tools/xenconsoled: Log Xen boot messages at startup.

When xenconsoled starts, there will be log lines in the Xen console ring from
boot, even though VIRQ_CON_RING is not yet pending.

Add a force option to handle_hv_logs() which bypasses the event channel check,
allowing xenconsoled to drain the Xen boot messages when it starts, rather
than at the first subsequent time that VIRQ_CON_RING becomes set.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

diff --git a/tools/console/daemon/io.c b/tools/console/daemon/io.c
index b1268fa8c4ac12184bd6805cb4438cc93d48eb12..ac08b5b48a6a72c80762d32d6b833ae1748995a2 100644 (file)
--- a/tools/console/daemon/io.c
+++ b/tools/console/daemon/io.c
@@ -907,15 +907,15 @@ static void handle_xs(void)
        free(vec);
 }
 
-static void handle_hv_logs(xc_evtchn *xce_handle)
+static void handle_hv_logs(xc_evtchn *xce_handle, bool force)
 {
        static char buffer[1024*16];
        char *bufptr = buffer;
        unsigned int size;
        static uint32_t index = 0;
-       evtchn_port_or_error_t port;
+       evtchn_port_or_error_t port = -1;
 
-       if ((port = xc_evtchn_pending(xce_handle)) == -1)
+       if (!force && ((port = xc_evtchn_pending(xce_handle)) == -1))
                return;
 
        do
@@ -938,7 +938,8 @@ static void handle_hv_logs(xc_evtchn *xce_handle)
                                       "%d (%s)", errno, strerror(errno));
        } while (size == sizeof(buffer));
 
-       (void)xc_evtchn_unmask(xce_handle, port);
+       if (port != -1)
+               (void)xc_evtchn_unmask(xce_handle, port);
 }
 
 static void handle_log_reload(void)
@@ -1024,6 +1025,8 @@ void handle_io(void)
                              "%d (%s)", errno, strerror(errno));
                        goto out;
                }
+               /* Log the boot dmesg even if VIRQ_CON_RING isn't pending. */
+               handle_hv_logs(xce_handle, true);
        }
 
        xcg_handle = xc_gnttab_open(NULL, 0);
@@ -1134,7 +1137,7 @@ void handle_io(void)
                                      errno, strerror(errno));
                                break;
                        } else if (fds[xce_pollfd_idx].revents & POLLIN)
-                               handle_hv_logs(xce_handle);
+                               handle_hv_logs(xce_handle, false);
 
                        xce_pollfd_idx = -1;
                }