaque)
{
- struct XenConsole *con = opaque;
+ XenConsole *con = opaque;
return ring_free_bytes(con);
}

static void xencons_receive(void *opaque, const uint8_t *buf, int len)
{
- struct XenConsole *con = opaque;
+ XenConsole *con = opaque;
struct xencons_interface *intf = con->sring;
XENCONS_RING_IDX prod;
int i, max;
@@ -141,10 +153,10 @@ static void xencons_receive(void *opaque, const uint8_t *buf, int len)
}
xen_wmb();
intf->in_prod = prod;
- xen_pv_send_notify(&con->xendev);
+ xen_device_notify_event_channel(XEN_DEVICE(con), con->event_channel, NULL);
}

-static void xencons_send(struct XenConsole *con)
+static bool xencons_send(XenConsole *con)
{
ssize_t len, size;

@@ -159,174 +171,436 @@ static void xencons_send(struct XenConsole *con)
if (len < 1) {
if (!con->backlog) {
con->backlog = 1;
- xen_pv_printf(&con->xendev, 1,
- "backlog piling up, nobody listening?\n");
}
} else {
buffer_advance(&con->buffer, len);
if (con->backlog && len == size) {
con->backlog = 0;
- xen_pv_printf(&con->xendev, 1, "backlog is gone\n");
}
}
+ return len > 0;
}

/* -------------------------------------------------------------------- */

-static int store_con_info(struct XenConsole *con)
+static bool con_event(void *_xendev)
{
- Chardev *cs = qemu_chr_fe_get_driver(&con->chr);
- char *pts = NULL;
- char *dom_path;
- g_autoptr(GString) path = NULL;
+ XenConsole *con = XEN_CONSOLE_DEVICE(_xendev);
+ bool done_something;
+
+ if (xen_device_backend_get_state(&con->xendev) != XenbusStateConnected) {
+ return false;
+ }
+
+ done_something = buffer_append(con);
+
+ if (con->buffer.size - con->buffer.consumed) {
+ done_something |= xencons_send(con);
+ }
+ return done_something;
+}
+
+/* -------------------------------------------------------------------- */
+
+static bool xen_console_connect(XenDevice *xendev, Error **errp)
+{
+ XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
+ unsigned int port, limit;
+
+ if (xen_device_frontend_scanf(xendev, "ring-ref", "%u",
+ &con->ring_ref) != 1) {
+ error_setg(errp, "failed to read ring-ref");
+ return false;
+ }

- /* Only continue if we're talking to a pty. */
- if (!CHARDEV_IS_PTY(cs)) {
- return 0;
+ if (xen_device_frontend_scanf(xendev, "port", "%u", &port) != 1) {
+ error_setg(errp, "failed to read remote port");
+ return false;
}
- pts = cs->filename + 4;

- dom_path = qemu_xen_xs_get_domain_path(xenstore, xen_domid);
- if (!dom_path) {
- return 0;
+ if (xen_device_frontend_scanf(xendev, "limit", "%u", &limit) == 1) {
+ con->buffer.max_capacity = limit;
}

- path = g_string_new(dom_path);
- free(dom_path);
+ con->event_channel = xen_device_bind_event_channel(xendev, port,
+ con_event,
+ con,
+ errp);
+ if (!con->event_channel) {
+ return false;
+ }

- if (con->xendev.dev) {
- g_string_append_printf(path, "/device/console/%d", con->xendev.dev);
+ if (!con->dev) {
+ xen_pfn_t mfn = (xen_pfn_t)con->ring_ref;
+ con->sring = qemu_xen_foreignmem_map(xendev->frontend_id, NULL,
+ PROT_READ | PROT_WRITE,
+ 1, &mfn, NULL);
+ if (!con->sring) {
+ error_setg(errp, "failed to map console page");
+ return false;
+ }
} else {
- g_string_append(path, "/console");
+ con->sring = xen_device_map_grant_refs(xendev,
+ &con->ring_ref, 1,
+ PROT_READ | PROT_WRITE,
+ errp);
+ if (!con->sring) {
+ error_prepend(errp, "failed to map grant ref: ");
+ return false;
+ }
}
- g_string_append(path, "/tty");

