Hi,
Keir Fraser wrote:

On 07/01/2009 09:41, "Akio Takebe" <takebe_akio@xxxxxxxxxxxxxx> wrote:

hvm_set_callback_irq_level() and so on call vioapic_irq_positive_edge()
before spin_unlock(&d->arch.hvm_domain.irq_lock).
I think it cause a deadlock.
If it is right, how should we fix them?
What do you think?

Doesn't vioapic_irq_positive_edge() clearly expect to be called with that
lock held?

I concern about that vioapic_deliver() calls vcpu_kick(). If vcpu0 has the lock 
and
vcpu1 cannot get lock and spin then vcpu0 sleep in another function,
it may cause deadlock because vioapic_irq_positive_edge() may call vcpu_kick().
For example, the following function is OK?
1087 static void time_calibration_rendezvous(void *_r)
1088 {
1089 struct cpu_calibration *c = &this_cpu(cpu_calibration);
1090 struct calibration_rendezvous *r = _r;
1091 unsigned int total_cpus = cpus_weight(r->cpu_calibration_map);
1092
1093 if ( smp_processor_id() == 0 )
1094 {
1095 while ( atomic_read(&r->nr_cpus) != (total_cpus - 1) )
1096 cpu_relax();
1097 r->master_stime = read_platform_stime();
1098 rdtscll(r->master_tsc_stamp);
1099 mb(); /* write r->master_* /then/ signal */
1100 atomic_inc(&r->nr_cpus);
1101 c->local_tsc_stamp = r->master_tsc_stamp;
1102 }
1103 else
1104 {
1105 atomic_inc(&r->nr_cpus);
1106 while ( atomic_read(&r->nr_cpus) != total_cpus )
1107 cpu_relax();
1108 mb(); /* receive signal /then/ read r->master_* */
1109 if ( boot_cpu_has(X86_FEATURE_CONSTANT_TSC) )
1110 wrmsrl(MSR_IA32_TSC, r->master_tsc_stamp);
1111 rdtscll(c->local_tsc_stamp);
1112 }
1113
1114 c->stime_local_stamp = get_s_time();
1115 c->stime_master_stamp = r->master_stime;
1116
1117 raise_softirq(TIME_CALIBRATE_SOFTIRQ);
1118 }
Best Regards,
Akio Takebe
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