Re: [Qemu-devel] [PATCH v3 3/4] Fixes RTC bug with base datetime shifts in clock=vm

[Paolo Bonzini]

On 18/10/2018 09:12, Artem Pisarenko wrote:
> +    rtc_host_datetime_offset = rtc_ref_start_datetime - rtc_start_datetime;
> +    rtc_ref_start_datetime = rtc_start_datetime;

Because of this, multiple rtc options have funny effects.

Can squash this instead:

diff --git a/vl.c b/vl.c
index 1b349b78bd..4c332a5469 100644
--- a/vl.c
+++ b/vl.c
@@ -249,6 +249,7 @@ static struct {
 static QemuOptsList qemu_rtc_opts = {
     .name = "rtc",
     .head = QTAILQ_HEAD_INITIALIZER(qemu_rtc_opts.head),
+    .merge_lists = true,
     .desc = {
         {
             .name = "base",
@@ -886,6 +887,11 @@ static void configure_rtc(QemuOpts *opts)
 {
     const char *value;

+    /* Set defaults */
+    rtc_clock = QEMU_CLOCK_HOST;
+    rtc_ref_start_datetime = qemu_clock_get_ms(QEMU_CLOCK_HOST) / 1000;
+    rtc_realtime_clock_offset = qemu_clock_get_ms(QEMU_CLOCK_REALTIME)
/ 1000;
+
     value = qemu_opt_get(opts, "base");
     if (value) {
         if (!strcmp(value, "utc")) {
@@ -3048,9 +3054,6 @@ int main(int argc, char **argv, char **envp)
         error_reportf_err(err, "cannot initialize crypto: ");
         exit(1);
     }
-    rtc_clock = QEMU_CLOCK_HOST;
-    rtc_ref_start_datetime = qemu_clock_get_ms(QEMU_CLOCK_HOST) / 1000;
-    rtc_realtime_clock_offset = qemu_clock_get_ms(QEMU_CLOCK_REALTIME)
/ 1000;

     QLIST_INIT (&vm_change_state_head);
     os_setup_early_signal_handling();
@@ -3770,7 +3771,6 @@ int main(int argc, char **argv, char **envp)
                 if (!opts) {
                     exit(1);
                 }
-                configure_rtc(opts);
                 break;
             case QEMU_OPTION_tb_size:
 #ifndef CONFIG_TCG
@@ -3988,6 +3988,8 @@ int main(int argc, char **argv, char **envp)
         exit(EXIT_FAILURE);
     }

+    configure_rtc(qemu_find_opts_singleton("rtc"));
+
     machine_class = select_machine();

     set_memory_options(&ram_slots, &maxram_size, machine_class);