diff mbox series

[v5,01/14] cpu-timers, icount: new modules

Message ID 20200812183250.9221-2-cfontana@suse.de
State New
Headers show
Series QEMU cpus.c refactoring part2 | expand

Commit Message

Claudio Fontana Aug. 12, 2020, 6:32 p.m. UTC
refactoring of cpus.c continues with cpu timer state extraction.

cpu-timers: responsible for the softmmu cpu timers state,
            including cpu clocks and ticks.

icount: counts the TCG instructions executed. As such it is specific to
the TCG accelerator. Therefore, it is built only under CONFIG_TCG.

One complication is due to qtest, which uses an icount field to warp time
as part of qtest (qtest_clock_warp).

In order to solve this problem, provide a separate counter for qtest.

This requires fixing assumptions scattered in the code that
qtest_enabled() implies icount_enabled(), checking each specific case.

Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
---
 MAINTAINERS                  |   2 +
 accel/qtest.c                |   6 +-
 accel/tcg/cpu-exec.c         |  43 ++-
 accel/tcg/tcg-all.c          |   7 +-
 accel/tcg/translate-all.c    |   3 +-
 dma-helpers.c                |   4 +-
 docs/replay.txt              |   6 +-
 exec.c                       |   4 -
 hw/core/ptimer.c             |   8 +-
 hw/i386/x86.c                |   1 +
 include/exec/cpu-all.h       |   4 +
 include/exec/exec-all.h      |   4 +-
 include/qemu/timer.h         |  24 +-
 include/sysemu/cpu-timers.h  |  81 +++++
 include/sysemu/cpus.h        |  12 +-
 include/sysemu/qtest.h       |   2 +
 include/sysemu/replay.h      |   4 +-
 replay/replay.c              |   6 +-
 softmmu/Makefile.objs        |   2 +
 softmmu/cpu-timers.c         | 284 ++++++++++++++++
 softmmu/cpus.c               | 750 +------------------------------------------
 softmmu/icount.c             | 497 ++++++++++++++++++++++++++++
 softmmu/qtest.c              |  34 +-
 softmmu/timers-state.h       |  69 ++++
 softmmu/vl.c                 |  11 +-
 stubs/Makefile.objs          |   4 +-
 stubs/clock-warp.c           |   7 -
 stubs/cpu-get-clock.c        |   3 +-
 stubs/cpu-get-icount.c       |  21 --
 stubs/icount.c               |  52 +++
 stubs/qemu-timer-notify-cb.c |   8 +
 stubs/qtest.c                |   5 +
 target/alpha/translate.c     |   3 +-
 target/arm/helper.c          |   7 +-
 target/riscv/csr.c           |   8 +-
 tests/ptimer-test-stubs.c    |   7 +-
 tests/test-timed-average.c   |   2 +-
 util/main-loop.c             |  12 +-
 util/qemu-timer.c            |  14 +-
 39 files changed, 1158 insertions(+), 863 deletions(-)
 create mode 100644 include/sysemu/cpu-timers.h
 create mode 100644 softmmu/cpu-timers.c
 create mode 100644 softmmu/icount.c
 create mode 100644 softmmu/timers-state.h
 delete mode 100644 stubs/clock-warp.c
 delete mode 100644 stubs/cpu-get-icount.c
 create mode 100644 stubs/icount.c
 create mode 100644 stubs/qemu-timer-notify-cb.c

Comments

Richard Henderson Aug. 14, 2020, 8:20 p.m. UTC | #1
On 8/12/20 11:32 AM, Claudio Fontana wrote:
> +/*
> + * Return the icount enablement state:
> + *
> + * 0 = Disabled - Do not count executed instructions.
> + * 1 = Enabled - Fixed conversion of insn to ns via "shift" option
> + * 2 = Enabled - Runtime adaptive algorithm to compute shift
> + */
> +int icount_enabled(void);

Why does use_icount need to change to a function?

If it does, or even if this just comes under the heading of cleanup, it should
certainly be done in a separate patch.

Either way, I think we should expose the fact that this is always disabled when
#ifndef CONFIG_TCG, just like we do for tcg_enabled().

> -        if (use_icount) {
> -            return cpu_get_icount();
> +        if (icount_enabled()) {
> +            return icount_get();

Renaming of other functions like this should also be done in a separate patch.


r~
Claudio Fontana Aug. 19, 2020, 1:49 p.m. UTC | #2
Hello Richard,

On 8/14/20 10:20 PM, Richard Henderson wrote:
> On 8/12/20 11:32 AM, Claudio Fontana wrote:
>> +/*
>> + * Return the icount enablement state:
>> + *
>> + * 0 = Disabled - Do not count executed instructions.
>> + * 1 = Enabled - Fixed conversion of insn to ns via "shift" option
>> + * 2 = Enabled - Runtime adaptive algorithm to compute shift
>> + */
>> +int icount_enabled(void);
> 
> Why does use_icount need to change to a function?


It is not useful at this point, I'll change this.


> 
> If it does, or even if this just comes under the heading of cleanup, it should
> certainly be done in a separate patch.


Yes, I'll move it to a different series entirely.

> 
> Either way, I think we should expose the fact that this is always disabled when
> #ifndef CONFIG_TCG, just like we do for tcg_enabled().

Will do.

> 
>> -        if (use_icount) {
>> -            return cpu_get_icount();
>> +        if (icount_enabled()) {
>> +            return icount_get();
> 
> Renaming of other functions like this should also be done in a separate patch.

Is there a compelling reason to separate the new module/class from what are effectively its methods?
It seemed to me that creating a new icount module would warrant the name changes in the same patch.

> 
> 
> r~
> 

I will be out of office until end of the month,

thanks,

Claudio
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 0886eb3d2b..7dcc3ef4c8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2285,6 +2285,8 @@  F: softmmu/vl.c
 F: softmmu/main.c
 F: softmmu/cpus.c
 F: softmmu/cpu-throttle.c
+F: softmmu/cpu-timers.c
+F: softmmu/icount.c
 F: qapi/run-state.json
 
 Human Monitor (HMP)
diff --git a/accel/qtest.c b/accel/qtest.c
index 5b88f55921..119d0f16a4 100644
--- a/accel/qtest.c
+++ b/accel/qtest.c
@@ -19,14 +19,10 @@ 
 #include "sysemu/accel.h"
 #include "sysemu/qtest.h"
 #include "sysemu/cpus.h"
+#include "sysemu/cpu-timers.h"
 
 static int qtest_init_accel(MachineState *ms)
 {
-    QemuOpts *opts = qemu_opts_create(qemu_find_opts("icount"), NULL, 0,
-                                      &error_abort);
-    qemu_opt_set(opts, "shift", "0", &error_abort);
-    configure_icount(opts, &error_abort);
-    qemu_opts_del(opts);
     return 0;
 }
 
diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 66d38f9d85..b44e92b753 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -19,6 +19,7 @@ 
 
 #include "qemu/osdep.h"
 #include "qemu-common.h"
+#include "qemu/qemu-print.h"
 #include "cpu.h"
 #include "trace.h"
 #include "disas/disas.h"
@@ -36,6 +37,8 @@ 
 #include "hw/i386/apic.h"
 #endif
 #include "sysemu/cpus.h"
+#include "exec/cpu-all.h"
+#include "sysemu/cpu-timers.h"
 #include "sysemu/replay.h"
 
 /* -icount align implementation. */
@@ -56,6 +59,9 @@  typedef struct SyncClocks {
 #define MAX_DELAY_PRINT_RATE 2000000000LL
 #define MAX_NB_PRINTS 100
 
+static int64_t max_delay;
+static int64_t max_advance;
+
 static void align_clocks(SyncClocks *sc, CPUState *cpu)
 {
     int64_t cpu_icount;
@@ -65,7 +71,7 @@  static void align_clocks(SyncClocks *sc, CPUState *cpu)
     }
 
     cpu_icount = cpu->icount_extra + cpu_neg(cpu)->icount_decr.u16.low;
-    sc->diff_clk += cpu_icount_to_ns(sc->last_cpu_icount - cpu_icount);
+    sc->diff_clk += icount_to_ns(sc->last_cpu_icount - cpu_icount);
     sc->last_cpu_icount = cpu_icount;
 
     if (sc->diff_clk > VM_CLOCK_ADVANCE) {
@@ -98,9 +104,9 @@  static void print_delay(const SyncClocks *sc)
             (-sc->diff_clk / (float)1000000000LL <
              (threshold_delay - THRESHOLD_REDUCE))) {
             threshold_delay = (-sc->diff_clk / 1000000000LL) + 1;
-            printf("Warning: The guest is now late by %.1f to %.1f seconds\n",
-                   threshold_delay - 1,
-                   threshold_delay);
+            qemu_printf("Warning: The guest is now late by %.1f to %.1f seconds\n",
+                        threshold_delay - 1,
+                        threshold_delay);
             nb_prints++;
             last_realtime_clock = sc->realtime_clock;
         }
@@ -614,7 +620,7 @@  static inline bool cpu_handle_interrupt(CPUState *cpu,
 
     /* Finally, check if we need to exit to the main loop.  */
     if (unlikely(atomic_read(&cpu->exit_request))
-        || (use_icount
+        || (icount_enabled()
             && cpu_neg(cpu)->icount_decr.u16.low + cpu->icount_extra == 0)) {
         atomic_set(&cpu->exit_request, 0);
         if (cpu->exception_index == -1) {
@@ -655,10 +661,10 @@  static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
     }
 
     /* Instruction counter expired.  */
-    assert(use_icount);
+    assert(icount_enabled());
 #ifndef CONFIG_USER_ONLY
     /* Ensure global icount has gone forward */
-    cpu_update_icount(cpu);
+    icount_update(cpu);
     /* Refill decrementer and continue execution.  */
     insns_left = MIN(0xffff, cpu->icount_budget);
     cpu_neg(cpu)->icount_decr.u16.low = insns_left;
@@ -758,3 +764,26 @@  int cpu_exec(CPUState *cpu)
 
     return ret;
 }
+
+#ifndef CONFIG_USER_ONLY
+
+void dump_drift_info(void)
+{
+    if (!icount_enabled()) {
+        return;
+    }
+
+    qemu_printf("Host - Guest clock  %"PRIi64" ms\n",
+                (cpu_get_clock() - icount_get()) / SCALE_MS);
+    if (icount_align_option) {
+        qemu_printf("Max guest delay     %"PRIi64" ms\n",
+                    -max_delay / SCALE_MS);
+        qemu_printf("Max guest advance   %"PRIi64" ms\n",
+                    max_advance / SCALE_MS);
+    } else {
+        qemu_printf("Max guest delay     NA\n");
+        qemu_printf("Max guest advance   NA\n");
+    }
+}
+
+#endif /* !CONFIG_USER_ONLY */
diff --git a/accel/tcg/tcg-all.c b/accel/tcg/tcg-all.c
index eace2c113b..f1feea20c8 100644
--- a/accel/tcg/tcg-all.c
+++ b/accel/tcg/tcg-all.c
@@ -29,6 +29,7 @@ 
 #include "qom/object.h"
 #include "cpu.h"
 #include "sysemu/cpus.h"
+#include "sysemu/cpu-timers.h"
 #include "qemu/main-loop.h"
 #include "tcg/tcg.h"
 #include "qapi/error.h"
@@ -65,7 +66,7 @@  static void tcg_handle_interrupt(CPUState *cpu, int mask)
         qemu_cpu_kick(cpu);
     } else {
         atomic_set(&cpu_neg(cpu)->icount_decr.u16.high, -1);
-        if (use_icount &&
+        if (icount_enabled() &&
             !cpu->can_do_io
             && (mask & ~old_mask) != 0) {
             cpu_abort(cpu, "Raised interrupt while not in I/O function");
@@ -104,7 +105,7 @@  static bool check_tcg_memory_orders_compatible(void)
 
 static bool default_mttcg_enabled(void)
 {
-    if (use_icount || TCG_OVERSIZED_GUEST) {
+    if (icount_enabled() || TCG_OVERSIZED_GUEST) {
         return false;
     } else {
 #ifdef TARGET_SUPPORTS_MTTCG
@@ -146,7 +147,7 @@  static void tcg_set_thread(Object *obj, const char *value, Error **errp)
     if (strcmp(value, "multi") == 0) {
         if (TCG_OVERSIZED_GUEST) {
             error_setg(errp, "No MTTCG when guest word size > hosts");
-        } else if (use_icount) {
+        } else if (icount_enabled()) {
             error_setg(errp, "No MTTCG when icount is enabled");
         } else {
 #ifndef TARGET_SUPPORTS_MTTCG
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 2d83013633..c39ff7b047 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -57,6 +57,7 @@ 
 #include "qemu/main-loop.h"
 #include "exec/log.h"
 #include "sysemu/cpus.h"
+#include "sysemu/cpu-timers.h"
 #include "sysemu/tcg.h"
 
