RE: [PATCH 4/4] iommu: Add domain window handling functions

[Yoder Stuart-B08248]

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Monday, February 04, 2013 5:36 PM
> To: Joerg Roedel
> Cc: Sethi Varun-B16395; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Wood Scott-
> B07421; Yoder Stuart-B08248
> Subject: Re: [PATCH 4/4] iommu: Add domain window handling functions
> 
> On 02/04/2013 07:02:14 AM, Joerg Roedel wrote:
> > On Thu, Jan 31, 2013 at 09:32:26AM +0000, Sethi Varun-B16395 wrote:
> > > We need a mechanism to determine the maximum number of subwindows
> > supported by PAMU. How about representing it in the iommu_domain
> > structure:
> > > struct  iommu_domain {
> > > 	struct iommu_ops *ops;
> > > 	void *priv;
> > > 	iommu_fault_handler_t handler;
> > > 	void *handler_token;
> > > 	struct iommu_domain_geometry geometry;
> > > 	u32 max_sub_windows; -----> maximum number of sub windows
> > supported by the hardware.
> > > }
> >
> > I`ll leave that flag to the private-data of the IOMMU domain. Instead
> > I
> > added a DOMAIN_ATTR_WINDOWS attribute to get/set the number of
> > subwindows. I'll post the updated patch-set soon.
> 
> If it's private data, how does the caller know what sort of geometry it
> can request?

The way I thought this could work based on the patch that Joerg posted today
was that when the domain is created the caller could read the DOMAIN_ATTR_WINDOWS 
domain_get_windows() to determine the max.  The initial/default value is the
max.  The caller could then set a smaller value if they wanted to.

Stuart

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/