livepatch: Fix documentation of timeout

The hypervisor expects the timeout from the hypercall to be in
nanoseconds, so document this correctly. Also correctly document
what happens when timeout is set to zero.

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>

docs/misc/livepatch.markdown

@@ -689,9 +689,9 @@ The caller provides:
   payload. If the operation takes more time than the upper bound of time
   the `rc` in `xen_livepatch_status' retrieved via **XEN_SYSCTL_LIVEPATCH_GET**
   will be -XEN_EBUSY.
- * `time` the upper bound of time (ms) the cmd should take. Zero means infinite.
-   If within the time the operation does not succeed the operation would go in
-   error state.
+ * `time` the upper bound of time (ns) the cmd should take. Zero means to use
+   the hypervisor default. If within the time the operation does not succeed
+   the operation would go in error state.
  * `pad` - *MUST* be zero.
 
 The return value will be zero unless the provided fields are incorrect.
@@ -706,9 +706,10 @@ The structure is as follow:
 struct xen_sysctl_livepatch_action {  
     xen_livepatch_name_t name;              /* IN, name of the patch. */  
     uint32_t cmd;                           /* IN: LIVEPATCH_ACTION_* */  
-    uint32_t time;                          /* IN: Zero if no timeout. */   
-                                            /* Or upper bound of time (ms) */   
-                                            /* for operation to take. */  
+    uint32_t time;                          /* IN: If zero then uses */
+                                            /* hypervisor default. */
+                                            /* Or upper bound of time (ns) */
+                                            /* for operation to take. */
 };  
 
 </pre>

tools/libxc/include/xenctrl.h

@@ -2703,7 +2703,7 @@ int xc_livepatch_list(xc_interface *xch, unsigned int max, unsigned int start,
  * The operations are asynchronous and the hypervisor may take a while
  * to complete them. The `timeout` offers an option to expire the
  * operation if it could not be completed within the specified time
- * (in ms). Value of 0 means let hypervisor decide the best timeout.
+ * (in ns). Value of 0 means let hypervisor decide the best timeout.
  */
 int xc_livepatch_apply(xc_interface *xch, char *name, uint32_t timeout);
 int xc_livepatch_revert(xc_interface *xch, char *name, uint32_t timeout);

xen/common/livepatch.c

@@ -1227,8 +1227,8 @@ static int schedule_work(struct payload *data, uint32_t cmd, uint32_t timeout)
     livepatch_work.data = data;
     livepatch_work.timeout = timeout ?: MILLISECS(30);
 
-    dprintk(XENLOG_DEBUG, LIVEPATCH "%s: timeout is %"PRI_stime"ms\n",
-            data->name, livepatch_work.timeout / MILLISECS(1));
+    dprintk(XENLOG_DEBUG, LIVEPATCH "%s: timeout is %"PRIu32"ns\n",
+            data->name, livepatch_work.timeout);
 
     atomic_set(&livepatch_work.semaphore, -1);
 

xen/include/public/sysctl.h

@@ -1067,8 +1067,9 @@ struct xen_sysctl_livepatch_action {
 #define LIVEPATCH_ACTION_APPLY        3
 #define LIVEPATCH_ACTION_REPLACE      4
     uint32_t cmd;                           /* IN: LIVEPATCH_ACTION_*. */
-    uint32_t timeout;                       /* IN: Zero if no timeout. */
-                                            /* Or upper bound of time (ms) */
+    uint32_t timeout;                       /* IN: If zero then uses */
+                                            /* hypervisor default. */
+                                            /* Or upper bound of time (ns) */
                                             /* for operation to take. */
 };
 typedef struct xen_sysctl_livepatch_action xen_sysctl_livepatch_action_t;