[PATCH v10 05/10] uacce: Enable IOMMU_DEV_FEAT_IOPF

[Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>]

The IOPF (I/O Page Fault) feature is now enabled independently from the
SVA feature, because some IOPF implementations are device-specific and
do not require IOMMU support for PCIe PRI or Arm SMMU stall.

Enable IOPF unconditionally when enabling SVA for now. In the future, if
a device driver implementing a uacce interface doesn't need IOPF
support, it will need to tell the uacce module, for example with a new
flag.

Acked-by: Zhangfei Gao <zhangfei.gao@xxxxxxxxxx>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
---
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Zhangfei Gao <zhangfei.gao@xxxxxxxxxx>
Cc: Zhou Wang <wangzhou1@xxxxxxxxxxxxx>
---
 drivers/misc/uacce/uacce.c | 39 +++++++++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index d07af4edfcac..6db7a98486ec 100644
--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -385,6 +385,33 @@ static void uacce_release(struct device *dev)
 	kfree(uacce);
 }
 
+static unsigned int uacce_enable_sva(struct device *parent, unsigned int flags)
+{
+	if (!(flags & UACCE_DEV_SVA))
+		return flags;
+
+	flags &= ~UACCE_DEV_SVA;
+
+	if (iommu_dev_enable_feature(parent, IOMMU_DEV_FEAT_IOPF))
+		return flags;
+
+	if (iommu_dev_enable_feature(parent, IOMMU_DEV_FEAT_SVA)) {
+		iommu_dev_disable_feature(parent, IOMMU_DEV_FEAT_IOPF);
+		return flags;
+	}
+
+	return flags | UACCE_DEV_SVA;
+}
+
+static void uacce_disable_sva(struct uacce_device *uacce)
+{
+	if (!(uacce->flags & UACCE_DEV_SVA))
+		return;
+
+	iommu_dev_disable_feature(uacce->parent, IOMMU_DEV_FEAT_SVA);
+	iommu_dev_disable_feature(uacce->parent, IOMMU_DEV_FEAT_IOPF);
+}
+
 /**
  * uacce_alloc() - alloc an accelerator
  * @parent: pointer of uacce parent device
@@ -404,11 +431,7 @@ struct uacce_device *uacce_alloc(struct device *parent,
 	if (!uacce)
 		return ERR_PTR(-ENOMEM);
 
-	if (flags & UACCE_DEV_SVA) {
-		ret = iommu_dev_enable_feature(parent, IOMMU_DEV_FEAT_SVA);
-		if (ret)
-			flags &= ~UACCE_DEV_SVA;
-	}
+	flags = uacce_enable_sva(parent, flags);
 
 	uacce->parent = parent;
 	uacce->flags = flags;
@@ -432,8 +455,7 @@ struct uacce_device *uacce_alloc(struct device *parent,
 	return uacce;
 
 err_with_uacce:
-	if (flags & UACCE_DEV_SVA)
-		iommu_dev_disable_feature(uacce->parent, IOMMU_DEV_FEAT_SVA);
+	uacce_disable_sva(uacce);
 	kfree(uacce);
 	return ERR_PTR(ret);
 }
@@ -487,8 +509,7 @@ void uacce_remove(struct uacce_device *uacce)
 	mutex_unlock(&uacce->queues_lock);
 
 	/* disable sva now since no opened queues */
-	if (uacce->flags & UACCE_DEV_SVA)
-		iommu_dev_disable_feature(uacce->parent, IOMMU_DEV_FEAT_SVA);
+	uacce_disable_sva(uacce);
 
 	if (uacce->cdev)
 		cdev_device_del(uacce->cdev, &uacce->dev);
-- 
2.30.0