[PATCH v6 02/12] iommu: Add pasid_bits field in struct dev_iommu

[Lu Baolu]

Use this field to save the pasid/ssid bits that a device is able to
support with its IOMMU hardware. It is a generic attribute of a device
and lifting it into the per-device dev_iommu struct makes it possible
to allocate a PASID for device without calls into the IOMMU drivers.
Any iommu driver which suports PASID related features should set this
field before features are enabled on the devices.

For initialization of this field in the VT-d driver, the
info->pasid_supported is only set for PCI devices. So the status is
that non-PCI SVA hasn't been supported yet. Setting this field only for
PCI devices has no functional change.

Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
---
 include/linux/iommu.h                       | 1 +
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 ++
 drivers/iommu/intel/iommu.c                 | 5 ++++-
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 5e1afe169549..b8ffaf2cb1d0 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -373,6 +373,7 @@ struct dev_iommu {
 	struct iommu_fwspec		*fwspec;
 	struct iommu_device		*iommu_dev;
 	void				*priv;
+	unsigned int			pasid_bits;
 };
 
 int iommu_device_register(struct iommu_device *iommu,
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 627a3ed5ee8f..afc63fce6107 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2681,6 +2681,8 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
 	    smmu->features & ARM_SMMU_FEAT_STALL_FORCE)
 		master->stall_enabled = true;
 
+	dev->iommu->pasid_bits = master->ssid_bits;
+
 	return &smmu->iommu;
 
 err_free_master:
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 2990f80c5e08..99643f897f26 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4624,8 +4624,11 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev)
 			if (pasid_supported(iommu)) {
 				int features = pci_pasid_features(pdev);
 
-				if (features >= 0)
+				if (features >= 0) {
 					info->pasid_supported = features | 1;
+					dev->iommu->pasid_bits =
+						fls(pci_max_pasids(pdev)) - 1;
+				}
 			}
 
 			if (info->ats_supported && ecap_prs(iommu->ecap) &&
-- 
2.25.1