- if (xenstore_write_str(con->console, path->str, pts)) {
- fprintf(stderr, "xenstore_write_str for '%s' fail", path->str);
- return -1;
+ trace_xen_console_connect(con->dev, con->ring_ref, port,
+ con->buffer.max_capacity);
+
+ qemu_chr_fe_set_handlers(&con->chr, xencons_can_receive,
+ xencons_receive, NULL, NULL, con, NULL,
+ true);
+ return true;
+}
+
+static void xen_console_disconnect(XenDevice *xendev, Error **errp)
+{
+ XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
+
+ trace_xen_console_disconnect(con->dev);
+
+ qemu_chr_fe_set_handlers(&con->chr, NULL, NULL, NULL, NULL,
+ con, NULL, true);
+
+ if (con->event_channel) {
+ xen_device_unbind_event_channel(xendev, con->event_channel,
+ errp);
+ con->event_channel = NULL;
+ }
+
+ if (con->sring) {
+ if (!con->dev) {
+ qemu_xen_foreignmem_unmap(con->sring, 1);
+ } else {
+ xen_device_unmap_grant_refs(xendev, con->sring,
+ &con->ring_ref, 1, errp);
+ }
+ con->sring = NULL;
}
- return 0;
}

-static int con_init(struct XenLegacyDevice *xendev)
+static void xen_console_frontend_changed(XenDevice *xendev,
+ enum xenbus_state frontend_state,
+ Error **errp)
{
- struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
- char *type, *dom, label[32];
- int ret = 0;
- const char *output;
-
- /* setup */
- dom = qemu_xen_xs_get_domain_path(xenstore, con->xendev.dom);
- if (!xendev->dev) {
- snprintf(con->console, sizeof(con->console), "%s/console", dom);
- } else {
- snprintf(con->console, sizeof(con->console), "%s/device/console/%d", dom, xendev->dev);
+ ERRP_GUARD();
+ enum xenbus_state backend_state = xen_device_backend_get_state(xendev);
+
+ switch (frontend_state) {
+ case XenbusStateInitialised:
+ case XenbusStateConnected:
+ if (backend_state == XenbusStateConnected) {
+ break;
+ }
+
+ xen_console_disconnect(xendev, errp);
+ if (*errp) {
+ break;
+ }
+
+ if (!xen_console_connect(xendev, errp)) {
+ xen_device_backend_set_state(xendev, XenbusStateClosing);
+ break;
+ }
+
+ xen_device_backend_set_state(xendev, XenbusStateConnected);
+ break;
+
+ case XenbusStateClosing:
+ xen_device_backend_set_state(xendev, XenbusStateClosing);
+ break;
+
+ case XenbusStateClosed:
+ case XenbusStateUnknown:
+ xen_console_disconnect(xendev, errp);
+ if (*errp) {
+ break;
+ }
+
+ xen_device_backend_set_state(xendev, XenbusStateClosed);
+ break;
+
+ default:
+ break;
}
- free(dom);
+}

- type = xenstore_read_str(con->console, "type");
- if (!type || strcmp(type, "ioemu") != 0) {
- xen_pv_printf(xendev, 1, "not for me (type=%s)\n", type);
- ret = -1;
- goto out;
+static char *xen_console_get_name(XenDevice *xendev, Error **errp)
+{
+ XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
+
+ if (con->dev == -1) {
+ XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
+ char fe_path[XENSTORE_ABS_PATH_MAX + 1];
+ char *value;
+ int idx = 1;
+
+ /* Theoretically we could go up to INT_MAX here but that's overkill */
+ while (idx < 100) {
+ snprintf(fe_path, sizeof(fe_path),
+ "/local/domain/%u/device/console/%u",
+ xendev->frontend_id, idx);
+ value = qemu_xen_xs_read(xenbus->xsh, XBT_NULL, fe_path, NULL);
+ if (!value) {
+ if (errno == ENOENT) {
+ con->dev = idx;
+ goto found;
+ }
+ error_setg(errp, "cannot read %s: %s", fe_path,
+ strerror(errno));
+ return NULL;
+ }
+ free(value);
+ idx++;
+ }
+ error_setg(errp, "cannot find device index for console device");
+ return NULL;
}
+ found:
+ return g_strdup_printf("%u", con->dev);
+}
+
+static void xen_console_unrealize(XenDevice *xendev)
+{
+ XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
+
+ trace_xen_console_unrealize(con->dev);

