Messages in this thread Patch in this message | | | Subject | Re: [PATCH] iommu: Fallback to default setting when def_domain_type() callback returns 0 | From | Robin Murphy <> | Date | Tue, 6 Jul 2021 10:27:43 +0100 |
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On 2021-07-06 07:51, Kai-Heng Feng wrote: > Commit 28b41e2c6aeb ("iommu: Move def_domain type check for untrusted > device into core") not only moved the check for untrusted device to > IOMMU core, it also introduced a behavioral change by returning > def_domain_type() directly without checking its return value. That makes > many devices no longer use the default IOMMU setting. > > So revert back to the old behavior which defaults to > iommu_def_domain_type when driver callback returns 0. > > Fixes: 28b41e2c6aeb ("iommu: Move def_domain type check for untrusted device into core")
Are you sure about that? From that same commit:
@@ -1507,7 +1509,7 @@ static int iommu_alloc_default_domain(struct iommu_group *group, if (group->default_domain) return 0;
- type = iommu_get_def_domain_type(dev); + type = iommu_get_def_domain_type(dev) ? : iommu_def_domain_type;
return iommu_group_alloc_default_domain(dev->bus, group, type); }
AFAICS the other two callers should also handle 0 correctly. Have you seen a problem in practice?
Robin.
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> > --- > drivers/iommu/iommu.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 5419c4b9f27a..faac4f795025 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1507,14 +1507,15 @@ EXPORT_SYMBOL_GPL(fsl_mc_device_group); > static int iommu_get_def_domain_type(struct device *dev) > { > const struct iommu_ops *ops = dev->bus->iommu_ops; > + unsigned int type = 0; > > if (dev_is_pci(dev) && to_pci_dev(dev)->untrusted) > return IOMMU_DOMAIN_DMA; > > if (ops->def_domain_type) > - return ops->def_domain_type(dev); > + type = ops->def_domain_type(dev); > > - return 0; > + return (type == 0) ? iommu_def_domain_type : type; > } > > static int iommu_group_alloc_default_domain(struct bus_type *bus, >
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