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[Qemu-devel] [PATCH v3 5/5] Enable host-clock-based RTC
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] [PATCH v3 5/5] Enable host-clock-based RTC |
Date: |
Tue, 15 Sep 2009 13:36:04 +0200 |
User-agent: |
StGIT/0.14.3 |
Switch RTC emulations to the new host_clock instead of vm_clock by
default. This has the advantage that the emulated RTC will follow
automatically the host time while it might be tuned via NTP. vm_clock
can still be selected by passing '-rtc clock=vm' on the command line.
Note that some RTC emulations (at least M48T59) already use the host
time unconditionally while others (namely MC146818) do not. This patch
introduces the required infrastructure for selecting the base clock but
only converts MC146818 for now.
Signed-off-by: Jan Kiszka <address@hidden>
---
hw/mc146818rtc.c | 38 ++++++++++++++++++--------------------
qemu-config.c | 3 +++
qemu-options.hx | 14 ++++++++++----
sysemu.h | 2 ++
vl.c | 17 ++++++++++++++++-
5 files changed, 49 insertions(+), 25 deletions(-)
diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
index 9d6a627..bec5687 100644
--- a/hw/mc146818rtc.c
+++ b/hw/mc146818rtc.c
@@ -108,8 +108,8 @@ static void rtc_coalesced_timer_update(RTCState *s)
} else {
/* divide each RTC interval to 2 - 8 smaller intervals */
int c = MIN(s->irq_coalesced, 7) + 1;
- int64_t next_clock = qemu_get_clock(vm_clock) +
- muldiv64(s->period / c, get_ticks_per_sec(), 32768);
+ int64_t next_clock = qemu_get_clock(rtc_clock) +
+ muldiv64(s->period / c, get_ticks_per_sec(), 32768);
qemu_mod_timer(s->coalesced_timer, next_clock);
}
}
@@ -161,7 +161,8 @@ static void rtc_timer_update(RTCState *s, int64_t
current_time)
/* compute 32 khz clock */
cur_clock = muldiv64(current_time, 32768, get_ticks_per_sec());
next_irq_clock = (cur_clock & ~(period - 1)) + period;
- s->next_periodic_time = muldiv64(next_irq_clock, get_ticks_per_sec(),
32768) + 1;
+ s->next_periodic_time =
+ muldiv64(next_irq_clock, get_ticks_per_sec(), 32768) + 1;
qemu_mod_timer(s->periodic_timer, s->next_periodic_time);
} else {
#ifdef TARGET_I386
@@ -232,7 +233,7 @@ static void cmos_ioport_write(void *opaque, uint32_t addr,
uint32_t data)
/* UIP bit is read only */
s->cmos_data[RTC_REG_A] = (data & ~REG_A_UIP) |
(s->cmos_data[RTC_REG_A] & REG_A_UIP);
- rtc_timer_update(s, qemu_get_clock(vm_clock));
+ rtc_timer_update(s, qemu_get_clock(rtc_clock));
break;
case RTC_REG_B:
if (data & REG_B_SET) {
@@ -246,7 +247,7 @@ static void cmos_ioport_write(void *opaque, uint32_t addr,
uint32_t data)
}
}
s->cmos_data[RTC_REG_B] = data;
- rtc_timer_update(s, qemu_get_clock(vm_clock));
+ rtc_timer_update(s, qemu_get_clock(rtc_clock));
break;
case RTC_REG_C:
case RTC_REG_D:
@@ -605,18 +606,17 @@ static int rtc_initfn(ISADevice *dev)
rtc_set_date_from_host(s);
- s->periodic_timer = qemu_new_timer(vm_clock,
- rtc_periodic_timer, s);
+ s->periodic_timer = qemu_new_timer(rtc_clock, rtc_periodic_timer, s);
#ifdef TARGET_I386
if (rtc_td_hack)
- s->coalesced_timer = qemu_new_timer(vm_clock, rtc_coalesced_timer, s);
+ s->coalesced_timer =
+ qemu_new_timer(rtc_clock, rtc_coalesced_timer, s);
#endif
- s->second_timer = qemu_new_timer(vm_clock,
