Re: [PATCH v2 12/14] iommu: Consolidate the default_domain setup to one function

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, Mar 30, 2023 at 07:23:56PM +0100, Robin Murphy wrote:

> > I changed it like this:
> > 
> > 	dom = __iommu_domain_alloc(bus, req_type);
> > 	if (!dom && !target_type &&
> > 	    (req_type == IOMMU_DOMAIN_IDENTITY ||
> > 	     req_type == IOMMU_DOMAIN_DMA_FQ)) {
> > 		dom = __iommu_domain_alloc(bus, IOMMU_DOMAIN_DMA);
> > 
> > So the auto selection only happens if the target_type is not automatic.
> 
> You mean "is automatic"?

Yep

> I'm missing how target_type and req_type are
> related here, but the general principle should be that if we have derived
> the type from iommu_def_domain_type, because we had nothing more specific
> from either a sysfs request or iommu_get_def_domain_type(), then a
> !IOMMU_DOMAIN_DMA failure can retry with IOMMU_DOMAIN_DMA. Otherwise any
> failure should be final.

Ok, can do

Jason