[PATCH] iommu: Remove functions that support private domain

[Prakhya, Sai Praneeth]

Hi Joerg,

> -----Original Message-----
> From: Joerg Roedel <joro at 8bytes.org>
> Sent: Thursday, May 14, 2020 11:33 AM
> To: Prakhya, Sai Praneeth <sai.praneeth.prakhya at intel.com>
> Cc: iommu at lists.linux-foundation.org; Lu Baolu <baolu.lu at linux.intel.com>
> Subject: Re: [PATCH] iommu: Remove functions that support private domain
> 
> On Thu, May 14, 2020 at 05:51:39PM +0000, Prakhya, Sai Praneeth wrote:
> > Sorry! didn't get that quite well. When you meant "per-group
> > default-domain patch-set", do you mean the patch set that I am working
> > on which changes iommu group default domain dynamically by writing to
> > sysfs file?
> 
> Not only the sysfs file, but also changing it at boot already. Note that changing
> the default-domain at runtime is only possible for single-device groups.

Could you please explain why we shouldn't change default-domain for an iommu group that has multiple devices?

I am asking this particularly because the patch set I am working on allows to change default-domain for an iommu group that has multiple devices. The pre-requisite being that all the devices in the group should already be unbounded from the device driver and the default-domain preferences of all the devices in the group shouldn't have conflicting types i.e. some devices cannot say they *only* need identity domain while other devices in the same group say that they *only* need to be in DMA domain. In this case, we will not be able to decide upon a default-domain for the iommu group.

> I'll queue that patch tomorrow.

Great! I will take a look at it.

Regards,
Sai