[PATCH v5 14/14] iommu/arm-smmu-v3: Report events that belong to devices attached to vIOMMU

Nicolin Chen
2025-01-07T17:11:23Z

Aside from the IOPF framework, iommufd provides an additional pathway to
report hardware events, via the vEVENTQ of vIOMMU infrastructure.

Define an iommu_vevent_arm_smmuv3 uAPI structure, and report stage-1 events
in the threaded IRQ handler.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 7 +++
include/uapi/linux/iommufd.h | 15 +++++
.../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 22 +++++++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 58 +++++++++++--------
4 files changed, 77 insertions(+), 25 deletions(-)

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 4435ad7db776..d24c3d8ee397 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1066,6 +1066,7 @@ struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
int arm_smmu_attach_prepare_vmaster(struct arm_smmu_attach_state *state,
struct iommu_domain *domain);
void arm_smmu_attach_commit_vmaster(struct arm_smmu_attach_state *state);
+int arm_vmaster_report_event(struct arm_smmu_vmaster *vmaster, u64 *evt);
#else
#define arm_smmu_hw_info NULL
#define arm_vsmmu_alloc NULL
@@ -1081,6 +1082,12 @@ static inline void
arm_smmu_attach_commit_vmaster(struct arm_smmu_attach_state *state)
{
}
+
+static inline int arm_vmaster_report_event(struct arm_smmu_vmaster *vmaster,
+ u64 *evt)
+{
+ return -EOPNOTSUPP;
+}
#endif /* CONFIG_ARM_SMMU_V3_IOMMUFD */

#endif /* _ARM_SMMU_V3_H */
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 0a08aa82e7cc..55e3d5a14cca 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -1016,9 +1016,24 @@ struct iommu_ioas_change_process {
/**
* enum iommu_veventq_type - Virtual Event Queue Type
* @IOMMU_VEVENTQ_TYPE_DEFAULT: Reserved for future use
+ * @IOMMU_VEVENTQ_TYPE_ARM_SMMUV3: ARM SMMUv3 Virtual Event Queue
*/
enum iommu_veventq_type {
IOMMU_VEVENTQ_TYPE_DEFAULT = 0,
+ IOMMU_VEVENTQ_TYPE_ARM_SMMUV3 = 1,
+};
+
+/**
+ * struct iommu_vevent_arm_smmuv3 - ARM SMMUv3 Virtual Event
+ * (IOMMU_VEVENTQ_TYPE_ARM_SMMUV3)
+ * @evt: 256-bit ARM SMMUv3 Event record, little-endian.
+ * (Refer to "7.3 Event records" in SMMUv3 HW Spec)
+ *
+ * StreamID field reports a virtual device ID. To receive a virtual event for a
+ * device, a vDEVICE must be allocated via IOMMU_VDEVICE_ALLOC.
+ */
+struct iommu_vevent_arm_smmuv3 {
+ __aligned_le64 evt[4];
};

/**
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
index 2b6253ef0e8f..82b4513e56f3 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
@@ -389,9 +389,15 @@ static int arm_vsmmu_cache_invalidate(struct iommufd_viommu *viommu,
return ret;
}

+static bool arm_vsmmu_supports_veventq(unsigned int type)
+{
+ return type == IOMMU_VEVENTQ_TYPE_ARM_SMMUV3;
+}
+
static const struct iommufd_viommu_ops arm_vsmmu_ops = {
.alloc_domain_nested = arm_vsmmu_alloc_domain_nested,
.cache_invalidate = arm_vsmmu_cache_invalidate,
+ .supports_veventq = arm_vsmmu_supports_veventq,
};

struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
@@ -447,4 +453,20 @@ struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
return &vsmmu->core;
}

