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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH, RFC v2] x86/HVM: assorted RTC emulation adjustments (was Re: Big Bug:Time in VM goes slower...)
Below/attached a second draft of a patch to fix not only this
issue, but a few more with the RTC emulation.
Keir, Tim, Yang, others - the change to xen/arch/x86/hvm/vpt.c really
looks more like a hack than a solution, but I don't see another
way without much more intrusive changes. The point is that we
want the RTC code to decide whether to generate an interrupt
(so that RTC_PF can become set correctly even without RTC_PIE
getting enabled by the guest).
Additionally I wonder whether alarm_timer_update() shouldn't
bail on non-conforming RTC_*_ALARM values (as those would
never match the values they get compared against, whereas
with the current way of handling this they would appear to
match - i.e. set RTC_AF and possibly generate an interrupt -
some other point in time). I realize the behavior here may not
be precisely specified, but the specification saying "the current
time has matched the alarm time" means to me a value by value
comparison, which implies that non-conforming values would
never match (since non-conforming current time values could
get replaced at any time by the hardware due to overflow
detection).
Jan
- don't call rtc_timer_update() on REG_A writes when the value didn't
change (doing the call always was reported to cause wall clock time
lagging with the JVM running on Windows)
- don't call rtc_timer_update() on REG_B writes at all
- only call alarm_timer_update() on REG_B writes when relevant bits
change
- only call check_update_timer() on REG_B writes when SET changes
- instead properly handle AF and PF when the guest is not also setting
AIE/PIE respectively (for UF this was already the case, only a
comment was slightly inaccurate)
- raise the RTC IRQ not only when UIE gets set while UF was already
set, but generalize this to cover AIE and PIE as well
- properly mask off bit 7 when retrieving the hour values in
alarm_timer_update(), and properly use RTC_HOURS_ALARM's bit 7 when
converting from 12- to 24-hour value
- also handle the two other possible clock bases
- use RTC_* names in a couple of places where literal numbers were used
so far
--- a/xen/arch/x86/hvm/rtc.c
+++ b/xen/arch/x86/hvm/rtc.c
@@ -50,11 +50,24 @@ static void rtc_set_time(RTCState *s);
static inline int from_bcd(RTCState *s, int a);
static inline int convert_hour(RTCState *s, int hour);
-static void rtc_periodic_cb(struct vcpu *v, void *opaque)
+static void rtc_toggle_irq(RTCState *s)
+{
+ struct domain *d = vrtc_domain(s);
+
+ ASSERT(spin_is_locked(&s->lock));
+ s->hw.cmos_data[RTC_REG_C] |= RTC_IRQF;
+ hvm_isa_irq_deassert(d, RTC_IRQ);
+ hvm_isa_irq_assert(d, RTC_IRQ);
+}
+
+void rtc_periodic_interrupt(void *opaque)
{
RTCState *s = opaque;
+
spin_lock(&s->lock);
- s->hw.cmos_data[RTC_REG_C] |= 0xc0;
+ s->hw.cmos_data[RTC_REG_C] |= RTC_PF;
+ if ( s->hw.cmos_data[RTC_REG_B] & RTC_PIE )
+ rtc_toggle_irq(s);
spin_unlock(&s->lock);
}
@@ -68,19 +81,25 @@ static void rtc_timer_update(RTCState *s
