@@ -443,6 +443,8 @@ static void iommu_notifier_release(struct mmu_notifier *mn, struct mm_struct *mm
dev_WARN(bond->dev, "possible leak of PASID %u",
io_mm->pasid);
+ iopf_queue_flush_dev(bond->dev, io_mm->pasid);
+
spin_lock(&iommu_sva_lock);
next = list_next_entry(bond, mm_head);
@@ -590,6 +592,12 @@ int __iommu_sva_unbind_device(struct device *dev, int pasid)
goto out_unlock;
}
+ /*
+ * Caller stopped the device from issuing PASIDs, now make sure they are
+ * out of the fault queue.
+ */
+ iopf_queue_flush_dev(dev, pasid);
+
/* spin_lock_irq matches the one in wait_event_lock_irq */
spin_lock_irq(&iommu_sva_lock);
list_for_each_entry(bond, ¶m->mm_list, dev_head) {
@@ -615,6 +623,8 @@ static void __iommu_sva_unbind_device_all(struct device *dev)
if (!param)
return;
+ iopf_queue_flush_dev(dev, IOMMU_PASID_INVALID);
+
spin_lock_irq(&iommu_sva_lock);
list_for_each_entry_safe(bond, next, ¶m->mm_list, dev_head)
io_mm_detach_locked(bond, true);
@@ -680,6 +690,9 @@ EXPORT_SYMBOL_GPL(iommu_sva_find);
* overrides it. Similarly, @min_pasid overrides the lower PASID limit supported
* by the IOMMU.
*
+ * If the device should support recoverable I/O Page Faults (e.g. PCI PRI), the
+ * IOMMU_SVA_FEAT_IOPF feature must be requested.
+ *
* @mm_exit is called when an address space bound to the device is about to be
* torn down by exit_mmap. After @mm_exit returns, the device must not issue any
* more transaction with the PASID given as argument. The handler gets an opaque
@@ -707,7 +720,7 @@ int iommu_sva_init_device(struct device *dev, unsigned long features,
if (!domain || !domain->ops->sva_init_device)
return -ENODEV;
- if (features)
+ if (features & ~IOMMU_SVA_FEAT_IOPF)
return -EINVAL;
param = kzalloc(sizeof(*param), GFP_KERNEL);
@@ -734,10 +747,20 @@ int iommu_sva_init_device(struct device *dev, unsigned long features,
if (ret)
goto err_unlock;
+ if (features & IOMMU_SVA_FEAT_IOPF) {
+ ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf,
+ dev);
+ if (ret)
+ goto err_shutdown;
+ }
+
dev->iommu_param->sva_param = param;
mutex_unlock(&dev->iommu_param->sva_lock);
return 0;
+err_shutdown:
+ if (domain->ops->sva_shutdown_device)
+ domain->ops->sva_shutdown_device(dev);
err_unlock:
mutex_unlock(&dev->iommu_param->sva_lock);
kfree(param);
@@ -766,6 +789,7 @@ void iommu_sva_shutdown_device(struct device *dev)
goto out_unlock;
__iommu_sva_unbind_device_all(dev);
+ iommu_unregister_device_fault_handler(dev);
if (domain->ops->sva_shutdown_device)
domain->ops->sva_shutdown_device(dev);
@@ -2342,9 +2342,9 @@ EXPORT_SYMBOL_GPL(iommu_fwspec_add_ids);
* iommu_sva_init_device() must be called first, to initialize the required SVA
* features. @flags must be a subset of these features.
*
- * The caller must pin down using get_user_pages*() all mappings shared with the
- * device. mlock() isn't sufficient, as it doesn't prevent minor page faults
- * (e.g. copy-on-write).
+ * If IOMMU_SVA_FEAT_IOPF isn't requested, the caller must pin down using
+ * get_user_pages*() all mappings shared with the device. mlock() isn't
+ * sufficient, as it doesn't prevent minor page faults (e.g. copy-on-write).
*
* On success, 0 is returned and @pasid contains a valid ID. Otherwise, an error
* is returned.
@@ -65,6 +65,8 @@ typedef int (*iommu_mm_exit_handler_t)(struct device *dev, int pasid, void *);
#define IOMMU_PASID_INVALID (-1)
+#define IOMMU_SVA_FEAT_IOPF (1 << 0)
+
struct iommu_domain_geometry {
dma_addr_t aperture_start; /* First address that can be mapped */
dma_addr_t aperture_end; /* Last address that can be mapped */
Let users call iommu_sva_init_device() with the IOMMU_SVA_FEAT_IOPF flag, that enables the I/O Page Fault queue. The IOMMU driver checks is the device supports a form of page fault, in which case they add the device to a fault queue. If the device doesn't support page faults, the IOMMU driver aborts iommu_sva_init_device(). 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. Add iopf_queue_flush() calls in a few strategic locations. Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> --- drivers/iommu/iommu-sva.c | 26 +++++++++++++++++++++++++- drivers/iommu/iommu.c | 6 +++--- include/linux/iommu.h | 2 ++ 3 files changed, 30 insertions(+), 4 deletions(-)