On 2024-08-07 12:41 am, Jason Gunthorpe wrote:
For SMMUv3 the parent must be a S2 domain, which can be composed
into a IOMMU_DOMAIN_NESTED.
In future the S2 parent will also need a VMID linked to the VIOMMU and
even to KVM.
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 6bbe4aa7b9511c..5faaccef707ef1 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3103,7 +3103,8 @@ arm_smmu_domain_alloc_user(struct device *dev, u32 flags,
const struct iommu_user_data *user_data)
{
struct arm_smmu_master *master = dev_iommu_priv_get(dev);
- const u32 PAGING_FLAGS = IOMMU_HWPT_ALLOC_DIRTY_TRACKING;
+ const u32 PAGING_FLAGS = IOMMU_HWPT_ALLOC_DIRTY_TRACKING |
+ IOMMU_HWPT_ALLOC_NEST_PARENT;
struct arm_smmu_domain *smmu_domain;
int ret;
@@ -3116,6 +3117,14 @@ arm_smmu_domain_alloc_user(struct device *dev, u32 flags,
if (!smmu_domain)
return ERR_PTR(-ENOMEM);
+ if (flags & IOMMU_HWPT_ALLOC_NEST_PARENT) {
+ if (!(master->smmu->features & ARM_SMMU_FEAT_TRANS_S2)) {
Nope, nesting needs to rely on FEAT_NESTING, that's why it exists. S2
alone isn't sufficient - without S1 there's nothing to expose to
userspace, so zero point in having a "nested" domain with nothing to
nest into it - but furthermore we need S2 *without* unsafe broken TLBs.
Thanks,
Robin.
+ ret = -EOPNOTSUPP;
+ goto err_free;
+ }
+ smmu_domain->stage = ARM_SMMU_DOMAIN_S2;
+ }
+
smmu_domain->domain.type = IOMMU_DOMAIN_UNMANAGED;
smmu_domain->domain.ops = arm_smmu_ops.default_domain_ops;
ret = arm_smmu_domain_finalise(smmu_domain, master->smmu, flags);
