[PATCH v9 RFC 0/3] Generic IOMMU pooled allocator

[PATCH v9 RFC 0/3] Generic IOMMU pooled allocator

[Sowmini Varadhan]

Addresses latest BenH comments: need_flush checks, add support
for dma mask and align_order. 

Sowmini Varadhan (3):
  Break up monolithic iommu table/lock into finer graularity pools and
    lock
  Make sparc64 use scalable lib/iommu-common.c functions
  Make LDC use common iommu poll management functions

 arch/sparc/include/asm/iommu_64.h |    7 +-
 arch/sparc/kernel/iommu.c         |  172 ++++++------------------
 arch/sparc/kernel/iommu_common.h  |    8 -
 arch/sparc/kernel/ldc.c           |  153 +++++++++------------
 arch/sparc/kernel/pci_sun4v.c     |  183 ++++++++++++--------------
 include/linux/iommu-common.h      |   51 +++++++
 lib/Makefile                      |    2 +-
 lib/iommu-common.c                |  266 +++++++++++++++++++++++++++++++++++++
 8 files changed, 511 insertions(+), 331 deletions(-)
 create mode 100644 include/linux/iommu-common.h
 create mode 100644 lib/iommu-common.c

[PATCHv9 RFC 1/3] Break up monolithic iommu table/lock into finer graularity pools and lock

[Sowmini Varadhan]

Investigation of multithreaded iperf experiments on an ethernet
interface show the iommu->lock as the hottest lock identified by
lockstat, with something of the order of  21M contentions out of
27M acquisitions, and an average wait time of 26 us for the lock.
This is not efficient. A more scalable design is to follow the ppc
model, where the iommu_map_table has multiple pools, each stretching
over a segment of the map, and with a separate lock for each pool.
This model allows for better parallelization of the iommu map search.

This patch adds the iommu range alloc/free function infrastructure.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
---
v2 changes:
  - incorporate David Miller editorial comments: sparc specific
    fields moved from iommu-common into sparc's iommu_64.h
  - make the npools value an input parameter, for the case when
    the iommu map size is not very large
  - cookie_to_index mapping, and optimizations for span-boundary
    check, for use case such as LDC.
v3: eliminate iommu_sparc, rearrange the ->demap indirection to
    be invoked under the pool lock.

v4: David Miller review changes:
  - s/IOMMU_ERROR_CODE/DMA_ERROR_CODE
  - page_table_map_base and page_table_shift are unsigned long, not u32.

v5: Feedback from benh@kernel.crashing.org and aik@ozlabs.ru
  - removed ->cookie_to_index and ->demap indirection: caller should
    invoke these as needed before calling into the generic allocator

v6: Benh/DaveM discussion eliminationg iommu_tbl_ops, but retaining flush_all
    optimization.

v7: one-time initialization of pool_hash from iommu_tbl_pool_init()

v8: Benh code review comments.

v9: More Benh code review comments, added dma_mask, align_order logic to
    iommu_tbl_range_alloc.

 include/linux/iommu-common.h |   51 ++++++++
 lib/Makefile                 |    2 +-
 lib/iommu-common.c           |  266 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 318 insertions(+), 1 deletions(-)
 create mode 100644 include/linux/iommu-common.h
 create mode 100644 lib/iommu-common.c

diff --git a/include/linux/iommu-common.h b/include/linux/iommu-common.h
new file mode 100644
index 0000000..bbced83
--- /dev/null
+++ b/include/linux/iommu-common.h
@@ -0,0 +1,51 @@
+#ifndef _LINUX_IOMMU_COMMON_H
+#define _LINUX_IOMMU_COMMON_H
+
+#include <linux/spinlock_types.h>
+#include <linux/device.h>
+#include <asm/page.h>
+
+#define IOMMU_POOL_HASHBITS     4
+#define IOMMU_NR_POOLS          (1 << IOMMU_POOL_HASHBITS)
+
+struct iommu_pool {
+	unsigned long	start;
+	unsigned long	end;
+	unsigned long	hint;
+	spinlock_t	lock;
+};
+
+struct iommu_map_table {
+	unsigned long		table_map_base;
+	unsigned long		table_shift;
+	unsigned long		nr_pools;
+	void			(*lazy_flush)(struct iommu_map_table *);
+	unsigned long		poolsize;
+	struct iommu_pool	pools[IOMMU_NR_POOLS];
+	u32			flags;
+#define	IOMMU_HAS_LARGE_POOL	0x00000001
+#define	IOMMU_NO_SPAN_BOUND	0x00000002
+#define	IOMMU_NEED_FLUSH	0x00000004
+	struct iommu_pool	large_pool;
+	unsigned long		*map;
+};
+
+extern void iommu_tbl_pool_init(struct iommu_map_table *iommu,
+				unsigned long num_entries,
+				u32 table_shift,
+				void (*lazy_flush)(struct iommu_map_table *),
+				bool large_pool, u32 npools,
+				bool skip_span_boundary_check);
+
+extern unsigned long iommu_tbl_range_alloc(struct device *dev,
+					   struct iommu_map_table *iommu,
+					   unsigned long npages,
+					   unsigned long *handle,
+					   unsigned long mask,
+					   unsigned int align_order);
+
+extern void iommu_tbl_range_free(struct iommu_map_table *iommu,
+				 u64 dma_addr, unsigned long npages,
+				 unsigned long entry);
+
+#endif
diff --git a/lib/Makefile b/lib/Makefile
index 58f74d2..60c22e6 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -106,7 +106,7 @@ obj-$(CONFIG_AUDIT_GENERIC) += audit.o
 obj-$(CONFIG_AUDIT_COMPAT_GENERIC) += compat_audit.o
 
