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Date: Mon, 3 Jun 2019 18:03:37 +0200
From: Cornelia Huck <cohuck@redhat.com>
Subject: Re: [PATCH v3 8/8] virtio/s390: make airq summary indicators DMA
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To: Michael Mueller <mimu@linux.ibm.com>
Cc: KVM Mailing List <kvm@vger.kernel.org>, Linux-S390 Mailing List <linux-s390@vger.kernel.org>, Sebastian Ott <sebott@linux.ibm.com>, Heiko Carstens <heiko.carstens@de.ibm.com>, Halil Pasic <pasic@linux.ibm.com>, virtualization@lists.linux-foundation.org, "Michael S . Tsirkin" <mst@redhat.com>, Christoph Hellwig <hch@infradead.org>, Thomas Huth <thuth@redhat.com>, Christian Borntraeger <borntraeger@de.ibm.com>, Viktor Mihajlovski <mihajlov@linux.ibm.com>, Vasily Gorbik <gor@linux.ibm.com>, Janosch Frank <frankja@linux.ibm.com>, Claudio Imbrenda <imbrenda@linux.ibm.com>, Farhan Ali <alifm@linux.ibm.com>, Eric Farman <farman@linux.ibm.com>, Pierre Morel <pmorel@linux.ibm.com>

On Wed, 29 May 2019 14:26:57 +0200
Michael Mueller <mimu@linux.ibm.com> wrote:

> From: Halil Pasic <pasic@linux.ibm.com>
> 
> Hypervisor needs to interact with the summary indicators, so these
> need to be DMA memory as well (at least for protected virtualization
> guests).
> 
> Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
> Signed-off-by: Michael Mueller <mimu@linux.ibm.com>
> ---
>  drivers/s390/virtio/virtio_ccw.c | 26 +++++++++++++++++++-------
>  1 file changed, 19 insertions(+), 7 deletions(-)

(...)

> @@ -1501,6 +1508,11 @@ static int __init virtio_ccw_init(void)
>  {
>  	/* parse no_auto string before we do anything further */
>  	no_auto_parse();
> +
> +	summary_indicators = cio_dma_zalloc(MAX_AIRQ_AREAS);
> +	if (!summary_indicators)
> +		return -ENOMEM;
> +
>  	return ccw_driver_register(&virtio_ccw_driver);

Don't you need to free summary_indicators again if registering the
driver fails?

>  }
>  device_initcall(virtio_ccw_init);