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s390x/tcg: fix locking problem with tcg_s390_tod_updated 

tcg_s390_tod_updated() is always called with the iothread being locked
(e.g. from S390TODClass->set() e.g. via HELPER(sck) or on incoming
migration). The helper we call takes the lock itself - bad.

Let's change that by factoring out updating the ckc timer. This now looks
much nicer than having to call a helper from another function.

While touching it we also make sure that env->ckc is updated even if the
new value is -1ULL, for now it would not have been modified in that case.

Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180629170520.13671-1-david@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
David Hildenbrand 2018-06-29 19:05:20 +02:00 committed by Cornelia Huck
parent d44444b074
commit 30c8db0e21
1 changed files with 16 additions and 10 deletions
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26
target/s390x/misc_helper.c
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@ -149,26 +149,23 @@ uint64_t HELPER(stck)(CPUS390XState *env)
return tod.low;
}
/* Set Clock Comparator */
void HELPER(sckc)(CPUS390XState *env, uint64_t time)
static void update_ckc_timer(CPUS390XState *env)
{
S390TODState *td = s390_get_todstate();
uint64_t time;
/* stop the timer and remove pending CKC IRQs */
timer_del(env->tod_timer);
qemu_mutex_lock_iothread();
g_assert(qemu_mutex_iothread_locked());
env->pending_int &= ~INTERRUPT_EXT_CLOCK_COMPARATOR;
qemu_mutex_unlock_iothread();
/* the tod has to exceed the ckc, this can never happen if ckc is all 1's */
if (time == -1ULL) {
if (env->ckc == -1ULL) {
return;
}
env->ckc = time;
/* difference between origins */
time -= td->base.low;
time = env->ckc - td->base.low;
/* nanoseconds */
time = tod2time(time);
@ -176,12 +173,21 @@ void HELPER(sckc)(CPUS390XState *env, uint64_t time)
timer_mod(env->tod_timer, time);
}
/* Set Clock Comparator */
void HELPER(sckc)(CPUS390XState *env, uint64_t ckc)
{
env->ckc = ckc;
qemu_mutex_lock_iothread();
update_ckc_timer(env);
qemu_mutex_unlock_iothread();
}
void tcg_s390_tod_updated(CPUState *cs, run_on_cpu_data opaque)
{
S390CPU *cpu = S390_CPU(cs);
CPUS390XState *env = &cpu->env;
helper_sckc(env, env->ckc);
update_ckc_timer(&cpu->env);
}
/* Set Clock */