 obj-$(CONFIG_SWIOTLB) += swiotlb.o
-obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o
+obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o iommu-common.o
 obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o
 obj-$(CONFIG_NOTIFIER_ERROR_INJECTION) += notifier-error-inject.o
 obj-$(CONFIG_CPU_NOTIFIER_ERROR_INJECT) += cpu-notifier-error-inject.o
diff --git a/lib/iommu-common.c b/lib/iommu-common.c
new file mode 100644
index 0000000..b99f1d7
--- /dev/null
+++ b/lib/iommu-common.c
@@ -0,0 +1,266 @@
+/*
+ * IOMMU mmap management and range allocation functions.
+ * Based almost entirely upon the powerpc iommu allocator.
+ */
+
+#include <linux/export.h>
+#include <linux/bitmap.h>
+#include <linux/bug.h>
+#include <linux/iommu-helper.h>
+#include <linux/iommu-common.h>
+#include <linux/dma-mapping.h>
+#include <linux/hash.h>
+
+unsigned long iommu_large_alloc = 15;
+
+static	DEFINE_PER_CPU(unsigned int, iommu_pool_hash);
+
+static inline bool need_flush(struct iommu_map_table *iommu)
+{
+	return (iommu->lazy_flush != NULL &&
+		(iommu->flags & IOMMU_NEED_FLUSH) != 0);
+}
+
+static inline void set_flush(struct iommu_map_table *iommu)
+{
+	iommu->flags |= IOMMU_NEED_FLUSH;
+}
+
+static inline void clear_flush(struct iommu_map_table *iommu)
+{
+	iommu->flags &= ~IOMMU_NEED_FLUSH;
+}
+
+static void setup_iommu_pool_hash(void)
+{
+	unsigned int i;
+	static bool do_once;
+
+	if (do_once)
+		return;
+	do_once = true;
+	for_each_possible_cpu(i)
+		per_cpu(iommu_pool_hash, i) = hash_32(i, IOMMU_POOL_HASHBITS);
+}
+
+/*
+ * Initialize iommu_pool entries for the iommu_map_table. `num_entries'
+ * is the number of table entries. If `large_pool' is set to true,
+ * the top 1/4 of the table will be set aside for pool allocations
+ * of more than iommu_large_alloc pages.
+ */
+extern void iommu_tbl_pool_init(struct iommu_map_table *iommu,
+				unsigned long num_entries,
+				u32 table_shift,
+				void (*lazy_flush)(struct iommu_map_table *),
+				bool large_pool, u32 npools,
+				bool skip_span_boundary_check)
+{
+	unsigned int start, i;
+	struct iommu_pool *p = &(iommu->large_pool);
+
+	setup_iommu_pool_hash();
+	if (npools == 0)
+		iommu->nr_pools = IOMMU_NR_POOLS;
+	else
+		iommu->nr_pools = npools;
+	BUG_ON(npools > IOMMU_NR_POOLS);
+
+	iommu->table_shift = table_shift;
+	iommu->lazy_flush = lazy_flush;
+	start = 0;
+	if (skip_span_boundary_check)
+		iommu->flags |= IOMMU_NO_SPAN_BOUND;
+	if (large_pool)
+		iommu->flags |= IOMMU_HAS_LARGE_POOL;
+
+	if (!large_pool)
+		iommu->poolsize = num_entries/iommu->nr_pools;
+	else
+		iommu->poolsize = (num_entries * 3 / 4)/iommu->nr_pools;
+	for (i = 0; i < iommu->nr_pools; i++) {
+		spin_lock_init(&(iommu->pools[i].lock));
+		iommu->pools[i].start = start;
+		iommu->pools[i].hint = start;
+		start += iommu->poolsize; /* start for next pool */
+		iommu->pools[i].end = start - 1;
+	}
+	if (!large_pool)
+		return;
+	/* initialize large_pool */
+	spin_lock_init(&(p->lock));
+	p->start = start;
+	p->hint = p->start;
+	p->end = num_entries;
+}
+EXPORT_SYMBOL(iommu_tbl_pool_init);
+
+unsigned long iommu_tbl_range_alloc(struct device *dev,
+				struct iommu_map_table *iommu,
+				unsigned long npages,
+				unsigned long *handle,
+				unsigned long mask,
+				unsigned int align_order)
+{
+	unsigned int pool_hash = __this_cpu_read(iommu_pool_hash);
+	unsigned long n, end, start, limit, boundary_size;
+	struct iommu_pool *pool;
+	int pass = 0;
+	unsigned int pool_nr;
+	unsigned int npools = iommu->nr_pools;
+	unsigned long flags;
+	bool large_pool = ((iommu->flags & IOMMU_HAS_LARGE_POOL) != 0);
+	bool largealloc = (large_pool && npages > iommu_large_alloc);
+	unsigned long shift;
+	unsigned long align_mask = 0;
+
+	if (align_order > 0)
+		align_mask = 0xffffffffffffffffl >> (64 - align_order);
+
+	/* Sanity check */
+	if (unlikely(npages == 0)) {
+		WARN_ON_ONCE(1);
+		return DMA_ERROR_CODE;
+	}
+
+	if (largealloc) {
+		pool = &(iommu->large_pool);
+		pool_nr = 0; /* to keep compiler happy */
+	} else {
+		/* pick out pool_nr */
+		pool_nr =  pool_hash & (npools - 1);
+		pool = &(iommu->pools[pool_nr]);
+	}
+	spin_lock_irqsave(&pool->lock, flags);
+
+ again:
+	if (pass == 0 && handle && *handle &&
+	    (*handle >= pool->start) && (*handle < pool->end))
+		start = *handle;
+	else
+		start = pool->hint;
+
+	limit = pool->end;
+
+	/* The case below can happen if we have a small segment appended
+	 * to a large, or when the previous alloc was at the very end of
+	 * the available space. If so, go back to the beginning. If a
+	 * flush is needed, it will get done based on the return value
+	 * from iommu_area_alloc() below.
+	 */
+	if (start >= limit)
+		start = pool->start;
+	shift = iommu->table_map_base >> iommu->table_shift;
+	if (limit + shift > mask) {
+		limit = mask - shift + 1;
+		/* If we're constrained on address range, first try
+		 * at the masked hint to avoid O(n) search complexity,
+		 * but on second pass, start at 0 in pool 0.
+		 */
+		if ((start & mask) >= limit || pass > 0) {
+			spin_unlock(&(pool->lock));
+			pool = &(iommu->pools[0]);
+			spin_lock(&(pool->lock));
+			start = pool->start;
+		} else {
+			start &= mask;
+		}
+	}
+
+	if (dev)
+		boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
+				      1 << iommu->table_shift);
+	else
+		boundary_size = ALIGN(1UL << 32, 1 << iommu->table_shift);
+
+	boundary_size = boundary_size >> iommu->table_shift;
+	/*
+	 * if the skip_span_boundary_check had been set during init, we set
+	 * things up so that iommu_is_span_boundary() merely checks if the
+	 * (index + npages) < num_tsb_entries
+	 */
+	if ((iommu->flags & IOMMU_NO_SPAN_BOUND) != 0) {
+		shift = 0;
+		boundary_size = iommu->poolsize * iommu->nr_pools;
+	}
+	n = iommu_area_alloc(iommu->map, limit, start, npages, shift,
+			     boundary_size, align_mask);
+	if (n == -1) {
+		if (likely(pass == 0)) {
+			/* First failure, rescan from the beginning.  */
+			pool->hint = pool->start;
+			set_flush(iommu);
+			pass++;
+			goto again;
+		} else if (!largealloc && pass <= iommu->nr_pools) {
+			spin_unlock(&(pool->lock));
+			pool_nr = (pool_nr + 1) & (iommu->nr_pools - 1);
+			pool = &(iommu->pools[pool_nr]);
+			spin_lock(&(pool->lock));
+			pool->hint = pool->start;
+			set_flush(iommu);
+			pass++;
+			goto again;
+		} else {
+			/* give up */
+			n = DMA_ERROR_CODE;
+			goto bail;
+		}
+	}
+	if (n < pool->hint || need_flush(iommu)) {
+		clear_flush(iommu);
+		iommu->lazy_flush(iommu);
+	}
+
+	end = n + npages;
+	pool->hint = end;
+
+	/* Update handle for SG allocations */
+	if (handle)
+		*handle = end;
+bail:
+	spin_unlock_irqrestore(&(pool->lock), flags);
+
+	return n;
+}
+EXPORT_SYMBOL(iommu_tbl_range_alloc);
+
+static struct iommu_pool *get_pool(struct iommu_map_table *tbl,
+				   unsigned long entry)
+{
+	struct iommu_pool *p;
+	unsigned long largepool_start = tbl->large_pool.start;
+	bool large_pool = ((tbl->flags & IOMMU_HAS_LARGE_POOL) != 0);
+
+	/* The large pool is the last pool at the top of the table */
+	if (large_pool && entry >= largepool_start) {
+		p = &tbl->large_pool;
+	} else {
+		unsigned int pool_nr = entry / tbl->poolsize;
+
+		BUG_ON(pool_nr >= tbl->nr_pools);
+		p = &tbl->pools[pool_nr];
+	}
+	return p;
+}
+
+/* Caller supplies the index of the entry into the iommu map table
+ * itself when the mapping from dma_addr to the entry is not the
+ * default addr->entry mapping below.
+ */
+void iommu_tbl_range_free(struct iommu_map_table *iommu, u64 dma_addr,
+			  unsigned long npages, unsigned long entry)
+{
+	struct iommu_pool *pool;
+	unsigned long flags;
+	unsigned long shift = iommu->table_shift;
+
+	if (entry == DMA_ERROR_CODE) /* use default addr->entry mapping */
+		entry = (dma_addr - iommu->table_map_base) >> shift;
+	pool = get_pool(iommu, entry);
+
+	spin_lock_irqsave(&(pool->lock), flags);
+	bitmap_clear(iommu->map, entry, npages);
+	spin_unlock_irqrestore(&(pool->lock), flags);
+}
+EXPORT_SYMBOL(iommu_tbl_range_free);
-- 
1.7.1

[PATCH v9 RFC 2/3] sparc: Make sparc64 use scalable lib/iommu-common.c functions

[Sowmini Varadhan]

In iperf experiments running linux as the Tx side (TCP client) with
10 threads results in a severe performance drop when TSO is disabled,
indicating a weakness in the software that can be avoided by using
the scalable IOMMU arena DMA allocation.

Baseline numbers before this patch:
   with default settings (TSO enabled) :    9-9.5 Gbps
   Disable TSO using ethtool- drops badly:  2-3 Gbps.

After this patch, iperf client with 10 threads, can give a
throughput of at least 8.5 Gbps, even when TSO is disabled.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
---
v2: moved sparc specific fileds into iommu_sparc
v3: converted all sparc users of iommu, so lot of cleanup and streamlining
v4: David Miller review change:
    - s/IOMMU_ERROR_CODE/DMA_ERROR_CODE
    - reverts pci_impl.h (now that all iommu usage has been converted)
v5: benh/aik feedback modifies the function signatures: pass in 
    modified args to iommmu_tbl_pool_init() and iommu_tbl_range_free()
v6: removed iommu_tbl_ops. Pass flush_all as function pointer to 
    iommu_tbl_pool_init
v7: move pool_hash initialization to iommu_tbl_pool_init()
v8: BenH comments
v9: more BenH comments
 arch/sparc/include/asm/iommu_64.h |    7 +-
 arch/sparc/kernel/iommu.c         |  172 +++++++++--------------------------
 arch/sparc/kernel/iommu_common.h  |    8 --
 arch/sparc/kernel/pci_sun4v.c     |  183 +++++++++++++++++--------------------
 4 files changed, 128 insertions(+), 242 deletions(-)

diff --git a/arch/sparc/include/asm/iommu_64.h b/arch/sparc/include/asm/iommu_64.h
index 2b9321a..cd0d69f 100644
--- a/arch/sparc/include/asm/iommu_64.h
+++ b/arch/sparc/include/asm/iommu_64.h
@@ -16,6 +16,7 @@
 #define IOPTE_WRITE   0x0000000000000002UL
 
 #define IOMMU_NUM_CTXS	4096
+#include <linux/iommu-common.h>
 
 struct iommu_arena {
 	unsigned long	*map;
@@ -24,11 +25,10 @@ struct iommu_arena {
 };
 
 struct iommu {
+	struct iommu_map_table	tbl;
 	spinlock_t		lock;
-	struct iommu_arena	arena;
-	void			(*flush_all)(struct iommu *);
+	u32			dma_addr_mask;
 	iopte_t			*page_table;
-	u32			page_table_map_base;
 	unsigned long		iommu_control;
 	unsigned long		iommu_tsbbase;
 	unsigned long		iommu_flush;
@@ -40,7 +40,6 @@ struct iommu {
 	unsigned long		dummy_page_pa;
 	unsigned long		ctx_lowest_free;
 	DECLARE_BITMAP(ctx_bitmap, IOMMU_NUM_CTXS);
-	u32			dma_addr_mask;
 };
 
 struct strbuf {
diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
index bfa4d0c..5320689 100644
--- a/arch/sparc/kernel/iommu.c
+++ b/arch/sparc/kernel/iommu.c
@@ -13,6 +13,7 @@
 #include <linux/errno.h>
 #include <linux/iommu-helper.h>
 #include <linux/bitmap.h>
+#include <linux/iommu-common.h>
 
 #ifdef CONFIG_PCI
 #include <linux/pci.h>
@@ -45,8 +46,9 @@
 			       "i" (ASI_PHYS_BYPASS_EC_E))
 
 /* Must be invoked under the IOMMU lock. */
-static void iommu_flushall(struct iommu *iommu)
+static void iommu_flushall(struct iommu_map_table *iommu_map_table)
 {
+	struct iommu *iommu = container_of(iommu_map_table, struct iommu, tbl);
 	if (iommu->iommu_flushinv) {
 		iommu_write(iommu->iommu_flushinv, ~(u64)0);
 	} else {
@@ -87,94 +89,6 @@ static inline void iopte_make_dummy(struct iommu *iommu, iopte_t *iopte)
 	iopte_val(*iopte) = val;
 }
 