+int arm_vmaster_report_event(struct arm_smmu_vmaster *vmaster, u64 *evt)
+{
+ struct iommu_vevent_arm_smmuv3 vevt =
+ *(struct iommu_vevent_arm_smmuv3 *)evt;
+
+ vevt.evt[0] &= ~EVTQ_0_SID;
+ vevt.evt[0] |= FIELD_PREP(EVTQ_0_SID, vmaster->vsid);
+
+ vevt.evt[0] = cpu_to_le64(vevt.evt[0]);
+ vevt.evt[1] = cpu_to_le64(vevt.evt[1]);
+
+ return iommufd_viommu_report_event(&vmaster->vsmmu->core,
+ IOMMU_VEVENTQ_TYPE_ARM_SMMUV3, &vevt,
+ sizeof(vevt));
+}
+
MODULE_IMPORT_NS("IOMMUFD");
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 686c171dd273..59fbc342a095 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1812,8 +1812,8 @@ static void arm_smmu_decode_event(struct arm_smmu_device *smmu, u64 *raw,
mutex_unlock(&smmu->streams_mutex);
}

-static int arm_smmu_handle_event(struct arm_smmu_device *smmu,
- struct arm_smmu_event *event)
+static int arm_smmu_handle_event(struct arm_smmu_device *smmu, u64 *evt,
+ struct arm_smmu_event *event)
{
int ret = 0;
u32 perm = 0;
@@ -1831,31 +1831,30 @@ static int arm_smmu_handle_event(struct arm_smmu_device *smmu,
return -EOPNOTSUPP;
}

- if (!event->stall)
- return -EOPNOTSUPP;
-
- if (event->read)
- perm |= IOMMU_FAULT_PERM_READ;
- else
- perm |= IOMMU_FAULT_PERM_WRITE;
+ if (event->stall) {
+ if (event->read)
+ perm |= IOMMU_FAULT_PERM_READ;
+ else
+ perm |= IOMMU_FAULT_PERM_WRITE;

- if (event->instruction)
- perm |= IOMMU_FAULT_PERM_EXEC;
+ if (event->instruction)
+ perm |= IOMMU_FAULT_PERM_EXEC;

- if (event->privileged)
- perm |= IOMMU_FAULT_PERM_PRIV;
+ if (event->privileged)
+ perm |= IOMMU_FAULT_PERM_PRIV;

- flt->type = IOMMU_FAULT_PAGE_REQ;
- flt->prm = (struct iommu_fault_page_request) {
- .flags = IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE,
- .grpid = event->stag,
- .perm = perm,
- .addr = event->iova,
- };
+ flt->type = IOMMU_FAULT_PAGE_REQ;
+ flt->prm = (struct iommu_fault_page_request){
+ .flags = IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE,
+ .grpid = event->stag,
+ .perm = perm,
+ .addr = event->iova,
+ };

- if (event->ssv) {
- flt->prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
- flt->prm.pasid = event->ssid;
+ if (event->ssv) {
+ flt->prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
+ flt->prm.pasid = event->ssid;
+ }
}

mutex_lock(&smmu->streams_mutex);
@@ -1865,7 +1864,16 @@ static int arm_smmu_handle_event(struct arm_smmu_device *smmu,
goto out_unlock;
}

- ret = iommu_report_device_fault(master->dev, &fault_evt);
+ if (event->stall) {
+ ret = iommu_report_device_fault(master->dev, &fault_evt);
+ } else {
+ down_read(&master->vmaster_rwsem);
+ if (master->vmaster && !event->s2)
+ ret = arm_vmaster_report_event(master->vmaster, evt);
+ else
+ ret = -EFAULT; /* Unhandled events should be pinned */
+ up_read(&master->vmaster_rwsem);
+ }
out_unlock:
mutex_unlock(&smmu->streams_mutex);
return ret;
@@ -1943,7 +1951,7 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
do {
while (!queue_remove_raw(q, evt)) {
arm_smmu_decode_event(smmu, evt, &event);
- if (arm_smmu_handle_event(smmu, &event))
+ if (arm_smmu_handle_event(smmu, evt, &event))
arm_smmu_dump_event(smmu, evt, &event, &rs);

put_device(event.dev);
--
2.43.0