 /* #define DEBUG_TB_INVALIDATE */
@@ -369,7 +370,7 @@  static int cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb,
 
  found:
     if (reset_icount && (tb_cflags(tb) & CF_USE_ICOUNT)) {
-        assert(use_icount);
+        assert(icount_enabled());
         /* Reset the cycle counter to the start of the block
            and shift if to the number of actually executed instructions */
         cpu_neg(cpu)->icount_decr.u16.low += num_insns - i;
diff --git a/dma-helpers.c b/dma-helpers.c
index 2a77b5a9cb..240ef4d5b8 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -13,7 +13,7 @@ 
 #include "trace-root.h"
 #include "qemu/thread.h"
 #include "qemu/main-loop.h"
-#include "sysemu/cpus.h"
+#include "sysemu/cpu-timers.h"
 #include "qemu/range.h"
 
 /* #define DEBUG_IOMMU */
@@ -151,7 +151,7 @@  static void dma_blk_cb(void *opaque, int ret)
          * from several sectors. This code splits all SGs into several
          * groups. SGs in every group do not overlap.
          */
-        if (mem && use_icount && dbs->dir == DMA_DIRECTION_FROM_DEVICE) {
+        if (mem && icount_enabled() && dbs->dir == DMA_DIRECTION_FROM_DEVICE) {
             int i;
             for (i = 0 ; i < dbs->iov.niov ; ++i) {
                 if (ranges_overlap((intptr_t)dbs->iov.iov[i].iov_base,
diff --git a/docs/replay.txt b/docs/replay.txt
index 70c27edb36..8952e6d852 100644
--- a/docs/replay.txt
+++ b/docs/replay.txt
@@ -184,11 +184,11 @@  is then incremented (which is called "warping" the virtual clock) as
 soon as the timer fires or the CPUs need to go out of the idle state.
 Two functions are used for this purpose; because these actions change
 virtual machine state and must be deterministic, each of them creates a
-checkpoint.  qemu_start_warp_timer checks if the CPUs are idle and if so
-starts accounting real time to virtual clock.  qemu_account_warp_timer
+checkpoint.  icount_start_warp_timer checks if the CPUs are idle and if so
+starts accounting real time to virtual clock.  icount_account_warp_timer
 is called when the CPUs get an interrupt or when the warp timer fires,
 and it warps the virtual clock by the amount of real time that has passed
-since qemu_start_warp_timer.
+since icount_start_warp_timer.
 
 Bottom halves
 -------------
diff --git a/exec.c b/exec.c
index 6f381f98e2..a89ffa93c1 100644
--- a/exec.c
+++ b/exec.c
@@ -102,10 +102,6 @@  uintptr_t qemu_host_page_size;
 intptr_t qemu_host_page_mask;
 
 #if !defined(CONFIG_USER_ONLY)
-/* 0 = Do not count executed instructions.
-   1 = Precise instruction counting.
-   2 = Adaptive rate instruction counting.  */
-int use_icount;
 
 typedef struct PhysPageEntry PhysPageEntry;
 
diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c
index b5a54e2536..c6d2beb1da 100644
--- a/hw/core/ptimer.c
+++ b/hw/core/ptimer.c
@@ -7,11 +7,11 @@ 
  */
 
 #include "qemu/osdep.h"
-#include "qemu/timer.h"
 #include "hw/ptimer.h"
 #include "migration/vmstate.h"
 #include "qemu/host-utils.h"
 #include "sysemu/replay.h"
+#include "sysemu/cpu-timers.h"
 #include "sysemu/qtest.h"
 #include "block/aio.h"
 #include "sysemu/cpus.h"
@@ -134,7 +134,8 @@  static void ptimer_reload(ptimer_state *s, int delta_adjust)
      * on the current generation of host machines.
      */
 
-    if (s->enabled == 1 && (delta * period < 10000) && !use_icount) {
+    if (s->enabled == 1 && (delta * period < 10000) &&
+        !icount_enabled() && !qtest_enabled()) {
         period = 10000 / delta;
         period_frac = 0;
     }
@@ -217,7 +218,8 @@  uint64_t ptimer_get_count(ptimer_state *s)
             uint32_t period_frac = s->period_frac;
             uint64_t period = s->period;
 
-            if (!oneshot && (s->delta * period < 10000) && !use_icount) {
+            if (!oneshot && (s->delta * period < 10000) &&
+                !icount_enabled() && !qtest_enabled()) {
                 period = 10000 / s->delta;
                 period_frac = 0;
             }
diff --git a/hw/i386/x86.c b/hw/i386/x86.c
index 67bee1bcb8..58cf2229d5 100644
--- a/hw/i386/x86.c
+++ b/hw/i386/x86.c
@@ -34,6 +34,7 @@ 
 #include "sysemu/numa.h"
 #include "sysemu/replay.h"
 #include "sysemu/sysemu.h"
+#include "sysemu/cpu-timers.h"
 #include "trace.h"
 
 #include "hw/i386/x86.h"
diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index fc403d456b..25b6005a91 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -407,8 +407,12 @@  static inline bool tlb_hit(target_ulong tlb_addr, target_ulong addr)
     return tlb_hit_page(tlb_addr, addr & TARGET_PAGE_MASK);
 }
 
+#ifdef CONFIG_TCG
+void dump_drift_info(void);
 void dump_exec_info(void);
 void dump_opcount_info(void);
+#endif /* CONFIG_TCG */
+
 #endif /* !CONFIG_USER_ONLY */
 
 /* Returns: 0 on success, -1 on error */
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 3cf88272df..e019b505a5 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -25,7 +25,7 @@ 
 #ifdef CONFIG_TCG
 #include "exec/cpu_ldst.h"
 #endif
-#include "sysemu/cpus.h"
+#include "sysemu/cpu-timers.h"
 
 /* allow to see translation results - the slowdown should be negligible, so we leave it */
 #define DEBUG_DISAS
@@ -497,7 +497,7 @@  static inline uint32_t tb_cflags(const TranslationBlock *tb)
 static inline uint32_t curr_cflags(void)
 {
     return (parallel_cpus ? CF_PARALLEL : 0)
-         | (use_icount ? CF_USE_ICOUNT : 0);
+         | (icount_enabled() ? CF_USE_ICOUNT : 0);
 }
 
 /* TranslationBlock invalidate API */
diff --git a/include/qemu/timer.h b/include/qemu/timer.h
index 6a8b48b5a9..2f7afc1f68 100644
--- a/include/qemu/timer.h
+++ b/include/qemu/timer.h
@@ -166,8 +166,8 @@  bool qemu_clock_expired(QEMUClockType type);
  *
  * Determine whether a clock should be used for deadline
  * calculations. Some clocks, for instance vm_clock with
- * use_icount set, do not count in nanoseconds. Such clocks
- * are not used for deadline calculations, and are presumed
+ * icount_enabled() set, do not count in nanoseconds.
+ * Such clocks are not used for deadline calculations, and are presumed
  * to interrupt any poll using qemu_notify/aio_notify
  * etc.
  *
@@ -224,13 +224,6 @@  void qemu_clock_notify(QEMUClockType type);
  */
 void qemu_clock_enable(QEMUClockType type, bool enabled);
 
-/**
- * qemu_start_warp_timer:
- *
- * Starts a timer for virtual clock update
- */
-void qemu_start_warp_timer(void);
-
 /**
  * qemu_clock_run_timers:
  * @type: clock on which to operate
@@ -791,12 +784,6 @@  static inline int64_t qemu_soonest_timeout(int64_t timeout1, int64_t timeout2)
  */
 void init_clocks(QEMUTimerListNotifyCB *notify_cb);
 
-int64_t cpu_get_ticks(void);
-/* Caller must hold BQL */
-void cpu_enable_ticks(void);
-/* Caller must hold BQL */
-void cpu_disable_ticks(void);
-
 static inline int64_t get_max_clock_jump(void)
 {
     /* This should be small enough to prevent excessive interrupts from being
@@ -850,13 +837,6 @@  static inline int64_t get_clock(void)
 }
 #endif
 
-/* icount */
-int64_t cpu_get_icount_raw(void);
-int64_t cpu_get_icount(void);
-int64_t cpu_get_clock(void);
-int64_t cpu_icount_to_ns(int64_t icount);
-void    cpu_update_icount(CPUState *cpu);
-
 /*******************************************/
 /* host CPU ticks (if available) */
 
diff --git a/include/sysemu/cpu-timers.h b/include/sysemu/cpu-timers.h
new file mode 100644
index 0000000000..07d724672f
--- /dev/null
+++ b/include/sysemu/cpu-timers.h
@@ -0,0 +1,81 @@ 
+/*
+ * CPU timers state API
+ *
+ * Copyright 2020 SUSE LLC
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+#ifndef SYSEMU_CPU_TIMERS_H
+#define SYSEMU_CPU_TIMERS_H
+
+#include "qemu/timer.h"
+
+/* init the whole cpu timers API, including icount, ticks, and cpu_throttle */
+void cpu_timers_init(void);
+
+/* icount - Instruction Counter API */
+
+/*
+ * Return the icount enablement state:
+ *
+ * 0 = Disabled - Do not count executed instructions.
+ * 1 = Enabled - Fixed conversion of insn to ns via "shift" option
+ * 2 = Enabled - Runtime adaptive algorithm to compute shift
+ */
+int icount_enabled(void);
+/*
+ * Update the icount with the executed instructions. Called by
+ * cpus-tcg vCPU thread so the main-loop can see time has moved forward.
+ */
+void icount_update(CPUState *cpu);
+
+/* get raw icount value */
+int64_t icount_get_raw(void);
+
+/* return the virtual CPU time in ns, based on the instruction counter. */
+int64_t icount_get(void);
+/*
+ * convert an instruction counter value to ns, based on the icount shift.
+ * This shift is set as a fixed value with the icount "shift" option
+ * (precise mode), or it is constantly approximated and corrected at
+ * runtime in adaptive mode.
+ */
+int64_t icount_to_ns(int64_t icount);
+
+/* configure the icount options, including "shift" */
+void icount_configure(QemuOpts *opts, Error **errp);
+
+/* used by tcg vcpu thread to calc icount budget */
+int64_t icount_round(int64_t count);
+
+/* if the CPUs are idle, start accounting real time to virtual clock. */
+void icount_start_warp_timer(void);
+void icount_account_warp_timer(void);
+
+/*
+ * CPU Ticks and Clock
+ */
+
+/* Caller must hold BQL */
+void cpu_enable_ticks(void);
+/* Caller must hold BQL */
+void cpu_disable_ticks(void);
+
+/*
+ * return the time elapsed in VM between vm_start and vm_stop.  Unless
+ * icount is active, cpu_get_ticks() uses units of the host CPU cycle
+ * counter.
+ */
+int64_t cpu_get_ticks(void);
+
+/*
+ * Returns the monotonic time elapsed in VM, i.e.,
+ * the time between vm_start and vm_stop
+ */
+int64_t cpu_get_clock(void);
+
+void qemu_timer_notify_cb(void *opaque, QEMUClockType type);
+
+#endif /* SYSEMU_CPU_TIMERS_H */
diff --git a/include/sysemu/cpus.h b/include/sysemu/cpus.h
index 3c1da6a018..149de000a0 100644
--- a/include/sysemu/cpus.h
+++ b/include/sysemu/cpus.h
@@ -4,33 +4,23 @@ 
 #include "qemu/timer.h"
 
 /* cpus.c */
+bool all_cpu_threads_idle(void);
 bool qemu_in_vcpu_thread(void);
 void qemu_init_cpu_loop(void);
 void resume_all_vcpus(void);
 void pause_all_vcpus(void);
 void cpu_stop_current(void);
-void cpu_ticks_init(void);
 
-void configure_icount(QemuOpts *opts, Error **errp);
-extern int use_icount;
 extern int icount_align_option;
 