-/* Based almost entirely upon the ppc64 iommu allocator.  If you use the 'handle'
- * facility it must all be done in one pass while under the iommu lock.
- *
- * On sun4u platforms, we only flush the IOMMU once every time we've passed
- * over the entire page table doing allocations.  Therefore we only ever advance
- * the hint and cannot backtrack it.
- */
-unsigned long iommu_range_alloc(struct device *dev,
-				struct iommu *iommu,
-				unsigned long npages,
-				unsigned long *handle)
-{
-	unsigned long n, end, start, limit, boundary_size;
-	struct iommu_arena *arena = &iommu->arena;
-	int pass = 0;
-
-	/* This allocator was derived from x86_64's bit string search */
-
-	/* Sanity check */
-	if (unlikely(npages == 0)) {
-		if (printk_ratelimit())
-			WARN_ON(1);
-		return DMA_ERROR_CODE;
-	}
-
-	if (handle && *handle)
-		start = *handle;
-	else
-		start = arena->hint;
-
-	limit = arena->limit;
-
-	/* The case below can happen if we have a small segment appended
-	 * to a large, or when the previous alloc was at the very end of
-	 * the available space. If so, go back to the beginning and flush.
-	 */
-	if (start >= limit) {
-		start = 0;
-		if (iommu->flush_all)
-			iommu->flush_all(iommu);
-	}
-
- again:
-
-	if (dev)
-		boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
-				      1 << IO_PAGE_SHIFT);
-	else
-		boundary_size = ALIGN(1UL << 32, 1 << IO_PAGE_SHIFT);
-
-	n = iommu_area_alloc(arena->map, limit, start, npages,
-			     iommu->page_table_map_base >> IO_PAGE_SHIFT,
-			     boundary_size >> IO_PAGE_SHIFT, 0);
-	if (n == -1) {
-		if (likely(pass < 1)) {
-			/* First failure, rescan from the beginning.  */
-			start = 0;
-			if (iommu->flush_all)
-				iommu->flush_all(iommu);
-			pass++;
-			goto again;
-		} else {
-			/* Second failure, give up */
-			return DMA_ERROR_CODE;
-		}
-	}
-
-	end = n + npages;
-
-	arena->hint = end;
-
-	/* Update handle for SG allocations */
-	if (handle)
-		*handle = end;
-
-	return n;
-}
-
-void iommu_range_free(struct iommu *iommu, dma_addr_t dma_addr, unsigned long npages)
-{
-	struct iommu_arena *arena = &iommu->arena;
-	unsigned long entry;
-
-	entry = (dma_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT;
-
-	bitmap_clear(arena->map, entry, npages);
-}
-
 int iommu_table_init(struct iommu *iommu, int tsbsize,
 		     u32 dma_offset, u32 dma_addr_mask,
 		     int numa_node)
@@ -187,22 +101,20 @@ int iommu_table_init(struct iommu *iommu, int tsbsize,
 	/* Setup initial software IOMMU state. */
 	spin_lock_init(&iommu->lock);
 	iommu->ctx_lowest_free = 1;
-	iommu->page_table_map_base = dma_offset;
+	iommu->tbl.table_map_base = dma_offset;
 	iommu->dma_addr_mask = dma_addr_mask;
 
 	/* Allocate and initialize the free area map.  */
 	sz = num_tsb_entries / 8;
 	sz = (sz + 7UL) & ~7UL;
-	iommu->arena.map = kmalloc_node(sz, GFP_KERNEL, numa_node);
-	if (!iommu->arena.map) {
-		printk(KERN_ERR "IOMMU: Error, kmalloc(arena.map) failed.\n");
+	iommu->tbl.map = kmalloc_node(sz, GFP_KERNEL, numa_node);
+	if (!iommu->tbl.map)
 		return -ENOMEM;
-	}
-	memset(iommu->arena.map, 0, sz);
-	iommu->arena.limit = num_tsb_entries;
+	memset(iommu->tbl.map, 0, sz);
 
-	if (tlb_type != hypervisor)
-		iommu->flush_all = iommu_flushall;
+	iommu_tbl_pool_init(&iommu->tbl, num_tsb_entries, IO_PAGE_SHIFT,
+			    (tlb_type != hypervisor ? iommu_flushall : NULL),
+			    false, 1, false);
 
 	/* Allocate and initialize the dummy page which we
 	 * set inactive IO PTEs to point to.
@@ -235,18 +147,20 @@ int iommu_table_init(struct iommu *iommu, int tsbsize,
 	iommu->dummy_page = 0UL;
 
 out_free_map:
-	kfree(iommu->arena.map);
-	iommu->arena.map = NULL;
+	kfree(iommu->tbl.map);
+	iommu->tbl.map = NULL;
 
 	return -ENOMEM;
 }
 
-static inline iopte_t *alloc_npages(struct device *dev, struct iommu *iommu,
+static inline iopte_t *alloc_npages(struct device *dev,
+				    struct iommu *iommu,
 				    unsigned long npages)
 {
 	unsigned long entry;
 
-	entry = iommu_range_alloc(dev, iommu, npages, NULL);
+	entry = iommu_tbl_range_alloc(dev, &iommu->tbl, npages, NULL,
+				      (unsigned long)(-1), 0);
 	if (unlikely(entry == DMA_ERROR_CODE))
 		return NULL;
 
@@ -284,7 +198,7 @@ static void *dma_4u_alloc_coherent(struct device *dev, size_t size,
 				   dma_addr_t *dma_addrp, gfp_t gfp,
 				   struct dma_attrs *attrs)
 {
-	unsigned long flags, order, first_page;
+	unsigned long order, first_page;
 	struct iommu *iommu;
 	struct page *page;
 	int npages, nid;
@@ -306,16 +220,14 @@ static void *dma_4u_alloc_coherent(struct device *dev, size_t size,
 
 	iommu = dev->archdata.iommu;
 
-	spin_lock_irqsave(&iommu->lock, flags);
 	iopte = alloc_npages(dev, iommu, size >> IO_PAGE_SHIFT);
-	spin_unlock_irqrestore(&iommu->lock, flags);
 
 	if (unlikely(iopte == NULL)) {
 		free_pages(first_page, order);
 		return NULL;
 	}
 
-	*dma_addrp = (iommu->page_table_map_base +
+	*dma_addrp = (iommu->tbl.table_map_base +
 		      ((iopte - iommu->page_table) << IO_PAGE_SHIFT));
 	ret = (void *) first_page;
 	npages = size >> IO_PAGE_SHIFT;
@@ -336,16 +248,12 @@ static void dma_4u_free_coherent(struct device *dev, size_t size,
 				 struct dma_attrs *attrs)
 {
 	struct iommu *iommu;
-	unsigned long flags, order, npages;
+	unsigned long order, npages;
 
 	npages = IO_PAGE_ALIGN(size) >> IO_PAGE_SHIFT;
 	iommu = dev->archdata.iommu;
 
-	spin_lock_irqsave(&iommu->lock, flags);
-
-	iommu_range_free(iommu, dvma, npages);
-
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	iommu_tbl_range_free(&iommu->tbl, dvma, npages, DMA_ERROR_CODE);
 
 	order = get_order(size);
 	if (order < 10)
@@ -375,8 +283,8 @@ static dma_addr_t dma_4u_map_page(struct device *dev, struct page *page,
 	npages = IO_PAGE_ALIGN(oaddr + sz) - (oaddr & IO_PAGE_MASK);
 	npages >>= IO_PAGE_SHIFT;
 
-	spin_lock_irqsave(&iommu->lock, flags);
 	base = alloc_npages(dev, iommu, npages);
+	spin_lock_irqsave(&iommu->lock, flags);
 	ctx = 0;
 	if (iommu->iommu_ctxflush)
 		ctx = iommu_alloc_ctx(iommu);
@@ -385,7 +293,7 @@ static dma_addr_t dma_4u_map_page(struct device *dev, struct page *page,
 	if (unlikely(!base))
 		goto bad;
 
-	bus_addr = (iommu->page_table_map_base +
+	bus_addr = (iommu->tbl.table_map_base +
 		    ((base - iommu->page_table) << IO_PAGE_SHIFT));
 	ret = bus_addr | (oaddr & ~IO_PAGE_MASK);
 	base_paddr = __pa(oaddr & IO_PAGE_MASK);
@@ -496,7 +404,7 @@ static void dma_4u_unmap_page(struct device *dev, dma_addr_t bus_addr,
 	npages = IO_PAGE_ALIGN(bus_addr + sz) - (bus_addr & IO_PAGE_MASK);
 	npages >>= IO_PAGE_SHIFT;
 	base = iommu->page_table +
-		((bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
+		((bus_addr - iommu->tbl.table_map_base) >> IO_PAGE_SHIFT);
 	bus_addr &= IO_PAGE_MASK;
 
 	spin_lock_irqsave(&iommu->lock, flags);
@@ -515,11 +423,10 @@ static void dma_4u_unmap_page(struct device *dev, dma_addr_t bus_addr,
 	for (i = 0; i < npages; i++)
 		iopte_make_dummy(iommu, base + i);
 
-	iommu_range_free(iommu, bus_addr, npages);
-
 	iommu_free_ctx(iommu, ctx);
-
 	spin_unlock_irqrestore(&iommu->lock, flags);
+
+	iommu_tbl_range_free(&iommu->tbl, bus_addr, npages, DMA_ERROR_CODE);
 }
 
 static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
@@ -567,7 +474,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
 	max_seg_size = dma_get_max_seg_size(dev);
 	seg_boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
 				  IO_PAGE_SIZE) >> IO_PAGE_SHIFT;
-	base_shift = iommu->page_table_map_base >> IO_PAGE_SHIFT;
+	base_shift = iommu->tbl.table_map_base >> IO_PAGE_SHIFT;
 	for_each_sg(sglist, s, nelems, i) {
 		unsigned long paddr, npages, entry, out_entry = 0, slen;
 		iopte_t *base;
@@ -581,7 +488,8 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
 		/* Allocate iommu entries for that segment */
 		paddr = (unsigned long) SG_ENT_PHYS_ADDRESS(s);
 		npages = iommu_num_pages(paddr, slen, IO_PAGE_SIZE);
-		entry = iommu_range_alloc(dev, iommu, npages, &handle);
+		entry = iommu_tbl_range_alloc(dev, &iommu->tbl, npages,
+					      &handle, (unsigned long)(-1), 0);
 
 		/* Handle failure */
 		if (unlikely(entry == DMA_ERROR_CODE)) {
@@ -594,7 +502,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
 		base = iommu->page_table + entry;
 
