On Tue, Aug 20, 2019 at 01:06:30PM -0600, Jordan Crouse wrote: > Support the DOMAIN_ATTR_SPLIT_TABLES attribute to let the leaf driver > know if split pagetables are enabled for the domain. > > Signed-off-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx> > --- > > drivers/iommu/arm-smmu.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 3f41cf7..6a512ff 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -1442,6 +1442,9 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain, > case DOMAIN_ATTR_NESTING: > *(int *)data = (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED); > return 0; > + case DOMAIN_ATTR_SPLIT_TABLES: > + *(int *)data = !!(smmu_domain->split_pagetables); > + return 0; Hmm. Could you move the setting of this attribute into arm_smmu_domain_set_attr() and reject it if the ias != 48 in there? That way the user of the domain can request this feature, rather than us enforcing it based on the compatible string. I'd also prefer to call it DOMAIN_ATTR_USE_TTBR1 instead, since it's pretty ARM specific at this point. Will