-/* drift information for info jit command */
-extern int64_t max_delay;
-extern int64_t max_advance;
-void dump_drift_info(void);
-
 /* Unblock cpu */
 void qemu_cpu_kick_self(void);
-void qemu_timer_notify_cb(void *opaque, QEMUClockType type);
 
 void cpu_synchronize_all_states(void);
 void cpu_synchronize_all_post_reset(void);
 void cpu_synchronize_all_post_init(void);
 void cpu_synchronize_all_pre_loadvm(void);
 
-void qtest_clock_warp(int64_t dest);
-
 #ifndef CONFIG_USER_ONLY
 /* vl.c */
 /* *-user doesn't have configurable SMP topology */
diff --git a/include/sysemu/qtest.h b/include/sysemu/qtest.h
index eedd3664f0..4c53537ef3 100644
--- a/include/sysemu/qtest.h
+++ b/include/sysemu/qtest.h
@@ -30,4 +30,6 @@  void qtest_server_set_send_handler(void (*send)(void *, const char *),
                                  void *opaque);
 void qtest_server_inproc_recv(void *opaque, const char *buf);
 
+int64_t qtest_get_virtual_clock(void);
+
 #endif
diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h
index 5471bb514d..a140d69a73 100644
--- a/include/sysemu/replay.h
+++ b/include/sysemu/replay.h
@@ -109,12 +109,12 @@  int64_t replay_read_clock(ReplayClockKind kind);
 #define REPLAY_CLOCK(clock, value)                                      \
     (replay_mode == REPLAY_MODE_PLAY ? replay_read_clock((clock))       \
         : replay_mode == REPLAY_MODE_RECORD                             \
-            ? replay_save_clock((clock), (value), cpu_get_icount_raw()) \
+            ? replay_save_clock((clock), (value), icount_get_raw()) \
         : (value))
 #define REPLAY_CLOCK_LOCKED(clock, value)                               \
     (replay_mode == REPLAY_MODE_PLAY ? replay_read_clock((clock))       \
         : replay_mode == REPLAY_MODE_RECORD                             \
-            ? replay_save_clock((clock), (value), cpu_get_icount_raw_locked()) \
+            ? replay_save_clock((clock), (value), icount_get_raw_locked()) \
         : (value))
 
 /* Processing data from random generators */
diff --git a/replay/replay.c b/replay/replay.c
index 83ed9e0e24..4c1457b07e 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -11,10 +11,10 @@ 
 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
+#include "sysemu/cpu-timers.h"
 #include "sysemu/replay.h"
 #include "sysemu/runstate.h"
 #include "replay-internal.h"
-#include "qemu/timer.h"
 #include "qemu/main-loop.h"
 #include "qemu/option.h"
 #include "sysemu/cpus.h"
@@ -64,7 +64,7 @@  bool replay_next_event_is(int event)
 
 uint64_t replay_get_current_icount(void)
 {
-    return cpu_get_icount_raw();
+    return icount_get_raw();
 }
 
 int replay_get_instructions(void)
@@ -345,7 +345,7 @@  void replay_start(void)
         error_reportf_err(replay_blockers->data, "Record/replay: ");
         exit(1);
     }
-    if (!use_icount) {
+    if (!icount_enabled()) {
         error_report("Please enable icount to use record/replay");
         exit(1);
     }
diff --git a/softmmu/Makefile.objs b/softmmu/Makefile.objs
index a414a74c50..9c0125f37b 100644
--- a/softmmu/Makefile.objs
+++ b/softmmu/Makefile.objs
@@ -7,6 +7,8 @@  obj-y += balloon.o
 obj-y += ioport.o
 obj-y += memory.o
 obj-y += memory_mapping.o
+obj-y += cpu-timers.o
+obj-$(CONFIG_TCG) += icount.o
 
 obj-y += qtest.o
 
diff --git a/softmmu/cpu-timers.c b/softmmu/cpu-timers.c
new file mode 100644
index 0000000000..64addb315d
--- /dev/null
+++ b/softmmu/cpu-timers.c
@@ -0,0 +1,284 @@ 
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qemu/cutils.h"
+#include "migration/vmstate.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "exec/exec-all.h"
+#include "sysemu/cpus.h"
+#include "sysemu/qtest.h"
+#include "qemu/main-loop.h"
+#include "qemu/option.h"
+#include "qemu/seqlock.h"
+#include "sysemu/replay.h"
+#include "sysemu/runstate.h"
+#include "hw/core/cpu.h"
+#include "sysemu/cpu-timers.h"
+#include "sysemu/cpu-throttle.h"
+#include "timers-state.h"
+
+/* clock and ticks */
+
+static int64_t cpu_get_ticks_locked(void)
+{
+    int64_t ticks = timers_state.cpu_ticks_offset;
+    if (timers_state.cpu_ticks_enabled) {
+        ticks += cpu_get_host_ticks();
+    }
+
+    if (timers_state.cpu_ticks_prev > ticks) {
+        /* Non increasing ticks may happen if the host uses software suspend. */
+        timers_state.cpu_ticks_offset += timers_state.cpu_ticks_prev - ticks;
+        ticks = timers_state.cpu_ticks_prev;
+    }
+
+    timers_state.cpu_ticks_prev = ticks;
+    return ticks;
+}
+
+/*
+ * return the time elapsed in VM between vm_start and vm_stop.  Unless
+ * icount is active, cpu_get_ticks() uses units of the host CPU cycle
+ * counter.
+ */
+int64_t cpu_get_ticks(void)
+{
+    int64_t ticks;
+
+    if (icount_enabled()) {
+        return icount_get();
+    }
+
+    qemu_spin_lock(&timers_state.vm_clock_lock);
+    ticks = cpu_get_ticks_locked();
+    qemu_spin_unlock(&timers_state.vm_clock_lock);
+    return ticks;
+}
+
+int64_t cpu_get_clock_locked(void)
+{
+    int64_t time;
+
+    time = timers_state.cpu_clock_offset;
+    if (timers_state.cpu_ticks_enabled) {
+        time += get_clock();
+    }
+
+    return time;
+}
+
+/*
+ * Return the monotonic time elapsed in VM, i.e.,
+ * the time between vm_start and vm_stop
+ */
+int64_t cpu_get_clock(void)
+{
+    int64_t ti;
+    unsigned start;
+
+    do {
+        start = seqlock_read_begin(&timers_state.vm_clock_seqlock);
+        ti = cpu_get_clock_locked();
+    } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start));
+
+    return ti;
+}
+
+/*
+ * enable cpu_get_ticks()
+ * Caller must hold BQL which serves as mutex for vm_clock_seqlock.
+ */
+void cpu_enable_ticks(void)
+{
+    seqlock_write_lock(&timers_state.vm_clock_seqlock,
+                       &timers_state.vm_clock_lock);
+    if (!timers_state.cpu_ticks_enabled) {
+        timers_state.cpu_ticks_offset -= cpu_get_host_ticks();
+        timers_state.cpu_clock_offset -= get_clock();
+        timers_state.cpu_ticks_enabled = 1;
+    }
+    seqlock_write_unlock(&timers_state.vm_clock_seqlock,
+                       &timers_state.vm_clock_lock);
+}
+
+/*
+ * disable cpu_get_ticks() : the clock is stopped. You must not call
+ * cpu_get_ticks() after that.
+ * Caller must hold BQL which serves as mutex for vm_clock_seqlock.
+ */
+void cpu_disable_ticks(void)
+{
+    seqlock_write_lock(&timers_state.vm_clock_seqlock,
+                       &timers_state.vm_clock_lock);
+    if (timers_state.cpu_ticks_enabled) {
+        timers_state.cpu_ticks_offset += cpu_get_host_ticks();
+        timers_state.cpu_clock_offset = cpu_get_clock_locked();
+        timers_state.cpu_ticks_enabled = 0;
+    }
+    seqlock_write_unlock(&timers_state.vm_clock_seqlock,
+                         &timers_state.vm_clock_lock);
+}
+
+static bool icount_state_needed(void *opaque)
+{
+    return icount_enabled();
+}
+
+static bool icount_shift_state_needed(void *opaque)
+{
+    return icount_enabled() == 2;
+}
+
+static bool warp_timer_state_needed(void *opaque)
+{
+    TimersState *s = opaque;
+    return s->icount_warp_timer != NULL;
+}
+
+static bool adjust_timers_state_needed(void *opaque)
+{
+    TimersState *s = opaque;
+    return s->icount_rt_timer != NULL;
+}
+
+/*
+ * Subsection for warp timer migration is optional, because may not be created
+ */
+static const VMStateDescription icount_vmstate_warp_timer = {
+    .name = "timer/icount/warp_timer",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = warp_timer_state_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT64(vm_clock_warp_start, TimersState),
+        VMSTATE_TIMER_PTR(icount_warp_timer, TimersState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription icount_vmstate_adjust_timers = {
+    .name = "timer/icount/timers",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = adjust_timers_state_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_TIMER_PTR(icount_rt_timer, TimersState),
+        VMSTATE_TIMER_PTR(icount_vm_timer, TimersState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static const VMStateDescription icount_vmstate_shift = {
+    .name = "timer/icount/shift",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = icount_shift_state_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT16(icount_time_shift, TimersState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+/*
+ * This is a subsection for icount migration.
+ */
+static const VMStateDescription icount_vmstate_timers = {
+    .name = "timer/icount",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = icount_state_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT64(qemu_icount_bias, TimersState),
+        VMSTATE_INT64(qemu_icount, TimersState),
+        VMSTATE_END_OF_LIST()
+    },
+    .subsections = (const VMStateDescription * []) {
+        &icount_vmstate_warp_timer,
+        &icount_vmstate_adjust_timers,
+        &icount_vmstate_shift,
+        NULL
+    }
+};
+
+static const VMStateDescription vmstate_timers = {
+    .name = "timer",
+    .version_id = 2,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT64(cpu_ticks_offset, TimersState),
+        VMSTATE_UNUSED(8),
+        VMSTATE_INT64_V(cpu_clock_offset, TimersState, 2),
+        VMSTATE_END_OF_LIST()
+    },
+    .subsections = (const VMStateDescription * []) {
+        &icount_vmstate_timers,
+        NULL
+    }
+};
+
+static void do_nothing(CPUState *cpu, run_on_cpu_data unused)
+{
+}
+
+void qemu_timer_notify_cb(void *opaque, QEMUClockType type)
+{
+    if (!icount_enabled() || type != QEMU_CLOCK_VIRTUAL) {
+        qemu_notify_event();
+        return;
+    }
+
+    if (qemu_in_vcpu_thread()) {
+        /*
+         * A CPU is currently running; kick it back out to the
+         * tcg_cpu_exec() loop so it will recalculate its
+         * icount deadline immediately.
+         */
+        qemu_cpu_kick(current_cpu);
+    } else if (first_cpu) {
+        /*
+         * qemu_cpu_kick is not enough to kick a halted CPU out of
+         * qemu_tcg_wait_io_event.  async_run_on_cpu, instead,
+         * causes cpu_thread_is_idle to return false.  This way,
+         * handle_icount_deadline can run.
+         * If we have no CPUs at all for some reason, we don't
+         * need to do anything.
+         */
+        async_run_on_cpu(first_cpu, do_nothing, RUN_ON_CPU_NULL);
+    }
+}
+
+TimersState timers_state;
+
+/* initialize timers state and the cpu throttle for convenience */
+void cpu_timers_init(void)
+{
+    seqlock_init(&timers_state.vm_clock_seqlock);
+    qemu_spin_init(&timers_state.vm_clock_lock);
+    vmstate_register(NULL, 0, &vmstate_timers, &timers_state);
+
+    cpu_throttle_init();
+}
diff --git a/softmmu/cpus.c b/softmmu/cpus.c
index a802e899ab..54fdb2761c 100644
--- a/softmmu/cpus.c
+++ b/softmmu/cpus.c
@@ -58,11 +58,10 @@ 
 #include "hw/nmi.h"
 #include "sysemu/replay.h"
 #include "sysemu/runstate.h"
+#include "sysemu/cpu-timers.h"
 #include "hw/boards.h"
 #include "hw/hw.h"
 
-#include "sysemu/cpu-throttle.h"
-
 #ifdef CONFIG_LINUX
 
 #include <sys/prctl.h>
@@ -83,9 +82,6 @@ 
 
 static QemuMutex qemu_global_mutex;
 
