[PATCH 8/8] iommu/vt-d: Make use of iova deferred flushing

[Joerg Roedel]

From: Joerg Roedel <jroedel@xxxxxxx>

Remove the deferred flushing implementation in the Intel
VT-d driver and use the one from the common iova code
instead.

Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
 drivers/iommu/intel-iommu.c | 197 +++++++++-----------------------------------
 1 file changed, 38 insertions(+), 159 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 687f18f..d5e8b86 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -458,31 +458,6 @@ static LIST_HEAD(dmar_rmrr_units);
 #define for_each_rmrr_units(rmrr) \
 	list_for_each_entry(rmrr, &dmar_rmrr_units, list)
 
-static void flush_unmaps_timeout(unsigned long data);
-
-struct deferred_flush_entry {
-	unsigned long iova_pfn;
-	unsigned long nrpages;
-	struct dmar_domain *domain;
-	struct page *freelist;
-};
-
-#define HIGH_WATER_MARK 250
-struct deferred_flush_table {
-	int next;
-	struct deferred_flush_entry entries[HIGH_WATER_MARK];
-};
-
-struct deferred_flush_data {
-	spinlock_t lock;
-	int timer_on;
-	struct timer_list timer;
-	long size;
-	struct deferred_flush_table *tables;
-};
-
-static DEFINE_PER_CPU(struct deferred_flush_data, deferred_flush);
-
 /* bitmap for indexing intel_iommus */
 static int g_num_of_iommus;
 
@@ -1309,6 +1284,13 @@ static void dma_free_pagelist(struct page *freelist)
 	}
 }
 
+static void iova_entry_free(unsigned long data)
+{
+	struct page *freelist = (struct page *)data;
+
+	dma_free_pagelist(freelist);
+}
+
 /* iommu handling */
 static int iommu_alloc_root_entry(struct intel_iommu *iommu)
 {
@@ -1622,6 +1604,25 @@ static void iommu_flush_iotlb_psi(struct intel_iommu *iommu,
 				      addr, mask);
 }
 
+static void iommu_flush_iova(struct iova_domain *iovad)
+{
+	struct dmar_domain *domain;
+	int idx;
+
+	domain = container_of(iovad, struct dmar_domain, iovad);
+
+	for_each_domain_iommu(idx, domain) {
+		struct intel_iommu *iommu = g_iommus[idx];
+		u16 did = domain->iommu_did[iommu->seq_id];
+
+		iommu->flush.flush_iotlb(iommu, did, 0, 0, DMA_TLB_DSI_FLUSH);
+
+		if (!cap_caching_mode(iommu->cap))
+			iommu_flush_dev_iotlb(get_iommu_domain(iommu, did),
+					      0, MAX_AGAW_PFN_WIDTH);
+	}
+}
+
 static void iommu_disable_protect_mem_regions(struct intel_iommu *iommu)
 {
 	u32 pmen;
@@ -1932,9 +1933,16 @@ static int domain_init(struct dmar_domain *domain, struct intel_iommu *iommu,
 {
 	int adjust_width, agaw;
 	unsigned long sagaw;
+	int err;
 
 	init_iova_domain(&domain->iovad, VTD_PAGE_SIZE, IOVA_START_PFN,
 			DMA_32BIT_PFN);
+
+	err = init_iova_flush_queue(&domain->iovad,
+				    iommu_flush_iova, iova_entry_free);
+	if (err)
+		return err;
+
 	domain_reserve_special_ranges(domain);
 
 	/* calculate AGAW */
@@ -1986,14 +1994,6 @@ static void domain_exit(struct dmar_domain *domain)
 	if (!domain)
 		return;
 
-	/* Flush any lazy unmaps that may reference this domain */
-	if (!intel_iommu_strict) {
-		int cpu;
-
-		for_each_possible_cpu(cpu)
-			flush_unmaps_timeout(cpu);
-	}
-
 	/* Remove associated devices and clear attached or cached domains */
 	rcu_read_lock();
 	domain_remove_dev_info(domain);
@@ -3206,7 +3206,7 @@ static int __init init_dmars(void)
 	bool copied_tables = false;
 	struct device *dev;
 	struct intel_iommu *iommu;
-	int i, ret, cpu;
+	int i, ret;
 
 	/*
 	 * for each drhd
@@ -3239,22 +3239,6 @@ static int __init init_dmars(void)
 		goto error;
 	}
 
-	for_each_possible_cpu(cpu) {
-		struct deferred_flush_data *dfd = per_cpu_ptr(&deferred_flush,
-							      cpu);
-
-		dfd->tables = kzalloc(g_num_of_iommus *
-				      sizeof(struct deferred_flush_table),
-				      GFP_KERNEL);
-		if (!dfd->tables) {
-			ret = -ENOMEM;
-			goto free_g_iommus;
-		}
-
-		spin_lock_init(&dfd->lock);
-		setup_timer(&dfd->timer, flush_unmaps_timeout, cpu);
-	}
-
 	for_each_active_iommu(iommu, drhd) {
 		g_iommus[iommu->seq_id] = iommu;
 
