[RFC v16 2/9] iommu: Introduce iommu_get_nesting

Eric Auger
2021-10-27T10:45:17Z

Add iommu_get_nesting() which allow to retrieve whether a domain
uses nested stages.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 ++++++++
drivers/iommu/arm/arm-smmu/arm-smmu.c | 8 ++++++++
drivers/iommu/intel/iommu.c | 13 +++++++++++++
drivers/iommu/iommu.c | 10 ++++++++++
include/linux/iommu.h | 8 ++++++++
5 files changed, 47 insertions(+)

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 a388e318f86e..61477853a536 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2731,6 +2731,13 @@ static int arm_smmu_enable_nesting(struct iommu_domain *domain)
return ret;
}

+static bool arm_smmu_get_nesting(struct iommu_domain *domain)
+{
+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+
+ return smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED;
+}
+
static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args)
{
return iommu_fwspec_add_ids(dev, args->args, 1);
@@ -2845,6 +2852,7 @@ static struct iommu_ops arm_smmu_ops = {
.release_device = arm_smmu_release_device,
.device_group = arm_smmu_device_group,
.enable_nesting = arm_smmu_enable_nesting,
+ .get_nesting = arm_smmu_get_nesting,
.of_xlate = arm_smmu_of_xlate,
.get_resv_regions = arm_smmu_get_resv_regions,
.put_resv_regions = generic_iommu_put_resv_regions,
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 4bc75c4ce402..167cf1d51279 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -1522,6 +1522,13 @@ static int arm_smmu_enable_nesting(struct iommu_domain *domain)
return ret;
}

+static bool arm_smmu_get_nesting(struct iommu_domain *domain)
+{
+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+
+ return smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED;
+}
+
static int arm_smmu_set_pgtable_quirks(struct iommu_domain *domain,
unsigned long quirks)
{
@@ -1595,6 +1602,7 @@ static struct iommu_ops arm_smmu_ops = {
.probe_finalize = arm_smmu_probe_finalize,
.device_group = arm_smmu_device_group,
.enable_nesting = arm_smmu_enable_nesting,
+ .get_nesting = arm_smmu_get_nesting,
.set_pgtable_quirks = arm_smmu_set_pgtable_quirks,
.of_xlate = arm_smmu_of_xlate,
.get_resv_regions = arm_smmu_get_resv_regions,
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index d75f59ae28e6..e42767bd47f9 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5524,6 +5524,18 @@ intel_iommu_enable_nesting(struct iommu_domain *domain)
return ret;
}

+static bool intel_iommu_get_nesting(struct iommu_domain *domain)
+{
+ struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+ bool nesting;
+
+ spin_lock_irqsave(&device_domain_lock, flags);
+ nesting = dmar_domain->flags & DOMAIN_FLAG_NESTING_MODE &&
+ !(dmar_domain->flags & DOMAIN_FLAG_USE_FIRST_LEVEL);
+ spin_unlock_irqrestore(&device_domain_lock, flags);
+ return nesting;
+}
+
/*
* Check that the device does not live on an external facing PCI port that is
* marked as untrusted. Such devices should not be able to apply quirks and
@@ -5561,6 +5573,7 @@ const struct iommu_ops intel_iommu_ops = {
.domain_alloc = intel_iommu_domain_alloc,
.domain_free = intel_iommu_domain_free,
.enable_nesting = intel_iommu_enable_nesting,
+ .get_nesting = intel_iommu_get_nesting,
.attach_dev = intel_iommu_attach_device,
.detach_dev = intel_iommu_detach_device,
.aux_attach_dev = intel_iommu_aux_attach_device,
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 6033c263c6e6..3e639c4e8015 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2843,6 +2843,16 @@ int iommu_enable_nesting(struct iommu_domain *domain)
}
EXPORT_SYMBOL_GPL(iommu_enable_nesting);

+bool iommu_get_nesting(struct iommu_domain *domain)
+{
+ if (domain->type != IOMMU_DOMAIN_UNMANAGED)
+ return false;
+ if (!domain->ops->enable_nesting)
+ return false;
+ return domain->ops->get_nesting(domain);
+}
+EXPORT_SYMBOL_GPL(iommu_get_nesting);
+
int iommu_set_pgtable_quirks(struct iommu_domain *domain,
unsigned long quirk)
{
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index e34a1b1c805b..846e19151f40 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -213,6 +213,7 @@ struct iommu_iotlb_gather {
* group and attached to the groups domain
* @device_group: find iommu group for a particular device
* @enable_nesting: Enable nesting
+ * @get_nesting: get whether the domain uses nested stages
* @set_pgtable_quirks: Set io page table quirks (IO_PGTABLE_QUIRK_*)
* @get_resv_regions: Request list of reserved regions for a device
* @put_resv_regions: Free list of reserved regions for a device
@@ -271,6 +272,7 @@ struct iommu_ops {
void (*probe_finalize)(struct device *dev);
struct iommu_group *(*device_group)(struct device *dev);
int (*enable_nesting)(struct iommu_domain *domain);
+ bool (*get_nesting)(struct iommu_domain *domain);
int (*set_pgtable_quirks)(struct iommu_domain *domain,
unsigned long quirks);

@@ -690,6 +692,7 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev,
void *drvdata);
void iommu_sva_unbind_device(struct iommu_sva *handle);
u32 iommu_sva_get_pasid(struct iommu_sva *handle);
+bool iommu_get_nesting(struct iommu_domain *domain);

#else /* CONFIG_IOMMU_API */

@@ -1108,6 +1111,11 @@ static inline struct iommu_fwspec *dev_iommu_fwspec_get(struct device *dev)
{
return NULL;
}
+
+static inline bool iommu_get_nesting(struct iommu_domain *domain)
+{
+ return false;
+}
#endif /* CONFIG_IOMMU_API */

/**
--
2.26.3