-int64_t max_delay;
-int64_t max_advance;
-
 bool cpu_is_stopped(CPUState *cpu)
 {
     return cpu->stopped || !runstate_is_running();
@@ -116,7 +112,7 @@  static bool cpu_thread_is_idle(CPUState *cpu)
     return true;
 }
 
-static bool all_cpu_threads_idle(void)
+bool all_cpu_threads_idle(void)
 {
     CPUState *cpu;
 
@@ -128,688 +124,9 @@  static bool all_cpu_threads_idle(void)
     return true;
 }
 
-/***********************************************************/
-/* guest cycle counter */
-
-/* Protected by TimersState seqlock */
-
-static bool icount_sleep = true;
-/* Arbitrarily pick 1MIPS as the minimum allowable speed.  */
-#define MAX_ICOUNT_SHIFT 10
-
-typedef struct TimersState {
-    /* Protected by BQL.  */
-    int64_t cpu_ticks_prev;
-    int64_t cpu_ticks_offset;
-
-    /* Protect fields that can be respectively read outside the
-     * BQL, and written from multiple threads.
-     */
-    QemuSeqLock vm_clock_seqlock;
-    QemuSpin vm_clock_lock;
-
-    int16_t cpu_ticks_enabled;
-
-    /* Conversion factor from emulated instructions to virtual clock ticks.  */
-    int16_t icount_time_shift;
-
-    /* Compensate for varying guest execution speed.  */
-    int64_t qemu_icount_bias;
-
-    int64_t vm_clock_warp_start;
-    int64_t cpu_clock_offset;
-
-    /* Only written by TCG thread */
-    int64_t qemu_icount;
-
-    /* for adjusting icount */
-    QEMUTimer *icount_rt_timer;
-    QEMUTimer *icount_vm_timer;
-    QEMUTimer *icount_warp_timer;
-} TimersState;
-
-static TimersState timers_state;
 bool mttcg_enabled;
 
