[PATCH v3 1/4] iommu: Introduce device_iommu_capable()

Robin Murphy
2022-04-05T23:42:20Z

iommu_capable() only really works for systems where all IOMMU instances
are completely homogeneous, and all devices are IOMMU-mapped. Implement
the new variant which can give an accurate answer for whichever device
the caller is actually interested in.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---

v3: New patch; now that the dev_iommu_ops() work has landed we can go
straight to a proper implementation. Also s/dev/device/ to match
the precedent of device_iommu_mapped() for the public API.

drivers/iommu/amd/iommu.c | 2 +-
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 +-
drivers/iommu/arm/arm-smmu/arm-smmu.c | 2 +-
drivers/iommu/arm/arm-smmu/qcom_iommu.c | 2 +-
drivers/iommu/fsl_pamu_domain.c | 2 +-
drivers/iommu/intel/iommu.c | 2 +-
drivers/iommu/iommu.c | 25 ++++++++++++++++++++-
drivers/iommu/s390-iommu.c | 2 +-
include/linux/iommu.h | 8 ++++++-
9 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 1160a13c80ab..e412a50dce59 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2132,7 +2132,7 @@ static phys_addr_t amd_iommu_iova_to_phys(struct iommu_domain *dom,
return ops->iova_to_phys(ops, iova);
}

-static bool amd_iommu_capable(enum iommu_cap cap)
+static bool amd_iommu_capable(struct device *dev, enum iommu_cap cap)
{
switch (cap) {
case IOMMU_CAP_CACHE_COHERENCY:
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 73b7b1b17b77..b221525c31b9 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1981,7 +1981,7 @@ static const struct iommu_flush_ops arm_smmu_flush_ops = {
};

/* IOMMU API */
-static bool arm_smmu_capable(enum iommu_cap cap)
+static bool arm_smmu_capable(struct device *dev, enum iommu_cap cap)
{
switch (cap) {
case IOMMU_CAP_CACHE_COHERENCY:
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index f0bec4a35df5..34cab56b9c6d 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -1313,7 +1313,7 @@ static phys_addr_t arm_smmu_iova_to_phys(struct iommu_domain *domain,
return ops->iova_to_phys(ops, iova);
}

-static bool arm_smmu_capable(enum iommu_cap cap)
+static bool arm_smmu_capable(struct device *dev, enum iommu_cap cap)
{
switch (cap) {
case IOMMU_CAP_CACHE_COHERENCY:
diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index 80af00f468b4..028649203d33 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -493,7 +493,7 @@ static phys_addr_t qcom_iommu_iova_to_phys(struct iommu_domain *domain,
return ret;
}

-static bool qcom_iommu_capable(enum iommu_cap cap)
+static bool qcom_iommu_capable(struct device *dev, enum iommu_cap cap)
{
switch (cap) {
case IOMMU_CAP_CACHE_COHERENCY:
diff --git a/drivers/iommu/fsl_pamu_domain.c b/drivers/iommu/fsl_pamu_domain.c
index 7274f86b2bc4..ddf5ab28615c 100644
--- a/drivers/iommu/fsl_pamu_domain.c
+++ b/drivers/iommu/fsl_pamu_domain.c
@@ -177,7 +177,7 @@ static phys_addr_t fsl_pamu_iova_to_phys(struct iommu_domain *domain,
return iova;
}

-static bool fsl_pamu_capable(enum iommu_cap cap)
+static bool fsl_pamu_capable(struct device *dev, enum iommu_cap cap)
{
return cap == IOMMU_CAP_CACHE_COHERENCY;
}
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 21111491ddfd..255304eb3b1f 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4544,7 +4544,7 @@ static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
return phys;
}

-static bool intel_iommu_capable(enum iommu_cap cap)
+static bool intel_iommu_capable(struct device *dev, enum iommu_cap cap)
{
if (cap == IOMMU_CAP_CACHE_COHERENCY)
return domain_update_iommu_snooping(NULL);
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index efad7c1675e0..469574e84e6a 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1889,12 +1889,35 @@ static int iommu_bus_init(struct bus_type *bus)
return err;
}

+/**
+ * device_iommu_capable() - check for a general IOMMU capability
+ * @dev: device to which the capability would be relevant, if available
+ * @cap: IOMMU capability
+ *
+ * Return: true if an IOMMU is present and supports the given capability
+ * for the given device, otherwise false.
+ */
+bool device_iommu_capable(struct device *dev, enum iommu_cap cap)
+{
+ const struct iommu_ops *ops;
+
+ if (!dev->iommu || !dev->iommu->iommu_dev)
+ return false;
+
+ ops = dev_iommu_ops(dev);
+ if (!ops->capable)
+ return false;
+
+ return ops->capable(dev, cap);
+}
+EXPORT_SYMBOL_GPL(device_iommu_capable);
+
bool iommu_capable(struct bus_type *bus, enum iommu_cap cap)
{
if (!bus->iommu_ops || !bus->iommu_ops->capable)
return false;

- return bus->iommu_ops->capable(cap);
+ return bus->iommu_ops->capable(NULL, cap);
}
EXPORT_SYMBOL_GPL(iommu_capable);

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index 5f5f4bd91e6f..ea4ba9de04af 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -39,7 +39,7 @@ static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
return container_of(dom, struct s390_domain, domain);
}

-static bool s390_iommu_capable(enum iommu_cap cap)
+static bool s390_iommu_capable(struct device *dev, enum iommu_cap cap)
{
switch (cap) {
case IOMMU_CAP_CACHE_COHERENCY:
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 4a25f8241207..1fa927e6f1c6 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -219,7 +219,7 @@ struct iommu_iotlb_gather {
* @owner: Driver module providing these ops
*/
struct iommu_ops {
- bool (*capable)(enum iommu_cap);
+ bool (*capable)(struct device *dev, enum iommu_cap);

/* Domain allocation and freeing by the iommu driver */
struct iommu_domain *(*domain_alloc)(unsigned iommu_domain_type);
@@ -415,6 +415,7 @@ static inline const struct iommu_ops *dev_iommu_ops(struct device *dev)
#define IOMMU_GROUP_NOTIFY_UNBOUND_DRIVER 6 /* Post Driver unbind */

extern int bus_iommu_probe(struct bus_type *bus);
+extern bool device_iommu_capable(struct device *dev, enum iommu_cap cap);
extern bool iommu_capable(struct bus_type *bus, enum iommu_cap cap);
extern struct iommu_domain *iommu_domain_alloc(struct device *dev);
extern struct iommu_group *iommu_group_get_by_id(int id);
@@ -682,6 +683,11 @@ struct iommu_device {};
struct iommu_fault_param {};
struct iommu_iotlb_gather {};

+static inline bool device_iommu_capable(struct device *dev, enum iommu_cap cap)
+{
+ return false;
+}
+
static inline bool iommu_capable(struct bus_type *bus, enum iommu_cap cap)
{
return false;
--
2.28.0.dirty