- output = xenstore_read_str(con->console, "output");
+ /* Disconnect from the frontend in case this has not already happened */
+ xen_console_disconnect(xendev, NULL);

- /* no Xen override, use qemu output device */
- if (output == NULL) {
- if (con->xendev.dev) {
- qemu_chr_fe_init(&con->chr, serial_hd(con->xendev.dev),
- &error_abort);
+ qemu_chr_fe_deinit(&con->chr, false);
+}
+
+static void xen_console_realize(XenDevice *xendev, Error **errp)
+{
+ ERRP_GUARD();
+ XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
+ Chardev *cs = qemu_chr_fe_get_driver(&con->chr);
+ unsigned int u;
+
+ if (!cs) {
+ error_setg(errp, "no backing character device");
+ return;
+ }
+
+ if (con->dev == -1) {
+ error_setg(errp, "no device index provided");
+ return;
+ }
+
+ /*
+ * The Xen primary console is special. The ring-ref is actually a GFN to
+ * be mapped directly as foreignmem (not a grant ref), and the guest port
+ * was allocated *for* the guest by the toolstack. The guest gets these
+ * through HVMOP_get_param and can use the console long before it's got
+ * XenStore up and running. We cannot create those for a Xen guest.
+ */
+ if (!con->dev) {
+ if (xen_device_frontend_scanf(xendev, "ring-ref", "%u", &u) != 1 ||
+ xen_device_frontend_scanf(xendev, "port", "%u", &u) != 1) {
+ error_setg(errp, "cannot create primary Xen console");
+ return;
}
+ }
+
+ trace_xen_console_realize(con->dev, object_get_typename(OBJECT(cs)));
+
+ if (CHARDEV_IS_PTY(cs)) {
+ /* Strip the leading 'pty:' */
+ xen_device_frontend_printf(xendev, "tty", "%s", cs->filename + 4);
+ }
+
+ /* No normal PV driver initialization for the primary console */
+ if (!con->dev) {
+ xen_console_connect(xendev, errp);
+ }
+}
+
+static char *console_frontend_path(struct qemu_xs_handle *xenstore,
+ unsigned int dom_id, unsigned int dev)
+{
+ if (!dev) {
+ return g_strdup_printf("/local/domain/%u/console", dom_id);
} else {
- snprintf(label, sizeof(label), "xencons%d", con->xendev.dev);
- qemu_chr_fe_init(&con->chr,
- /*
- * FIXME: sure we want to support implicit
- * muxed monitors here?
- */
- qemu_chr_new_mux_mon(label, output, NULL),
- &error_abort);
+ return g_strdup_printf("/local/domain/%u/device/console/%u", dom_id,
+ dev);
}
+}

- store_con_info(con);
+static char *xen_console_get_frontend_path(XenDevice *xendev, Error **errp)
+{
+ XenConsole *con = XEN_CONSOLE_DEVICE(xendev);
+ XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
+ char *ret = console_frontend_path(xenbus->xsh, xendev->frontend_id,
+ con->dev);

-out:
- g_free(type);
+ if (!ret) {
+ error_setg(errp, "failed to create frontend path");
+ }
return ret;
}