 		/* Convert entry to a dma_addr_t */
-		dma_addr = iommu->page_table_map_base +
+		dma_addr = iommu->tbl.table_map_base +
 			(entry << IO_PAGE_SHIFT);
 		dma_addr |= (s->offset & ~IO_PAGE_MASK);
 
@@ -654,15 +562,17 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
 			vaddr = s->dma_address & IO_PAGE_MASK;
 			npages = iommu_num_pages(s->dma_address, s->dma_length,
 						 IO_PAGE_SIZE);
-			iommu_range_free(iommu, vaddr, npages);
 
-			entry = (vaddr - iommu->page_table_map_base)
+			entry = (vaddr - iommu->tbl.table_map_base)
 				>> IO_PAGE_SHIFT;
 			base = iommu->page_table + entry;
 
 			for (j = 0; j < npages; j++)
 				iopte_make_dummy(iommu, base + j);
 
+			iommu_tbl_range_free(&iommu->tbl, vaddr, npages,
+					     DMA_ERROR_CODE);
+
 			s->dma_address = DMA_ERROR_CODE;
 			s->dma_length = 0;
 		}
@@ -684,10 +594,11 @@ static unsigned long fetch_sg_ctx(struct iommu *iommu, struct scatterlist *sg)
 	if (iommu->iommu_ctxflush) {
 		iopte_t *base;
 		u32 bus_addr;
+		struct iommu_map_table *tbl = &iommu->tbl;
 
 		bus_addr = sg->dma_address & IO_PAGE_MASK;
 		base = iommu->page_table +
-			((bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
+			((bus_addr - tbl->table_map_base) >> IO_PAGE_SHIFT);
 
 		ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;
 	}
@@ -723,9 +634,8 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
 		if (!len)
 			break;
 		npages = iommu_num_pages(dma_handle, len, IO_PAGE_SIZE);
-		iommu_range_free(iommu, dma_handle, npages);
 
-		entry = ((dma_handle - iommu->page_table_map_base)
+		entry = ((dma_handle - iommu->tbl.table_map_base)
 			 >> IO_PAGE_SHIFT);
 		base = iommu->page_table + entry;
 
@@ -737,6 +647,8 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
 		for (i = 0; i < npages; i++)
 			iopte_make_dummy(iommu, base + i);
 
+		iommu_tbl_range_free(&iommu->tbl, dma_handle, npages,
+				     DMA_ERROR_CODE);
 		sg = sg_next(sg);
 	}
 
@@ -770,9 +682,10 @@ static void dma_4u_sync_single_for_cpu(struct device *dev,
 	if (iommu->iommu_ctxflush &&
 	    strbuf->strbuf_ctxflush) {
 		iopte_t *iopte;
+		struct iommu_map_table *tbl = &iommu->tbl;
 
 		iopte = iommu->page_table +
-			((bus_addr - iommu->page_table_map_base)>>IO_PAGE_SHIFT);
+			((bus_addr - tbl->table_map_base)>>IO_PAGE_SHIFT);
 		ctx = (iopte_val(*iopte) & IOPTE_CONTEXT) >> 47UL;
 	}
 
@@ -805,9 +718,10 @@ static void dma_4u_sync_sg_for_cpu(struct device *dev,
 	if (iommu->iommu_ctxflush &&
 	    strbuf->strbuf_ctxflush) {
 		iopte_t *iopte;
+		struct iommu_map_table *tbl = &iommu->tbl;
 
-		iopte = iommu->page_table +
-			((sglist[0].dma_address - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
+		iopte = iommu->page_table + ((sglist[0].dma_address -
+			tbl->table_map_base) >> IO_PAGE_SHIFT);
 		ctx = (iopte_val(*iopte) & IOPTE_CONTEXT) >> 47UL;
 	}
 
diff --git a/arch/sparc/kernel/iommu_common.h b/arch/sparc/kernel/iommu_common.h
index 1ec0de4..f4be0d7 100644
--- a/arch/sparc/kernel/iommu_common.h
+++ b/arch/sparc/kernel/iommu_common.h
@@ -48,12 +48,4 @@ static inline int is_span_boundary(unsigned long entry,
 	return iommu_is_span_boundary(entry, nr, shift, boundary_size);
 }
 
-unsigned long iommu_range_alloc(struct device *dev,
-				struct iommu *iommu,
-				unsigned long npages,
-				unsigned long *handle);
-void iommu_range_free(struct iommu *iommu,
-		      dma_addr_t dma_addr,
-		      unsigned long npages);
-
 #endif /* _IOMMU_COMMON_H */
diff --git a/arch/sparc/kernel/pci_sun4v.c b/arch/sparc/kernel/pci_sun4v.c
index 47ddbd4..d2fe57d 100644
--- a/arch/sparc/kernel/pci_sun4v.c
+++ b/arch/sparc/kernel/pci_sun4v.c
@@ -15,6 +15,7 @@
 #include <linux/export.h>
 #include <linux/log2.h>
 #include <linux/of_device.h>
+#include <linux/iommu-common.h>
 
 #include <asm/iommu.h>
 #include <asm/irq.h>
@@ -155,15 +156,13 @@ static void *dma_4v_alloc_coherent(struct device *dev, size_t size,
 
 	iommu = dev->archdata.iommu;
 
-	spin_lock_irqsave(&iommu->lock, flags);
-	entry = iommu_range_alloc(dev, iommu, npages, NULL);
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	entry = iommu_tbl_range_alloc(dev, &iommu->tbl, npages, NULL,
+				      (unsigned long)(-1), 0);
 
 	if (unlikely(entry == DMA_ERROR_CODE))
 		goto range_alloc_fail;
 
-	*dma_addrp = (iommu->page_table_map_base +
-		      (entry << IO_PAGE_SHIFT));
+	*dma_addrp = (iommu->tbl.table_map_base + (entry << IO_PAGE_SHIFT));
 	ret = (void *) first_page;
 	first_page = __pa(first_page);
 
@@ -188,45 +187,46 @@ static void *dma_4v_alloc_coherent(struct device *dev, size_t size,
 	return ret;
 
 iommu_map_fail:
-	/* Interrupts are disabled.  */
-	spin_lock(&iommu->lock);
-	iommu_range_free(iommu, *dma_addrp, npages);
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	iommu_tbl_range_free(&iommu->tbl, *dma_addrp, npages, DMA_ERROR_CODE);
 
 range_alloc_fail:
 	free_pages(first_page, order);
 	return NULL;
 }
 
+static void dma_4v_iommu_demap(void *demap_arg, unsigned long entry,
+			       unsigned long npages)
+{
+	u32 devhandle = *(u32 *)demap_arg;
+	unsigned long num, flags;
+
+	local_irq_save(flags);
+	do {
+		num = pci_sun4v_iommu_demap(devhandle,
+					    HV_PCI_TSBID(0, entry),
+					    npages);
+
+		entry += num;
+		npages -= num;
+	} while (npages != 0);
+	local_irq_restore(flags);
+}
+
 static void dma_4v_free_coherent(struct device *dev, size_t size, void *cpu,
 				 dma_addr_t dvma, struct dma_attrs *attrs)
 {
 	struct pci_pbm_info *pbm;
 	struct iommu *iommu;
-	unsigned long flags, order, npages, entry;
+	unsigned long order, npages, entry;
 	u32 devhandle;
 
 	npages = IO_PAGE_ALIGN(size) >> IO_PAGE_SHIFT;
 	iommu = dev->archdata.iommu;
 	pbm = dev->archdata.host_controller;
 	devhandle = pbm->devhandle;
-	entry = ((dvma - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
-
-	spin_lock_irqsave(&iommu->lock, flags);
-
-	iommu_range_free(iommu, dvma, npages);
-
-	do {
-		unsigned long num;
-
-		num = pci_sun4v_iommu_demap(devhandle, HV_PCI_TSBID(0, entry),
-					    npages);
-		entry += num;
-		npages -= num;
-	} while (npages != 0);
-
-	spin_unlock_irqrestore(&iommu->lock, flags);
-
+	entry = ((dvma - iommu->tbl.table_map_base) >> IO_PAGE_SHIFT);
+	dma_4v_iommu_demap(&devhandle, entry, npages);
+	iommu_tbl_range_free(&iommu->tbl, dvma, npages, DMA_ERROR_CODE);
 	order = get_order(size);
 	if (order < 10)
 		free_pages((unsigned long)cpu, order);
@@ -253,15 +253,13 @@ static dma_addr_t dma_4v_map_page(struct device *dev, struct page *page,
 	npages = IO_PAGE_ALIGN(oaddr + sz) - (oaddr & IO_PAGE_MASK);
 	npages >>= IO_PAGE_SHIFT;
 
-	spin_lock_irqsave(&iommu->lock, flags);
-	entry = iommu_range_alloc(dev, iommu, npages, NULL);
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	entry = iommu_tbl_range_alloc(dev, &iommu->tbl, npages, NULL,
+				      (unsigned long)(-1), 0);
 
 	if (unlikely(entry == DMA_ERROR_CODE))
 		goto bad;
 
-	bus_addr = (iommu->page_table_map_base +
-		    (entry << IO_PAGE_SHIFT));
+	bus_addr = (iommu->tbl.table_map_base + (entry << IO_PAGE_SHIFT));
 	ret = bus_addr | (oaddr & ~IO_PAGE_MASK);
 	base_paddr = __pa(oaddr & IO_PAGE_MASK);
 	prot = HV_PCI_MAP_ATTR_READ;
@@ -290,11 +288,7 @@ static dma_addr_t dma_4v_map_page(struct device *dev, struct page *page,
 	return DMA_ERROR_CODE;
 
 iommu_map_fail:
-	/* Interrupts are disabled.  */
-	spin_lock(&iommu->lock);
-	iommu_range_free(iommu, bus_addr, npages);
-	spin_unlock_irqrestore(&iommu->lock, flags);
-
+	iommu_tbl_range_free(&iommu->tbl, bus_addr, npages, DMA_ERROR_CODE);
 	return DMA_ERROR_CODE;
 }
 