ASSERT(spin_is_locked(&s->lock));
period_code = s->hw.cmos_data[RTC_REG_A] & RTC_RATE_SELECT;
- if ( (period_code != 0) && (s->hw.cmos_data[RTC_REG_B] & RTC_PIE) )
+ switch ( s->hw.cmos_data[RTC_REG_A] & RTC_DIV_CTL )
{
- if ( period_code <= 2 )
+ case RTC_REF_CLCK_32KHZ:
+ if ( (period_code != 0) && (period_code <= 2) )
period_code += 7;
-
- period = 1 << (period_code - 1); /* period in 32 Khz cycles */
- period = DIV_ROUND((period * 1000000000ULL), 32768); /* period in ns */
- create_periodic_time(v, &s->pt, period, period, RTC_IRQ,
- rtc_periodic_cb, s);
- }
- else
- {
+ /* fall through */
+ case RTC_REF_CLCK_1MHZ:
+ case RTC_REF_CLCK_4MHZ:
+ if ( period_code != 0 )
+ {
+ period = 1 << (period_code - 1); /* period in 32 Khz cycles */
+ period = DIV_ROUND(period * 1000000000ULL, 32768); /* in ns */
+ create_periodic_time(v, &s->pt, period, period, RTC_IRQ, NULL, s);
+ break;
+ }
+ /* fall through */
+ default:
destroy_periodic_time(&s->pt);
+ break;
}
}
@@ -102,7 +121,7 @@ static void check_update_timer(RTCState
guest_usec = get_localtime_us(d) % USEC_PER_SEC;
if (guest_usec >= (USEC_PER_SEC - 244))
{
- /* RTC is in update cycle when enabling UIE */
+ /* RTC is in update cycle */
s->hw.cmos_data[RTC_REG_A] |= RTC_UIP;
next_update_time = (USEC_PER_SEC - guest_usec) * NS_PER_USEC;
expire_time = NOW() + next_update_time;
@@ -144,7 +163,6 @@ static void rtc_update_timer(void *opaqu
static void rtc_update_timer2(void *opaque)
{
RTCState *s = opaque;
- struct domain *d = vrtc_domain(s);
spin_lock(&s->lock);
if (!(s->hw.cmos_data[RTC_REG_B] & RTC_SET))
@@ -152,11 +170,7 @@ static void rtc_update_timer2(void *opaq
s->hw.cmos_data[RTC_REG_C] |= RTC_UF;
s->hw.cmos_data[RTC_REG_A] &= ~RTC_UIP;
if ((s->hw.cmos_data[RTC_REG_B] & RTC_UIE))
- {
- s->hw.cmos_data[RTC_REG_C] |= RTC_IRQF;
- hvm_isa_irq_deassert(d, RTC_IRQ);
- hvm_isa_irq_assert(d, RTC_IRQ);
- }
+ rtc_toggle_irq(s);
check_update_timer(s);
}
spin_unlock(&s->lock);
@@ -175,21 +189,18 @@ static void alarm_timer_update(RTCState
stop_timer(&s->alarm_timer);
- if ((s->hw.cmos_data[RTC_REG_B] & RTC_AIE) &&
- !(s->hw.cmos_data[RTC_REG_B] & RTC_SET))
+ if ( !(s->hw.cmos_data[RTC_REG_B] & RTC_SET) )
{
s->current_tm = gmtime(get_localtime(d));
rtc_copy_date(s);
alarm_sec = from_bcd(s, s->hw.cmos_data[RTC_SECONDS_ALARM]);
alarm_min = from_bcd(s, s->hw.cmos_data[RTC_MINUTES_ALARM]);
- alarm_hour = from_bcd(s, s->hw.cmos_data[RTC_HOURS_ALARM]);
- alarm_hour = convert_hour(s, alarm_hour);
+ alarm_hour = convert_hour(s, s->hw.cmos_data[RTC_HOURS_ALARM]);
cur_sec = from_bcd(s, s->hw.cmos_data[RTC_SECONDS]);
cur_min = from_bcd(s, s->hw.cmos_data[RTC_MINUTES]);
- cur_hour = from_bcd(s, s->hw.cmos_data[RTC_HOURS]);
- cur_hour = convert_hour(s, cur_hour);
+ cur_hour = convert_hour(s, s->hw.cmos_data[RTC_HOURS]);
next_update_time = USEC_PER_SEC - (get_localtime_us(d) % USEC_PER_SEC);
next_update_time = next_update_time * NS_PER_USEC + NOW();
@@ -343,7 +354,6 @@ static void alarm_timer_update(RTCState
static void rtc_alarm_cb(void *opaque)
{
RTCState *s = opaque;
- struct domain *d = vrtc_domain(s);
spin_lock(&s->lock);
if (!(s->hw.cmos_data[RTC_REG_B] & RTC_SET))
