[PATCH v8 01/11] iommu: Add max_pasids field in struct iommu_device

Lu Baolu
2022-06-07T01:53:47Z

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 supports 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/intel-iommu.h | 3 ++-
include/linux/iommu.h | 2 ++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 1 +
drivers/iommu/intel/dmar.c | 7 +++++++
4 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 4f29139bbfc3..e065cbe3c857 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -479,7 +479,6 @@ enum {
#define VTD_FLAG_IRQ_REMAP_PRE_ENABLED (1 << 1)
#define VTD_FLAG_SVM_CAPABLE (1 << 2)

-extern int intel_iommu_sm;
extern spinlock_t device_domain_lock;

#define sm_supported(iommu) (intel_iommu_sm && ecap_smts((iommu)->ecap))
@@ -786,6 +785,7 @@ struct context_entry *iommu_context_addr(struct intel_iommu *iommu, u8 bus,
extern const struct iommu_ops intel_iommu_ops;

#ifdef CONFIG_INTEL_IOMMU
+extern int intel_iommu_sm;
extern int iommu_calculate_agaw(struct intel_iommu *iommu);
extern int iommu_calculate_max_sagaw(struct intel_iommu *iommu);
extern int dmar_disabled;
@@ -802,6 +802,7 @@ static inline int iommu_calculate_max_sagaw(struct intel_iommu *iommu)
}
#define dmar_disabled (1)
#define intel_iommu_enabled (0)
+#define intel_iommu_sm (0)
#endif

static inline const char *decode_prq_descriptor(char *str, size_t size,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 5e1afe169549..03fbb1b71536 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
+ * @max_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 max_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..ae8ec8df47c1 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.max_pasids = 1UL << 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 592c1e1a5d4b..6c338888061a 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -1123,6 +1123,13 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)

raw_spin_lock_init(&iommu->register_lock);

+ /*
+ * A value of N in PSS field of eCap register indicates hardware
+ * supports PASID field of N+1 bits.
+ */
+ if (pasid_supported(iommu))
+ iommu->iommu.max_pasids = 2UL << ecap_pss(iommu->ecap);
+
/*
* 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