@@ -3437,10 +3421,9 @@ static int __init init_dmars(void)
 		disable_dmar_iommu(iommu);
 		free_dmar_iommu(iommu);
 	}
-free_g_iommus:
-	for_each_possible_cpu(cpu)
-		kfree(per_cpu_ptr(&deferred_flush, cpu)->tables);
+
 	kfree(g_iommus);
+
 error:
 	return ret;
 }
@@ -3645,110 +3628,6 @@ static dma_addr_t intel_map_page(struct device *dev, struct page *page,
 				  dir, *dev->dma_mask);
 }
 
-static void flush_unmaps(struct deferred_flush_data *flush_data)
-{
-	int i, j;
-
-	flush_data->timer_on = 0;
-
-	/* just flush them all */
-	for (i = 0; i < g_num_of_iommus; i++) {
-		struct intel_iommu *iommu = g_iommus[i];
-		struct deferred_flush_table *flush_table =
-				&flush_data->tables[i];
-		if (!iommu)
-			continue;
-
-		if (!flush_table->next)
-			continue;
-
-		/* In caching mode, global flushes turn emulation expensive */
-		if (!cap_caching_mode(iommu->cap))
-			iommu->flush.flush_iotlb(iommu, 0, 0, 0,
-					 DMA_TLB_GLOBAL_FLUSH);
-		for (j = 0; j < flush_table->next; j++) {
-			unsigned long mask;
-			struct deferred_flush_entry *entry =
-						&flush_table->entries[j];
-			unsigned long iova_pfn = entry->iova_pfn;
-			unsigned long nrpages = entry->nrpages;
-			struct dmar_domain *domain = entry->domain;
-			struct page *freelist = entry->freelist;
-
-			/* On real hardware multiple invalidations are expensive */
-			if (cap_caching_mode(iommu->cap))
-				iommu_flush_iotlb_psi(iommu, domain,
-					mm_to_dma_pfn(iova_pfn),
-					nrpages, !freelist, 0);
-			else {
-				mask = ilog2(nrpages);
-				iommu_flush_dev_iotlb(domain,
-						(uint64_t)iova_pfn << PAGE_SHIFT, mask);
-			}
-			free_iova_fast(&domain->iovad, iova_pfn, nrpages);
-			if (freelist)
-				dma_free_pagelist(freelist);
-		}
-		flush_table->next = 0;
-	}
-
-	flush_data->size = 0;
-}
-
-static void flush_unmaps_timeout(unsigned long cpuid)
-{
-	struct deferred_flush_data *flush_data = per_cpu_ptr(&deferred_flush, cpuid);
-	unsigned long flags;
-
-	spin_lock_irqsave(&flush_data->lock, flags);
-	flush_unmaps(flush_data);
-	spin_unlock_irqrestore(&flush_data->lock, flags);
-}
-
-static void add_unmap(struct dmar_domain *dom, unsigned long iova_pfn,
-		      unsigned long nrpages, struct page *freelist)
-{
-	unsigned long flags;
-	int entry_id, iommu_id;
-	struct intel_iommu *iommu;
-	struct deferred_flush_entry *entry;
-	struct deferred_flush_data *flush_data;
-
-	flush_data = raw_cpu_ptr(&deferred_flush);
-
-	/* Flush all CPUs' entries to avoid deferring too much.  If
-	 * this becomes a bottleneck, can just flush us, and rely on
-	 * flush timer for the rest.
-	 */
-	if (flush_data->size == HIGH_WATER_MARK) {
-		int cpu;
-
-		for_each_online_cpu(cpu)
-			flush_unmaps_timeout(cpu);
-	}
-
-	spin_lock_irqsave(&flush_data->lock, flags);
-
-	iommu = domain_get_iommu(dom);
-	iommu_id = iommu->seq_id;
-
-	entry_id = flush_data->tables[iommu_id].next;
-	++(flush_data->tables[iommu_id].next);
-
-	entry = &flush_data->tables[iommu_id].entries[entry_id];
-	entry->domain = dom;
-	entry->iova_pfn = iova_pfn;
-	entry->nrpages = nrpages;
-	entry->freelist = freelist;
-
-	if (!flush_data->timer_on) {
-		mod_timer(&flush_data->timer, jiffies + msecs_to_jiffies(10));
-		flush_data->timer_on = 1;
-	}
-	flush_data->size++;
-	spin_unlock_irqrestore(&flush_data->lock, flags);
-}
-
 static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
 {
 	struct dmar_domain *domain;
@@ -3784,7 +3663,8 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
 		free_iova_fast(&domain->iovad, iova_pfn, dma_to_mm_pfn(nrpages));
 		dma_free_pagelist(freelist);
 	} else {
-		add_unmap(domain, iova_pfn, nrpages, freelist);
+		queue_iova(&domain->iovad, iova_pfn, nrpages,
+			   (unsigned long)freelist);
 		/*
 		 * queue up the release of the unmap to save the 1/6th of the
 		 * cpu used up by the iotlb flush operation...
@@ -4721,7 +4601,6 @@ static void free_all_cpu_cached_iovas(unsigned int cpu)
 static int intel_iommu_cpu_dead(unsigned int cpu)
 {
 	free_all_cpu_cached_iovas(cpu);
-	flush_unmaps_timeout(cpu);
 	return 0;
 }
 
-- 
2.7.4