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From: Halil Pasic <pasic@linux.ibm.com>
To: Sebastian Ott <sebott@linux.ibm.com>
Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org,
	Cornelia Huck <cohuck@redhat.com>,
	Martin Schwidefsky <schwidefsky@de.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>
Subject: Re: [PATCH 06/10] s390/cio: add basic protected virtualization support
Date: Wed, 8 May 2019 23:08:09 +0200	[thread overview]
Message-ID: <20190508230809.6b0faaf7.pasic@linux.ibm.com> (raw)
In-Reply-To: <alpine.LFD.2.21.1905081522300.1773@schleppi>

On Wed, 8 May 2019 15:46:42 +0200 (CEST)
Sebastian Ott <sebott@linux.ibm.com> wrote:

> 
> On Fri, 26 Apr 2019, Halil Pasic wrote:
> >  static struct ccw_device * io_subchannel_allocate_dev(struct subchannel *sch)
> >  {
> [..]
> > +	cdev->private = kzalloc(sizeof(struct ccw_device_private),
> > +				GFP_KERNEL | GFP_DMA);
> 
> Do we still need GFP_DMA here (since we now have cdev->private->dma_area)?
> 

We probably do not. I kept it GFP_DMA to keep changes to the
minimum. Should changing this in your opinion be a part of this patch?

> > @@ -1062,6 +1082,14 @@ static int io_subchannel_probe(struct subchannel *sch)
> >  	if (!io_priv)
> >  		goto out_schedule;
> >  
> > +	io_priv->dma_area = dma_alloc_coherent(&sch->dev,
> > +				sizeof(*io_priv->dma_area),
> > +				&io_priv->dma_area_dma, GFP_KERNEL);
> 
> This needs GFP_DMA.

Christoph already answered this one. Thanks Christoph!

> You use a genpool for ccw_private->dma and not for iopriv->dma - looks
> kinda inconsistent.
> 

Please have a look at patch #9. A virtio-ccw device uses the genpool of
it's ccw device (the pool from which ccw_private->dma is allicated) for
the ccw stuff it needs to do. AFAICT for a subchannel device and its API
all the DMA memory we need is iopriv->dma. So my thought was
constructing a genpool for that would be an overkill.

Are you comfortable with this answer, or should we change something?

Regards,
Halil

WARNING: multiple messages have this Message-ID (diff)
From: Halil Pasic <pasic@linux.ibm.com>
To: Sebastian Ott <sebott@linux.ibm.com>
Cc: Farhan Ali <alifm@linux.ibm.com>,
	linux-s390@vger.kernel.org, Thomas Huth <thuth@redhat.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Eric Farman <farman@linux.ibm.com>,
	virtualization@lists.linux-foundation.org,
	Christoph Hellwig <hch@infradead.org>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Viktor Mihajlovski <mihajlov@linux.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>
Subject: Re: [PATCH 06/10] s390/cio: add basic protected virtualization support
Date: Wed, 8 May 2019 23:08:09 +0200	[thread overview]
Message-ID: <20190508230809.6b0faaf7.pasic@linux.ibm.com> (raw)
In-Reply-To: <alpine.LFD.2.21.1905081522300.1773@schleppi>

On Wed, 8 May 2019 15:46:42 +0200 (CEST)
Sebastian Ott <sebott@linux.ibm.com> wrote:

> 
> On Fri, 26 Apr 2019, Halil Pasic wrote:
> >  static struct ccw_device * io_subchannel_allocate_dev(struct subchannel *sch)
> >  {
> [..]
> > +	cdev->private = kzalloc(sizeof(struct ccw_device_private),
> > +				GFP_KERNEL | GFP_DMA);
> 
> Do we still need GFP_DMA here (since we now have cdev->private->dma_area)?
> 

We probably do not. I kept it GFP_DMA to keep changes to the
minimum. Should changing this in your opinion be a part of this patch?

