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xen: add implementations of xen-block connect and disconnect functions...

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...and wire in the dataplane.

This patch adds the remaining code to make the xen-block XenDevice
functional. The parameters that a block frontend expects to find are
populated in the backend xenstore area, and the 'ring-ref' and
'event-channel' values specified in the frontend xenstore area are
mapped/bound and used to set up the dataplane.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Anthony Perard <anthony.perard@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
This commit is contained in:
Paul Durrant 2019-01-08 14:48:59 +00:00 • committed by Anthony PERARD
parent d4683cf952
commit b6af8926fb
5 changed files with 353 additions and 26 deletions
Download patch file Download diff file Expand all files Collapse all files

187
hw/xen/xen-bus.c
View file

@ -48,6 +48,54 @@ static char *xen_device_get_frontend_path(XenDevice *xendev)
xendev->frontend_id, device, xendev->name);
}
static void xen_device_unplug(XenDevice *xendev, Error **errp)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
const char *type = object_get_typename(OBJECT(xendev));
Error *local_err = NULL;
xs_transaction_t tid;
trace_xen_device_unplug(type, xendev->name);
/* Mimic the way the Xen toolstack does an unplug */
again:
tid = xs_transaction_start(xenbus->xsh);
if (tid == XBT_NULL) {
error_setg_errno(errp, errno, "failed xs_transaction_start");
return;
}
xs_node_printf(xenbus->xsh, tid, xendev->backend_path, "online",
&local_err, "%u", 0);
if (local_err) {
goto abort;
}
xs_node_printf(xenbus->xsh, tid, xendev->backend_path, "state",
&local_err, "%u", XenbusStateClosing);
if (local_err) {
goto abort;
}
if (!xs_transaction_end(xenbus->xsh, tid, false)) {
if (errno == EAGAIN) {
goto again;
}
error_setg_errno(errp, errno, "failed xs_transaction_end");
}
return;
abort:
/*
* We only abort if there is already a failure so ignore any error
* from ending the transaction.
*/
xs_transaction_end(xenbus->xsh, tid, true);
error_propagate(errp, local_err);
}
static void xen_bus_print_dev(Monitor *mon, DeviceState *dev, int indent)
{
XenDevice *xendev = XEN_DEVICE(dev);
@ -208,14 +256,26 @@ fail:
xen_bus_unrealize(bus, &error_abort);
}
static void xen_bus_unplug_request(HotplugHandler *hotplug,
DeviceState *dev,
Error **errp)
{
XenDevice *xendev = XEN_DEVICE(dev);
xen_device_unplug(xendev, errp);
}
static void xen_bus_class_init(ObjectClass *class, void *data)
{
BusClass *bus_class = BUS_CLASS(class);
HotplugHandlerClass *hotplug_class = HOTPLUG_HANDLER_CLASS(class);
bus_class->print_dev = xen_bus_print_dev;
bus_class->get_dev_path = xen_bus_get_dev_path;
bus_class->realize = xen_bus_realize;
bus_class->unrealize = xen_bus_unrealize;
hotplug_class->unplug_request = xen_bus_unplug_request;
}
static const TypeInfo xen_bus_type_info = {
@ -230,8 +290,8 @@ static const TypeInfo xen_bus_type_info = {
},
};
static void xen_device_backend_printf(XenDevice *xendev, const char *key,
const char *fmt, ...)
void xen_device_backend_printf(XenDevice *xendev, const char *key,
const char *fmt, ...)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
Error *local_err = NULL;
@ -287,6 +347,70 @@ enum xenbus_state xen_device_backend_get_state(XenDevice *xendev)
return xendev->backend_state;
}
static void xen_device_backend_set_online(XenDevice *xendev, bool online)
{
const char *type = object_get_typename(OBJECT(xendev));
if (xendev->backend_online == online) {
return;
}
trace_xen_device_backend_online(type, xendev->name, online);
xendev->backend_online = online;
xen_device_backend_printf(xendev, "online", "%u", online);
}
static void xen_device_backend_changed(void *opaque)
{
XenDevice *xendev = opaque;
const char *type = object_get_typename(OBJECT(xendev));
enum xenbus_state state;
unsigned int online;
trace_xen_device_backend_changed(type, xendev->name);
if (xen_device_backend_scanf(xendev, "state", "%u", &state) != 1) {
state = XenbusStateUnknown;
}
xen_device_backend_set_state(xendev, state);
if (xen_device_backend_scanf(xendev, "online", "%u", &online) != 1) {
online = 0;