 
-/* The current number of executed instructions is based on what we
- * originally budgeted minus the current state of the decrementing
- * icount counters in extra/u16.low.
- */
-static int64_t cpu_get_icount_executed(CPUState *cpu)
-{
-    return (cpu->icount_budget -
-            (cpu_neg(cpu)->icount_decr.u16.low + cpu->icount_extra));
-}
-
-/*
- * Update the global shared timer_state.qemu_icount to take into
- * account executed instructions. This is done by the TCG vCPU
- * thread so the main-loop can see time has moved forward.
- */
-static void cpu_update_icount_locked(CPUState *cpu)
-{
-    int64_t executed = cpu_get_icount_executed(cpu);
-    cpu->icount_budget -= executed;
-
-    atomic_set_i64(&timers_state.qemu_icount,
-                   timers_state.qemu_icount + executed);
-}
-
-/*
- * Update the global shared timer_state.qemu_icount to take into
- * account executed instructions. This is done by the TCG vCPU
- * thread so the main-loop can see time has moved forward.
- */
-void cpu_update_icount(CPUState *cpu)
-{
-    seqlock_write_lock(&timers_state.vm_clock_seqlock,
-                       &timers_state.vm_clock_lock);
-    cpu_update_icount_locked(cpu);
-    seqlock_write_unlock(&timers_state.vm_clock_seqlock,
-                         &timers_state.vm_clock_lock);
-}
-
-static int64_t cpu_get_icount_raw_locked(void)
-{
-    CPUState *cpu = current_cpu;
-
-    if (cpu && cpu->running) {
-        if (!cpu->can_do_io) {
-            error_report("Bad icount read");
-            exit(1);
-        }
-        /* Take into account what has run */
-        cpu_update_icount_locked(cpu);
-    }
-    /* The read is protected by the seqlock, but needs atomic64 to avoid UB */
-    return atomic_read_i64(&timers_state.qemu_icount);
-}
-
-static int64_t cpu_get_icount_locked(void)
-{
-    int64_t icount = cpu_get_icount_raw_locked();
-    return atomic_read_i64(&timers_state.qemu_icount_bias) +
-        cpu_icount_to_ns(icount);
-}
-
-int64_t cpu_get_icount_raw(void)
-{
-    int64_t icount;
-    unsigned start;
-
-    do {
-        start = seqlock_read_begin(&timers_state.vm_clock_seqlock);
-        icount = cpu_get_icount_raw_locked();
-    } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start));
-
-    return icount;
-}
-
-/* Return the virtual CPU time, based on the instruction counter.  */
-int64_t cpu_get_icount(void)
-{
-    int64_t icount;
-    unsigned start;
-
-    do {
-        start = seqlock_read_begin(&timers_state.vm_clock_seqlock);
-        icount = cpu_get_icount_locked();
-    } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start));
-
-    return icount;
-}
-
-int64_t cpu_icount_to_ns(int64_t icount)
-{
-    return icount << atomic_read(&timers_state.icount_time_shift);
-}
-
-static int64_t cpu_get_ticks_locked(void)
-{
-    int64_t ticks = timers_state.cpu_ticks_offset;
-    if (timers_state.cpu_ticks_enabled) {
-        ticks += cpu_get_host_ticks();
-    }
-
-    if (timers_state.cpu_ticks_prev > ticks) {
-        /* Non increasing ticks may happen if the host uses software suspend.  */
-        timers_state.cpu_ticks_offset += timers_state.cpu_ticks_prev - ticks;
-        ticks = timers_state.cpu_ticks_prev;
-    }
-
-    timers_state.cpu_ticks_prev = ticks;
-    return ticks;
-}
-
-/* return the time elapsed in VM between vm_start and vm_stop.  Unless
- * icount is active, cpu_get_ticks() uses units of the host CPU cycle
- * counter.
- */
-int64_t cpu_get_ticks(void)
-{
-    int64_t ticks;
-
-    if (use_icount) {
-        return cpu_get_icount();
-    }
-
-    qemu_spin_lock(&timers_state.vm_clock_lock);
-    ticks = cpu_get_ticks_locked();
-    qemu_spin_unlock(&timers_state.vm_clock_lock);
-    return ticks;
-}
-
-static int64_t cpu_get_clock_locked(void)
-{
-    int64_t time;
-
-    time = timers_state.cpu_clock_offset;
-    if (timers_state.cpu_ticks_enabled) {
-        time += get_clock();
-    }
-
-    return time;
-}
-
-/* Return the monotonic time elapsed in VM, i.e.,
- * the time between vm_start and vm_stop
- */
-int64_t cpu_get_clock(void)
-{
-    int64_t ti;
-    unsigned start;
-
-    do {
-        start = seqlock_read_begin(&timers_state.vm_clock_seqlock);
-        ti = cpu_get_clock_locked();
-    } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start));
-
-    return ti;
-}
-
-/* enable cpu_get_ticks()
- * Caller must hold BQL which serves as mutex for vm_clock_seqlock.
- */
-void cpu_enable_ticks(void)
-{
-    seqlock_write_lock(&timers_state.vm_clock_seqlock,
-                       &timers_state.vm_clock_lock);
-    if (!timers_state.cpu_ticks_enabled) {
-        timers_state.cpu_ticks_offset -= cpu_get_host_ticks();
-        timers_state.cpu_clock_offset -= get_clock();
-        timers_state.cpu_ticks_enabled = 1;
-    }
-    seqlock_write_unlock(&timers_state.vm_clock_seqlock,
-                       &timers_state.vm_clock_lock);
-}
-
-/* disable cpu_get_ticks() : the clock is stopped. You must not call
- * cpu_get_ticks() after that.
- * Caller must hold BQL which serves as mutex for vm_clock_seqlock.
- */
-void cpu_disable_ticks(void)
-{
-    seqlock_write_lock(&timers_state.vm_clock_seqlock,
-                       &timers_state.vm_clock_lock);
-    if (timers_state.cpu_ticks_enabled) {
-        timers_state.cpu_ticks_offset += cpu_get_host_ticks();
-        timers_state.cpu_clock_offset = cpu_get_clock_locked();
-        timers_state.cpu_ticks_enabled = 0;
-    }
-    seqlock_write_unlock(&timers_state.vm_clock_seqlock,
-                         &timers_state.vm_clock_lock);
-}
-
-/* Correlation between real and virtual time is always going to be
-   fairly approximate, so ignore small variation.
-   When the guest is idle real and virtual time will be aligned in
-   the IO wait loop.  */
-#define ICOUNT_WOBBLE (NANOSECONDS_PER_SECOND / 10)
-
-static void icount_adjust(void)
-{
-    int64_t cur_time;
-    int64_t cur_icount;
-    int64_t delta;
-
-    /* Protected by TimersState mutex.  */
-    static int64_t last_delta;
-
-    /* If the VM is not running, then do nothing.  */
-    if (!runstate_is_running()) {
-        return;
-    }
-
-    seqlock_write_lock(&timers_state.vm_clock_seqlock,
-                       &timers_state.vm_clock_lock);
-    cur_time = REPLAY_CLOCK_LOCKED(REPLAY_CLOCK_VIRTUAL_RT,
-                                   cpu_get_clock_locked());
-    cur_icount = cpu_get_icount_locked();
-
-    delta = cur_icount - cur_time;
-    /* FIXME: This is a very crude algorithm, somewhat prone to oscillation.  */
-    if (delta > 0
-        && last_delta + ICOUNT_WOBBLE < delta * 2
-        && timers_state.icount_time_shift > 0) {
-        /* The guest is getting too far ahead.  Slow time down.  */
-        atomic_set(&timers_state.icount_time_shift,
-                   timers_state.icount_time_shift - 1);
-    }
-    if (delta < 0
-        && last_delta - ICOUNT_WOBBLE > delta * 2
-        && timers_state.icount_time_shift < MAX_ICOUNT_SHIFT) {
-        /* The guest is getting too far behind.  Speed time up.  */
-        atomic_set(&timers_state.icount_time_shift,
-                   timers_state.icount_time_shift + 1);
-    }
-    last_delta = delta;
-    atomic_set_i64(&timers_state.qemu_icount_bias,
-                   cur_icount - (timers_state.qemu_icount
-                                 << timers_state.icount_time_shift));
-    seqlock_write_unlock(&timers_state.vm_clock_seqlock,
-                         &timers_state.vm_clock_lock);
-}
-
-static void icount_adjust_rt(void *opaque)
-{
-    timer_mod(timers_state.icount_rt_timer,
-              qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL_RT) + 1000);
-    icount_adjust();
-}
-
-static void icount_adjust_vm(void *opaque)
-{
-    timer_mod(timers_state.icount_vm_timer,
-                   qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
-                   NANOSECONDS_PER_SECOND / 10);
-    icount_adjust();
-}
-
-static int64_t qemu_icount_round(int64_t count)
-{
-    int shift = atomic_read(&timers_state.icount_time_shift);
-    return (count + (1 << shift) - 1) >> shift;
-}
-
-static void icount_warp_rt(void)
-{
-    unsigned seq;
-    int64_t warp_start;
-
-    /* The icount_warp_timer is rescheduled soon after vm_clock_warp_start
-     * changes from -1 to another value, so the race here is okay.
-     */
-    do {
-        seq = seqlock_read_begin(&timers_state.vm_clock_seqlock);
-        warp_start = timers_state.vm_clock_warp_start;
-    } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, seq));
-
-    if (warp_start == -1) {
-        return;
-    }
-
-    seqlock_write_lock(&timers_state.vm_clock_seqlock,
-                       &timers_state.vm_clock_lock);
-    if (runstate_is_running()) {
-        int64_t clock = REPLAY_CLOCK_LOCKED(REPLAY_CLOCK_VIRTUAL_RT,
-                                            cpu_get_clock_locked());
-        int64_t warp_delta;
-
-        warp_delta = clock - timers_state.vm_clock_warp_start;
-        if (use_icount == 2) {
-            /*
-             * In adaptive mode, do not let QEMU_CLOCK_VIRTUAL run too
-             * far ahead of real time.
-             */
-            int64_t cur_icount = cpu_get_icount_locked();
-            int64_t delta = clock - cur_icount;
-            warp_delta = MIN(warp_delta, delta);
-        }
-        atomic_set_i64(&timers_state.qemu_icount_bias,
-                       timers_state.qemu_icount_bias + warp_delta);
-    }
-    timers_state.vm_clock_warp_start = -1;
-    seqlock_write_unlock(&timers_state.vm_clock_seqlock,
-                       &timers_state.vm_clock_lock);
-
-    if (qemu_clock_expired(QEMU_CLOCK_VIRTUAL)) {
-        qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
-    }
-}
-
-static void icount_timer_cb(void *opaque)
-{
-    /* No need for a checkpoint because the timer already synchronizes
-     * with CHECKPOINT_CLOCK_VIRTUAL_RT.
-     */
-    icount_warp_rt();
-}
-
-void qtest_clock_warp(int64_t dest)
-{
-    int64_t clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
-    AioContext *aio_context;
-    assert(qtest_enabled());
-    aio_context = qemu_get_aio_context();
-    while (clock < dest) {
-        int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
-                                                      QEMU_TIMER_ATTR_ALL);
-        int64_t warp = qemu_soonest_timeout(dest - clock, deadline);
-
-        seqlock_write_lock(&timers_state.vm_clock_seqlock,
-                           &timers_state.vm_clock_lock);
-        atomic_set_i64(&timers_state.qemu_icount_bias,
-                       timers_state.qemu_icount_bias + warp);
-        seqlock_write_unlock(&timers_state.vm_clock_seqlock,
-                             &timers_state.vm_clock_lock);
-
-        qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL);
-        timerlist_run_timers(aio_context->tlg.tl[QEMU_CLOCK_VIRTUAL]);
-        clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
-    }
-    qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
-}
-
-void qemu_start_warp_timer(void)
-{
-    int64_t clock;
-    int64_t deadline;
-
-    if (!use_icount) {
-        return;
-    }
-
-    /* Nothing to do if the VM is stopped: QEMU_CLOCK_VIRTUAL timers
-     * do not fire, so computing the deadline does not make sense.
-     */
-    if (!runstate_is_running()) {
-        return;
-    }
-
-    if (replay_mode != REPLAY_MODE_PLAY) {
-        if (!all_cpu_threads_idle()) {
-            return;
-        }
-
-        if (qtest_enabled()) {
-            /* When testing, qtest commands advance icount.  */
-            return;
-        }
-
-        replay_checkpoint(CHECKPOINT_CLOCK_WARP_START);
-    } else {
-        /* warp clock deterministically in record/replay mode */
-        if (!replay_checkpoint(CHECKPOINT_CLOCK_WARP_START)) {
-            /* vCPU is sleeping and warp can't be started.
-               It is probably a race condition: notification sent
-               to vCPU was processed in advance and vCPU went to sleep.
-               Therefore we have to wake it up for doing someting. */
-            if (replay_has_checkpoint()) {
-                qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
-            }
-            return;
-        }
-    }
-
-    /* We want to use the earliest deadline from ALL vm_clocks */
-    clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT);
-    deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
-                                          ~QEMU_TIMER_ATTR_EXTERNAL);
-    if (deadline < 0) {
-        static bool notified;
-        if (!icount_sleep && !notified) {
-            warn_report("icount sleep disabled and no active timers");
-            notified = true;
-        }
-        return;
-    }
-
-    if (deadline > 0) {
-        /*
-         * Ensure QEMU_CLOCK_VIRTUAL proceeds even when the virtual CPU goes to
-         * sleep.  Otherwise, the CPU might be waiting for a future timer
-         * interrupt to wake it up, but the interrupt never comes because
-         * the vCPU isn't running any insns and thus doesn't advance the
-         * QEMU_CLOCK_VIRTUAL.
-         */
-        if (!icount_sleep) {
-            /*
-             * We never let VCPUs sleep in no sleep icount mode.
-             * If there is a pending QEMU_CLOCK_VIRTUAL timer we just advance
-             * to the next QEMU_CLOCK_VIRTUAL event and notify it.
-             * It is useful when we want a deterministic execution time,
-             * isolated from host latencies.
-             */
-            seqlock_write_lock(&timers_state.vm_clock_seqlock,
-                               &timers_state.vm_clock_lock);
-            atomic_set_i64(&timers_state.qemu_icount_bias,
-                           timers_state.qemu_icount_bias + deadline);
-            seqlock_write_unlock(&timers_state.vm_clock_seqlock,
-                                 &timers_state.vm_clock_lock);
-            qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
-        } else {
-            /*
-             * We do stop VCPUs and only advance QEMU_CLOCK_VIRTUAL after some
-             * "real" time, (related to the time left until the next event) has
-             * passed. The QEMU_CLOCK_VIRTUAL_RT clock will do this.
-             * This avoids that the warps are visible externally; for example,
-             * you will not be sending network packets continuously instead of
-             * every 100ms.
-             */
-            seqlock_write_lock(&timers_state.vm_clock_seqlock,
-                               &timers_state.vm_clock_lock);
-            if (timers_state.vm_clock_warp_start == -1
-                || timers_state.vm_clock_warp_start > clock) {
-                timers_state.vm_clock_warp_start = clock;
-            }
-            seqlock_write_unlock(&timers_state.vm_clock_seqlock,
-                                 &timers_state.vm_clock_lock);
-            timer_mod_anticipate(timers_state.icount_warp_timer,
-                                 clock + deadline);
-        }
-    } else if (deadline == 0) {
-        qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
-    }
-}
-
-static void qemu_account_warp_timer(void)
-{
-    if (!use_icount || !icount_sleep) {
-        return;
-    }
-
-    /* Nothing to do if the VM is stopped: QEMU_CLOCK_VIRTUAL timers
-     * do not fire, so computing the deadline does not make sense.
-     */
-    if (!runstate_is_running()) {
-        return;
-    }
-
-    /* warp clock deterministically in record/replay mode */
-    if (!replay_checkpoint(CHECKPOINT_CLOCK_WARP_ACCOUNT)) {
-        return;
-    }
-
-    timer_del(timers_state.icount_warp_timer);
-    icount_warp_rt();
-}
-
-static bool icount_state_needed(void *opaque)
-{
-    return use_icount;
-}
-
-static bool warp_timer_state_needed(void *opaque)
-{
-    TimersState *s = opaque;
-    return s->icount_warp_timer != NULL;
-}
-
-static bool adjust_timers_state_needed(void *opaque)
-{
-    TimersState *s = opaque;
-    return s->icount_rt_timer != NULL;
-}
-
-static bool shift_state_needed(void *opaque)
-{
-    return use_icount == 2;
-}
-
-/*
- * Subsection for warp timer migration is optional, because may not be created
- */
-static const VMStateDescription icount_vmstate_warp_timer = {
-    .name = "timer/icount/warp_timer",
-    .version_id = 1,
-    .minimum_version_id = 1,
-    .needed = warp_timer_state_needed,
-    .fields = (VMStateField[]) {
-        VMSTATE_INT64(vm_clock_warp_start, TimersState),
-        VMSTATE_TIMER_PTR(icount_warp_timer, TimersState),
-        VMSTATE_END_OF_LIST()
-    }
-};
-
-static const VMStateDescription icount_vmstate_adjust_timers = {
-    .name = "timer/icount/timers",
-    .version_id = 1,
-    .minimum_version_id = 1,
-    .needed = adjust_timers_state_needed,
-    .fields = (VMStateField[]) {
-        VMSTATE_TIMER_PTR(icount_rt_timer, TimersState),
-        VMSTATE_TIMER_PTR(icount_vm_timer, TimersState),
-        VMSTATE_END_OF_LIST()
-    }
-};
-
-static const VMStateDescription icount_vmstate_shift = {
-    .name = "timer/icount/shift",
-    .version_id = 1,
-    .minimum_version_id = 1,
-    .needed = shift_state_needed,
-    .fields = (VMStateField[]) {
-        VMSTATE_INT16(icount_time_shift, TimersState),
-        VMSTATE_END_OF_LIST()
-    }
-};
-
-/*
- * This is a subsection for icount migration.
- */
-static const VMStateDescription icount_vmstate_timers = {
-    .name = "timer/icount",
-    .version_id = 1,
-    .minimum_version_id = 1,
-    .needed = icount_state_needed,
-    .fields = (VMStateField[]) {
-        VMSTATE_INT64(qemu_icount_bias, TimersState),
-        VMSTATE_INT64(qemu_icount, TimersState),
-        VMSTATE_END_OF_LIST()
-    },
-    .subsections = (const VMStateDescription*[]) {
-        &icount_vmstate_warp_timer,
-        &icount_vmstate_adjust_timers,
-        &icount_vmstate_shift,
-        NULL
-    }
-};
-
-static const VMStateDescription vmstate_timers = {
-    .name = "timer",
-    .version_id = 2,
-    .minimum_version_id = 1,
-    .fields = (VMStateField[]) {
-        VMSTATE_INT64(cpu_ticks_offset, TimersState),
-        VMSTATE_UNUSED(8),
-        VMSTATE_INT64_V(cpu_clock_offset, TimersState, 2),
-        VMSTATE_END_OF_LIST()
-    },
-    .subsections = (const VMStateDescription*[]) {
-        &icount_vmstate_timers,
-        NULL
-    }
-};
-
-void cpu_ticks_init(void)
-{
-    seqlock_init(&timers_state.vm_clock_seqlock);
-    qemu_spin_init(&timers_state.vm_clock_lock);
-    vmstate_register(NULL, 0, &vmstate_timers, &timers_state);
-    cpu_throttle_init();
-}
-
-void configure_icount(QemuOpts *opts, Error **errp)
-{
-    const char *option = qemu_opt_get(opts, "shift");
-    bool sleep = qemu_opt_get_bool(opts, "sleep", true);
-    bool align = qemu_opt_get_bool(opts, "align", false);
-    long time_shift = -1;
-
-    if (!option) {
-        if (qemu_opt_get(opts, "align") != NULL) {
-            error_setg(errp, "Please specify shift option when using align");
-        }
-        return;
-    }
-
-    if (align && !sleep) {
-        error_setg(errp, "align=on and sleep=off are incompatible");
-        return;
-    }
-
-    if (strcmp(option, "auto") != 0) {
-        if (qemu_strtol(option, NULL, 0, &time_shift) < 0
-            || time_shift < 0 || time_shift > MAX_ICOUNT_SHIFT) {
-            error_setg(errp, "icount: Invalid shift value");
-            return;
-        }
-    } else if (icount_align_option) {
-        error_setg(errp, "shift=auto and align=on are incompatible");
-        return;
-    } else if (!icount_sleep) {
-        error_setg(errp, "shift=auto and sleep=off are incompatible");
-        return;
-    }
-
-    icount_sleep = sleep;
-    if (icount_sleep) {
-        timers_state.icount_warp_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT,
-                                         icount_timer_cb, NULL);
-    }
-
-    icount_align_option = align;
-
-    if (time_shift >= 0) {
-        timers_state.icount_time_shift = time_shift;
-        use_icount = 1;
-        return;
-    }
-
-    use_icount = 2;
-
-    /* 125MIPS seems a reasonable initial guess at the guest speed.
-       It will be corrected fairly quickly anyway.  */
-    timers_state.icount_time_shift = 3;
-
-    /* Have both realtime and virtual time triggers for speed adjustment.
-       The realtime trigger catches emulated time passing too slowly,
-       the virtual time trigger catches emulated time passing too fast.
-       Realtime triggers occur even when idle, so use them less frequently
-       than VM triggers.  */
-    timers_state.vm_clock_warp_start = -1;
-    timers_state.icount_rt_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL_RT,
-                                   icount_adjust_rt, NULL);
-    timer_mod(timers_state.icount_rt_timer,
-                   qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL_RT) + 1000);
-    timers_state.icount_vm_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
-                                        icount_adjust_vm, NULL);
-    timer_mod(timers_state.icount_vm_timer,
-                   qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
-                   NANOSECONDS_PER_SECOND / 10);
-}
-
 /***********************************************************/
 /* TCG vCPU kick timer
  *
@@ -854,35 +171,6 @@  static void qemu_cpu_kick_rr_cpus(void)
     };
 }
 