@@ -304,7 +298,7 @@ static void dma_4v_unmap_page(struct device *dev, dma_addr_t bus_addr,
 {
 	struct pci_pbm_info *pbm;
 	struct iommu *iommu;
-	unsigned long flags, npages;
+	unsigned long npages;
 	long entry;
 	u32 devhandle;
 
@@ -321,22 +315,9 @@ static void dma_4v_unmap_page(struct device *dev, dma_addr_t bus_addr,
 	npages = IO_PAGE_ALIGN(bus_addr + sz) - (bus_addr & IO_PAGE_MASK);
 	npages >>= IO_PAGE_SHIFT;
 	bus_addr &= IO_PAGE_MASK;
-
-	spin_lock_irqsave(&iommu->lock, flags);
-
-	iommu_range_free(iommu, bus_addr, npages);
-
-	entry = (bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT;
-	do {
-		unsigned long num;
-
-		num = pci_sun4v_iommu_demap(devhandle, HV_PCI_TSBID(0, entry),
-					    npages);
-		entry += num;
-		npages -= num;
-	} while (npages != 0);
-
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	entry = (bus_addr - iommu->tbl.table_map_base) >> IO_PAGE_SHIFT;
+	dma_4v_iommu_demap(&devhandle, entry, npages);
+	iommu_tbl_range_free(&iommu->tbl, bus_addr, npages, DMA_ERROR_CODE);
 }
 
 static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
@@ -371,14 +352,14 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
 	/* Init first segment length for backout at failure */
 	outs->dma_length = 0;
 
-	spin_lock_irqsave(&iommu->lock, flags);
+	local_irq_save(flags);
 
 	iommu_batch_start(dev, prot, ~0UL);
 
 	max_seg_size = dma_get_max_seg_size(dev);
 	seg_boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
 				  IO_PAGE_SIZE) >> IO_PAGE_SHIFT;
-	base_shift = iommu->page_table_map_base >> IO_PAGE_SHIFT;
+	base_shift = iommu->tbl.table_map_base >> IO_PAGE_SHIFT;
 	for_each_sg(sglist, s, nelems, i) {
 		unsigned long paddr, npages, entry, out_entry = 0, slen;
 
@@ -391,7 +372,8 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
 		/* Allocate iommu entries for that segment */
 		paddr = (unsigned long) SG_ENT_PHYS_ADDRESS(s);
 		npages = iommu_num_pages(paddr, slen, IO_PAGE_SIZE);
-		entry = iommu_range_alloc(dev, iommu, npages, &handle);
+		entry = iommu_tbl_range_alloc(dev, &iommu->tbl, npages,
+					      &handle, (unsigned long)(-1), 0);
 
 		/* Handle failure */
 		if (unlikely(entry == DMA_ERROR_CODE)) {
@@ -404,8 +386,7 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
 		iommu_batch_new_entry(entry);
 
 		/* Convert entry to a dma_addr_t */
-		dma_addr = iommu->page_table_map_base +
-			(entry << IO_PAGE_SHIFT);
+		dma_addr = iommu->tbl.table_map_base + (entry << IO_PAGE_SHIFT);
 		dma_addr |= (s->offset & ~IO_PAGE_MASK);
 
 		/* Insert into HW table */
@@ -451,7 +432,7 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
 	if (unlikely(err < 0L))
 		goto iommu_map_failed;
 
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	local_irq_restore(flags);
 
 	if (outcount < incount) {
 		outs = sg_next(outs);
@@ -469,7 +450,8 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
 			vaddr = s->dma_address & IO_PAGE_MASK;
 			npages = iommu_num_pages(s->dma_address, s->dma_length,
 						 IO_PAGE_SIZE);
-			iommu_range_free(iommu, vaddr, npages);
+			iommu_tbl_range_free(&iommu->tbl, vaddr, npages,
+					     DMA_ERROR_CODE);
 			/* XXX demap? XXX */
 			s->dma_address = DMA_ERROR_CODE;
 			s->dma_length = 0;
@@ -477,7 +459,7 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
 		if (s == outs)
 			break;
 	}
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	local_irq_restore(flags);
 
 	return 0;
 }
@@ -489,7 +471,7 @@ static void dma_4v_unmap_sg(struct device *dev, struct scatterlist *sglist,
 	struct pci_pbm_info *pbm;
 	struct scatterlist *sg;
 	struct iommu *iommu;
-	unsigned long flags;
+	unsigned long flags, entry;
 	u32 devhandle;
 
 	BUG_ON(direction == DMA_NONE);
@@ -498,33 +480,27 @@ static void dma_4v_unmap_sg(struct device *dev, struct scatterlist *sglist,
 	pbm = dev->archdata.host_controller;
 	devhandle = pbm->devhandle;
 	
-	spin_lock_irqsave(&iommu->lock, flags);
+	local_irq_save(flags);
 
 	sg = sglist;
 	while (nelems--) {
 		dma_addr_t dma_handle = sg->dma_address;
 		unsigned int len = sg->dma_length;
-		unsigned long npages, entry;
+		unsigned long npages;
+		struct iommu_map_table *tbl = &iommu->tbl;
+		unsigned long shift = IO_PAGE_SHIFT;
 
 		if (!len)
 			break;
 		npages = iommu_num_pages(dma_handle, len, IO_PAGE_SIZE);
-		iommu_range_free(iommu, dma_handle, npages);
-
-		entry = ((dma_handle - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
-		while (npages) {
-			unsigned long num;
-
-			num = pci_sun4v_iommu_demap(devhandle, HV_PCI_TSBID(0, entry),
-						    npages);
-			entry += num;
-			npages -= num;
-		}
-
+		entry = ((dma_handle - tbl->table_map_base) >> shift);
+		dma_4v_iommu_demap(&devhandle, entry, npages);
+		iommu_tbl_range_free(&iommu->tbl, dma_handle, npages,
+				     DMA_ERROR_CODE);
 		sg = sg_next(sg);
 	}
 
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	local_irq_restore(flags);
 }
 
 static struct dma_map_ops sun4v_dma_ops = {
@@ -550,30 +526,33 @@ static void pci_sun4v_scan_bus(struct pci_pbm_info *pbm, struct device *parent)
 }
 
 static unsigned long probe_existing_entries(struct pci_pbm_info *pbm,
-					    struct iommu *iommu)
+					    struct iommu_map_table *iommu)
 {
-	struct iommu_arena *arena = &iommu->arena;
-	unsigned long i, cnt = 0;
+	struct iommu_pool *pool;
+	unsigned long i, pool_nr, cnt = 0;
 	u32 devhandle;
 
 	devhandle = pbm->devhandle;
-	for (i = 0; i < arena->limit; i++) {
-		unsigned long ret, io_attrs, ra;
-
-		ret = pci_sun4v_iommu_getmap(devhandle,
-					     HV_PCI_TSBID(0, i),
-					     &io_attrs, &ra);
-		if (ret == HV_EOK) {
-			if (page_in_phys_avail(ra)) {
-				pci_sun4v_iommu_demap(devhandle,
-						      HV_PCI_TSBID(0, i), 1);
-			} else {
-				cnt++;
-				__set_bit(i, arena->map);
+	for (pool_nr = 0; pool_nr < iommu->nr_pools; pool_nr++) {
+		pool = &(iommu->pools[pool_nr]);
+		for (i = pool->start; i <= pool->end; i++) {
+			unsigned long ret, io_attrs, ra;
+
+			ret = pci_sun4v_iommu_getmap(devhandle,
+						     HV_PCI_TSBID(0, i),
+						     &io_attrs, &ra);
+			if (ret == HV_EOK) {
+				if (page_in_phys_avail(ra)) {
+					pci_sun4v_iommu_demap(devhandle,
+							      HV_PCI_TSBID(0,
+							      i), 1);
+				} else {
+					cnt++;
+					__set_bit(i, iommu->map);
+				}
 			}
 		}
 	}
-
 	return cnt;
 }
 
@@ -603,20 +582,22 @@ static int pci_sun4v_iommu_init(struct pci_pbm_info *pbm)
 	/* Setup initial software IOMMU state. */
 	spin_lock_init(&iommu->lock);
 	iommu->ctx_lowest_free = 1;
-	iommu->page_table_map_base = dma_offset;
+	iommu->tbl.table_map_base = dma_offset;
 	iommu->dma_addr_mask = dma_mask;
 
 	/* Allocate and initialize the free area map.  */
 	sz = (num_tsb_entries + 7) / 8;
 	sz = (sz + 7UL) & ~7UL;
-	iommu->arena.map = kzalloc(sz, GFP_KERNEL);
-	if (!iommu->arena.map) {
+	iommu->tbl.map = kzalloc(sz, GFP_KERNEL);
+	if (!iommu->tbl.map) {
 		printk(KERN_ERR PFX "Error, kmalloc(arena.map) failed.\n");
 		return -ENOMEM;
 	}
-	iommu->arena.limit = num_tsb_entries;
-
-	sz = probe_existing_entries(pbm, iommu);
+	iommu_tbl_pool_init(&iommu->tbl, num_tsb_entries, IO_PAGE_SHIFT,
+			    NULL, false /* no large_pool */,
+			    0 /* default npools */,
+			    false /* want span boundary checking */);
+	sz = probe_existing_entries(pbm, &iommu->tbl);
 	if (sz)
 		printk("%s: Imported %lu TSB entries from OBP\n",
 		       pbm->name, sz);
-- 
1.7.1

[PATCH v9 RFC 3/3] sparc: Make LDC use common iommu poll management functions

[Sowmini Varadhan]

Note that this conversion is only being done to consolidate the
code and ensure that the common code provides the sufficient
abstraction. It is not expected to result in any noticeable
performance improvement, as there is typically one ldc_iommu
per vnet_port, and each one has 8k entries, with a typical
request for 1-4 pages.  Thus LDC uses npools == 1.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
---
v3: added this file to be a consumer of the common iommu library
v4: removed ->cookie_to_index and ->demap from iommu_tbl_ops and instead
    inline these calls into ldc before calling into iommu-common
v6: remove iommu_tbl_ops
v7: move pool_hash initialization to iommu_tbl_pool_init
v8: BenH comments
v9: More BenH comments
 arch/sparc/kernel/ldc.c |  153 ++++++++++++++++++++---------------------------
 1 files changed, 65 insertions(+), 88 deletions(-)

diff --git a/arch/sparc/kernel/ldc.c b/arch/sparc/kernel/ldc.c
index 274a9f5..d2ae0f7 100644
--- a/arch/sparc/kernel/ldc.c
+++ b/arch/sparc/kernel/ldc.c
@@ -15,6 +15,7 @@
 #include <linux/list.h>
 #include <linux/init.h>
 #include <linux/bitmap.h>
+#include <linux/iommu-common.h>
 