}
xen_device_backend_set_online(xendev, !!online);
/*
* If the toolstack (or unplug request callback) has set the backend
* state to Closing, but there is no active frontend (i.e. the
* state is not Connected) then set the backend state to Closed.
*/
if (xendev->backend_state == XenbusStateClosing &&
xendev->frontend_state != XenbusStateConnected) {
xen_device_backend_set_state(xendev, XenbusStateClosed);
}
/*
* If a backend is still 'online' then its state should be cycled
* back round to InitWait in order for a new frontend instance to
* connect. This may happen when, for example, a frontend driver is
* re-installed or updated.
* If a backend is not 'online' then the device should be destroyed.
*/
if (xendev->backend_online &&
xendev->backend_state == XenbusStateClosed) {
xen_device_backend_set_state(xendev, XenbusStateInitWait);
} else if (!xendev->backend_online &&
(xendev->backend_state == XenbusStateClosed ||
xendev->backend_state == XenbusStateInitialising ||
xendev->backend_state == XenbusStateInitWait ||
xendev->backend_state == XenbusStateUnknown)) {
object_unparent(OBJECT(xendev));
}
}
static void xen_device_backend_create(XenDevice *xendev, Error **errp)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
@ -307,6 +431,27 @@ static void xen_device_backend_create(XenDevice *xendev, Error **errp)
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to create backend: ");
return;
}
xendev->backend_state_watch =
xen_bus_add_watch(xenbus, xendev->backend_path,
"state", xen_device_backend_changed,
xendev, &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to watch backend state: ");
return;
}
xendev->backend_online_watch =
xen_bus_add_watch(xenbus, xendev->backend_path,
"online", xen_device_backend_changed,
xendev, &local_err);
if (local_err) {
error_propagate_prepend(errp, local_err,
"failed to watch backend online: ");
return;
}
}
@ -315,6 +460,16 @@ static void xen_device_backend_destroy(XenDevice *xendev)
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
Error *local_err = NULL;
if (xendev->backend_online_watch) {
xen_bus_remove_watch(xenbus, xendev->backend_online_watch, NULL);
xendev->backend_online_watch = NULL;
}
if (xendev->backend_state_watch) {
xen_bus_remove_watch(xenbus, xendev->backend_state_watch, NULL);
xendev->backend_state_watch = NULL;
}
if (!xendev->backend_path) {
return;
}
@ -331,8 +486,8 @@ static void xen_device_backend_destroy(XenDevice *xendev)
}
}
static void xen_device_frontend_printf(XenDevice *xendev, const char *key,
const char *fmt, ...)
void xen_device_frontend_printf(XenDevice *xendev, const char *key,
const char *fmt, ...)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
Error *local_err = NULL;
@ -350,8 +505,8 @@ static void xen_device_frontend_printf(XenDevice *xendev, const char *key,
}
}
static int xen_device_frontend_scanf(XenDevice *xendev, const char *key,
const char *fmt, ...)
int xen_device_frontend_scanf(XenDevice *xendev, const char *key,
const char *fmt, ...)
{
XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
va_list ap;
@ -407,24 +562,6 @@ static void xen_device_frontend_changed(void *opaque)
error_reportf_err(local_err, "frontend change error: ");
}
}
/*
* If a backend is still 'online' then its state should be cycled
* back round to InitWait in order for a new frontend instance to
* connect. This may happen when, for example, a frontend driver is
* re-installed or updated.
*/
if (xendev->backend_state == XenbusStateClosed) {
unsigned int online;
if (xen_device_backend_scanf(xendev, "online", "%u", &online) != 1) {
online = 0;
}
if (online) {
xen_device_backend_set_state(xendev, XenbusStateInitWait);
}
}
}
static void xen_device_frontend_create(XenDevice *xendev, Error **errp)
@ -824,9 +961,9 @@ static void xen_device_realize(DeviceState *dev, Error **errp)
xendev->frontend_path);
xen_device_backend_printf(xendev, "frontend-id", "%u",
xendev->frontend_id);
xen_device_backend_printf(xendev, "online", "%u", 1);
xen_device_backend_printf(xendev, "hotplug-status", "connected");
xen_device_backend_set_online(xendev, true);
xen_device_backend_set_state(xendev, XenbusStateInitWait);
xen_device_frontend_printf(xendev, "backend", "%s",