@@ -351,11 +361,7 @@ static void rtc_alarm_cb(void *opaque)
s->hw.cmos_data[RTC_REG_C] |= RTC_AF;
/* alarm interrupt */
if (s->hw.cmos_data[RTC_REG_B] & RTC_AIE)
- {
- s->hw.cmos_data[RTC_REG_C] |= RTC_IRQF;
- hvm_isa_irq_deassert(d, RTC_IRQ);
- hvm_isa_irq_assert(d, RTC_IRQ);
- }
+ rtc_toggle_irq(s);
alarm_timer_update(s);
}
spin_unlock(&s->lock);
@@ -365,6 +371,7 @@ static int rtc_ioport_write(void *opaque
{
RTCState *s = opaque;
struct domain *d = vrtc_domain(s);
+ uint32_t orig, mask;
spin_lock(&s->lock);
@@ -382,6 +389,7 @@ static int rtc_ioport_write(void *opaque
return 0;
}
+ orig = s->hw.cmos_data[s->hw.cmos_index];
switch ( s->hw.cmos_index )
{
case RTC_SECONDS_ALARM:
@@ -405,9 +413,9 @@ static int rtc_ioport_write(void *opaque
break;
case RTC_REG_A:
/* UIP bit is read only */
- s->hw.cmos_data[RTC_REG_A] = (data & ~RTC_UIP) |
- (s->hw.cmos_data[RTC_REG_A] & RTC_UIP);
- rtc_timer_update(s);
+ s->hw.cmos_data[RTC_REG_A] = (data & ~RTC_UIP) | (orig & RTC_UIP);
+ if ( (data ^ orig) & (RTC_RATE_SELECT | RTC_DIV_CTL) )
+ rtc_timer_update(s);
break;
case RTC_REG_B:
if ( data & RTC_SET )
@@ -415,7 +423,7 @@ static int rtc_ioport_write(void *opaque
/* set mode: reset UIP mode */
s->hw.cmos_data[RTC_REG_A] &= ~RTC_UIP;
/* adjust cmos before stopping */
- if (!(s->hw.cmos_data[RTC_REG_B] & RTC_SET))
+ if (!(orig & RTC_SET))
{
s->current_tm = gmtime(get_localtime(d));
rtc_copy_date(s);
@@ -424,21 +432,26 @@ static int rtc_ioport_write(void *opaque
else
{
/* if disabling set mode, update the time */
- if ( s->hw.cmos_data[RTC_REG_B] & RTC_SET )
+ if ( orig & RTC_SET )
rtc_set_time(s);
}
- /* if the interrupt is already set when the interrupt become
- * enabled, raise an interrupt immediately*/
- if ((data & RTC_UIE) && !(s->hw.cmos_data[RTC_REG_B] & RTC_UIE))
- if (s->hw.cmos_data[RTC_REG_C] & RTC_UF)
+ /*
+ * If the interrupt is already set when the interrupt becomes
+ * enabled, raise an interrupt immediately.
+ * NB: RTC_{A,P,U}IE == RTC_{A,P,U}F respectively.
+ */
+ for ( mask = RTC_UIE; mask <= RTC_PIE; mask <<= 1 )
+ if ( (data & mask) && !(orig & mask) &&
+ (s->hw.cmos_data[RTC_REG_C] & mask) )
{
- hvm_isa_irq_deassert(d, RTC_IRQ);
- hvm_isa_irq_assert(d, RTC_IRQ);
+ rtc_toggle_irq(s);
+ break;
}
s->hw.cmos_data[RTC_REG_B] = data;
- rtc_timer_update(s);
- check_update_timer(s);
- alarm_timer_update(s);
+ if ( (data ^ orig) & RTC_SET )
+ check_update_timer(s);
+ if ( (data ^ orig) & (RTC_24H | RTC_DM_BINARY | RTC_SET) )
+ alarm_timer_update(s);
break;
case RTC_REG_C:
case RTC_REG_D:
@@ -453,7 +466,7 @@ static int rtc_ioport_write(void *opaque
static inline int to_bcd(RTCState *s, int a)
{
- if ( s->hw.cmos_data[RTC_REG_B] & 0x04 )
+ if ( s->hw.cmos_data[RTC_REG_B] & RTC_DM_BINARY )
return a;
else
return ((a / 10) << 4) | (a % 10);
@@ -461,7 +474,7 @@ static inline int to_bcd(RTCState *s, in
static inline int from_bcd(RTCState *s, int a)
{
- if ( s->hw.cmos_data[RTC_REG_B] & 0x04 )
+ if ( s->hw.cmos_data[RTC_REG_B] & RTC_DM_BINARY )
return a;
else
return ((a >> 4) * 10) + (a & 0x0f);
@@ -469,12 +482,14 @@ static inline int from_bcd(RTCState *s,
/* Hours in 12 hour mode are in 1-12 range, not 0-11.