-static void do_nothing(CPUState *cpu, run_on_cpu_data unused)
-{
-}
-
-void qemu_timer_notify_cb(void *opaque, QEMUClockType type)
-{
-    if (!use_icount || type != QEMU_CLOCK_VIRTUAL) {
-        qemu_notify_event();
-        return;
-    }
-
-    if (qemu_in_vcpu_thread()) {
-        /* A CPU is currently running; kick it back out to the
-         * tcg_cpu_exec() loop so it will recalculate its
-         * icount deadline immediately.
-         */
-        qemu_cpu_kick(current_cpu);
-    } else if (first_cpu) {
-        /* qemu_cpu_kick is not enough to kick a halted CPU out of
-         * qemu_tcg_wait_io_event.  async_run_on_cpu, instead,
-         * causes cpu_thread_is_idle to return false.  This way,
-         * handle_icount_deadline can run.
-         * If we have no CPUs at all for some reason, we don't
-         * need to do anything.
-         */
-        async_run_on_cpu(first_cpu, do_nothing, RUN_ON_CPU_NULL);
-    }
-}
-
 static void kick_tcg_thread(void *opaque)
 {
     timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick());
@@ -1272,7 +560,7 @@  static int64_t tcg_get_icount_limit(void)
             deadline = INT32_MAX;
         }
 
-        return qemu_icount_round(deadline);
+        return icount_round(deadline);
     } else {
         return replay_get_instructions();
     }
@@ -1288,7 +576,7 @@  static void notify_aio_contexts(void)
 static void handle_icount_deadline(void)
 {
     assert(qemu_in_vcpu_thread());
-    if (use_icount) {
+    if (icount_enabled()) {
         int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
                                                       QEMU_TIMER_ATTR_ALL);
 
@@ -1300,7 +588,7 @@  static void handle_icount_deadline(void)
 
 static void prepare_icount_for_run(CPUState *cpu)
 {
-    if (use_icount) {
+    if (icount_enabled()) {
         int insns_left;
 
         /* These should always be cleared by process_icount_data after
@@ -1325,9 +613,9 @@  static void prepare_icount_for_run(CPUState *cpu)
 
 static void process_icount_data(CPUState *cpu)
 {
-    if (use_icount) {
+    if (icount_enabled()) {
         /* Account for executed instructions */
-        cpu_update_icount(cpu);
+        icount_update(cpu);
 
         /* Reset the counters */
         cpu_neg(cpu)->icount_decr.u16.low = 0;
@@ -1428,7 +716,7 @@  static void *qemu_tcg_rr_cpu_thread_fn(void *arg)
         replay_mutex_lock();
         qemu_mutex_lock_iothread();
         /* Account partial waits to QEMU_CLOCK_VIRTUAL.  */
-        qemu_account_warp_timer();
+        icount_account_warp_timer();
 
         /* Run the timers here.  This is much more efficient than
          * waking up the I/O thread and waiting for completion.
@@ -1486,7 +774,7 @@  static void *qemu_tcg_rr_cpu_thread_fn(void *arg)
             atomic_mb_set(&cpu->exit_request, 0);
         }
 
-        if (use_icount && all_cpu_threads_idle()) {
+        if (icount_enabled() && all_cpu_threads_idle()) {
             /*
              * When all cpus are sleeping (e.g in WFI), to avoid a deadlock
              * in the main_loop, wake it up in order to start the warp timer.
@@ -1639,7 +927,7 @@  static void *qemu_tcg_cpu_thread_fn(void *arg)
     CPUState *cpu = arg;
 
     assert(tcg_enabled());
-    g_assert(!use_icount);
+    g_assert(!icount_enabled());
 
     rcu_register_thread();
     tcg_register_thread();
@@ -2218,21 +1506,3 @@  void qmp_inject_nmi(Error **errp)
     nmi_monitor_handle(monitor_get_cpu_index(), errp);
 }
 
-void dump_drift_info(void)
-{
-    if (!use_icount) {
-        return;
-    }
-
-    qemu_printf("Host - Guest clock  %"PRIi64" ms\n",
-                (cpu_get_clock() - cpu_get_icount())/SCALE_MS);
-    if (icount_align_option) {
-        qemu_printf("Max guest delay     %"PRIi64" ms\n",
-                    -max_delay / SCALE_MS);
-        qemu_printf("Max guest advance   %"PRIi64" ms\n",
-                    max_advance / SCALE_MS);
-    } else {
-        qemu_printf("Max guest delay     NA\n");
-        qemu_printf("Max guest advance   NA\n");
-    }
-}
diff --git a/softmmu/icount.c b/softmmu/icount.c
new file mode 100644
index 0000000000..d4fe48c1f2
--- /dev/null
+++ b/softmmu/icount.c
@@ -0,0 +1,497 @@ 
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qemu/cutils.h"
+#include "migration/vmstate.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "exec/exec-all.h"
+#include "sysemu/cpus.h"
+#include "sysemu/qtest.h"
+#include "qemu/main-loop.h"
+#include "qemu/option.h"
+#include "qemu/seqlock.h"
+#include "sysemu/replay.h"
+#include "sysemu/runstate.h"
+#include "hw/core/cpu.h"
+#include "sysemu/cpu-timers.h"
+#include "sysemu/cpu-throttle.h"
+#include "timers-state.h"
+
+/*
+ * ICOUNT: Instruction Counter
+ *
+ * this module is split off from cpu-timers because the icount part
+ * is TCG-specific, and does not need to be built for other accels.
+ */
+static bool icount_sleep = true;
+/* Arbitrarily pick 1MIPS as the minimum allowable speed.  */
+#define MAX_ICOUNT_SHIFT 10
+
+/*
+ * 0 = Do not count executed instructions.
+ * 1 = Fixed conversion of insn to ns via "shift" option
+ * 2 = Runtime adaptive algorithm to compute shift
+ */
+static int use_icount;
+
+int icount_enabled(void)
+{
+    return use_icount;
+}
+
+static void icount_enable_precise(void)
+{
+    use_icount = 1;
+}
+
+static void icount_enable_adaptive(void)
+{
+    use_icount = 2;
+}
+
+/*
+ * The current number of executed instructions is based on what we
+ * originally budgeted minus the current state of the decrementing
+ * icount counters in extra/u16.low.
+ */
+static int64_t icount_get_executed(CPUState *cpu)
+{
+    return (cpu->icount_budget -
+            (cpu_neg(cpu)->icount_decr.u16.low + cpu->icount_extra));
+}
+
+/*
+ * Update the global shared timer_state.qemu_icount to take into
+ * account executed instructions. This is done by the TCG vCPU
+ * thread so the main-loop can see time has moved forward.
+ */
+static void icount_update_locked(CPUState *cpu)
+{
+    int64_t executed = icount_get_executed(cpu);
+    cpu->icount_budget -= executed;
+
+    atomic_set_i64(&timers_state.qemu_icount,
+                   timers_state.qemu_icount + executed);
+}
+
+/*
+ * Update the global shared timer_state.qemu_icount to take into
+ * account executed instructions. This is done by the TCG vCPU
+ * thread so the main-loop can see time has moved forward.
+ */
+void icount_update(CPUState *cpu)
+{
+    seqlock_write_lock(&timers_state.vm_clock_seqlock,
+                       &timers_state.vm_clock_lock);
+    icount_update_locked(cpu);
+    seqlock_write_unlock(&timers_state.vm_clock_seqlock,
+                         &timers_state.vm_clock_lock);
+}
+
+static int64_t icount_get_raw_locked(void)
+{
+    CPUState *cpu = current_cpu;
+
+    if (cpu && cpu->running) {
+        if (!cpu->can_do_io) {
+            error_report("Bad icount read");
+            exit(1);
+        }
+        /* Take into account what has run */
+        icount_update_locked(cpu);
+    }
+    /* The read is protected by the seqlock, but needs atomic64 to avoid UB */
+    return atomic_read_i64(&timers_state.qemu_icount);
+}
+
+static int64_t icount_get_locked(void)
+{
+    int64_t icount = icount_get_raw_locked();
+    return atomic_read_i64(&timers_state.qemu_icount_bias) +
+        icount_to_ns(icount);
+}
+
+int64_t icount_get_raw(void)
+{
+    int64_t icount;
+    unsigned start;
+
+    do {
+        start = seqlock_read_begin(&timers_state.vm_clock_seqlock);
+        icount = icount_get_raw_locked();
+    } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start));
+
+    return icount;
+}
+
+/* Return the virtual CPU time, based on the instruction counter.  */
+int64_t icount_get(void)
+{
+    int64_t icount;
+    unsigned start;
+
+    do {
+        start = seqlock_read_begin(&timers_state.vm_clock_seqlock);
+        icount = icount_get_locked();
+    } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start));
+
+    return icount;
+}
+
+int64_t icount_to_ns(int64_t icount)
+{
+    return icount << atomic_read(&timers_state.icount_time_shift);
+}
+
+/*
+ * Correlation between real and virtual time is always going to be
+ * fairly approximate, so ignore small variation.
+ * When the guest is idle real and virtual time will be aligned in
+ * the IO wait loop.
+ */
+#define ICOUNT_WOBBLE (NANOSECONDS_PER_SECOND / 10)
+
+static void icount_adjust(void)
+{
+    int64_t cur_time;
+    int64_t cur_icount;
+    int64_t delta;
+
+    /* Protected by TimersState mutex.  */
+    static int64_t last_delta;
+
+    /* If the VM is not running, then do nothing.  */
+    if (!runstate_is_running()) {
+        return;
+    }
+
+    seqlock_write_lock(&timers_state.vm_clock_seqlock,
+                       &timers_state.vm_clock_lock);
+    cur_time = REPLAY_CLOCK_LOCKED(REPLAY_CLOCK_VIRTUAL_RT,
+                                   cpu_get_clock_locked());
+    cur_icount = icount_get_locked();
+
+    delta = cur_icount - cur_time;
+    /* FIXME: This is a very crude algorithm, somewhat prone to oscillation.  */
+    if (delta > 0
+        && last_delta + ICOUNT_WOBBLE < delta * 2
+        && timers_state.icount_time_shift > 0) {
+        /* The guest is getting too far ahead.  Slow time down.  */
+        atomic_set(&timers_state.icount_time_shift,
+                   timers_state.icount_time_shift - 1);
+    }
+    if (delta < 0
+        && last_delta - ICOUNT_WOBBLE > delta * 2
+        && timers_state.icount_time_shift < MAX_ICOUNT_SHIFT) {
+        /* The guest is getting too far behind.  Speed time up.  */
+        atomic_set(&timers_state.icount_time_shift,
+                   timers_state.icount_time_shift + 1);
+    }
+    last_delta = delta;
+    atomic_set_i64(&timers_state.qemu_icount_bias,
+                   cur_icount - (timers_state.qemu_icount
+                                 << timers_state.icount_time_shift));
+    seqlock_write_unlock(&timers_state.vm_clock_seqlock,
+                         &timers_state.vm_clock_lock);
+}
+
+static void icount_adjust_rt(void *opaque)
+{
+    timer_mod(timers_state.icount_rt_timer,
+              qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL_RT) + 1000);
+    icount_adjust();
+}
+
+static void icount_adjust_vm(void *opaque)
+{
+    timer_mod(timers_state.icount_vm_timer,
+                   qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
+                   NANOSECONDS_PER_SECOND / 10);
+    icount_adjust();
+}
+
+int64_t icount_round(int64_t count)
+{
+    int shift = atomic_read(&timers_state.icount_time_shift);
+    return (count + (1 << shift) - 1) >> shift;
+}
+
+static void icount_warp_rt(void)
+{
+    unsigned seq;
+    int64_t warp_start;
+
+    /*
+     * The icount_warp_timer is rescheduled soon after vm_clock_warp_start
+     * changes from -1 to another value, so the race here is okay.
+     */
+    do {
+        seq = seqlock_read_begin(&timers_state.vm_clock_seqlock);
+        warp_start = timers_state.vm_clock_warp_start;
+    } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, seq));
+
+    if (warp_start == -1) {
+        return;
+    }
+
+    seqlock_write_lock(&timers_state.vm_clock_seqlock,
+                       &timers_state.vm_clock_lock);
+    if (runstate_is_running()) {
+        int64_t clock = REPLAY_CLOCK_LOCKED(REPLAY_CLOCK_VIRTUAL_RT,
+                                            cpu_get_clock_locked());
+        int64_t warp_delta;
+
+        warp_delta = clock - timers_state.vm_clock_warp_start;
+        if (icount_enabled() == 2) {
+            /*
+             * In adaptive mode, do not let QEMU_CLOCK_VIRTUAL run too
+             * far ahead of real time.
+             */
+            int64_t cur_icount = icount_get_locked();
+            int64_t delta = clock - cur_icount;
+            warp_delta = MIN(warp_delta, delta);
+        }
+        atomic_set_i64(&timers_state.qemu_icount_bias,
+                       timers_state.qemu_icount_bias + warp_delta);
+    }
+    timers_state.vm_clock_warp_start = -1;
+    seqlock_write_unlock(&timers_state.vm_clock_seqlock,
+                       &timers_state.vm_clock_lock);
+
+    if (qemu_clock_expired(QEMU_CLOCK_VIRTUAL)) {
+        qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
+    }
+}
+
+static void icount_timer_cb(void *opaque)
+{
+    /*
+     * No need for a checkpoint because the timer already synchronizes
+     * with CHECKPOINT_CLOCK_VIRTUAL_RT.
+     */
+    icount_warp_rt();
+}
+
+void icount_start_warp_timer(void)
+{
+    int64_t clock;
+    int64_t deadline;
+
+    assert(icount_enabled());
+
+    /*
+     * Nothing to do if the VM is stopped: QEMU_CLOCK_VIRTUAL timers
+     * do not fire, so computing the deadline does not make sense.
+     */
+    if (!runstate_is_running()) {
+        return;
+    }
+
+    if (replay_mode != REPLAY_MODE_PLAY) {
+        if (!all_cpu_threads_idle()) {
+            return;
+        }
+
+        if (qtest_enabled()) {
+            /* When testing, qtest commands advance icount.  */
+            return;
+        }
+
+        replay_checkpoint(CHECKPOINT_CLOCK_WARP_START);
+    } else {
+        /* warp clock deterministically in record/replay mode */
+        if (!replay_checkpoint(CHECKPOINT_CLOCK_WARP_START)) {
+            /*
+             * vCPU is sleeping and warp can't be started.
+             * It is probably a race condition: notification sent
+             * to vCPU was processed in advance and vCPU went to sleep.
+             * Therefore we have to wake it up for doing someting.
+             */
+            if (replay_has_checkpoint()) {
+                qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
+            }
+            return;
+        }
+    }
+
+    /* We want to use the earliest deadline from ALL vm_clocks */
+    clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT);
+    deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+                                          ~QEMU_TIMER_ATTR_EXTERNAL);
+    if (deadline < 0) {
+        static bool notified;
+        if (!icount_sleep && !notified) {
+            warn_report("icount sleep disabled and no active timers");
+            notified = true;
+        }
+        return;
+    }
+
+    if (deadline > 0) {
+        /*
+         * Ensure QEMU_CLOCK_VIRTUAL proceeds even when the virtual CPU goes to
+         * sleep.  Otherwise, the CPU might be waiting for a future timer
+         * interrupt to wake it up, but the interrupt never comes because
+         * the vCPU isn't running any insns and thus doesn't advance the
+         * QEMU_CLOCK_VIRTUAL.
+         */
+        if (!icount_sleep) {
+            /*
+             * We never let VCPUs sleep in no sleep icount mode.
+             * If there is a pending QEMU_CLOCK_VIRTUAL timer we just advance
+             * to the next QEMU_CLOCK_VIRTUAL event and notify it.
+             * It is useful when we want a deterministic execution time,
+             * isolated from host latencies.
+             */
+            seqlock_write_lock(&timers_state.vm_clock_seqlock,
+                               &timers_state.vm_clock_lock);
+            atomic_set_i64(&timers_state.qemu_icount_bias,
+                           timers_state.qemu_icount_bias + deadline);
+            seqlock_write_unlock(&timers_state.vm_clock_seqlock,
+                                 &timers_state.vm_clock_lock);
+            qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
+        } else {
+            /*
+             * We do stop VCPUs and only advance QEMU_CLOCK_VIRTUAL after some
+             * "real" time, (related to the time left until the next event) has
+             * passed. The QEMU_CLOCK_VIRTUAL_RT clock will do this.
+             * This avoids that the warps are visible externally; for example,
+             * you will not be sending network packets continuously instead of
+             * every 100ms.
+             */
+            seqlock_write_lock(&timers_state.vm_clock_seqlock,
+                               &timers_state.vm_clock_lock);
+            if (timers_state.vm_clock_warp_start == -1
+                || timers_state.vm_clock_warp_start > clock) {
+                timers_state.vm_clock_warp_start = clock;
+            }
+            seqlock_write_unlock(&timers_state.vm_clock_seqlock,
+                                 &timers_state.vm_clock_lock);
+            timer_mod_anticipate(timers_state.icount_warp_timer,
+                                 clock + deadline);
+        }
+    } else if (deadline == 0) {
+        qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
+    }
+}
+
+void icount_account_warp_timer(void)
+{
+    if (!use_icount || !icount_sleep) {
+        return;
+    }
+
+    /*
+     * Nothing to do if the VM is stopped: QEMU_CLOCK_VIRTUAL timers
+     * do not fire, so computing the deadline does not make sense.
+     */
+    if (!runstate_is_running()) {
+        return;
+    }
+
+    /* warp clock deterministically in record/replay mode */
+    if (!replay_checkpoint(CHECKPOINT_CLOCK_WARP_ACCOUNT)) {
+        return;
+    }
+
+    timer_del(timers_state.icount_warp_timer);
+    icount_warp_rt();
+}
+
+void icount_configure(QemuOpts *opts, Error **errp)
+{
+    const char *option = qemu_opt_get(opts, "shift");
+    bool sleep = qemu_opt_get_bool(opts, "sleep", true);
+    bool align = qemu_opt_get_bool(opts, "align", false);
+    long time_shift = -1;
+
+    if (!option) {
+        if (qemu_opt_get(opts, "align") != NULL) {
+            error_setg(errp, "Please specify shift option when using align");
+        }
+        return;
+    }
+
+    if (align && !sleep) {
+        error_setg(errp, "align=on and sleep=off are incompatible");
+        return;
+    }
+
+    if (strcmp(option, "auto") != 0) {
+        if (qemu_strtol(option, NULL, 0, &time_shift) < 0
+            || time_shift < 0 || time_shift > MAX_ICOUNT_SHIFT) {
+            error_setg(errp, "icount: Invalid shift value");
+            return;
+        }
+    } else if (icount_align_option) {
+        error_setg(errp, "shift=auto and align=on are incompatible");
+        return;
+    } else if (!icount_sleep) {
+        error_setg(errp, "shift=auto and sleep=off are incompatible");
+        return;
+    }
+
+    icount_sleep = sleep;
+    if (icount_sleep) {
+        timers_state.icount_warp_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT,
+                                         icount_timer_cb, NULL);
+    }
+
+    icount_align_option = align;
+
+    if (time_shift >= 0) {
+        timers_state.icount_time_shift = time_shift;
+        icount_enable_precise();
+        return;
+    }
+
+    icount_enable_adaptive();
+
+    /*
+     * 125MIPS seems a reasonable initial guess at the guest speed.
+     * It will be corrected fairly quickly anyway.
+     */
+    timers_state.icount_time_shift = 3;
+
+    /*
+     * Have both realtime and virtual time triggers for speed adjustment.
+     * The realtime trigger catches emulated time passing too slowly,
+     * the virtual time trigger catches emulated time passing too fast.
+     * Realtime triggers occur even when idle, so use them less frequently
+     * than VM triggers.
+     */
+    timers_state.vm_clock_warp_start = -1;
+    timers_state.icount_rt_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL_RT,
+                                   icount_adjust_rt, NULL);
+    timer_mod(timers_state.icount_rt_timer,
+                   qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL_RT) + 1000);
+    timers_state.icount_vm_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
+                                        icount_adjust_vm, NULL);
+    timer_mod(timers_state.icount_vm_timer,
+                   qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
+                   NANOSECONDS_PER_SECOND / 10);
+}
diff --git a/softmmu/qtest.c b/softmmu/qtest.c
index 5672b75c35..737779ea7f 100644
--- a/softmmu/qtest.c
+++ b/softmmu/qtest.c
@@ -21,7 +21,7 @@ 
 #include "exec/memory.h"
 #include "hw/irq.h"
 #include "sysemu/accel.h"
-#include "sysemu/cpus.h"
+#include "sysemu/cpu-timers.h"
 #include "qemu/config-file.h"
 #include "qemu/option.h"
 #include "qemu/error-report.h"
@@ -273,6 +273,38 @@  static void qtest_irq_handler(void *opaque, int n, int level)
     }
 }
 