 #include <asm/hypervisor.h>
 #include <asm/iommu.h>
@@ -27,6 +28,10 @@
 #define DRV_MODULE_VERSION	"1.1"
 #define DRV_MODULE_RELDATE	"July 22, 2008"
 
+#define COOKIE_PGSZ_CODE	0xf000000000000000ULL
+#define COOKIE_PGSZ_CODE_SHIFT	60ULL
+
+
 static char version[] =
 	DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";
 #define LDC_PACKET_SIZE		64
@@ -98,10 +103,10 @@ static const struct ldc_mode_ops stream_ops;
 int ldom_domaining_enabled;
 
 struct ldc_iommu {
-	/* Protects arena alloc/free.  */
+	/* Protects ldc_unmap.  */
 	spinlock_t			lock;
-	struct iommu_arena		arena;
 	struct ldc_mtable_entry		*page_table;
+	struct iommu_map_table		iommu_map_table;
 };
 
 struct ldc_channel {
@@ -998,31 +1003,59 @@ static void free_queue(unsigned long num_entries, struct ldc_packet *q)
 	free_pages((unsigned long)q, order);
 }
 
+static unsigned long ldc_cookie_to_index(u64 cookie, void *arg)
+{
+	u64 szcode = cookie >> COOKIE_PGSZ_CODE_SHIFT;
+	/* struct ldc_iommu *ldc_iommu = (struct ldc_iommu *)arg; */
+
+	cookie &= ~COOKIE_PGSZ_CODE;
+
+	return (cookie >> (13ULL + (szcode * 3ULL)));
+}
+
+static void ldc_demap(struct ldc_iommu *iommu, unsigned long id, u64 cookie,
+		      unsigned long entry, unsigned long npages)
+{
+	struct ldc_mtable_entry *base;
+	unsigned long i, shift;
+
+	shift = (cookie >> COOKIE_PGSZ_CODE_SHIFT) * 3;
+	base = iommu->page_table + entry;
+	for (i = 0; i < npages; i++) {
+		if (base->cookie)
+			sun4v_ldc_revoke(id, cookie + (i << shift),
+					 base->cookie);
+		base->mte = 0;
+	}
+}
+
 /* XXX Make this configurable... XXX */
 #define LDC_IOTABLE_SIZE	(8 * 1024)
 
-static int ldc_iommu_init(struct ldc_channel *lp)
+static int ldc_iommu_init(const char *name, struct ldc_channel *lp)
 {
 	unsigned long sz, num_tsb_entries, tsbsize, order;
-	struct ldc_iommu *iommu = &lp->iommu;
+	struct ldc_iommu *ldc_iommu = &lp->iommu;
+	struct iommu_map_table *iommu = &ldc_iommu->iommu_map_table;
 	struct ldc_mtable_entry *table;
 	unsigned long hv_err;
 	int err;
 
 	num_tsb_entries = LDC_IOTABLE_SIZE;
 	tsbsize = num_tsb_entries * sizeof(struct ldc_mtable_entry);
-
-	spin_lock_init(&iommu->lock);
+	spin_lock_init(&ldc_iommu->lock);
 
 	sz = num_tsb_entries / 8;
 	sz = (sz + 7UL) & ~7UL;
-	iommu->arena.map = kzalloc(sz, GFP_KERNEL);
-	if (!iommu->arena.map) {
+	iommu->map = kzalloc(sz, GFP_KERNEL);
+	if (!iommu->map) {
 		printk(KERN_ERR PFX "Alloc of arena map failed, sz=%lu\n", sz);
 		return -ENOMEM;
 	}
-
-	iommu->arena.limit = num_tsb_entries;
+	iommu_tbl_pool_init(iommu, num_tsb_entries, PAGE_SHIFT,
+			    NULL, false /* no large pool */,
+			    1 /* npools */,
+			    true /* skip span boundary check */);
 
 	order = get_order(tsbsize);
 
@@ -1037,7 +1070,7 @@ static int ldc_iommu_init(struct ldc_channel *lp)
 
 	memset(table, 0, PAGE_SIZE << order);
 
-	iommu->page_table = table;
+	ldc_iommu->page_table = table;
 
 	hv_err = sun4v_ldc_set_map_table(lp->id, __pa(table),
 					 num_tsb_entries);
@@ -1049,31 +1082,32 @@ static int ldc_iommu_init(struct ldc_channel *lp)
 
 out_free_table:
 	free_pages((unsigned long) table, order);
-	iommu->page_table = NULL;
+	ldc_iommu->page_table = NULL;
 
 out_free_map:
-	kfree(iommu->arena.map);
-	iommu->arena.map = NULL;
+	kfree(iommu->map);
+	iommu->map = NULL;
 
 	return err;
 }
 
 static void ldc_iommu_release(struct ldc_channel *lp)
 {
-	struct ldc_iommu *iommu = &lp->iommu;
+	struct ldc_iommu *ldc_iommu = &lp->iommu;
+	struct iommu_map_table *iommu = &ldc_iommu->iommu_map_table;
 	unsigned long num_tsb_entries, tsbsize, order;
 
 	(void) sun4v_ldc_set_map_table(lp->id, 0, 0);
 
-	num_tsb_entries = iommu->arena.limit;
+	num_tsb_entries = iommu->poolsize * iommu->nr_pools;
 	tsbsize = num_tsb_entries * sizeof(struct ldc_mtable_entry);
 	order = get_order(tsbsize);
 
-	free_pages((unsigned long) iommu->page_table, order);
-	iommu->page_table = NULL;
+	free_pages((unsigned long) ldc_iommu->page_table, order);
+	ldc_iommu->page_table = NULL;
 
-	kfree(iommu->arena.map);
-	iommu->arena.map = NULL;
+	kfree(iommu->map);
+	iommu->map = NULL;
 }
 
 struct ldc_channel *ldc_alloc(unsigned long id,
@@ -1140,7 +1174,7 @@ struct ldc_channel *ldc_alloc(unsigned long id,
 
 	lp->id = id;
 
-	err = ldc_iommu_init(lp);
+	err = ldc_iommu_init(name, lp);
 	if (err)
 		goto out_free_ldc;
 
@@ -1885,40 +1919,6 @@ int ldc_read(struct ldc_channel *lp, void *buf, unsigned int size)
 }
 EXPORT_SYMBOL(ldc_read);
 
-static long arena_alloc(struct ldc_iommu *iommu, unsigned long npages)
-{
-	struct iommu_arena *arena = &iommu->arena;
-	unsigned long n, start, end, limit;
-	int pass;
-
-	limit = arena->limit;
-	start = arena->hint;
-	pass = 0;
-
-again:
-	n = bitmap_find_next_zero_area(arena->map, limit, start, npages, 0);
-	end = n + npages;
-	if (unlikely(end >= limit)) {
-		if (likely(pass < 1)) {
-			limit = start;
-			start = 0;
-			pass++;
-			goto again;
-		} else {
-			/* Scanned the whole thing, give up. */
-			return -1;
-		}
-	}
-	bitmap_set(arena->map, n, npages);
-
-	arena->hint = end;
-
-	return n;
-}
-
-#define COOKIE_PGSZ_CODE	0xf000000000000000ULL
-#define COOKIE_PGSZ_CODE_SHIFT	60ULL
-
 static u64 pagesize_code(void)
 {
 	switch (PAGE_SIZE) {
@@ -1945,23 +1945,14 @@ static u64 make_cookie(u64 index, u64 pgsz_code, u64 page_offset)
 		page_offset);
 }
 
-static u64 cookie_to_index(u64 cookie, unsigned long *shift)
-{
-	u64 szcode = cookie >> COOKIE_PGSZ_CODE_SHIFT;
-
-	cookie &= ~COOKIE_PGSZ_CODE;
-
-	*shift = szcode * 3;
-
-	return (cookie >> (13ULL + (szcode * 3ULL)));
-}
 
 static struct ldc_mtable_entry *alloc_npages(struct ldc_iommu *iommu,
 					     unsigned long npages)
 {
 	long entry;
 
-	entry = arena_alloc(iommu, npages);
+	entry = iommu_tbl_range_alloc(NULL, &iommu->iommu_map_table,
+				      npages, NULL, (unsigned long)-1, 0);
 	if (unlikely(entry < 0))
 		return NULL;
 
@@ -2090,7 +2081,7 @@ int ldc_map_sg(struct ldc_channel *lp,
 	       struct ldc_trans_cookie *cookies, int ncookies,
 	       unsigned int map_perm)
 {
-	unsigned long i, npages, flags;
+	unsigned long i, npages;
 	struct ldc_mtable_entry *base;
 	struct cookie_state state;
 	struct ldc_iommu *iommu;
@@ -2109,9 +2100,7 @@ int ldc_map_sg(struct ldc_channel *lp,
 
 	iommu = &lp->iommu;
 
-	spin_lock_irqsave(&iommu->lock, flags);
 	base = alloc_npages(iommu, npages);
-	spin_unlock_irqrestore(&iommu->lock, flags);
 
 	if (!base)
 		return -ENOMEM;
@@ -2136,7 +2125,7 @@ int ldc_map_single(struct ldc_channel *lp,
 		   struct ldc_trans_cookie *cookies, int ncookies,
 		   unsigned int map_perm)
 {
-	unsigned long npages, pa, flags;
+	unsigned long npages, pa;
 	struct ldc_mtable_entry *base;
 	struct cookie_state state;
 	struct ldc_iommu *iommu;
@@ -2152,9 +2141,7 @@ int ldc_map_single(struct ldc_channel *lp,
 
 	iommu = &lp->iommu;
 
