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authorStefano Stabellini <sstabellini@kernel.org>2017-07-06 10:59:17 -0700
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2017-08-31 09:45:55 -0400
commit0a9c75c2c7258f2c50d2c62430ccca3eec9f866f (patch)
tree0144d0245ca6e3cd0211fcf3294913936fa0afb3 /drivers/xen
parent9be07334f99e1f9e0b244d73528bc3afce126735 (diff)
xen/pvcalls: xenbus state handling
Introduce the code to handle xenbus state changes. Implement the probe function for the pvcalls backend. Write the supported versions, max-page-order and function-calls nodes to xenstore, as required by the protocol. Introduce stub functions for disconnecting/connecting to a frontend. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/pvcalls-back.c155
1 files changed, 155 insertions, 0 deletions
diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index 9044cf21b31c..72d2fce27a34 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -25,20 +25,175 @@
#include <xen/xenbus.h>
#include <xen/interface/io/pvcalls.h>
+#define PVCALLS_VERSIONS "1"
+#define MAX_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
+
struct pvcalls_back_global {
struct list_head frontends;
struct semaphore frontends_lock;
} pvcalls_back_global;
+static int backend_connect(struct xenbus_device *dev)
+{
+ return 0;
+}
+
+static int backend_disconnect(struct xenbus_device *dev)
+{
+ return 0;
+}
+
static int pvcalls_back_probe(struct xenbus_device *dev,
const struct xenbus_device_id *id)
{
+ int err, abort;
+ struct xenbus_transaction xbt;
+
+again:
+ abort = 1;
+
+ err = xenbus_transaction_start(&xbt);
+ if (err) {
+ pr_warn("%s cannot create xenstore transaction\n", __func__);
+ return err;
+ }
+
+ err = xenbus_printf(xbt, dev->nodename, "versions", "%s",
+ PVCALLS_VERSIONS);
+ if (err) {
+ pr_warn("%s write out 'versions' failed\n", __func__);
+ goto abort;
+ }
+
+ err = xenbus_printf(xbt, dev->nodename, "max-page-order", "%u",
+ MAX_RING_ORDER);
+ if (err) {
+ pr_warn("%s write out 'max-page-order' failed\n", __func__);
+ goto abort;
+ }
+
+ err = xenbus_printf(xbt, dev->nodename, "function-calls",
+ XENBUS_FUNCTIONS_CALLS);
+ if (err) {
+ pr_warn("%s write out 'function-calls' failed\n", __func__);
+ goto abort;
+ }
+
+ abort = 0;
+abort:
+ err = xenbus_transaction_end(xbt, abort);
+ if (err) {
+ if (err == -EAGAIN && !abort)
+ goto again;
+ pr_warn("%s cannot complete xenstore transaction\n", __func__);
+ return err;
+ }
+
+ if (abort)
+ return -EFAULT;
+
+ xenbus_switch_state(dev, XenbusStateInitWait);
+
return 0;
}
+static void set_backend_state(struct xenbus_device *dev,
+ enum xenbus_state state)
+{
+ while (dev->state != state) {
+ switch (dev->state) {
+ case XenbusStateClosed:
+ switch (state) {
+ case XenbusStateInitWait:
+ case XenbusStateConnected:
+ xenbus_switch_state(dev, XenbusStateInitWait);
+ break;
+ case XenbusStateClosing:
+ xenbus_switch_state(dev, XenbusStateClosing);
+ break;
+ default:
+ __WARN();
+ }
+ break;
+ case XenbusStateInitWait:
+ case XenbusStateInitialised:
+ switch (state) {
+ case XenbusStateConnected:
+ backend_connect(dev);
+ xenbus_switch_state(dev, XenbusStateConnected);
+ break;
+ case XenbusStateClosing:
+ case XenbusStateClosed:
+ xenbus_switch_state(dev, XenbusStateClosing);
+ break;
+ default:
+ __WARN();
+ }
+ break;
+ case XenbusStateConnected:
+ switch (state) {
+ case XenbusStateInitWait:
+ case XenbusStateClosing:
+ case XenbusStateClosed:
+ down(&pvcalls_back_global.frontends_lock);
+ backend_disconnect(dev);
+ up(&pvcalls_back_global.frontends_lock);
+ xenbus_switch_state(dev, XenbusStateClosing);
+ break;
+ default:
+ __WARN();
+ }
+ break;
+ case XenbusStateClosing:
+ switch (state) {
+ case XenbusStateInitWait:
+ case XenbusStateConnected:
+ case XenbusStateClosed:
+ xenbus_switch_state(dev, XenbusStateClosed);
+ break;
+ default:
+ __WARN();
+ }
+ break;
+ default:
+ __WARN();
+ }
+ }
+}
+
static void pvcalls_back_changed(struct xenbus_device *dev,
enum xenbus_state frontend_state)
{
+ switch (frontend_state) {
+ case XenbusStateInitialising:
+ set_backend_state(dev, XenbusStateInitWait);
+ break;
+
+ case XenbusStateInitialised:
+ case XenbusStateConnected:
+ set_backend_state(dev, XenbusStateConnected);
+ break;
+
+ case XenbusStateClosing:
+ set_backend_state(dev, XenbusStateClosing);
+ break;
+
+ case XenbusStateClosed:
+ set_backend_state(dev, XenbusStateClosed);
+ if (xenbus_dev_is_online(dev))
+ break;
+ device_unregister(&dev->dev);
+ break;
+ case XenbusStateUnknown:
+ set_backend_state(dev, XenbusStateClosed);
+ device_unregister(&dev->dev);
+ break;
+
+ default:
+ xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
+ frontend_state);
+ break;
+ }
}
static int pvcalls_back_remove(struct xenbus_device *dev)