+static int64_t qtest_clock_counter;
+
+int64_t qtest_get_virtual_clock(void)
+{
+    return atomic_read_i64(&qtest_clock_counter);
+}
+
+static void qtest_set_virtual_clock(int64_t count)
+{
+    atomic_set_i64(&qtest_clock_counter, count);
+}
+
+static void qtest_clock_warp(int64_t dest)
+{
+    int64_t clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+    AioContext *aio_context;
+    assert(qtest_enabled());
+    aio_context = qemu_get_aio_context();
+    while (clock < dest) {
+        int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL,
+                                                      QEMU_TIMER_ATTR_ALL);
+        int64_t warp = qemu_soonest_timeout(dest - clock, deadline);
+
+        qtest_set_virtual_clock(qtest_get_virtual_clock() + warp);
+
+        qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL);
+        timerlist_run_timers(aio_context->tlg.tl[QEMU_CLOCK_VIRTUAL]);
+        clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+    }
+    qemu_clock_notify(QEMU_CLOCK_VIRTUAL);
+}
+
 static void qtest_process_command(CharBackend *chr, gchar **words)
 {
     const gchar *command;
diff --git a/softmmu/timers-state.h b/softmmu/timers-state.h
new file mode 100644
index 0000000000..db4e60f18f
--- /dev/null
+++ b/softmmu/timers-state.h
@@ -0,0 +1,69 @@ 
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef TIMERS_STATE_H
+#define TIMERS_STATE_H
+
+/* timers state, for sharing between icount and cpu-timers */
+
+typedef struct TimersState {
+    /* Protected by BQL.  */
+    int64_t cpu_ticks_prev;
+    int64_t cpu_ticks_offset;
+
+    /*
+     * Protect fields that can be respectively read outside the
+     * BQL, and written from multiple threads.
+     */
+    QemuSeqLock vm_clock_seqlock;
+    QemuSpin vm_clock_lock;
+
+    int16_t cpu_ticks_enabled;
+
+    /* Conversion factor from emulated instructions to virtual clock ticks.  */
+    int16_t icount_time_shift;
+
+    /* Compensate for varying guest execution speed.  */
+    int64_t qemu_icount_bias;
+
+    int64_t vm_clock_warp_start;
+    int64_t cpu_clock_offset;
+
+    /* Only written by TCG thread */
+    int64_t qemu_icount;
+
+    /* for adjusting icount */
+    QEMUTimer *icount_rt_timer;
+    QEMUTimer *icount_vm_timer;
+    QEMUTimer *icount_warp_timer;
+} TimersState;
+
+extern TimersState timers_state;
+
+/*
+ * icount needs this internal from cpu-timers when adjusting the icount shift.
+ */
+int64_t cpu_get_clock_locked(void);
+
+#endif /* TIMERS_STATE_H */
diff --git a/softmmu/vl.c b/softmmu/vl.c
index 4eb9d1f7fd..8e77df7bea 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -74,6 +74,7 @@ 
 #include "hw/audio/soundhw.h"
 #include "audio/audio.h"
 #include "sysemu/cpus.h"
+#include "sysemu/cpu-timers.h"
 #include "migration/colo.h"
 #include "migration/postcopy-ram.h"
 #include "sysemu/kvm.h"
@@ -2692,7 +2693,7 @@  static void user_register_global_props(void)
 
 static int do_configure_icount(void *opaque, QemuOpts *opts, Error **errp)
 {
-    configure_icount(opts, errp);
+    icount_configure(opts, errp);
     return 0;
 }
 
@@ -2802,7 +2803,7 @@  static void configure_accelerators(const char *progname)
         error_report("falling back to %s", ac->name);
     }
 
-    if (use_icount && !(tcg_enabled() || qtest_enabled())) {
+    if (icount_enabled() && !tcg_enabled()) {
         error_report("-icount is not allowed with hardware virtualization");
         exit(1);
     }
@@ -4237,7 +4238,11 @@  void qemu_init(int argc, char **argv, char **envp)
         semihosting_arg_fallback(kernel_filename, kernel_cmdline);
     }
 
