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Subject: Re: [Xen-devel] [PATCH] xen: do not re-use pirq number cached in pci
 device msi msg data
To: Dan Streetman <ddstreet@ieee.org>,
        Stefano Stabellini <sstabellini@kernel.org>
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Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
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From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Date: Tue, 10 Jan 2017 18:28:26 -0500
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>> In the Xen code I can still see:
>>
>>     case ECS_PIRQ: {
>>         struct pirq *pirq = pirq_info(d1, chn1->u.pirq.irq);
>>
>>         if ( !pirq )
>>             break;
>>         if ( !is_hvm_domain(d1) )
>>             pirq_guest_unbind(d1, pirq);
>>
>> which means that pirq_guest_unbind should only be called on evtchn_close
>> if the guest is not an HVM guest.

A few lines further down we have:

        pirq->evtchn = 0;
        pirq_cleanup_check(pirq, d1);
        unlink_pirq_port(chn1, d1->vcpu[chn1->notify_vcpu_id]);
#ifdef CONFIG_X86
        if ( is_hvm_domain(d1) && domain_pirq_to_irq(d1, pirq->pirq) > 0 )
            unmap_domain_pirq_emuirq(d1, pirq->pirq);
#endif

which is where we free up the pirq.

-boris