linux-kernel - [PATCH 3/9] iommu: Add common code to handle IO page faults

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Date:   Tue, 11 Jul 2023 09:06:36 +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>
Subject: [PATCH 3/9] iommu: Add common code to handle IO page faults

The individual iommu drivers report iommu faults by calling
iommu_report_device_fault(), where a pre-registered device fault handler
is called to route the fault to another fault handler installed on the
corresponding iommu domain.

The pre-registered device fault handler is static and won't be dynamic
as the fault handler is eventually per iommu domain. Replace the device
fault handler with a static common code to avoid unnecessary code.

Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 drivers/iommu/iommu.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index da340f11c5f5..41328f03e8b4 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1278,6 +1278,28 @@ int iommu_unregister_device_fault_handler(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(iommu_unregister_device_fault_handler);
 
+static int iommu_handle_io_pgfault(struct device *dev,
+				   struct iommu_fault *fault)
+{
+	struct iommu_domain *domain;
+
+	if (fault->type != IOMMU_FAULT_PAGE_REQ)
+		return -EINVAL;
+
+	if (fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID)
+		domain = iommu_get_domain_for_dev_pasid(dev, fault->prm.pasid, 0);
+	else
+		domain = iommu_get_domain_for_dev(dev);
+
+	if (!domain || !domain->iopf_handler)
+		return -ENODEV;
+
+	if (domain->iopf_handler == iommu_sva_handle_iopf)
+		return iommu_queue_iopf(fault, dev);
+
+	return domain->iopf_handler(fault, dev, domain->fault_data);
+}
+
 /**
  * iommu_report_device_fault() - Report fault event to device driver
  * @dev: the device
@@ -1320,7 +1342,7 @@ int iommu_report_device_fault(struct device *dev, struct iommu_fault_event *evt)
 		mutex_unlock(&fparam->lock);
 	}
 
-	ret = fparam->handler(&evt->fault, fparam->data);
+	ret = iommu_handle_io_pgfault(dev, &evt->fault);
 	if (ret && evt_pending) {
 		mutex_lock(&fparam->lock);
 		list_del(&evt_pending->list);
-- 
2.34.1