Hi,
On Mon, Jun 21, 2021 at 7:05 PM Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> wrote:
>
> On 6/22/21 7:52 AM, Douglas Anderson wrote:
> > @@ -1519,7 +1542,8 @@ static int iommu_get_def_domain_type(struct device *dev)
> >
> > static int iommu_group_alloc_default_domain(struct bus_type *bus,
> > struct iommu_group *group,
> > - unsigned int type)
> > + unsigned int type,
> > + struct device *dev)
> > {
> > struct iommu_domain *dom;
> >
> > @@ -1534,6 +1558,12 @@ static int iommu_group_alloc_default_domain(struct bus_type *bus,
> > if (!dom)
> > return -ENOMEM;
> >
> > + /* Save the strictness requests from the device */
> > + if (dev && type == IOMMU_DOMAIN_DMA) {
> > + dom->request_non_strict = dev->request_non_strict_iommu;
> > + dom->force_strict = dev->force_strict_iommu;
> > + }
> > +
>
> An iommu default domain might be used by multiple devices which might
> have different "strict" attributions. Then who could override who?
My gut instinct would be that if multiple devices were part of a given
domain that it would be combined like this:
1. Any device that requests strict makes the domain strict force strict.
2. To request non-strict all of the devices in the domain would have
to request non-strict.
To do that I'd have to change my patchset obviously, but I don't think
it should be hard. We can just keep a count of devices and a count of
the strict vs. non-strict requests? If there are no other blockers
I'll try to do that in my v2.
-Doug
