linux-kernel - [PATCH 1/2] iommu/vt-d: Remove debugfs use of private data field

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Date: Fri,  8 Mar 2024 18:38:10 +0800
From: Jingqi Liu <Jingqi.liu@...el.com>
To: iommu@...ts.linux.dev,
	Lu Baolu <baolu.lu@...ux.intel.com>,
	Tian Kevin <kevin.tian@...el.com>,
	Joerg Roedel <joro@...tes.org>,
	Will Deacon <will@...nel.org>,
	Robin Murphy <robin.murphy@....com>
Cc: linux-kernel@...r.kernel.org,
	Jingqi Liu <Jingqi.liu@...el.com>
Subject: [PATCH 1/2] iommu/vt-d: Remove debugfs use of private data field

Since the page fault report and response have been tracked by ftrace,
the users can easily calculate the time used for a page fault
handling. There's no need to expose the similar functionality in
debugfs. Hence, remove the corresponding operations in debugfs.

Signed-off-by: Jingqi Liu <Jingqi.liu@...el.com>
---
 drivers/iommu/intel/debugfs.c | 7 -------
 drivers/iommu/intel/perf.h    | 1 -
 drivers/iommu/intel/svm.c     | 9 ---------
 3 files changed, 17 deletions(-)

diff --git a/drivers/iommu/intel/debugfs.c b/drivers/iommu/intel/debugfs.c
index 86b506af7daa..affbf4a1558d 100644
--- a/drivers/iommu/intel/debugfs.c
+++ b/drivers/iommu/intel/debugfs.c
@@ -706,7 +706,6 @@ static ssize_t dmar_perf_latency_write(struct file *filp,
 			dmar_latency_disable(iommu, DMAR_LATENCY_INV_IOTLB);
 			dmar_latency_disable(iommu, DMAR_LATENCY_INV_DEVTLB);
 			dmar_latency_disable(iommu, DMAR_LATENCY_INV_IEC);
-			dmar_latency_disable(iommu, DMAR_LATENCY_PRQ);
 		}
 		rcu_read_unlock();
 		break;
@@ -728,12 +727,6 @@ static ssize_t dmar_perf_latency_write(struct file *filp,
 			dmar_latency_enable(iommu, DMAR_LATENCY_INV_IEC);
 		rcu_read_unlock();
 		break;
-	case 4:
-		rcu_read_lock();
-		for_each_active_iommu(iommu, drhd)
-			dmar_latency_enable(iommu, DMAR_LATENCY_PRQ);
-		rcu_read_unlock();
-		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/drivers/iommu/intel/perf.h b/drivers/iommu/intel/perf.h
index fd6db8049d1a..df9a36942d64 100644
--- a/drivers/iommu/intel/perf.h
+++ b/drivers/iommu/intel/perf.h
@@ -11,7 +11,6 @@ enum latency_type {
 	DMAR_LATENCY_INV_IOTLB = 0,
 	DMAR_LATENCY_INV_DEVTLB,
 	DMAR_LATENCY_INV_IEC,
-	DMAR_LATENCY_PRQ,
 	DMAR_LATENCY_NUM
 };
 
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index c1bed89b1026..4b2eeb55489d 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -583,12 +583,6 @@ static void intel_svm_prq_report(struct intel_iommu *iommu, struct device *dev,
 		event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
 		event.fault.prm.private_data[0] = desc->priv_data[0];
 		event.fault.prm.private_data[1] = desc->priv_data[1];
-	} else if (dmar_latency_enabled(iommu, DMAR_LATENCY_PRQ)) {
-		/*
-		 * If the private data fields are not used by hardware, use it
-		 * to monitor the prq handle latency.
-		 */
-		event.fault.prm.private_data[0] = ktime_to_ns(ktime_get());
 	}
 
 	iommu_report_device_fault(dev, &event);
@@ -768,9 +762,6 @@ void intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
 		if (private_present) {
 			desc.qw2 = prm->private_data[0];
 			desc.qw3 = prm->private_data[1];
-		} else if (prm->private_data[0]) {
-			dmar_latency_update(iommu, DMAR_LATENCY_PRQ,
-				ktime_to_ns(ktime_get()) - prm->private_data[0]);
 		}
 
 		qi_submit_sync(iommu, &desc, 1, 0);
-- 
2.21.3