> > @@ -1062,6 +1082,14 @@ static int io_subchannel_probe(struct subchannel *sch)
> >  	if (!io_priv)
> >  		goto out_schedule;
> >  
> > +	io_priv->dma_area = dma_alloc_coherent(&sch->dev,
> > +				sizeof(*io_priv->dma_area),
> > +				&io_priv->dma_area_dma, GFP_KERNEL);
> 
> This needs GFP_DMA.

Christoph already answered this one. Thanks Christoph!

> You use a genpool for ccw_private->dma and not for iopriv->dma - looks
> kinda inconsistent.
> 

Please have a look at patch #9. A virtio-ccw device uses the genpool of
it's ccw device (the pool from which ccw_private->dma is allicated) for
the ccw stuff it needs to do. AFAICT for a subchannel device and its API
all the DMA memory we need is iopriv->dma. So my thought was
constructing a genpool for that would be an overkill.

Are you comfortable with this answer, or should we change something?

Regards,
Halil

  parent reply	other threads:[~2019-05-08 21:08 UTC|newest]

Thread overview: 182+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-26 18:32 [PATCH 00/10] s390: virtio: support protected virtualization Halil Pasic
2019-04-26 18:32 ` Halil Pasic
2019-04-26 18:32 ` [PATCH 01/10] virtio/s390: use vring_create_virtqueue Halil Pasic
2019-04-26 18:32   ` Halil Pasic
2019-05-03  9:17   ` Cornelia Huck
2019-05-03 20:04     ` Michael S. Tsirkin
2019-05-03 20:04       ` Michael S. Tsirkin
2019-05-04 14:03       ` Halil Pasic
2019-05-04 14:03         ` Halil Pasic
2019-05-05 11:15         ` Cornelia Huck
2019-05-05 11:15           ` Cornelia Huck
2019-05-07 13:58           ` Christian Borntraeger
2019-05-07 13:58             ` Christian Borntraeger
2019-05-08 20:12             ` Halil Pasic
2019-05-08 20:12               ` Halil Pasic
2019-05-10 14:07             ` Cornelia Huck
2019-05-10 14:07               ` Cornelia Huck
2019-05-12 16:47               ` Michael S. Tsirkin
2019-05-12 16:47                 ` Michael S. Tsirkin
2019-05-13  9:52                 ` Cornelia Huck
2019-05-13  9:52                   ` Cornelia Huck
2019-05-13 12:27                   ` Michael Mueller
2019-05-13 12:27                     ` Michael Mueller
2019-05-13 12:29                     ` Cornelia Huck
2019-05-13 12:29                       ` Cornelia Huck
2019-04-26 18:32 ` [PATCH 02/10] virtio/s390: DMA support for virtio-ccw Halil Pasic
2019-04-26 18:32   ` Halil Pasic
2019-05-03  9:31   ` Cornelia Huck
2019-04-26 18:32 ` [PATCH 03/10] virtio/s390: enable packed ring Halil Pasic
2019-04-26 18:32   ` Halil Pasic
2019-05-03  9:44   ` Cornelia Huck
2019-05-05 15:13     ` Thomas Huth
2019-05-05 15:13       ` Thomas Huth
2019-04-26 18:32 ` [PATCH 04/10] s390/mm: force swiotlb for protected virtualization Halil Pasic
2019-04-26 18:32   ` Halil Pasic
2019-04-26 19:27   ` Christoph Hellwig
2019-04-26 19:27     ` Christoph Hellwig
2019-04-29 13:59     ` Halil Pasic
2019-04-29 13:59       ` Halil Pasic
2019-04-29 14:05       ` Christian Borntraeger
2019-04-29 14:05         ` Christian Borntraeger
2019-05-13 12:50         ` Michael Mueller
2019-05-13 12:50           ` Michael Mueller
