Fixes RTC bug with base datetime shifts in clock=vm
This makes all current "-rtc" option parameters combinations produce fixed/unambiguous RTC timedate reference for hardware emulation frontends. It restores determinism of guest execution when used with clock=vm and specified base <datetime> value. Buglink: https://bugs.launchpad.net/qemu/+bug/1797033 Signed-off-by: Artem Pisarenko <artem.k.pisarenko@gmail.com> Message-Id: <1d963c3e013dfedafa1f6edb9fb219b7e49e39da.1539846575.git.artem.k.pisarenko@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Artem Pisarenko
Paolo Bonzini
parent
7e166ebd8c
commit
eb6a520991
62
vl.c
62
vl.c
@ -152,8 +152,10 @@ static enum {
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RTC_BASE_LOCALTIME,
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RTC_BASE_DATETIME,
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} rtc_base_type = RTC_BASE_UTC;
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static int rtc_host_datetime_offset = -1; /* valid only for host rtc_clock and
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rtc_base_type=RTC_BASE_DATETIME */
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static time_t rtc_ref_start_datetime;
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static int rtc_realtime_clock_offset; /* used only with QEMU_CLOCK_REALTIME */
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static int rtc_host_datetime_offset = -1; /* valid & used only with
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RTC_BASE_DATETIME */
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QEMUClockType rtc_clock;
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int vga_interface_type = VGA_NONE;
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static DisplayOptions dpy;
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@ -247,6 +249,7 @@ static struct {
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static QemuOptsList qemu_rtc_opts = {
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.name = "rtc",
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.head = QTAILQ_HEAD_INITIALIZER(qemu_rtc_opts.head),
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.merge_lists = true,
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.desc = {
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{
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.name = "base",
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@ -785,32 +788,42 @@ void qemu_system_vmstop_request(RunState state)
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}
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/***********************************************************/
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/* real time host monotonic timer */
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static time_t qemu_timedate(void)
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/* RTC reference time/date access */
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static time_t qemu_ref_timedate(void)
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{
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return qemu_clock_get_ms(QEMU_CLOCK_HOST) / 1000;
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time_t value = qemu_clock_get_ms(rtc_clock) / 1000;
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switch (rtc_clock) {
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case QEMU_CLOCK_REALTIME:
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value -= rtc_realtime_clock_offset;
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/* no break */
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case QEMU_CLOCK_VIRTUAL:
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value += rtc_ref_start_datetime;
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break;
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case QEMU_CLOCK_HOST:
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if (rtc_base_type == RTC_BASE_DATETIME) {
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value -= rtc_host_datetime_offset;
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}
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break;
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default:
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assert(0);
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}
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return value;
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}
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/***********************************************************/
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/* RTC reference time/date access */
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void qemu_get_timedate(struct tm *tm, int offset)
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{
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time_t ti = qemu_timedate();
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time_t ti = qemu_ref_timedate();
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ti += offset;
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switch (rtc_base_type) {
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case RTC_BASE_DATETIME:
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case RTC_BASE_UTC:
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gmtime_r(&ti, tm);
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break;
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case RTC_BASE_LOCALTIME:
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localtime_r(&ti, tm);
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break;
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case RTC_BASE_DATETIME:
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ti -= rtc_host_datetime_offset;
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gmtime_r(&ti, tm);
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break;
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}
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}
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@ -819,6 +832,7 @@ int qemu_timedate_diff(struct tm *tm)
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time_t seconds;
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switch (rtc_base_type) {
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case RTC_BASE_DATETIME:
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case RTC_BASE_UTC:
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seconds = mktimegm(tm);
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break;
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@ -829,17 +843,14 @@ int qemu_timedate_diff(struct tm *tm)
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seconds = mktime(&tmp);
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break;
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}
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case RTC_BASE_DATETIME:
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seconds = mktimegm(tm) + rtc_host_datetime_offset;
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break;
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default:
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abort();
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}
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return seconds - qemu_timedate();
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return seconds - qemu_ref_timedate();
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}
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static void configure_rtc_host_datetime_offset(const char *startdate)
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static void configure_rtc_base_datetime(const char *startdate)
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{
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time_t rtc_start_datetime;
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struct tm tm;
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@ -865,14 +876,19 @@ static void configure_rtc_host_datetime_offset(const char *startdate)
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"'2006-06-17T16:01:21' or '2006-06-17'\n");
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exit(1);
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}
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rtc_host_datetime_offset = (qemu_clock_get_ms(QEMU_CLOCK_HOST) / 1000)
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- rtc_start_datetime;
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rtc_host_datetime_offset = rtc_ref_start_datetime - rtc_start_datetime;
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rtc_ref_start_datetime = rtc_start_datetime;
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}
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static void configure_rtc(QemuOpts *opts)
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{
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const char *value;
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/* Set defaults */
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rtc_clock = QEMU_CLOCK_HOST;
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rtc_ref_start_datetime = qemu_clock_get_ms(QEMU_CLOCK_HOST) / 1000;
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rtc_realtime_clock_offset = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
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value = qemu_opt_get(opts, "base");
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if (value) {
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if (!strcmp(value, "utc")) {
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@ -885,7 +901,7 @@ static void configure_rtc(QemuOpts *opts)
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replay_add_blocker(blocker);
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} else {
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rtc_base_type = RTC_BASE_DATETIME;
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configure_rtc_host_datetime_offset(value);
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configure_rtc_base_datetime(value);
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}
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}
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value = qemu_opt_get(opts, "clock");
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@ -3035,7 +3051,6 @@ int main(int argc, char **argv, char **envp)
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error_reportf_err(err, "cannot initialize crypto: ");
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exit(1);
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}
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rtc_clock = QEMU_CLOCK_HOST;
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QLIST_INIT (&vm_change_state_head);
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os_setup_early_signal_handling();
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@ -3755,7 +3770,6 @@ int main(int argc, char **argv, char **envp)
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if (!opts) {
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exit(1);
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}
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configure_rtc(opts);
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break;
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case QEMU_OPTION_tb_size:
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#ifndef CONFIG_TCG
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@ -3973,6 +3987,8 @@ int main(int argc, char **argv, char **envp)
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exit(EXIT_FAILURE);
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}
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configure_rtc(qemu_find_opts_singleton("rtc"));
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machine_class = select_machine();
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set_memory_options(&ram_slots, &maxram_size, machine_class);
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