Re: [PATCH] iommu/arm-smmu: Force identity domains for legacy binding
On Tue, 10 May 2022 09:38:58 +0100, Robin Murphy wrote: > When using the legacy "mmu-masters" DT binding, we reject DMA domains > since we have no guarantee of driver probe order and thus can't rely on > client drivers getting the correct DMA ops. However, we can do better > than fall back to the old no-default-domain behaviour now, by forcing an > identity default domain instead. This also means that detaching from a > VFIO domain can actually work - that looks to have been broken for over > 6 years, so clearly isn't something that legacy binding users care > about, but we may as well make the driver code make sense anyway. > > [...] Applied to will (for-joerg/arm-smmu/updates), thanks! [1/1] iommu/arm-smmu: Force identity domains for legacy binding https://git.kernel.org/will/c/628bf55b6204 Cheers, -- Will https://fixes.arm64.dev https://next.arm64.dev https://will.arm64.dev ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
[PATCH] iommu/arm-smmu: Force identity domains for legacy binding
When using the legacy "mmu-masters" DT binding, we reject DMA domains since we have no guarantee of driver probe order and thus can't rely on client drivers getting the correct DMA ops. However, we can do better than fall back to the old no-default-domain behaviour now, by forcing an identity default domain instead. This also means that detaching from a VFIO domain can actually work - that looks to have been broken for over 6 years, so clearly isn't something that legacy binding users care about, but we may as well make the driver code make sense anyway. Suggested-by: Jason Gunthorpe Signed-off-by: Robin Murphy --- drivers/iommu/arm/arm-smmu/arm-smmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c index 568cce590ccc..e7ec2b74a28d 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c @@ -1574,6 +1574,9 @@ static int arm_smmu_def_domain_type(struct device *dev) struct arm_smmu_master_cfg *cfg = dev_iommu_priv_get(dev); const struct arm_smmu_impl *impl = cfg->smmu->impl; + if (using_legacy_binding) + return IOMMU_DOMAIN_IDENTITY; + if (impl && impl->def_domain_type) return impl->def_domain_type(dev); -- 2.35.3.dirty ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
