[PATCH v7 01/10] iommu: Add pasids field in struct iommu_device

Lu Baolu
2022-05-19T07:24:38Z

Use this field to keep the number of supported PASIDs that an IOMMU
hardware is able to support. This is a generic attribute of an IOMMU
and lifting it into the per-IOMMU device structure 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 enabling them on the devices.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
include/linux/iommu.h | 2 ++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 1 +
drivers/iommu/intel/dmar.c | 4 ++++
3 files changed, 7 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 5e1afe169549..da423e87f248 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -318,12 +318,14 @@ struct iommu_domain_ops {
* @list: Used by the iommu-core to keep a list of registered iommus
* @ops: iommu-ops for talking to this iommu
* @dev: struct device for sysfs handling
+ * @pasids: number of supported PASIDs
*/
struct iommu_device {
struct list_head list;
const struct iommu_ops *ops;
struct fwnode_handle *fwnode;
struct device *dev;
+ u32 pasids;
};

/**
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 88817a3376ef..6e2cd082c670 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3546,6 +3546,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
/* SID/SSID sizes */
smmu->ssid_bits = FIELD_GET(IDR1_SSIDSIZE, reg);
smmu->sid_bits = FIELD_GET(IDR1_SIDSIZE, reg);
+ smmu->iommu.pasids = smmu->ssid_bits;

/*
* If the SMMU supports fewer bits than would fill a single L2 stream
diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 4de960834a1b..1c3cf267934d 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -1126,6 +1126,10 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)

raw_spin_lock_init(&iommu->register_lock);

+ /* Supports full 20-bit PASID in scalable mode. */
+ if (ecap_pasid(iommu->ecap))
+ iommu->iommu.pasids = 1UL << 20;
+
/*
* This is only for hotplug; at boot time intel_iommu_enabled won't
* be set yet. When intel_iommu_init() runs, it registers the units
--
2.25.1