- rtc_update_second, s);
- s->second_timer2 = qemu_new_timer(vm_clock,
- rtc_update_second2, s);
+ s->second_timer = qemu_new_timer(rtc_clock, rtc_update_second, s);
+ s->second_timer2 = qemu_new_timer(rtc_clock, rtc_update_second2, s);
- s->next_second_time = qemu_get_clock(vm_clock) + (get_ticks_per_sec() *
99) / 100;
+ s->next_second_time =
+ qemu_get_clock(rtc_clock) + (get_ticks_per_sec() * 99) / 100;
qemu_mod_timer(s->second_timer2, s->next_second_time);
register_ioport_write(base, 2, 1, cmos_ioport_write, s);
@@ -747,14 +747,12 @@ RTCState *rtc_mm_init(target_phys_addr_t base, int
it_shift, qemu_irq irq,
s->base_year = base_year;
rtc_set_date_from_host(s);
- s->periodic_timer = qemu_new_timer(vm_clock,
- rtc_periodic_timer, s);
- s->second_timer = qemu_new_timer(vm_clock,
- rtc_update_second, s);
- s->second_timer2 = qemu_new_timer(vm_clock,
- rtc_update_second2, s);
+ s->periodic_timer = qemu_new_timer(rtc_clock, rtc_periodic_timer, s);
+ s->second_timer = qemu_new_timer(rtc_clock, rtc_update_second, s);
+ s->second_timer2 = qemu_new_timer(rtc_clock, rtc_update_second2, s);
- s->next_second_time = qemu_get_clock(vm_clock) + (get_ticks_per_sec() *
99) / 100;
+ s->next_second_time =
+ qemu_get_clock(rtc_clock) + (get_ticks_per_sec() * 99) / 100;
qemu_mod_timer(s->second_timer2, s->next_second_time);
io_memory = cpu_register_io_memory(rtc_mm_read, rtc_mm_write, s);
diff --git a/qemu-config.c b/qemu-config.c
index 45a3e09..35c3277 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -158,6 +158,9 @@ QemuOptsList qemu_rtc_opts = {
{
.name = "base",
.type = QEMU_OPT_STRING,
+ },{
+ .name = "clock",
+ .type = QEMU_OPT_STRING,
#ifdef TARGET_I386
},{
.name = "driftfix",
diff --git a/qemu-options.hx b/qemu-options.hx
index 586474e..f21e9f9 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1500,22 +1500,28 @@ DEF("startdate", HAS_ARG, QEMU_OPTION_startdate, "")
#ifdef TARGET_I386
DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \
- "-rtc [base=utc|localtime|date][,driftfix=none|slew]\n" \
- " set the RTC base, enable drift fix for clock ticks\n")
+ "-rtc [base=utc|localtime|date][,clock=host|vm][,driftfix=none|slew]\n" \
+ " set the RTC base and clock, enable drift fix for clock
ticks\n")
#else
DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \
- "-rtc [base=utc|localtime|date]\n" \
+ "-rtc [base=utc|localtime|date][,clock=host|vm]\n" \
" set the RTC base and clock\n")
#endif
STEXI
address@hidden -rtc [base=utc|localtime|@var{date}][,driftfix=none|slew]
address@hidden -rtc
[base=utc|localtime|@var{date}][,clock=host|vm][,driftfix=none|slew]
Specify @option{base} as @code{utc} or @code{localtime} to let the RTC start
at the current
UTC or local time, respectively. @code{localtime} is required for correct date
in
MS-DOS or Windows. To start at a specific point in time, provide @var{date} in
the
format @code{2006-06-17T16:01:21} or @code{2006-06-17}. The default base is
UTC.
+By default the RTC is driven by the host system time. This allows to use the
+RTC as accurate reference clock inside the guest, specifically if the host
+time is smoothly following an accurate external reference clock, e.g. via NTP.
