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

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Message-Id: <20230817234047.195194-11-baolu.lu@linux.intel.com>
Date:   Fri, 18 Aug 2023 07:40:46 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Kevin Tian <kevin.tian@...el.com>,
        Jean-Philippe Brucker <jean-philippe@...aro.org>,
        Nicolin Chen <nicolinc@...dia.com>
Cc:     Yi Liu <yi.l.liu@...el.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        iommu@...ts.linux.dev, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Lu Baolu <baolu.lu@...ux.intel.com>,
        Jason Gunthorpe <jgg@...dia.com>
Subject: [PATCH v3 10/11] iommu: Add debugging on domain lifetime for iopf

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@...dia.com>
Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 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