-    cpu_ticks_init();
+    /* initialize cpu timers and VCPU throttle modules */
+    cpu_timers_init();
+
+    /* spice needs the timers to be initialized by this point */
+    qemu_spice_init();
 
     if (default_net) {
         QemuOptsList *net = qemu_find_opts("net");
diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index d42046afe4..e97ad407fa 100644
--- a/stubs/Makefile.objs
+++ b/stubs/Makefile.objs
@@ -1,7 +1,8 @@ 
 stub-obj-y += blk-commit-all.o
 stub-obj-y += cmos.o
 stub-obj-y += cpu-get-clock.o
-stub-obj-y += cpu-get-icount.o
+stub-obj-y += qemu-timer-notify-cb.o
+stub-obj-y += icount.o
 stub-obj-y += dump.o
 stub-obj-y += error-printf.o
 stub-obj-y += fdset.o
@@ -37,7 +38,6 @@  stub-obj-y += arch_type.o
 stub-obj-y += bdrv-next-monitor-owned.o
 stub-obj-y += blockdev-close-all-bdrv-states.o
 stub-obj-y += change-state-handler.o
-stub-obj-y += clock-warp.o
 stub-obj-y += fd-register.o
 stub-obj-y += fw_cfg.o
 stub-obj-y += get-vm-name.o
diff --git a/stubs/clock-warp.c b/stubs/clock-warp.c
deleted file mode 100644
index b53e5dd94c..0000000000
--- a/stubs/clock-warp.c
+++ /dev/null
@@ -1,7 +0,0 @@ 
-#include "qemu/osdep.h"
-#include "qemu/timer.h"
-
-void qemu_start_warp_timer(void)
-{
-}
-
diff --git a/stubs/cpu-get-clock.c b/stubs/cpu-get-clock.c
index 5a92810e87..9e92404816 100644
--- a/stubs/cpu-get-clock.c
+++ b/stubs/cpu-get-clock.c
@@ -1,5 +1,6 @@ 
 #include "qemu/osdep.h"
-#include "qemu/timer.h"
+#include "sysemu/cpu-timers.h"
+#include "qemu/main-loop.h"
 
 int64_t cpu_get_clock(void)
 {
diff --git a/stubs/cpu-get-icount.c b/stubs/cpu-get-icount.c
deleted file mode 100644
index b35f844638..0000000000
--- a/stubs/cpu-get-icount.c
+++ /dev/null
@@ -1,21 +0,0 @@ 
-#include "qemu/osdep.h"
-#include "qemu/timer.h"
-#include "sysemu/cpus.h"
-#include "qemu/main-loop.h"
-
-int use_icount;
-
-int64_t cpu_get_icount(void)
-{
-    abort();
-}
-
-int64_t cpu_get_icount_raw(void)
-{
-    abort();
-}
-
-void qemu_timer_notify_cb(void *opaque, QEMUClockType type)
-{
-    qemu_notify_event();
-}
diff --git a/stubs/icount.c b/stubs/icount.c
new file mode 100644
index 0000000000..3b35001051
--- /dev/null
+++ b/stubs/icount.c
@@ -0,0 +1,52 @@ 
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "sysemu/cpu-timers.h"
+
+/* icount - Instruction Counter API */
+
+/*
+ * Return the icount enablement state:
+ *
+ * 0 = Disabled - Do not count executed instructions.
+ */
+int icount_enabled(void)
+{
+    return 0;
+}
+void icount_update(CPUState *cpu)
+{
+    abort();
+}
+void icount_configure(QemuOpts *opts, Error **errp)
+{
+    /* signal error */
+    error_setg(errp, "cannot configure icount, TCG support not available");
+}
+int64_t icount_get_raw(void)
+{
+    abort();
+    return 0;
+}
+int64_t icount_get(void)
+{
+    abort();
+    return 0;
+}
+int64_t icount_to_ns(int64_t icount)
+{
+    abort();
+    return 0;
+}
+int64_t icount_round(int64_t count)
+{
+    abort();
+    return 0;
+}
+void icount_start_warp_timer(void)
+{
+    abort();
+}
+void icount_account_warp_timer(void)
+{
+    abort();
+}
diff --git a/stubs/qemu-timer-notify-cb.c b/stubs/qemu-timer-notify-cb.c
new file mode 100644
index 0000000000..845e46f8e0
--- /dev/null
+++ b/stubs/qemu-timer-notify-cb.c
@@ -0,0 +1,8 @@ 
+#include "qemu/osdep.h"
+#include "sysemu/cpu-timers.h"
+#include "qemu/main-loop.h"
+
+void qemu_timer_notify_cb(void *opaque, QEMUClockType type)
+{
+    qemu_notify_event();
+}
diff --git a/stubs/qtest.c b/stubs/qtest.c
index 891eb954fb..4666a49d7d 100644
--- a/stubs/qtest.c
+++ b/stubs/qtest.c
@@ -18,3 +18,8 @@  bool qtest_driver(void)
 {
     return false;
 }
+
+int64_t qtest_get_virtual_clock(void)
+{
+    return 0;
+}
diff --git a/target/alpha/translate.c b/target/alpha/translate.c
index 8870284f57..36be602179 100644
--- a/target/alpha/translate.c
+++ b/target/alpha/translate.c
@@ -20,6 +20,7 @@ 
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "sysemu/cpus.h"
+#include "sysemu/cpu-timers.h"
 #include "disas/disas.h"
 #include "qemu/host-utils.h"
 #include "exec/exec-all.h"
@@ -1329,7 +1330,7 @@  static DisasJumpType gen_mfpr(DisasContext *ctx, TCGv va, int regno)
     case 249: /* VMTIME */
         helper = gen_helper_get_vmtime;
     do_helper:
-        if (use_icount) {
+        if (icount_enabled()) {
             gen_io_start();
             helper(va);
             return DISAS_PC_STALE;
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 455c92b891..b04f4f9127 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -24,6 +24,7 @@ 
 #include "hw/irq.h"
 #include "hw/semihosting/semihost.h"
 #include "sysemu/cpus.h"
+#include "sysemu/cpu-timers.h"
 #include "sysemu/kvm.h"
 #include "sysemu/tcg.h"
 #include "qemu/range.h"
@@ -1206,17 +1207,17 @@  static int64_t cycles_ns_per(uint64_t cycles)
 
 static bool instructions_supported(CPUARMState *env)
 {
-    return use_icount == 1 /* Precise instruction counting */;
+    return icount_enabled() == 1; /* Precise instruction counting */
 }
 
 static uint64_t instructions_get_count(CPUARMState *env)
 {
-    return (uint64_t)cpu_get_icount_raw();
+    return (uint64_t)icount_get_raw();
 }
 
 static int64_t instructions_ns_per(uint64_t icount)
 {
-    return cpu_icount_to_ns((int64_t)icount);
+    return icount_to_ns((int64_t)icount);
 }
 #endif
 
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 6a96a01b1c..ab2b230991 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -242,8 +242,8 @@  static int write_vstart(CPURISCVState *env, int csrno, target_ulong val)
 static int read_instret(CPURISCVState *env, int csrno, target_ulong *val)
 {
 #if !defined(CONFIG_USER_ONLY)
-    if (use_icount) {
-        *val = cpu_get_icount();
+    if (icount_enabled()) {
+        *val = icount_get();
     } else {
         *val = cpu_get_host_ticks();
     }
@@ -257,8 +257,8 @@  static int read_instret(CPURISCVState *env, int csrno, target_ulong *val)
 static int read_instreth(CPURISCVState *env, int csrno, target_ulong *val)
 {
 #if !defined(CONFIG_USER_ONLY)
-    if (use_icount) {
-        *val = cpu_get_icount() >> 32;
+    if (icount_enabled()) {
+        *val = icount_get() >> 32;
     } else {
         *val = cpu_get_host_ticks() >> 32;
     }
diff --git a/tests/ptimer-test-stubs.c b/tests/ptimer-test-stubs.c
index ed393d9082..b4447a3e44 100644
--- a/tests/ptimer-test-stubs.c
+++ b/tests/ptimer-test-stubs.c
@@ -12,6 +12,7 @@ 
 #include "qemu/main-loop.h"
 #include "sysemu/replay.h"
 #include "migration/vmstate.h"
+#include "sysemu/cpu-timers.h"
 
 #include "ptimer-test.h"
 
@@ -30,8 +31,10 @@  QEMUTimerListGroup main_loop_tlg;
 
 int64_t ptimer_test_time_ns;
 
-/* Do not artificially limit period - see hw/core/ptimer.c.  */
-int use_icount = 1;
+int icount_enabled(void)
+{
+    return 0;
+}
 bool qtest_allowed;
 
 void timer_init_full(QEMUTimer *ts,
diff --git a/tests/test-timed-average.c b/tests/test-timed-average.c
index e2bcf5fe13..82c92500df 100644
--- a/tests/test-timed-average.c
+++ b/tests/test-timed-average.c
@@ -11,7 +11,7 @@ 
  */
 
 #include "qemu/osdep.h"
-
+#include "sysemu/cpu-timers.h"
 #include "qemu/timed-average.h"
 
 /* This is the clock for QEMU_CLOCK_VIRTUAL */
diff --git a/util/main-loop.c b/util/main-loop.c
index f69f055013..744b42fc54 100644
--- a/util/main-loop.c
+++ b/util/main-loop.c
@@ -27,7 +27,7 @@ 
 #include "qemu/cutils.h"
 #include "qemu/timer.h"
 #include "sysemu/qtest.h"
-#include "sysemu/cpus.h"
+#include "sysemu/cpu-timers.h"
 #include "sysemu/replay.h"
 #include "qemu/main-loop.h"
 #include "block/aio.h"
@@ -517,9 +517,13 @@  void main_loop_wait(int nonblocking)
     mlpoll.state = ret < 0 ? MAIN_LOOP_POLL_ERR : MAIN_LOOP_POLL_OK;
     notifier_list_notify(&main_loop_poll_notifiers, &mlpoll);
 
-    /* CPU thread can infinitely wait for event after
-       missing the warp */
-    qemu_start_warp_timer();
+    if (icount_enabled()) {
+        /*
+         * CPU thread can infinitely wait for event after
+         * missing the warp
+         */
+        icount_start_warp_timer();
+    }
     qemu_clock_run_all_timers();
 }
 
diff --git a/util/qemu-timer.c b/util/qemu-timer.c
index f62b4feecd..db51e68f25 100644
--- a/util/qemu-timer.c
+++ b/util/qemu-timer.c
@@ -26,8 +26,10 @@ 
 #include "qemu/main-loop.h"
 #include "qemu/timer.h"
 #include "qemu/lockable.h"
+#include "sysemu/cpu-timers.h"
 #include "sysemu/replay.h"
 #include "sysemu/cpus.h"
+#include "sysemu/qtest.h"
 
 #ifdef CONFIG_POSIX
 #include <pthread.h>
@@ -134,7 +136,7 @@  static void qemu_clock_init(QEMUClockType type, QEMUTimerListNotifyCB *notify_cb
 
 bool qemu_clock_use_for_deadline(QEMUClockType type)
 {
-    return !(use_icount && (type == QEMU_CLOCK_VIRTUAL));
+    return !(icount_enabled() && (type == QEMU_CLOCK_VIRTUAL));
 }
 
 void qemu_clock_notify(QEMUClockType type)
@@ -416,8 +418,8 @@  static bool timer_mod_ns_locked(QEMUTimerList *timer_list,
 static void timerlist_rearm(QEMUTimerList *timer_list)
 {
     /* Interrupt execution to force deadline recalculation.  */
-    if (timer_list->clock->type == QEMU_CLOCK_VIRTUAL) {
-        qemu_start_warp_timer();
+    if (icount_enabled() && timer_list->clock->type == QEMU_CLOCK_VIRTUAL) {
+        icount_start_warp_timer();
     }
     timerlist_notify(timer_list);
 }
@@ -633,8 +635,10 @@  int64_t qemu_clock_get_ns(QEMUClockType type)
         return get_clock();
     default:
     case QEMU_CLOCK_VIRTUAL:
-        if (use_icount) {
-            return cpu_get_icount();
+        if (icount_enabled()) {
+            return icount_get();
+        } else if (qtest_enabled()) { /* for qtest_clock_warp */
+            return qtest_get_virtual_clock();
         } else {
             return cpu_get_clock();
         }