-static int con_initialise(struct XenLegacyDevice *xendev)
+
+static Property xen_console_properties[] = {
+ DEFINE_PROP_CHR("chardev", XenConsole, chr),
+ DEFINE_PROP_INT32("idx", XenConsole, dev, -1),
+ DEFINE_PROP_END_OF_LIST(),
+};
+
+static void xen_console_class_init(ObjectClass *class, void *data)
{
- struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
- int limit;
-
- if (xenstore_read_int(con->console, "ring-ref", &con->ring_ref) == -1)
- return -1;
- if (xenstore_read_int(con->console, "port", &con->xendev.remote_port) == -1)
- return -1;
- if (xenstore_read_int(con->console, "limit", &limit) == 0)
- con->buffer.max_capacity = limit;
+ DeviceClass *dev_class = DEVICE_CLASS(class);
+ XenDeviceClass *xendev_class = XEN_DEVICE_CLASS(class);
+
+ xendev_class->backend = "console";
+ xendev_class->device = "console";
+ xendev_class->get_name = xen_console_get_name;
+ xendev_class->realize = xen_console_realize;
+ xendev_class->frontend_changed = xen_console_frontend_changed;
+ xendev_class->unrealize = xen_console_unrealize;
+ xendev_class->get_frontend_path = xen_console_get_frontend_path;
+
+ device_class_set_props(dev_class, xen_console_properties);
+}

- if (!xendev->dev) {
- xen_pfn_t mfn = con->ring_ref;
- con->sring = qemu_xen_foreignmem_map(con->xendev.dom, NULL,
- PROT_READ | PROT_WRITE,
- 1, &mfn, NULL);
- } else {
- con->sring = xen_be_map_grant_ref(xendev, con->ring_ref,
- PROT_READ | PROT_WRITE);
- }
- if (!con->sring)
- return -1;
+static const TypeInfo xen_console_type_info = {
+ .name = TYPE_XEN_CONSOLE_DEVICE,
+ .parent = TYPE_XEN_DEVICE,
+ .instance_size = sizeof(XenConsole),
+ .class_init = xen_console_class_init,
+};

- xen_be_bind_evtchn(&con->xendev);
- qemu_chr_fe_set_handlers(&con->chr, xencons_can_receive,
- xencons_receive, NULL, NULL, con, NULL, true);
-
- xen_pv_printf(xendev, 1,
- "ring mfn %d, remote port %d, local port %d, limit %zd\n",
- con->ring_ref,
- con->xendev.remote_port,
- con->xendev.local_port,
- con->buffer.max_capacity);
- return 0;
+static void xen_console_register_types(void)
+{
+ type_register_static(&xen_console_type_info);
}

-static void con_disconnect(struct XenLegacyDevice *xendev)
+type_init(xen_console_register_types)
+
+/* Called to instantiate a XenConsole when the backend is detected. */
+static void xen_console_device_create(XenBackendInstance *backend,
+ QDict *opts, Error **errp)
{
- struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
+ ERRP_GUARD();
+ XenBus *xenbus = xen_backend_get_bus(backend);
+ const char *name = xen_backend_get_name(backend);
+ unsigned long number;
+ char *fe = NULL, *type = NULL, *output = NULL;
+ char label[32];
+ XenDevice *xendev = NULL;
+ XenConsole *con;
+ Chardev *cd = NULL;
+ struct qemu_xs_handle *xsh = xenbus->xsh;
+
+ if (qemu_strtoul(name, NULL, 10, &number) || number > INT_MAX) {
+ error_setg(errp, "failed to parse name '%s'", name);
+ goto fail;
+ }

- qemu_chr_fe_deinit(&con->chr, false);
- xen_pv_unbind_evtchn(&con->xendev);
+ trace_xen_console_device_create(number);