+If you want to isolate the guest time from the host, even prevent it from
+progressing during suspension, you can set @option{clock} to @code{vm} instead.
+
Enable @option{driftfix} (i386 targets only) if you experience time drift
problems,
specifically with Windows' ACPI HAL. This option will try to figure out how
many timer interrupts were not processed by the Windows guest and will
diff --git a/sysemu.h b/sysemu.h
index 644a97d..c1dd1d3 100644
--- a/sysemu.h
+++ b/sysemu.h
@@ -5,6 +5,7 @@
#include "qemu-common.h"
#include "qemu-option.h"
#include "qemu-queue.h"
+#include "qemu-timer.h"
#include "qdict.h"
#ifdef _WIN32
@@ -134,6 +135,7 @@ extern int no_quit;
extern int semihosting_enabled;
extern int old_param;
extern int boot_menu;
+extern QEMUClock *rtc_clock;
#define MAX_NODES 64
extern int nb_numa_nodes;
diff --git a/vl.c b/vl.c
index 0594ee8..c0c8332 100644
--- a/vl.c
+++ b/vl.c
@@ -193,6 +193,7 @@ int vm_running;
int autostart;
static int rtc_utc = 1;
static int rtc_date_offset = -1; /* -1 means no change */
+QEMUClock *rtc_clock;
int vga_interface_type = VGA_CIRRUS;
#ifdef TARGET_SPARC
int graphic_width = 1024;
@@ -1052,6 +1053,8 @@ static void init_clocks(void)
rt_clock = qemu_new_clock(QEMU_CLOCK_REALTIME);
vm_clock = qemu_new_clock(QEMU_CLOCK_VIRTUAL);
host_clock = qemu_new_clock(QEMU_CLOCK_HOST);
+
+ rtc_clock = host_clock;
}
/* save a timer */
@@ -1630,6 +1633,17 @@ static void configure_rtc(QemuOpts *opts)
configure_rtc_date_offset(value, 0);
}
}
+ value = qemu_opt_get(opts, "clock");
+ if (value) {
+ if (!strcmp(value, "host")) {
+ rtc_clock = host_clock;
+ } else if (!strcmp(value, "vm")) {
+ rtc_clock = vm_clock;
+ } else {
+ fprintf(stderr, "qemu: invalid option value '%s'\n", value);
+ exit(1);
+ }
+ }
#ifdef CONFIG_TARGET_I386
value = qemu_opt_get(opts, "driftfix");
if (value) {
@@ -4740,6 +4754,8 @@ int main(int argc, char **argv, char **envp)
CPUState *env;
int show_vnc_port = 0;
+ init_clocks();
+
qemu_errors_to_file(stderr);
qemu_cache_utils_init(envp);
@@ -5605,7 +5621,6 @@ int main(int argc, char **argv, char **envp)
setvbuf(stdout, NULL, _IOLBF, 0);
#endif
- init_clocks();
if (init_timer_alarm() < 0) {
fprintf(stderr, "could not initialize alarm timer\n");
exit(1);
- [Qemu-devel] [PATCH v3 0/5] Improve PC RTC emulation, Jan Kiszka, 2009/09/15
- [Qemu-devel] [PATCH v3 2/5] win32: Drop dead dyntick timer code, Jan Kiszka, 2009/09/15
- [Qemu-devel] [PATCH v3 1/5] Rename QEMU_TIMER_* to QEMU_CLOCK_*, Jan Kiszka, 2009/09/15
- [Qemu-devel] [PATCH v3 5/5] Enable host-clock-based RTC,
Jan Kiszka <=
- [Qemu-devel] [PATCH v3 3/5] Introduce QEMU_CLOCK_HOST, Jan Kiszka, 2009/09/15
- [Qemu-devel] [PATCH v3 4/5] Refactor RTC command line switches, Jan Kiszka, 2009/09/15
- [Qemu-devel] Re: [PATCH v3 0/5] Improve PC RTC emulation, Jamie Lokier, 2009/09/15