* So we need convert it before using it*/
-static inline int convert_hour(RTCState *s, int hour)
+static inline int convert_hour(RTCState *s, int raw)
{
+ int hour = from_bcd(s, raw & 0x7f);
+
if (!(s->hw.cmos_data[RTC_REG_B] & RTC_24H))
{
hour %= 12;
- if (s->hw.cmos_data[RTC_HOURS] & 0x80)
+ if (raw & 0x80)
hour += 12;
}
return hour;
@@ -493,8 +508,7 @@ static void rtc_set_time(RTCState *s)
tm->tm_sec = from_bcd(s, s->hw.cmos_data[RTC_SECONDS]);
tm->tm_min = from_bcd(s, s->hw.cmos_data[RTC_MINUTES]);
- tm->tm_hour = from_bcd(s, s->hw.cmos_data[RTC_HOURS] & 0x7f);
- tm->tm_hour = convert_hour(s, tm->tm_hour);
+ tm->tm_hour = convert_hour(s, s->hw.cmos_data[RTC_HOURS]);
tm->tm_wday = from_bcd(s, s->hw.cmos_data[RTC_DAY_OF_WEEK]);
tm->tm_mday = from_bcd(s, s->hw.cmos_data[RTC_DAY_OF_MONTH]);
tm->tm_mon = from_bcd(s, s->hw.cmos_data[RTC_MONTH]) - 1;
--- a/xen/arch/x86/hvm/vpt.c
+++ b/xen/arch/x86/hvm/vpt.c
@@ -22,6 +22,7 @@
#include <asm/hvm/vpt.h>
#include <asm/event.h>
#include <asm/apic.h>
+#include <asm/mc146818rtc.h>
#define mode_is(d, name) \
((d)->arch.hvm_domain.params[HVM_PARAM_TIMER_MODE] == HVMPTM_##name)
@@ -218,6 +219,7 @@ void pt_update_irq(struct vcpu *v)
struct periodic_time *pt, *temp, *earliest_pt = NULL;
uint64_t max_lag = -1ULL;
int irq, is_lapic;
+ void *pt_priv;
spin_lock(&v->arch.hvm_vcpu.tm_lock);
@@ -251,13 +253,14 @@ void pt_update_irq(struct vcpu *v)
earliest_pt->irq_issued = 1;
irq = earliest_pt->irq;
is_lapic = (earliest_pt->source == PTSRC_lapic);
+ pt_priv = earliest_pt->priv;
spin_unlock(&v->arch.hvm_vcpu.tm_lock);
if ( is_lapic )
- {
vlapic_set_irq(vcpu_vlapic(v), irq, 0);
- }
+ else if ( irq == RTC_IRQ )
+ rtc_periodic_interrupt(pt_priv);
else
{
hvm_isa_irq_deassert(v->domain, irq);
--- a/xen/include/asm-x86/hvm/vpt.h
+++ b/xen/include/asm-x86/hvm/vpt.h
@@ -181,6 +181,7 @@ void rtc_migrate_timers(struct vcpu *v);
void rtc_deinit(struct domain *d);
void rtc_reset(struct domain *d);
void rtc_update_clock(struct domain *d);
+void rtc_periodic_interrupt(void *);
void pmtimer_init(struct vcpu *v);
void pmtimer_deinit(struct domain *d);
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