diff options
| author | Max Filippov <jcmvbkbc@gmail.com> | 2011-11-09 05:18:09 +0400 |
|---|---|---|
| committer | Anthony Liguori <aliguori@us.ibm.com> | 2011-11-09 12:06:20 -0600 |
| commit | 4f61927a41a098d06e642ffdea5fc285dc3a0e6b (patch) | |
| tree | d713bf00ea6d6c8e2d0bf0039b7a53605807abdc /hw/hpet.c | |
| parent | c0465d1a1d4c9562cfa7e91f6c31ea1bce22052c (diff) | |
| download | qemu-4f61927a41a098d06e642ffdea5fc285dc3a0e6b.zip | |
hpet: fix infinite loop in qemu_run_timers with -icount enabled
hpet_timer timer callback rearms itself based on difference between
current HPET tick counter and comparator value. Difference calculated by
the hpet_calculate_diff function is limited to non-negative values.
cur_tick is calculated via hpet_get_ticks that uses qemu_get_clock_ns(vm_clock).
With -icount enabled vm_clock doesn't advance during qemu_run_timers
loop thus once difference is zero, qemu_run_timers loops forever
handling hpet_timer.
Limit hpet_calculate_diff results to positive only values to avoid that
infinite loop.
This fixes the following qemu-system-x86_64 hang when it reaches
timer_irq_works() in the linux bootup:
[ 0.000000] Fast TSC calibration using PIT
[ 0.000000] Detected 1000.054 MHz processor.
[ 0.000031] Calibrating delay loop (skipped), value calculated using timer frequency.. 2000.10 BogoMIPS (lpj=10000540)
[ 0.000404] pid_max: default: 32768 minimum: 301
[ 0.001138] Mount-cache hash table entries: 256
[ 0.003883] Initializing cgroup subsys ns
[ 0.004035] Initializing cgroup subsys cpuacct
[ 0.004280] Initializing cgroup subsys freezer
[ 0.004790] Performance Events: AMD PMU driver.
[ 0.004985] ... version: 0
[ 0.005134] ... bit width: 48
[ 0.005285] ... generic registers: 4
[ 0.005437] ... value mask: 0000ffffffffffff
[ 0.005625] ... max period: 00007fffffffffff
[ 0.005807] ... fixed-purpose events: 0
[ 0.005957] ... event mask: 000000000000000f
[ 0.006275] SMP alternatives: switching to UP code
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'hw/hpet.c')
| -rw-r--r-- | hw/hpet.c | 4 |
1 files changed, 2 insertions, 2 deletions
@@ -157,14 +157,14 @@ static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current) cmp = (uint32_t)t->cmp; diff = cmp - (uint32_t)current; - diff = (int32_t)diff > 0 ? diff : (uint32_t)0; + diff = (int32_t)diff > 0 ? diff : (uint32_t)1; return (uint64_t)diff; } else { uint64_t diff, cmp; cmp = t->cmp; diff = cmp - current; - diff = (int64_t)diff > 0 ? diff : (uint64_t)0; + diff = (int64_t)diff > 0 ? diff : (uint64_t)1; return diff; } } |