iommu/vt-d: Make prq draining code generic

Currently draining page requests and responses for a pasid is part of SVA
implementation. This is because the driver only supports attaching an SVA
domain to a device pasid. As we are about to support attaching other types
of domains to a device pasid, the prq draining code becomes generic.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20230802212427.1497170-6-jacob.jun.pan@linux.intel.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel/iommu.c

@@ -4727,21 +4727,29 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
 	struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL);
 	struct iommu_domain *domain;
 
-	/* Domain type specific cleanup: */
 	domain = iommu_get_domain_for_dev_pasid(dev, pasid, 0);
-	if (domain) {
-		switch (domain->type) {
-		case IOMMU_DOMAIN_SVA:
-			intel_svm_remove_dev_pasid(dev, pasid);
-			break;
-		default:
-			/* should never reach here */
-			WARN_ON(1);
-			break;
-		}
+	if (WARN_ON_ONCE(!domain))
+		goto out_tear_down;
+
+	/*
+	 * The SVA implementation needs to handle its own stuffs like the mm
+	 * notification. Before consolidating that code into iommu core, let
+	 * the intel sva code handle it.
+	 */
+	if (domain->type == IOMMU_DOMAIN_SVA) {
+		intel_svm_remove_dev_pasid(dev, pasid);
+		goto out_tear_down;
 	}
 
+	/*
+	 * Should never reach here until we add support for attaching
+	 * non-SVA domain to a pasid.
+	 */
+	WARN_ON(1);
+
+out_tear_down:
 	intel_pasid_tear_down_entry(iommu, dev, pasid, false);
+	intel_drain_pasid_prq(dev, pasid);
 }
 
 const struct iommu_ops intel_iommu_ops = {

drivers/iommu/intel/iommu.h

@@ -844,6 +844,7 @@ int intel_svm_page_response(struct device *dev, struct iommu_fault_event *evt,
 			    struct iommu_page_response *msg);
 struct iommu_domain *intel_svm_domain_alloc(void);
 void intel_svm_remove_dev_pasid(struct device *dev, ioasid_t pasid);
+void intel_drain_pasid_prq(struct device *dev, u32 pasid);
 
 struct intel_svm_dev {
 	struct list_head list;
@@ -862,6 +863,7 @@ struct intel_svm {
 };
 #else
 static inline void intel_svm_check(struct intel_iommu *iommu) {}
+static inline void intel_drain_pasid_prq(struct device *dev, u32 pasid) {}
 static inline struct iommu_domain *intel_svm_domain_alloc(void)
 {
 	return NULL;

drivers/iommu/intel/svm.c

@@ -26,8 +26,6 @@
 #include "trace.h"
 
 static irqreturn_t prq_event_thread(int irq, void *d);
-static void intel_svm_drain_prq(struct device *dev, u32 pasid);
-#define to_intel_svm_dev(handle) container_of(handle, struct intel_svm_dev, sva)
 
 static DEFINE_XARRAY_ALLOC(pasid_private_array);
 static int pasid_private_add(ioasid_t pasid, void *priv)
@@ -382,17 +380,6 @@ void intel_svm_remove_dev_pasid(struct device *dev, u32 pasid)
 
 	if (sdev) {
 		list_del_rcu(&sdev->list);
-		/*
-		 * Flush the PASID cache and IOTLB for this device.
-		 * Note that we do depend on the hardware *not* using
-		 * the PASID any more. Just as we depend on other
-		 * devices never using PASIDs that they have no right
-		 * to use. We have a *shared* PASID table, because it's
-		 * large and has to be physically contiguous. So it's
-		 * hard to be as defensive as we might like.
-		 */
-		intel_pasid_tear_down_entry(iommu, dev, svm->pasid, false);
-		intel_svm_drain_prq(dev, svm->pasid);
 		kfree_rcu(sdev, rcu);
 
 		if (list_empty(&svm->devs)) {
@@ -449,7 +436,7 @@ static bool is_canonical_address(u64 addr)
 }
 
 /**
- * intel_svm_drain_prq - Drain page requests and responses for a pasid
+ * intel_drain_pasid_prq - Drain page requests and responses for a pasid
  * @dev: target device
  * @pasid: pasid for draining
  *
@@ -463,7 +450,7 @@ static bool is_canonical_address(u64 addr)
  * described in VT-d spec CH7.10 to drain all page requests and page
  * responses pending in the hardware.
  */
-static void intel_svm_drain_prq(struct device *dev, u32 pasid)
+void intel_drain_pasid_prq(struct device *dev, u32 pasid)
 {
 	struct device_domain_info *info;
 	struct dmar_domain *domain;