Messages in this thread | | | Date | Mon, 23 Nov 2020 13:03:36 +0000 | From | Will Deacon <> | Subject | Re: [PATCH v9 1/4] iommu: Move def_domain type check for untrusted device into core |
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Hi Baolu,
On Mon, Nov 23, 2020 at 08:55:17PM +0800, Lu Baolu wrote: > On 2020/11/23 20:04, Will Deacon wrote: > > On Sat, Nov 21, 2020 at 09:56:17PM +0800, Lu Baolu wrote: > > > @@ -1645,13 +1655,10 @@ struct __group_domain_type { > > > static int probe_get_default_domain_type(struct device *dev, void *data) > > > { > > > - const struct iommu_ops *ops = dev->bus->iommu_ops; > > > struct __group_domain_type *gtype = data; > > > unsigned int type = 0; > > > - if (ops->def_domain_type) > > > - type = ops->def_domain_type(dev); > > > - > > > + type = iommu_get_mandatory_def_domain_type(dev); > > > > afaict, this code is only called from probe_alloc_default_domain(), which > > has: > > > > /* Ask for default domain requirements of all devices in the group */ > > __iommu_group_for_each_dev(group, >ype, > > probe_get_default_domain_type); > > > > if (!gtype.type) > > gtype.type = iommu_def_domain_type; > > > > so is there actually a need to introduce the new > > iommu_get_mandatory_def_domain_type() function, given that a type of 0 > > always ends up resolving to the default domain type? > > Another consumer of this helper is in the next patch: > > + dev_def_dom = iommu_get_mandatory_def_domain_type(dev); > + > + /* Check if user requested domain is supported by the device or not */ > + if (!type) { > + /* > + * If the user hasn't requested any specific type of domain and > + * if the device supports both the domains, then default to the > + * domain the device was booted with > + */ > + type = iommu_get_def_domain_type(dev); > + } else if (dev_def_dom && type != dev_def_dom) { > + dev_err_ratelimited(prev_dev, "Device cannot be in %s domain\n", > + iommu_domain_type_str(type)); > + ret = -EINVAL; > + goto out; > + } > > I also added the untrusted device check in > iommu_get_mandatory_def_domain_type(), so that we don't need to care > about this in multiple places.
I see, but isn't this also setting the default domain type in the case that it gets back a type of 0? I think it would be nice to avoid having both iommu_get_mandatory_def_domain_type() and iommu_get_def_domain_type() of we can, as it's really not clear which one to use when and what is meant by "mandatory" imo.
Will
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