[Qemu-devel] [PATCH/RFC 2/4] Add -clock option.

[Luca Tettamanti <kronos.it@gmail.com>]

Allow user to override the list of available alarm timers and their
priority. The format of the options is -clock clk1,clk2,...

Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
---
 qemu/vl.c |   90 ++++++++++++++++++++++++++++++++++++++++----------
 1 files changed, 72 insertions(+), 18 deletions(-)

diff --git a/qemu/vl.c b/qemu/vl.c
index 33443ca..f0b4896 100644
--- a/qemu/vl.c
+++ b/qemu/vl.c
@@ -793,6 +793,71 @@ static struct qemu_alarm_timer alarm_timers[] = {
     {NULL, }
 };
 
+static void show_available_alarms()
+{
+    int i;
+
+    printf("Available alarm timers, in order of precedence:\n");
+    for (i = 0; alarm_timers[i].name; i++)
+        printf("%s\n", alarm_timers[i].name);
+}
+
+static void configure_alarms(char const *opt)
+{
+    int i;
+    int cur = 0;
+    int count = (sizeof(alarm_timers) / sizeof(*alarm_timers)) - 1;
+    char *arg;
+    char *name;
+    
+    if (!strcmp(opt, "help")) {
+        show_available_alarms();
+        exit(0);
+    }
+    
+    arg = strdup(opt);
+
+    /* Reorder the array */
+    name = strtok(arg, ",");
+    while (name) {
+        struct qemu_alarm_timer tmp;
+
+        for (i = 0; i < count; i++) {
+            if (!strcmp(alarm_timers[i].name, name))
+                break;
+        }
+
+        if (i == count) {
+            fprintf(stderr, "Unknown clock %s\n", name);
+            goto next;
+        }
+
+        if (i < cur)
+            /* Ignore */
+            goto next;
+
+	/* Swap */
+        tmp = alarm_timers[i];
+        alarm_timers[i] = alarm_timers[cur];
+        alarm_timers[cur] = tmp;
+
+        cur++;
+next:
+        name = strtok(NULL, ",");
+    }
+
+    free(arg);
+
+    if (cur) {
+	/* Disable remaining timers */
+        for (i = cur; i < count; i++)
+            alarm_timers[i].name = NULL;
+    }
+
+    /* debug */
+    show_available_alarms();
+}
+
 QEMUClock *rt_clock;
 QEMUClock *vm_clock;
 
@@ -1035,8 +1100,6 @@ static void host_alarm_handler(int host_signum)
 
 #define RTC_FREQ 1024
 
-static int use_rtc = 1;
-
 static void enable_sigio_timer(int fd)
 {
     struct sigaction act;
@@ -1058,9 +1121,6 @@ static int rtc_start_timer(struct qemu_alarm_timer *t)
 {
     int rtc_fd;
 
-    if (!use_rtc)
-            return -1;
-
     rtc_fd = open("/dev/rtc", O_RDONLY);
     if (rtc_fd < 0)
         return -1;
@@ -6566,9 +6626,8 @@ void help(void)
 	   "-daemonize      daemonize QEMU after initializing\n"
 #endif
            "-tdf            inject timer interrupts that got lost\n"
-#if defined(__linux__)
-           "-no-rtc         don't use /dev/rtc for timer alarm (do use gettimeofday)\n"
-#endif
+           "-clock          force the use of the given methods for timer alarm.\n"
+           "                To see what timers are available use -clock help\n"
 	   "-option-rom rom load a file, rom, into the option ROM space\n"
            "\n"
            "During emulation, the following keys are useful:\n"
@@ -6658,9 +6717,7 @@ enum {
     QEMU_OPTION_semihosting,
     QEMU_OPTION_incoming,
     QEMU_OPTION_tdf,
-#if defined(__linux__)
-    QEMU_OPTION_no_rtc,
-#endif
+    QEMU_OPTION_clock,
     QEMU_OPTION_cpu_vendor,
 };
 
@@ -6755,9 +6812,7 @@ const QEMUOption qemu_options[] = {
     { "semihosting", 0, QEMU_OPTION_semihosting },
 #endif
     { "tdf", 0, QEMU_OPTION_tdf }, /* enable time drift fix */
-#if defined(__linux__)
-    { "no-rtc", 0, QEMU_OPTION_no_rtc },
-#endif
+    { "clock", HAS_ARG, QEMU_OPTION_clock },
     { "cpu-vendor", HAS_ARG, QEMU_OPTION_cpu_vendor },
     { NULL },
 };
@@ -7477,11 +7532,10 @@ int main(int argc, char **argv)
                 break;
             case QEMU_OPTION_tdf:
                 time_drift_fix = 1;
-#if defined(__linux__)
-	    case QEMU_OPTION_no_rtc:
-		use_rtc = 0;
 		break;
-#endif
+            case QEMU_OPTION_clock:
+                configure_alarms(optarg);
+                break;
 	    case QEMU_OPTION_cpu_vendor:
 		cpu_vendor_string = optarg;
 		break;
-- 
1.5.2.4