[PATCH v3 10/11] iommu: Add debugging on domain lifetime for iopf

[Lu Baolu]

The iopf handling framework in the core requires the domain's lifetime
should cover all possible iopfs. This has been documented in the comments
for iommu_queue_iopf() which is the entry of the framework.

Add some debugging to enforce this.

Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
 drivers/iommu/io-pgfault.c |  3 +++
 drivers/iommu/iommu.c      | 24 ++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
index a61c2aabd1b8..bf667ed39b01 100644
--- a/drivers/iommu/io-pgfault.c
+++ b/drivers/iommu/io-pgfault.c
@@ -129,6 +129,9 @@ int iommu_queue_iopf(struct iommu_fault *fault, struct device *dev)
 		domain = iommu_get_domain_for_dev(dev);
 
 	if (!domain || !domain->iopf_handler) {
+		dev_warn_ratelimited(dev,
+			"iopf from pasid %d received without handler installed\n",
+			 fault->prm.pasid);
 		ret = -ENODEV;
 		goto cleanup_partial;
 	}
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 9b622088c741..c170bcd3f05e 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2032,6 +2032,28 @@ int iommu_deferred_attach(struct device *dev, struct iommu_domain *domain)
 	return 0;
 }
 
+static void assert_no_pending_iopf(struct device *dev, ioasid_t pasid)
+{
+	struct iommu_fault_param *iopf_param = dev->iommu->fault_param;
+	struct iommu_fault_event *evt;
+	struct iopf_fault *iopf;
+
+	if (!iopf_param)
+		return;
+
+	mutex_lock(&iopf_param->lock);
+	list_for_each_entry(iopf, &iopf_param->partial, list) {
+		if (WARN_ON(iopf->fault.prm.pasid == pasid))
+			break;
+	}
+
+	list_for_each_entry(evt, &iopf_param->faults, list) {
+		if (WARN_ON(evt->fault.prm.pasid == pasid))
+			break;
+	}
+	mutex_unlock(&iopf_param->lock);
+}
+
 void iommu_detach_device(struct iommu_domain *domain, struct device *dev)
 {
 	/* Caller must be a probed driver on dev */
@@ -2040,6 +2062,7 @@ void iommu_detach_device(struct iommu_domain *domain, struct device *dev)
 	if (!group)
 		return;
 
+	assert_no_pending_iopf(dev, IOMMU_NO_PASID);
 	mutex_lock(&group->mutex);
 	if (WARN_ON(domain != group->domain) ||
 	    WARN_ON(list_count_nodes(&group->devices) != 1))
@@ -3340,6 +3363,7 @@ void iommu_detach_device_pasid(struct iommu_domain *domain, struct device *dev,
 	/* Caller must be a probed driver on dev */
 	struct iommu_group *group = dev->iommu_group;
 
+	assert_no_pending_iopf(dev, pasid);
 	mutex_lock(&group->mutex);
 	__iommu_remove_group_pasid(group, pasid);
 	WARN_ON(xa_erase(&group->pasid_array, pasid) != domain);
-- 
2.34.1