2019-05-08 13:15   ` Claudio Imbrenda
2019-05-08 13:15     ` Claudio Imbrenda
2019-05-09 22:34     ` Halil Pasic
2019-05-09 22:34       ` Halil Pasic
2019-05-15 14:15       ` Michael Mueller
2019-05-15 14:15         ` Michael Mueller
     [not found]   ` <ad23f5e7-dc78-04af-c892-47bbc65134c6@linux.ibm.com>
2019-05-09 18:05     ` Jason J. Herne
2019-05-09 18:05       ` Jason J. Herne
2019-05-09 18:05       ` Jason J. Herne
2019-05-10  7:49       ` Claudio Imbrenda
2019-05-10  7:49         ` Claudio Imbrenda
2019-04-26 18:32 ` [PATCH 05/10] s390/cio: introduce DMA pools to cio Halil Pasic
2019-04-26 18:32   ` Halil Pasic
2019-05-08 13:18   ` Sebastian Ott
2019-05-08 13:18     ` Sebastian Ott
2019-05-08 21:22     ` Halil Pasic
2019-05-08 21:22       ` Halil Pasic
2019-05-09  8:40       ` Sebastian Ott
2019-05-09  8:40         ` Sebastian Ott
2019-05-09 10:11       ` Cornelia Huck
2019-05-09 10:11         ` Cornelia Huck
2019-05-09 22:11         ` Halil Pasic
2019-05-09 22:11           ` Halil Pasic
2019-05-10 14:10           ` Cornelia Huck
2019-05-10 14:10             ` Cornelia Huck
2019-05-12 18:22             ` Halil Pasic
2019-05-12 18:22               ` Halil Pasic
2019-05-13 13:29               ` Cornelia Huck
2019-05-13 13:29                 ` Cornelia Huck
2019-05-15 17:12                 ` Halil Pasic
2019-05-15 17:12                   ` Halil Pasic
2019-05-16  6:13                   ` Cornelia Huck
2019-05-16  6:13                     ` Cornelia Huck
2019-05-16 13:59               ` Sebastian Ott
2019-05-16 13:59                 ` Sebastian Ott
2019-05-20 12:13                 ` Halil Pasic
2019-05-20 12:13                   ` Halil Pasic
2019-05-21  8:46                   ` Michael Mueller
2019-05-21  8:46                     ` Michael Mueller
2019-05-22 12:07                   ` Sebastian Ott
2019-05-22 12:07                     ` Sebastian Ott
2019-05-22 22:12                     ` Halil Pasic
2019-05-22 22:12                       ` Halil Pasic
2019-05-23 15:17     ` Halil Pasic
2019-05-23 15:17       ` Halil Pasic
2019-04-26 18:32 ` [PATCH 06/10] s390/cio: add basic protected virtualization support Halil Pasic
2019-04-26 18:32   ` Halil Pasic
2019-05-08 13:46   ` Sebastian Ott
2019-05-08 13:46     ` Sebastian Ott
2019-05-08 13:54     ` Christoph Hellwig
2019-05-08 13:54       ` Christoph Hellwig
2019-05-08 21:08     ` Halil Pasic [this message]
2019-05-08 21:08       ` Halil Pasic
2019-05-09  8:52       ` Sebastian Ott
2019-05-09  8:52         ` Sebastian Ott
2019-05-08 14:23   ` Pierre Morel
2019-05-08 14:23     ` Pierre Morel
2019-05-13  9:41   ` Cornelia Huck
2019-05-13  9:41     ` Cornelia Huck
2019-05-14 14:47     ` Jason J. Herne
2019-05-14 14:47       ` Jason J. Herne
2019-05-15 21:08       ` Halil Pasic
2019-05-15 21:08         ` Halil Pasic
2019-05-16  6:32         ` Cornelia Huck
2019-05-16  6:32           ` Cornelia Huck
2019-05-16 13:42           ` Halil Pasic
2019-05-16 13:42             ` Halil Pasic
2019-05-16 13:54             ` Cornelia Huck
2019-05-16 13:54               ` Cornelia Huck
