From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alex Williamson <alex.williamson@hp.com>
Subject: Re: [PATCH 1/1] KVM: Fix potentially recursively get kvm lock
Date: Tue, 12 May 2009 15:36:27 -0600
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Cc: "Yang, Sheng" <sheng.yang@intel.com>, Avi Kivity <avi@redhat.com>,
	kvm@vger.kernel.org
To: Marcelo Tosatti <mtosatti@redhat.com>
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On Tue, 2009-05-12 at 16:44 -0300, Marcelo Tosatti wrote:
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 4d00942..ba067db 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -250,7 +250,15 @@ static void deassign_host_irq(struct kvm *kvm,
>  			disable_irq_nosync(assigned_dev->
>  					   host_msix_entries[i].vector);
>  
> +		/*
> +		 * FIXME: kvm_assigned_dev_interrupt_work_handler can deadlock
> +		 * with cancel_work_sync, since it requires kvm->lock for irq
> +		 * injection. This is a hack, the irq code must use
> +		 * a separate lock.
> +		 */
> +		mutex_unlock(&kvm->lock);
>  		cancel_work_sync(&assigned_dev->interrupt_work);
> +		mutex_lock(&kvm->lock);

Seems to work, I assume you've got a similar unlock/lock for the
MSI/INTx block.  Thanks,

Alex