Messages in this thread | | | Subject | Re: [PATCH v9 1/4] iommu: Move def_domain type check for untrusted device into core | From | Lu Baolu <> | Date | Mon, 23 Nov 2020 21:54:49 +0800 |
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Hi Will,
On 2020/11/23 21:03, Will Deacon wrote: > 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.
Yes, agreed. I will remove iommu_get_mandatory_def_domain_type() and keep iommu_get_def_domain_type() as the only helper in the next version.
Best regards, baolu
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