2019-05-15 20:51     ` Halil Pasic
2019-05-15 20:51       ` Halil Pasic
2019-05-16  6:29       ` Cornelia Huck
2019-05-16  6:29         ` Cornelia Huck
2019-05-18 18:11         ` Halil Pasic
2019-05-18 18:11           ` Halil Pasic
2019-05-20 10:21           ` Cornelia Huck
2019-05-20 10:21             ` Cornelia Huck
2019-05-20 12:34             ` Halil Pasic
2019-05-20 12:34               ` Halil Pasic
2019-05-20 13:43               ` Cornelia Huck
2019-05-20 13:43                 ` Cornelia Huck
2019-04-26 18:32 ` [PATCH 07/10] s390/airq: use DMA memory for adapter interrupts Halil Pasic
2019-04-26 18:32   ` Halil Pasic
2019-05-08 13:58   ` Sebastian Ott
2019-05-08 13:58     ` Sebastian Ott
2019-05-09 11:37   ` Cornelia Huck
2019-05-09 11:37     ` Cornelia Huck
2019-05-13 12:59   ` Cornelia Huck
2019-05-13 12:59     ` Cornelia Huck
2019-04-26 18:32 ` [PATCH 08/10] virtio/s390: add indirection to indicators access Halil Pasic
2019-04-26 18:32   ` Halil Pasic
2019-05-08 14:31   ` Pierre Morel
2019-05-08 14:31     ` Pierre Morel
2019-05-09 12:01     ` Pierre Morel
2019-05-09 12:01       ` Pierre Morel
2019-05-09 18:26       ` Halil Pasic
2019-05-09 18:26         ` Halil Pasic
2019-05-10  7:43         ` Pierre Morel
2019-05-10  7:43           ` Pierre Morel
2019-05-10 11:54           ` Halil Pasic
2019-05-10 11:54             ` Halil Pasic
2019-05-10 15:36             ` Pierre Morel
2019-05-10 15:36               ` Pierre Morel
2019-05-13 10:15               ` Cornelia Huck
2019-05-13 10:15                 ` Cornelia Huck
2019-05-16 15:24                 ` Pierre Morel
2019-05-16 15:24                   ` Pierre Morel
2019-04-26 18:32 ` [PATCH 09/10] virtio/s390: use DMA memory for ccw I/O and classic notifiers Halil Pasic
2019-04-26 18:32   ` Halil Pasic
2019-05-08 14:46   ` Pierre Morel
2019-05-08 14:46     ` Pierre Morel
2019-05-09 13:30     ` Pierre Morel
2019-05-09 13:30       ` Pierre Morel
2019-05-09 18:30       ` Halil Pasic
2019-05-09 18:30         ` Halil Pasic
2019-05-13 13:54   ` Cornelia Huck
2019-05-13 13:54     ` Cornelia Huck
2019-04-26 18:32 ` [PATCH 10/10] virtio/s390: make airq summary indicators DMA Halil Pasic
2019-04-26 18:32   ` Halil Pasic
2019-05-08 15:11   ` Pierre Morel
2019-05-08 15:11     ` Pierre Morel
2019-05-15 13:33     ` Michael Mueller
2019-05-15 13:33       ` Michael Mueller
2019-05-15 17:23       ` Halil Pasic
2019-05-15 17:23         ` Halil Pasic
2019-05-13 12:20   ` Cornelia Huck
2019-05-13 12:20     ` Cornelia Huck
2019-05-15 13:43     ` Michael Mueller
2019-05-15 13:43       ` Michael Mueller
2019-05-15 13:50       ` Cornelia Huck
2019-05-15 13:50         ` Cornelia Huck
2019-05-15 17:18       ` Halil Pasic
2019-05-15 17:18         ` Halil Pasic
2019-05-03  9:55 ` [PATCH 00/10] s390: virtio: support protected virtualization Cornelia Huck
2019-05-03 10:03   ` Juergen Gross
2019-05-03 13:33   ` Cornelia Huck
2019-05-03 13:33     ` Cornelia Huck
2019-05-04 13:58   ` Halil Pasic
2019-05-04 13:58     ` Halil Pasic

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