On Fri, Sep 14, 2018 at 03:30:24PM +0100, Robin Murphy wrote: > All we need is to wire up .flush_iotlb_all properly and implement the > domain attribute, and iommu-dma and io-pgtable-arm will do the rest for > us. Rather than bother implementing it for v7s format for the highly > unlikely chance of that being relevant, we can simply hide the > non-strict flag from io-pgtable for that combination just so anyone who > does actually try it will simply get over-invalidation instead of > failure to initialise domains. > > Signed-off-by: Robin Murphy <robin.mur...@arm.com> > --- > drivers/iommu/arm-smmu.c | 40 +++++++++++++++++++++++++++++++++------- > 1 file changed, 33 insertions(+), 7 deletions(-) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index fd1b80ef9490..aa5be334753b 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -246,6 +246,7 @@ struct arm_smmu_domain { > const struct iommu_gather_ops *tlb_ops; > struct arm_smmu_cfg cfg; > enum arm_smmu_domain_stage stage; > + bool non_strict; > struct mutex init_mutex; /* Protects smmu pointer */ > spinlock_t cb_lock; /* Serialises ATS1* ops and > TLB syncs */ > struct iommu_domain domain; > @@ -863,6 +864,9 @@ static int arm_smmu_init_domain_context(struct > iommu_domain *domain, > if (smmu->features & ARM_SMMU_FEAT_COHERENT_WALK) > pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_NO_DMA; > > + if (smmu_domain->non_strict && cfg->fmt != ARM_SMMU_CTX_FMT_AARCH32_S) > + pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
Does this mean we end up over-invalidating when using short-descriptor? Could we not bypass the flush queue in this case instead? Ideally, we'd just reject the domain attribute but I don't know if we know about the page-table format early enough for that. Alternatively, we could force long format if the attribute is set. What do you think? Will _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu