[PATCH v5 06/25] iommu/sva: Register page fault handler

[Jean-Philippe Brucker]

When enabling SVA, register the fault handler. Device driver will register
an I/O page fault queue before or after calling iommu_sva_enable. The
fault queue must be flushed before any io_mm is freed, to make sure that
its PASID isn't used in any fault queue, and can be reallocated.

Signed-off-by: Jean-Philippe Brucker <jean-phili...@linaro.org>
---
 drivers/iommu/Kconfig     |  1 +
 drivers/iommu/iommu-sva.c | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index bf620bf48da03..411a7ee2ab12d 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -106,6 +106,7 @@ config IOMMU_DMA
 config IOMMU_SVA
        bool
        select IOASID
+       select IOMMU_PAGE_FAULT
        select IOMMU_API
        select MMU_NOTIFIER
 
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index b177d6cbf4fff..00d5e7e895e80 100644
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -420,6 +420,12 @@ void iommu_sva_unbind_generic(struct iommu_sva *handle)
        if (WARN_ON(!param))
                return;
 
+       /*
+        * Caller stopped the device from issuing PASIDs, now make sure they are
+        * out of the fault queue.
+        */
+       iopf_queue_flush_dev(handle->dev, bond->io_mm->pasid);
+
        mutex_lock(&param->sva_lock);
        mutex_lock(&iommu_sva_lock);
        io_mm_detach(bond);
@@ -457,6 +463,10 @@ int iommu_sva_enable(struct device *dev, struct 
iommu_sva_param *sva_param)
                goto err_unlock;
        }
 
+       ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf, dev);
+       if (ret)
+               goto err_unlock;
+
        dev->iommu->sva_param = new_param;
        mutex_unlock(&param->sva_lock);
        return 0;
@@ -494,6 +504,7 @@ int iommu_sva_disable(struct device *dev)
                goto out_unlock;
        }
 
+       iommu_unregister_device_fault_handler(dev);
        kfree(param->sva_param);
        param->sva_param = NULL;
 out_unlock:
-- 
2.26.0

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