# HG changeset patch
# User Alex Williamson <alex.williamson@xxxxxx>
# Date 1179333727 21600
# Node ID afb27041a2ce4493b6c1d9cf87939858a96136d0
# Parent 8c5ebe559a4ddfa05a6291a9b33ae29ea202a462
[IA64] Fix deadlock of ptc.ga emulation
ptc_ga_remote_func() might be invoked by IPI with a schedule_lock
that is acquired. (e.g., inside of vcpu_migrate())
It will cause a deadlock.
Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>
---
xen/arch/ia64/vmx/vmmu.c | 29 ++++++++++++++++++-----------
1 files changed, 18 insertions(+), 11 deletions(-)
diff -r 8c5ebe559a4d -r afb27041a2ce xen/arch/ia64/vmx/vmmu.c
--- a/xen/arch/ia64/vmx/vmmu.c Tue May 15 15:32:23 2007 -0600
+++ b/xen/arch/ia64/vmx/vmmu.c Wed May 16 10:42:07 2007 -0600
@@ -563,13 +563,16 @@ static void ptc_ga_remote_func (void *va
struct ptc_ga_args *args = (struct ptc_ga_args *)varg;
VCPU *v = args->vcpu;
vadr = args->vadr;
+ int cpu = v->processor;
/* Try again if VCPU has migrated. */
- if (v->processor != current->processor)
+ if (cpu != current->processor)
return;
- vcpu_schedule_lock_irqsave(v, flags);
- if (v->processor != current->processor)
- goto bail;
+ local_irq_save(flags);
+ if (!spin_trylock(&per_cpu(schedule_data, cpu).schedule_lock))
+ goto bail2;
+ if (v->processor != cpu)
+ goto bail1;
oldrid = VMX(v, vrr[0]);
VMX(v, vrr[0]) = args->rid;
oldpsbits = VMX(v, psbits[0]);
@@ -587,8 +590,10 @@ static void ptc_ga_remote_func (void *va
ia64_set_pta(mpta);
ia64_dv_serialize_data();
args->vcpu = NULL;
-bail:
- vcpu_schedule_unlock_irqrestore(v, flags);
+bail1:
+ spin_unlock(&per_cpu(schedule_data, cpu).schedule_lock);
+bail2:
+ local_irq_restore(flags);
}
@@ -598,7 +603,7 @@ IA64FAULT vmx_vcpu_ptc_ga(VCPU *vcpu, u6
struct domain *d = vcpu->domain;
struct vcpu *v;
struct ptc_ga_args args;
- int proc;
+ int cpu;
args.vadr = va;
vcpu_get_rr(vcpu, va, &args.rid);
@@ -614,13 +619,15 @@ IA64FAULT vmx_vcpu_ptc_ga(VCPU *vcpu, u6
args.vcpu = v;
do {
- proc = v->processor;
- if (proc != vcpu->processor)
+ cpu = v->processor;
+ if (cpu != current->processor) {
+ spin_unlock_wait(&per_cpu(schedule_data, cpu).schedule_lock);
/* Flush VHPT on remote processors. */
- smp_call_function_single(proc, &ptc_ga_remote_func,
+ smp_call_function_single(cpu, &ptc_ga_remote_func,
&args, 0, 1);
- else
+ } else {
ptc_ga_remote_func(&args);
+ }
} while (args.vcpu != NULL);
}
return IA64_NO_FAULT;
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