[PATCH v2 10/12] iommu: Make iommu_queue_iopf() more generic

[Lu Baolu <baolu.lu@linux.intel.com>]

This completely separates the IO page fault handling framework from the
SVA implementation. Previously, the SVA implementation was tightly coupled
with the IO page fault handling framework. This makes SVA a "customer" of
the IO page fault handling framework by converting domain's page fault
handler to handle a group of faults and calling it directly from
iommu_queue_iopf().

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 include/linux/iommu.h      |  5 +++--
 drivers/iommu/iommu-sva.h  |  8 --------
 drivers/iommu/io-pgfault.c | 16 +++++++++++++---
 drivers/iommu/iommu-sva.c  | 11 ++---------
 drivers/iommu/iommu.c      |  2 +-
 5 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 607740e548f2..1dafe031a56c 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -40,6 +40,7 @@ struct notifier_block;
 struct iommu_sva;
 struct iommu_fault_event;
 struct iommu_dma_cookie;
+struct iopf_group;
 
 #define IOMMU_FAULT_PERM_READ	(1 << 0) /* read */
 #define IOMMU_FAULT_PERM_WRITE	(1 << 1) /* write */
@@ -179,8 +180,7 @@ struct iommu_domain {
 	unsigned long pgsize_bitmap;	/* Bitmap of page sizes in use */
 	struct iommu_domain_geometry geometry;
 	struct iommu_dma_cookie *iova_cookie;
-	enum iommu_page_response_code (*iopf_handler)(struct iommu_fault *fault,
-						      void *data);
+	int (*iopf_handler)(struct iopf_group *group);
 	void *fault_data;
 	union {
 		struct {
@@ -513,6 +513,7 @@ struct iopf_group {
 	struct list_head		faults;
 	struct work_struct		work;
 	struct device			*dev;
+	void				*data;
 };
 
 int iommu_device_register(struct iommu_device *iommu,
diff --git a/drivers/iommu/iommu-sva.h b/drivers/iommu/iommu-sva.h
index 510a7df23fba..cf41e88fac17 100644
--- a/drivers/iommu/iommu-sva.h
+++ b/drivers/iommu/iommu-sva.h
@@ -22,8 +22,6 @@ int iopf_queue_flush_dev(struct device *dev);
 struct iopf_queue *iopf_queue_alloc(const char *name);
 void iopf_queue_free(struct iopf_queue *queue);
 int iopf_queue_discard_partial(struct iopf_queue *queue);
-enum iommu_page_response_code
-iommu_sva_handle_iopf(struct iommu_fault *fault, void *data);
 void iopf_free_group(struct iopf_group *group);
 int iopf_queue_work(struct iopf_group *group, work_func_t func);
 int iommu_sva_handle_iopf_group(struct iopf_group *group);
@@ -65,12 +63,6 @@ static inline int iopf_queue_discard_partial(struct iopf_queue *queue)
 	return -ENODEV;
 }
 
-static inline enum iommu_page_response_code
-iommu_sva_handle_iopf(struct iommu_fault *fault, void *data)
-{
-	return IOMMU_PAGE_RESP_INVALID;
-}
-
 static inline void iopf_free_group(struct iopf_group *group)
 {
 }
diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
index 3614a800638c..c5cfa3dfa77b 100644
--- a/drivers/iommu/io-pgfault.c
+++ b/drivers/iommu/io-pgfault.c
@@ -11,8 +11,6 @@
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 
-#include "iommu-sva.h"
-
 /**
  * struct iopf_queue - IO Page Fault queue
  * @wq: the fault workqueue
@@ -106,6 +104,7 @@ int iommu_queue_iopf(struct iommu_fault *fault, struct device *dev)
 {
 	int ret;
 	struct iopf_group *group;
+	struct iommu_domain *domain;
 	struct iopf_fault *iopf, *next;
 	struct iopf_device_param *iopf_param;
 	struct dev_iommu *param = dev->iommu;
@@ -137,6 +136,16 @@ int iommu_queue_iopf(struct iommu_fault *fault, struct device *dev)
 		return 0;
 	}
 
+	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) {
+		ret = -ENODEV;
+		goto cleanup_partial;
+	}
+
 	group = kzalloc(sizeof(*group), GFP_KERNEL);
 	if (!group) {
 		/*
@@ -150,6 +159,7 @@ int iommu_queue_iopf(struct iommu_fault *fault, struct device *dev)
 
 	group->dev = dev;
 	group->last_fault.fault = *fault;
+	group->data = domain->fault_data;
 	INIT_LIST_HEAD(&group->faults);
 	list_add(&group->last_fault.list, &group->faults);
 
@@ -160,7 +170,7 @@ int iommu_queue_iopf(struct iommu_fault *fault, struct device *dev)
 			list_move(&iopf->list, &group->faults);
 	}
 
-	ret = iommu_sva_handle_iopf_group(group);
+	ret = domain->iopf_handler(group);
 	if (ret)
 		iopf_free_group(group);
 
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index ab42cfdd7636..668f4c2bcf65 100644
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -157,7 +157,7 @@ EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
 /*
  * I/O page fault handler for SVA
  */
-enum iommu_page_response_code
+static enum iommu_page_response_code
 iommu_sva_handle_iopf(struct iommu_fault *fault, void *data)
 {
 	vm_fault_t ret;
@@ -241,23 +241,16 @@ static void iopf_handler(struct work_struct *work)
 {
 	struct iopf_fault *iopf;
 	struct iopf_group *group;
-	struct iommu_domain *domain;
 	enum iommu_page_response_code status = IOMMU_PAGE_RESP_SUCCESS;
 
 	group = container_of(work, struct iopf_group, work);
-	domain = iommu_get_domain_for_dev_pasid(group->dev,
-				group->last_fault.fault.prm.pasid, 0);
-	if (!domain || !domain->iopf_handler)
-		status = IOMMU_PAGE_RESP_INVALID;
-
 	list_for_each_entry(iopf, &group->faults, list) {
 		/*
 		 * For the moment, errors are sticky: don't handle subsequent
 		 * faults in the group if there is an error.
 		 */
 		if (status == IOMMU_PAGE_RESP_SUCCESS)
-			status = domain->iopf_handler(&iopf->fault,
-						      domain->fault_data);
+			status = iommu_sva_handle_iopf(&iopf->fault, group->data);
 	}
 
 	iopf_complete_group(group->dev, &group->last_fault, status);
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 157a28a49473..535a36e3edc9 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -3330,7 +3330,7 @@ struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
 	domain->type = IOMMU_DOMAIN_SVA;
 	mmgrab(mm);
 	domain->mm = mm;
-	domain->iopf_handler = iommu_sva_handle_iopf;
+	domain->iopf_handler = iommu_sva_handle_iopf_group;
 	domain->fault_data = mm;
 
 	return domain;
-- 
2.34.1