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[Qemu-devel] [PULL 04/52] hpet: recover timer offset correctly
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 04/52] hpet: recover timer offset correctly |
Date: |
Fri, 12 Jan 2018 12:30:28 +0100 |
From: Maria Klimushenkova <address@hidden>
HPET saves its state by calculating the current time and recovers timer
offset using this calculated value. But these calculations include
divisions and multiplications. Therefore the timer state cannot be recovered
precise enough.
This patch introduces saving of the original value of the offset to
preserve the determinism of the timer.
Signed-off-by: Maria Klimushenkova <address@hidden>
Signed-off-by: Pavel Dovgalyuk <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/timer/hpet.c | 32 ++++++++++++++++++++++++++++++--
1 file changed, 30 insertions(+), 2 deletions(-)
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index 577371b..4904a60 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -70,6 +70,7 @@ typedef struct HPETState {
MemoryRegion iomem;
uint64_t hpet_offset;
+ bool hpet_offset_loaded;
qemu_irq irqs[HPET_NUM_IRQ_ROUTES];
uint32_t flags;
uint8_t rtc_irq_level;
@@ -221,7 +222,9 @@ static int hpet_pre_save(void *opaque)
HPETState *s = opaque;
/* save current counter value */
- s->hpet_counter = hpet_get_ticks(s);
+ if (hpet_enabled(s)) {
+ s->hpet_counter = hpet_get_ticks(s);
+ }
return 0;
}
@@ -232,6 +235,8 @@ static int hpet_pre_load(void *opaque)
/* version 1 only supports 3, later versions will load the actual value */
s->num_timers = HPET_MIN_TIMERS;
+ /* for checking whether the hpet_offset section is loaded */
+ s->hpet_offset_loaded = false;
return 0;
}
@@ -252,7 +257,10 @@ static int hpet_post_load(void *opaque, int version_id)
HPETState *s = opaque;
/* Recalculate the offset between the main counter and guest time */
- s->hpet_offset = ticks_to_ns(s->hpet_counter) -
qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ if (!s->hpet_offset_loaded) {
+ s->hpet_offset = ticks_to_ns(s->hpet_counter)
+ - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ }
/* Push number of timers into capability returned via HPET_ID */
s->capability &= ~HPET_ID_NUM_TIM_MASK;
@@ -267,6 +275,14 @@ static int hpet_post_load(void *opaque, int version_id)
return 0;
}
+static int hpet_offset_post_load(void *opaque, int version_id)
+{
+ HPETState *s = opaque;
+
+ s->hpet_offset_loaded = true;
+ return 0;
+}
+
static bool hpet_rtc_irq_level_needed(void *opaque)
{
HPETState *s = opaque;
@@ -285,6 +301,17 @@ static const VMStateDescription vmstate_hpet_rtc_irq_level
= {
}
};
+static const VMStateDescription vmstate_hpet_offset = {
+ .name = "hpet/offset",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .post_load = hpet_offset_post_load,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT64(hpet_offset, HPETState),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
static const VMStateDescription vmstate_hpet_timer = {
.name = "hpet_timer",
.version_id = 1,
@@ -320,6 +347,7 @@ static const VMStateDescription vmstate_hpet = {
},
.subsections = (const VMStateDescription*[]) {
&vmstate_hpet_rtc_irq_level,
+ &vmstate_hpet_offset,
NULL
}
};
--
1.8.3.1
[Qemu-devel] [PULL 05/52] i386/cpu/kvm: look at PMU's CPUID before setting MSRs, Paolo Bonzini, 2018/01/12
[Qemu-devel] [PULL 07/52] chardev: let g_idle_add() be with chardev gcontext, Paolo Bonzini, 2018/01/12
[Qemu-devel] [PULL 08/52] chardev: introduce qemu_chr_timeout_add_ms(), Paolo Bonzini, 2018/01/12
[Qemu-devel] [PULL 15/52] build-sys: add some sanitizers when --enable-debug if possible, Paolo Bonzini, 2018/01/12
[Qemu-devel] [PULL 10/52] build-sys: silence make by default or V=0, Paolo Bonzini, 2018/01/12
[Qemu-devel] [PULL 12/52] build-sys: compile with -Og or -O1 when --enable-debug, Paolo Bonzini, 2018/01/12