- if (con->sring) {
- if (!xendev->dev) {
- qemu_xen_foreignmem_unmap(con->sring, 1);
- } else {
- xen_be_unmap_grant_ref(xendev, con->sring, con->ring_ref);
+ fe = console_frontend_path(xsh, xen_domid, number);
+ if (fe == NULL) {
+ error_setg(errp, "failed to generate frontend path");
+ goto fail;
+ }
+
+ if (xs_node_scanf(xsh, XBT_NULL, fe, "type", errp, "%ms", &type) != 1) {
+ error_prepend(errp, "failed to read console device type: ");
+ goto fail;
+ }
+
+ if (strcmp(type, "ioemu")) {
+ error_setg(errp, "declining to handle console type '%s'",
+ type);
+ goto fail;
+ }
+
+ xendev = XEN_DEVICE(qdev_new(TYPE_XEN_CONSOLE_DEVICE));
+ con = XEN_CONSOLE_DEVICE(xendev);
+
+ con->dev = number;
+
+ snprintf(label, sizeof(label), "xencons%ld", number);
+
+ if (xs_node_scanf(xsh, XBT_NULL, fe, "output", NULL, "%ms", &output) == 1) {
+ /*
+ * FIXME: sure we want to support implicit
+ * muxed monitors here?
+ */
+ cd = qemu_chr_new_mux_mon(label, output, NULL);
+ if (!cd) {
+ error_setg(errp, "console: No valid chardev found at '%s': ",
+ output);
+ goto fail;
}
- con->sring = NULL;
+ } else if (number) {
+ cd = serial_hd(number);
+ if (!cd) {
+ error_prepend(errp, "console: No serial device #%ld found: ",
+ number);
+ goto fail;
+ }
+ } else {
+ /* No 'output' node on primary console: use null. */
+ cd = qemu_chr_new(label, "null", NULL);
+ if (!cd) {
+ error_setg(errp, "console: failed to create null device");
+ goto fail;
+ }
+ }
+
+ if (!qemu_chr_fe_init(&con->chr, cd, errp)) {
+ error_prepend(errp, "console: failed to initialize backing chardev: ");
+ goto fail;
+ }
+
+ if (qdev_realize_and_unref(DEVICE(xendev), BUS(xenbus), errp)) {
+ xen_backend_set_device(backend, xendev);
+ goto done;
+ }
+
+ error_prepend(errp, "realization of console device %lu failed: ",
+ number);
+
+ fail:
+ if (xendev) {
+ object_unparent(OBJECT(xendev));
}
+ done:
+ g_free(fe);
+ free(type);
+ free(output);
}

-static void con_event(struct XenLegacyDevice *xendev)
+static void xen_console_device_destroy(XenBackendInstance *backend,
+ Error **errp)
{
- struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
+ ERRP_GUARD();
+ XenDevice *xendev = xen_backend_get_device(backend);
+ XenConsole *con = XEN_CONSOLE_DEVICE(xendev);

- buffer_append(con);
- if (con->buffer.size - con->buffer.consumed)
- xencons_send(con);
-}
+ trace_xen_console_device_destroy(con->dev);

-/* -------------------------------------------------------------------- */
+ object_unparent(OBJECT(xendev));
+}

-struct XenDevOps xen_console_ops = {
- .size = sizeof(struct XenConsole),
- .flags = DEVOPS_FLAG_IGNORE_STATE|DEVOPS_FLAG_NEED_GNTDEV,
- .init = con_init,
- .initialise = con_initialise,
- .event = con_event,
- .disconnect = con_disconnect,
+static const XenBackendInfo xen_console_backend_info = {
+ .type = "console",
+ .create = xen_console_device_create,
+ .destroy = xen_console_device_destroy,
};
+
+static void xen_console_register_backend(void)
+{
+ xen_backend_register(&xen_console_backend_info);
+}
+
+xen_backend_init(xen_console_register_backend);
diff --git a/hw/xen/xen-legacy-backend.c b/hw/xen/xen-legacy-backend.c
index 4ded3cec23..124dd5f3d6 100644
--- a/hw/xen/xen-legacy-backend.c
+++ b/hw/xen/xen-legacy-backend.c
@@ -623,7 +623,6 @@ void xen_be_init(void)

xen_set_dynamic_sysbus();

- xen_be_register("console", &xen_console_ops);
xen_be_register("vkbd", &xen_kbdmouse_ops);
#ifdef CONFIG_VIRTFS
xen_be_register("9pfs", &xen_9pfs_ops);
--
2.40.1