On 2023/3/2 8:59, Jacob Pan wrote:
On VT-d platforms, legacy DMA requests without PASID use device’s
default domain, where RID_PASID is always attached. Device drivers
can then use the DMA API for all in-kernel DMA on the RID.
Ideally, devices capable of using ENQCMDS can also transparently use the
default domain, consequently DMA API. However, VT-d architecture
dictates that the PASID used by ENQCMDS must be different from the
RID_PASID value.
To provide support for transparent use of DMA API with non-RID_PASID
value, this patch implements the set_dev_pasid() function for the
default domain. The idea is that device drivers wishing to use ENQCMDS
to submit work on buffers mapped by DMA API will call
iommu_attach_device_pasid() beforehand.
Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
---
drivers/iommu/intel/iommu.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 10f657828d3a..a0cb3bc851ac 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4665,6 +4665,10 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
case IOMMU_DOMAIN_SVA:
intel_svm_remove_dev_pasid(dev, pasid);
break;
+ case IOMMU_DOMAIN_DMA:
+ case IOMMU_DOMAIN_DMA_FQ:
+ case IOMMU_DOMAIN_IDENTITY:
+ break;
default:
/* should never reach here */
WARN_ON(1);
@@ -4675,6 +4679,33 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
intel_pasid_tear_down_entry(iommu, dev, pasid, false);
}
+static int intel_iommu_set_dev_pasid(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid)
+{
+ struct device_domain_info *info = dev_iommu_priv_get(dev);
+ struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+ struct intel_iommu *iommu = info->iommu;
+ int ret = 0;
+
+ if (!sm_supported(iommu) || !info)
@info has been referenced. !info check makes no sense.
Add pasid_supported(iommu).
Do you need to check whether the domain is compatible for this rid
pasid?
+ return -ENODEV;
+
+ if (WARN_ON(pasid == PASID_RID2PASID))
+ return -EINVAL;
Add a call to domain_attach_iommu() here to get a refcount of the domain
ID. And call domain_detach_iommu() in intel_iommu_remove_dev_pasid().
+
+ if (hw_pass_through && domain_type_is_si(dmar_domain))
+ ret = intel_pasid_setup_pass_through(iommu, dmar_domain,
+ dev, pasid);
+ else if (dmar_domain->use_first_level)
+ ret = domain_setup_first_level(iommu, dmar_domain,
+ dev, pasid);
+ else
+ ret = intel_pasid_setup_second_level(iommu, dmar_domain,
+ dev, pasid);
+
+ return ret;
+}
Do you need to consider pasid cache invalidation?
+
const struct iommu_ops intel_iommu_ops = {
.capable = intel_iommu_capable,
.domain_alloc = intel_iommu_domain_alloc,
@@ -4702,6 +4733,7 @@ const struct iommu_ops intel_iommu_ops = {
.iova_to_phys = intel_iommu_iova_to_phys,
.free = intel_iommu_domain_free,
.enforce_cache_coherency = intel_iommu_enforce_cache_coherency,
+ .set_dev_pasid = intel_iommu_set_dev_pasid,
}
};
Best regards,
baolu
