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KVM: ia64: fix locking order entering guest 

Reorder locking as down_read() may return with local interrupts enabled,
which means we could go into vti_vcpu_run() with interrupts enabled.

This caused random crashes on the Altix as the timer interrupt tried
to read a memory mapped clock source, for which the TLB had not yet been
reinstated in the exit, before ipsr was retored.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Acked-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Jes Sorensen 2009-04-09 16:38:14 +02:00 committed by Avi Kivity
parent 99894a799f
commit d24d2c1cc4
1 changed files with 8 additions and 6 deletions
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14
arch/ia64/kvm/kvm-ia64.c
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@ -610,20 +610,22 @@ static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
int r;
again:
preempt_disable();
local_irq_disable();
if (signal_pending(current)) {
local_irq_enable();
preempt_enable();
r = -EINTR;
kvm_run->exit_reason = KVM_EXIT_INTR;
goto out;
}
/*
* down_read() may sleep and return with interrupts enabled
*/
down_read(&vcpu->kvm->slots_lock);
preempt_disable();
local_irq_disable();
vcpu->guest_mode = 1;
kvm_guest_enter();
down_read(&vcpu->kvm->slots_lock);
r = vti_vcpu_run(vcpu, kvm_run);
if (r < 0) {
local_irq_enable();