RE: [PATCH 5/5] iommu: Add DOMAIN_ATTR_WINDOWS domain attribute

[Sethi Varun-B16395]

> -----Original Message-----
> From: Joerg Roedel [mailto:joro@xxxxxxxxxx]
> Sent: Tuesday, February 05, 2013 6:36 PM
> To: Sethi Varun-B16395
> Cc: Stuart Yoder; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Wood Scott-B07421
> Subject: Re: [PATCH 5/5] iommu: Add DOMAIN_ATTR_WINDOWS domain attribute
> 
> On Tue, Feb 05, 2013 at 10:52:03AM +0000, Sethi Varun-B16395 wrote:
> > DOMAIN_ATTR_PAMU_ENABLE is required to enable a particular DMA window.
> > My point is about the domain geometry, which is incomplete in case of
> > PAMU without the number of subwindows. Geometry parameters are used
> > for initializing the PAMU window settings. Individual subwindows can
> > only be enabled, once the PAMU window has been initialized using the
> > geometry settings.
> 
> I understand that. What you do is:
> 
> 	/* Set geometry */
> 	set_attr(domain, DOMAIN_ATTR_GEOMETRY);
> 
> 	/* Set number of PAMU subwindows */
> 	set_attr(domain, DOMAIN_ATTR_WINDOWS);
> 
> 	/* Commit changes to hardware and enable the window */
> 	set_attr(domain, DOMAIN_ATTR_PAMU_ENABLE);
> 
> And I don't see any problem with that. The domain_attr interface was
> introduced to cope with device specifics, we don't change global
> interface data structures for that.
> 
> 
[Sethi Varun-B16395] But, then it would be mandatory to set the DOMAIN_ATTR_WINDOWS attribute in case of PAMU. I guess that it would be implementation specific. I am fine with the API.

-Varun

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