-	spin_lock_irqsave(&iommu->lock, flags);
 	base = alloc_npages(iommu, npages);
-	spin_unlock_irqrestore(&iommu->lock, flags);
 
 	if (!base)
 		return -ENOMEM;
@@ -2172,35 +2159,25 @@ int ldc_map_single(struct ldc_channel *lp,
 }
 EXPORT_SYMBOL(ldc_map_single);
 
+
 static void free_npages(unsigned long id, struct ldc_iommu *iommu,
 			u64 cookie, u64 size)
 {
-	struct iommu_arena *arena = &iommu->arena;
-	unsigned long i, shift, index, npages;
-	struct ldc_mtable_entry *base;
+	unsigned long npages, entry;
 
 	npages = PAGE_ALIGN(((cookie & ~PAGE_MASK) + size)) >> PAGE_SHIFT;
-	index = cookie_to_index(cookie, &shift);
-	base = iommu->page_table + index;
 
-	BUG_ON(index > arena->limit ||
-	       (index + npages) > arena->limit);
-
-	for (i = 0; i < npages; i++) {
-		if (base->cookie)
-			sun4v_ldc_revoke(id, cookie + (i << shift),
-					 base->cookie);
-		base->mte = 0;
-		__clear_bit(index + i, arena->map);
-	}
+	entry = ldc_cookie_to_index(cookie, iommu);
+	ldc_demap(iommu, id, cookie, entry, npages);
+	iommu_tbl_range_free(&iommu->iommu_map_table, cookie, npages, entry);
 }
 
 void ldc_unmap(struct ldc_channel *lp, struct ldc_trans_cookie *cookies,
 	       int ncookies)
 {
 	struct ldc_iommu *iommu = &lp->iommu;
-	unsigned long flags;
 	int i;
+	unsigned long flags;
 
 	spin_lock_irqsave(&iommu->lock, flags);
 	for (i = 0; i < ncookies; i++) {
-- 
1.7.1

Re: [PATCHv9 RFC 1/3] Break up monolithic iommu table/lock into finer graularity pools and lock

[Benjamin Herrenschmidt]

On Sun, 2015-04-05 at 07:49 -0400, Sowmini Varadhan wrote:
> +               if (likely(pass == 0)) {
> +                       /* First failure, rescan from the beginning.
> */
> +                       pool->hint = pool->start;
> +                       set_flush(iommu);
> +                       pass++;
> +                       goto again;
> +               } else if (!largealloc && pass <= iommu->nr_pools) {
> +                       spin_unlock(&(pool->lock));
> +                       pool_nr = (pool_nr + 1) & (iommu->nr_pools -
> 1);
> +                       pool = &(iommu->pools[pool_nr]);
> +                       spin_lock(&(pool->lock));
> +                       pool->hint = pool->start;
> +                       set_flush(iommu);
> +                       pass++;
> +                       goto again;

So you decided to keep the logic here that updates the hint instead of
just getting rid of need_flush alltogether ?

Out of curiosity, what's the rationale ? Did you find a reason why
resetting the hint in those two cases (rather than just setting "start"
appropriately) is actually useful ?

Cheers,
Ben.

Re: [PATCHv9 RFC 1/3] Break up monolithic iommu table/lock into finer graularity pools and lock

[Sowmini Varadhan]

On (04/05/15 22:26), Benjamin Herrenschmidt wrote:
> 
> So you decided to keep the logic here that updates the hint instead of
> just getting rid of need_flush alltogether ?
> 
> Out of curiosity, what's the rationale ? Did you find a reason why
> resetting the hint in those two cases (rather than just setting "start"
> appropriately) is actually useful ?

To be honest, I actually did not want to poke at this too much, given
that both ppc and sparc seem to have essentially the same
logic.

But my gut feeling is that if the pool->hint hasn't resulted
in a succesful area_alloc, we might as well reset it for the next
iommu*range_alloc-er, because it's likely that the next alloc
will also need to  wrap and search anyway..

--Sowmini

Re: [PATCHv9 RFC 1/3] Break up monolithic iommu table/lock into finer graularity pools and lock

[Benjamin Herrenschmidt]

On Sun, 2015-04-05 at 07:49 -0400, Sowmini Varadhan wrote:
> Investigation of multithreaded iperf experiments on an ethernet
> interface show the iommu->lock as the hottest lock identified by
> lockstat, with something of the order of  21M contentions out of
> 27M acquisitions, and an average wait time of 26 us for the lock.
> This is not efficient. A more scalable design is to follow the ppc
> model, where the iommu_map_table has multiple pools, each stretching
> over a segment of the map, and with a separate lock for each pool.
> This model allows for better parallelization of the iommu map search.
> 
> This patch adds the iommu range alloc/free function infrastructure.

Sorry for the delay, I'm swamped with "stuff" at the moment, I wanted to
try actually porting powerpc over and testing but didn't get a chance.

I'm happy with your last version, feel free to add my

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

I'll port powerpc over when I get a chance and if I find a need to tweak
something at that point, I'll send a separate patch on top of yours.

Cheers,
Ben.

> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
> ---
> v2 changes:
>   - incorporate David Miller editorial comments: sparc specific
>     fields moved from iommu-common into sparc's iommu_64.h
>   - make the npools value an input parameter, for the case when
>     the iommu map size is not very large
>   - cookie_to_index mapping, and optimizations for span-boundary
>     check, for use case such as LDC.
> v3: eliminate iommu_sparc, rearrange the ->demap indirection to
>     be invoked under the pool lock.
> 
> v4: David Miller review changes:
>   - s/IOMMU_ERROR_CODE/DMA_ERROR_CODE
>   - page_table_map_base and page_table_shift are unsigned long, not u32.
> 
> v5: Feedback from benh@kernel.crashing.org and aik@ozlabs.ru
>   - removed ->cookie_to_index and ->demap indirection: caller should
>     invoke these as needed before calling into the generic allocator
> 
> v6: Benh/DaveM discussion eliminationg iommu_tbl_ops, but retaining flush_all
>     optimization.
> 
> v7: one-time initialization of pool_hash from iommu_tbl_pool_init()
> 
> v8: Benh code review comments.
> 
> v9: More Benh code review comments, added dma_mask, align_order logic to
>     iommu_tbl_range_alloc.
> 
>  include/linux/iommu-common.h |   51 ++++++++
>  lib/Makefile                 |    2 +-
>  lib/iommu-common.c           |  266 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 318 insertions(+), 1 deletions(-)
>  create mode 100644 include/linux/iommu-common.h
>  create mode 100644 lib/iommu-common.c
> 
> diff --git a/include/linux/iommu-common.h b/include/linux/iommu-common.h
> new file mode 100644
> index 0000000..bbced83
> --- /dev/null
> +++ b/include/linux/iommu-common.h
> @@ -0,0 +1,51 @@
> +#ifndef _LINUX_IOMMU_COMMON_H
> +#define _LINUX_IOMMU_COMMON_H
> +
> +#include <linux/spinlock_types.h>
> +#include <linux/device.h>
> +#include <asm/page.h>
> +
> +#define IOMMU_POOL_HASHBITS     4
> +#define IOMMU_NR_POOLS          (1 << IOMMU_POOL_HASHBITS)
> +
> +struct iommu_pool {
> +	unsigned long	start;
> +	unsigned long	end;
> +	unsigned long	hint;
> +	spinlock_t	lock;
> +};
> +
> +struct iommu_map_table {
> +	unsigned long		table_map_base;
> +	unsigned long		table_shift;
> +	unsigned long		nr_pools;
> +	void			(*lazy_flush)(struct iommu_map_table *);
> +	unsigned long		poolsize;
> +	struct iommu_pool	pools[IOMMU_NR_POOLS];
> +	u32			flags;
> +#define	IOMMU_HAS_LARGE_POOL	0x00000001
> +#define	IOMMU_NO_SPAN_BOUND	0x00000002
> +#define	IOMMU_NEED_FLUSH	0x00000004
> +	struct iommu_pool	large_pool;
> +	unsigned long		*map;
> +};
> +
> +extern void iommu_tbl_pool_init(struct iommu_map_table *iommu,
> +				unsigned long num_entries,
> +				u32 table_shift,
> +				void (*lazy_flush)(struct iommu_map_table *),
> +				bool large_pool, u32 npools,
> +				bool skip_span_boundary_check);
> +
> +extern unsigned long iommu_tbl_range_alloc(struct device *dev,
> +					   struct iommu_map_table *iommu,
> +					   unsigned long npages,
> +					   unsigned long *handle,
> +					   unsigned long mask,
> +					   unsigned int align_order);
> +
> +extern void iommu_tbl_range_free(struct iommu_map_table *iommu,
> +				 u64 dma_addr, unsigned long npages,
> +				 unsigned long entry);
> +
> +#endif
> diff --git a/lib/Makefile b/lib/Makefile
> index 58f74d2..60c22e6 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -106,7 +106,7 @@ obj-$(CONFIG_AUDIT_GENERIC) += audit.o
>  obj-$(CONFIG_AUDIT_COMPAT_GENERIC) += compat_audit.o
>  
>  obj-$(CONFIG_SWIOTLB) += swiotlb.o
> -obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o
> +obj-$(CONFIG_IOMMU_HELPER) += iommu-helper.o iommu-common.o
>  obj-$(CONFIG_FAULT_INJECTION) += fault-inject.o
>  obj-$(CONFIG_NOTIFIER_ERROR_INJECTION) += notifier-error-inject.o
>  obj-$(CONFIG_CPU_NOTIFIER_ERROR_INJECT) += cpu-notifier-error-inject.o
> diff --git a/lib/iommu-common.c b/lib/iommu-common.c
> new file mode 100644
> index 0000000..b99f1d7
> --- /dev/null
> +++ b/lib/iommu-common.c
> @@ -0,0 +1,266 @@
> +/*
> + * IOMMU mmap management and range allocation functions.
> + * Based almost entirely upon the powerpc iommu allocator.
> + */
> +
> +#include <linux/export.h>
> +#include <linux/bitmap.h>
> +#include <linux/bug.h>
> +#include <linux/iommu-helper.h>
> +#include <linux/iommu-common.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/hash.h>
> +
> +unsigned long iommu_large_alloc = 15;
> +
> +static	DEFINE_PER_CPU(unsigned int, iommu_pool_hash);
> +
> +static inline bool need_flush(struct iommu_map_table *iommu)
> +{
> +	return (iommu->lazy_flush != NULL &&
> +		(iommu->flags & IOMMU_NEED_FLUSH) != 0);
> +}
> +
> +static inline void set_flush(struct iommu_map_table *iommu)
> +{
> +	iommu->flags |= IOMMU_NEED_FLUSH;
> +}
> +
> +static inline void clear_flush(struct iommu_map_table *iommu)
> +{
> +	iommu->flags &= ~IOMMU_NEED_FLUSH;
> +}
> +
> +static void setup_iommu_pool_hash(void)
> +{
> +	unsigned int i;
> +	static bool do_once;
> +
> +	if (do_once)
> +		return;
> +	do_once = true;
> +	for_each_possible_cpu(i)
> +		per_cpu(iommu_pool_hash, i) = hash_32(i, IOMMU_POOL_HASHBITS);
> +}
> +
> +/*
> + * Initialize iommu_pool entries for the iommu_map_table. `num_entries'
> + * is the number of table entries. If `large_pool' is set to true,
> + * the top 1/4 of the table will be set aside for pool allocations
> + * of more than iommu_large_alloc pages.
> + */
> +extern void iommu_tbl_pool_init(struct iommu_map_table *iommu,
> +				unsigned long num_entries,
> +				u32 table_shift,
> +				void (*lazy_flush)(struct iommu_map_table *),
> +				bool large_pool, u32 npools,
> +				bool skip_span_boundary_check)
> +{
> +	unsigned int start, i;
> +	struct iommu_pool *p = &(iommu->large_pool);
> +
> +	setup_iommu_pool_hash();
> +	if (npools == 0)
> +		iommu->nr_pools = IOMMU_NR_POOLS;
> +	else
> +		iommu->nr_pools = npools;
> +	BUG_ON(npools > IOMMU_NR_POOLS);
> +
> +	iommu->table_shift = table_shift;
> +	iommu->lazy_flush = lazy_flush;
> +	start = 0;
> +	if (skip_span_boundary_check)
> +		iommu->flags |= IOMMU_NO_SPAN_BOUND;
> +	if (large_pool)
> +		iommu->flags |= IOMMU_HAS_LARGE_POOL;
> +
> +	if (!large_pool)
> +		iommu->poolsize = num_entries/iommu->nr_pools;
> +	else
> +		iommu->poolsize = (num_entries * 3 / 4)/iommu->nr_pools;
> +	for (i = 0; i < iommu->nr_pools; i++) {
> +		spin_lock_init(&(iommu->pools[i].lock));
> +		iommu->pools[i].start = start;
> +		iommu->pools[i].hint = start;
> +		start += iommu->poolsize; /* start for next pool */
> +		iommu->pools[i].end = start - 1;
> +	}
> +	if (!large_pool)
> +		return;
> +	/* initialize large_pool */
> +	spin_lock_init(&(p->lock));
> +	p->start = start;
> +	p->hint = p->start;
> +	p->end = num_entries;
> +}
> +EXPORT_SYMBOL(iommu_tbl_pool_init);
> +
> +unsigned long iommu_tbl_range_alloc(struct device *dev,
> +				struct iommu_map_table *iommu,
> +				unsigned long npages,
> +				unsigned long *handle,
> +				unsigned long mask,
> +				unsigned int align_order)
> +{
> +	unsigned int pool_hash = __this_cpu_read(iommu_pool_hash);
> +	unsigned long n, end, start, limit, boundary_size;
> +	struct iommu_pool *pool;
> +	int pass = 0;
> +	unsigned int pool_nr;
> +	unsigned int npools = iommu->nr_pools;
> +	unsigned long flags;
> +	bool large_pool = ((iommu->flags & IOMMU_HAS_LARGE_POOL) != 0);
> +	bool largealloc = (large_pool && npages > iommu_large_alloc);
> +	unsigned long shift;
> +	unsigned long align_mask = 0;
> +
> +	if (align_order > 0)
> +		align_mask = 0xffffffffffffffffl >> (64 - align_order);
> +
> +	/* Sanity check */
> +	if (unlikely(npages == 0)) {
> +		WARN_ON_ONCE(1);
> +		return DMA_ERROR_CODE;
> +	}
> +
> +	if (largealloc) {
> +		pool = &(iommu->large_pool);
> +		pool_nr = 0; /* to keep compiler happy */
> +	} else {
> +		/* pick out pool_nr */
> +		pool_nr =  pool_hash & (npools - 1);
> +		pool = &(iommu->pools[pool_nr]);
> +	}
> +	spin_lock_irqsave(&pool->lock, flags);
> +
> + again:
> +	if (pass == 0 && handle && *handle &&
> +	    (*handle >= pool->start) && (*handle < pool->end))
> +		start = *handle;
> +	else
> +		start = pool->hint;
> +
> +	limit = pool->end;
> +
> +	/* The case below can happen if we have a small segment appended
> +	 * to a large, or when the previous alloc was at the very end of
> +	 * the available space. If so, go back to the beginning. If a
> +	 * flush is needed, it will get done based on the return value
> +	 * from iommu_area_alloc() below.
> +	 */
> +	if (start >= limit)
> +		start = pool->start;
> +	shift = iommu->table_map_base >> iommu->table_shift;
> +	if (limit + shift > mask) {
> +		limit = mask - shift + 1;
> +		/* If we're constrained on address range, first try
> +		 * at the masked hint to avoid O(n) search complexity,
> +		 * but on second pass, start at 0 in pool 0.
> +		 */
> +		if ((start & mask) >= limit || pass > 0) {
> +			spin_unlock(&(pool->lock));
> +			pool = &(iommu->pools[0]);
> +			spin_lock(&(pool->lock));
> +			start = pool->start;
> +		} else {
> +			start &= mask;
> +		}
> +	}
> +
> +	if (dev)
> +		boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
> +				      1 << iommu->table_shift);
> +	else
> +		boundary_size = ALIGN(1UL << 32, 1 << iommu->table_shift);
> +
> +	boundary_size = boundary_size >> iommu->table_shift;
> +	/*
> +	 * if the skip_span_boundary_check had been set during init, we set
> +	 * things up so that iommu_is_span_boundary() merely checks if the
> +	 * (index + npages) < num_tsb_entries
> +	 */
> +	if ((iommu->flags & IOMMU_NO_SPAN_BOUND) != 0) {
> +		shift = 0;
> +		boundary_size = iommu->poolsize * iommu->nr_pools;
> +	}
> +	n = iommu_area_alloc(iommu->map, limit, start, npages, shift,
> +			     boundary_size, align_mask);
> +	if (n == -1) {
> +		if (likely(pass == 0)) {
> +			/* First failure, rescan from the beginning.  */
> +			pool->hint = pool->start;
> +			set_flush(iommu);
> +			pass++;
> +			goto again;
> +		} else if (!largealloc && pass <= iommu->nr_pools) {
> +			spin_unlock(&(pool->lock));
> +			pool_nr = (pool_nr + 1) & (iommu->nr_pools - 1);
> +			pool = &(iommu->pools[pool_nr]);
> +			spin_lock(&(pool->lock));
> +			pool->hint = pool->start;
> +			set_flush(iommu);
> +			pass++;
> +			goto again;
> +		} else {
> +			/* give up */
> +			n = DMA_ERROR_CODE;
> +			goto bail;
> +		}
> +	}
> +	if (n < pool->hint || need_flush(iommu)) {
> +		clear_flush(iommu);
> +		iommu->lazy_flush(iommu);
> +	}
> +
> +	end = n + npages;
> +	pool->hint = end;
> +
> +	/* Update handle for SG allocations */
> +	if (handle)
> +		*handle = end;
> +bail:
> +	spin_unlock_irqrestore(&(pool->lock), flags);
> +
> +	return n;
> +}
> +EXPORT_SYMBOL(iommu_tbl_range_alloc);
> +
> +static struct iommu_pool *get_pool(struct iommu_map_table *tbl,
> +				   unsigned long entry)
> +{
> +	struct iommu_pool *p;
> +	unsigned long largepool_start = tbl->large_pool.start;
> +	bool large_pool = ((tbl->flags & IOMMU_HAS_LARGE_POOL) != 0);
> +
> +	/* The large pool is the last pool at the top of the table */
> +	if (large_pool && entry >= largepool_start) {
> +		p = &tbl->large_pool;
> +	} else {
> +		unsigned int pool_nr = entry / tbl->poolsize;
> +
> +		BUG_ON(pool_nr >= tbl->nr_pools);
> +		p = &tbl->pools[pool_nr];
> +	}
> +	return p;
> +}
> +
> +/* Caller supplies the index of the entry into the iommu map table
> + * itself when the mapping from dma_addr to the entry is not the
> + * default addr->entry mapping below.
> + */
> +void iommu_tbl_range_free(struct iommu_map_table *iommu, u64 dma_addr,
> +			  unsigned long npages, unsigned long entry)
> +{
> +	struct iommu_pool *pool;
> +	unsigned long flags;
> +	unsigned long shift = iommu->table_shift;
> +
> +	if (entry == DMA_ERROR_CODE) /* use default addr->entry mapping */
> +		entry = (dma_addr - iommu->table_map_base) >> shift;
> +	pool = get_pool(iommu, entry);
> +
> +	spin_lock_irqsave(&(pool->lock), flags);
> +	bitmap_clear(iommu->map, entry, npages);
> +	spin_unlock_irqrestore(&(pool->lock), flags);
> +}
> +EXPORT_SYMBOL(iommu_tbl_range_free);

Re: [PATCHv9 RFC 1/3] Break up monolithic iommu table/lock into finer graularity pools and lock

[Sowmini Varadhan]

On (04/08/15 18:30), Benjamin Herrenschmidt wrote:
> 
> I'm happy with your last version, feel free to add my
> 
> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

sounds good, I'll do this and rese a non-RFC version today.

Thanks for all the feedback - it was very useful to me, and
I'm much happier with the end-result.

--Sowmini