[PATCH RESEND v9 11/13] iommu/arm-smmu-v3: Add SVA device feature

Jean-Philippe Brucker
2020-08-17T17:22:56Z

Implement the IOMMU device feature callbacks to support the SVA feature.
At the moment dev_has_feat() returns false since I/O Page Faults isn't
yet implemented.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 26 ++++++
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 49 ++++++++++++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 79 +++++++++++++++++++
3 files changed, 154 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 7b14b48a26c7..ba34914813ff 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -646,6 +646,8 @@ struct arm_smmu_master {
u32 *sids;
unsigned int num_sids;
bool ats_enabled;
+ bool sva_enabled;
+ struct list_head bonds;
unsigned int ssid_bits;
};

@@ -687,10 +689,34 @@ bool arm_smmu_free_asid(struct arm_smmu_ctx_desc *cd);

#ifdef CONFIG_ARM_SMMU_V3_SVA
bool arm_smmu_sva_supported(struct arm_smmu_device *smmu);
+bool arm_smmu_master_sva_supported(struct arm_smmu_master *master);
+bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master);
+int arm_smmu_master_enable_sva(struct arm_smmu_master *master);
+int arm_smmu_master_disable_sva(struct arm_smmu_master *master);
#else /* CONFIG_ARM_SMMU_V3_SVA */
static inline bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
{
return false;
}
+
+static inline bool arm_smmu_master_sva_supported(struct arm_smmu_master *master)
+{
+ return false;
+}
+
+static inline bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master)
+{
+ return false;
+}
+
+static inline int arm_smmu_master_enable_sva(struct arm_smmu_master *master)
+{
+ return -ENODEV;
+}
+
+static inline int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
+{
+ return -ENODEV;
+}
#endif /* CONFIG_ARM_SMMU_V3_SVA */
#endif /* _ARM_SMMU_V3_H */
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index bf81d91ce71e..28027620cf2e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -10,6 +10,8 @@
#include "arm-smmu-v3.h"
#include "../../io-pgtable-arm.h"

+static DEFINE_MUTEX(sva_lock);
+
/*
* Try to reserve this ASID in the SMMU. If it is in use, try to steal it from
* the private entry. Careful here, we may be modifying the context tables of
@@ -196,3 +198,50 @@ bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)

return true;
}
+
+static bool arm_smmu_iopf_supported(struct arm_smmu_master *master)
+{
+ return false;
+}
+
+bool arm_smmu_master_sva_supported(struct arm_smmu_master *master)
+{
+ if (!(master->smmu->features & ARM_SMMU_FEAT_SVA))
+ return false;
+
+ /* SSID and IOPF support are mandatory for the moment */
+ return master->ssid_bits && arm_smmu_iopf_supported(master);
+}
+
+bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master)
+{
+ bool enabled;
+
+ mutex_lock(&sva_lock);
+ enabled = master->sva_enabled;
+ mutex_unlock(&sva_lock);
+ return enabled;
+}
+
+int arm_smmu_master_enable_sva(struct arm_smmu_master *master)
+{
+ mutex_lock(&sva_lock);
+ master->sva_enabled = true;
+ mutex_unlock(&sva_lock);
+
+ return 0;
+}
+
+int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
+{
+ mutex_lock(&sva_lock);
+ if (!list_empty(&master->bonds)) {
+ dev_err(master->dev, "cannot disable SVA, device is bound\n");
+ mutex_unlock(&sva_lock);
+ return -EBUSY;
+ }
+ master->sva_enabled = false;
+ mutex_unlock(&sva_lock);
+
+ return 0;
+}
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 15cb3d9c1a5d..5ed5bb42298f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2163,6 +2163,16 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
master = dev_iommu_priv_get(dev);
smmu = master->smmu;

+ /*
+ * Checking that SVA is disabled ensures that this device isn't bound to
+ * any mm, and can be safely detached from its old domain. Bonds cannot
+ * be removed concurrently since we're holding the group mutex.
+ */
+ if (arm_smmu_master_sva_enabled(master)) {
+ dev_err(dev, "cannot attach - SVA enabled\n");
+ return -EBUSY;
+ }
+
arm_smmu_detach_dev(master);

mutex_lock(&smmu_domain->init_mutex);
@@ -2310,6 +2320,7 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
master->smmu = smmu;
master->sids = fwspec->ids;
master->num_sids = fwspec->num_ids;
+ INIT_LIST_HEAD(&master->bonds);
dev_iommu_priv_set(dev, master);

/* Check the SIDs are in range of the SMMU and our stream table */
@@ -2362,6 +2373,7 @@ static void arm_smmu_release_device(struct device *dev)
return;

master = dev_iommu_priv_get(dev);
+ WARN_ON(arm_smmu_master_sva_enabled(master));
arm_smmu_detach_dev(master);
arm_smmu_disable_pasid(master);
kfree(master);
@@ -2479,6 +2491,69 @@ static void arm_smmu_get_resv_regions(struct device *dev,
iommu_dma_get_resv_regions(dev, head);
}

+static bool arm_smmu_dev_has_feature(struct device *dev,
+ enum iommu_dev_features feat)
+{
+ struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+
+ if (!master)
+ return false;
+
+ switch (feat) {
+ case IOMMU_DEV_FEAT_SVA:
+ return arm_smmu_master_sva_supported(master);
+ default:
+ return false;
+ }
+}
+
+static bool arm_smmu_dev_feature_enabled(struct device *dev,
+ enum iommu_dev_features feat)
+{
+ struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+
+ if (!master)
+ return false;
+
+ switch (feat) {
+ case IOMMU_DEV_FEAT_SVA:
+ return arm_smmu_master_sva_enabled(master);
+ default:
+ return false;
+ }
+}
+
+static int arm_smmu_dev_enable_feature(struct device *dev,
+ enum iommu_dev_features feat)
+{
+ if (!arm_smmu_dev_has_feature(dev, feat))
+ return -ENODEV;
+
+ if (arm_smmu_dev_feature_enabled(dev, feat))
+ return -EBUSY;
+
+ switch (feat) {
+ case IOMMU_DEV_FEAT_SVA:
+ return arm_smmu_master_enable_sva(dev_iommu_priv_get(dev));
+ default:
+ return -EINVAL;
+ }
+}
+
+static int arm_smmu_dev_disable_feature(struct device *dev,
+ enum iommu_dev_features feat)
+{
+ if (!arm_smmu_dev_feature_enabled(dev, feat))
+ return -EINVAL;
+
+ switch (feat) {
+ case IOMMU_DEV_FEAT_SVA:
+ return arm_smmu_master_disable_sva(dev_iommu_priv_get(dev));
+ default:
+ return -EINVAL;
+ }
+}
+
static struct iommu_ops arm_smmu_ops = {
.capable = arm_smmu_capable,
.domain_alloc = arm_smmu_domain_alloc,
@@ -2497,6 +2572,10 @@ static struct iommu_ops arm_smmu_ops = {
.of_xlate = arm_smmu_of_xlate,
.get_resv_regions = arm_smmu_get_resv_regions,
.put_resv_regions = generic_iommu_put_resv_regions,
+ .dev_has_feat = arm_smmu_dev_has_feature,
+ .dev_feat_enabled = arm_smmu_dev_feature_enabled,
+ .dev_enable_feat = arm_smmu_dev_enable_feature,
+ .dev_disable_feat = arm_smmu_dev_disable_feature,
.pgsize_bitmap = -1UL, /* Restricted during device attach */
};