[PATCH v2 1/6] iommu/core: split mapping to page sizes as supported by the hardware

[PATCH v2 1/6] iommu/core: split mapping to page sizes as supported by the hardware

[Ohad Ben-Cohen]

When mapping a memory region, split it to page sizes as supported
by the iommu hardware. Always prefer bigger pages, when possible,
in order to reduce the TLB pressure.

The logic to do that is now added to the IOMMU core, so neither the iommu
drivers themselves nor users of the IOMMU API have to duplicate it.

This allows a more lenient granularity of mappings; traditionally the
IOMMU API took 'order' (of a page) as a mapping size, and directly let
the low level iommu drivers handle the mapping, but now that the IOMMU
core can split arbitrary memory regions into pages, we can remove this
limitation, so users don't have to split those regions by themselves.

Currently the supported page sizes are advertised once and they then
remain static. That works well for OMAP (and seemingly MSM too) but
it would probably not fly with intel's hardware, where the page size
capabilities seem to have the potential to be different between
several DMA remapping devices. This limitation can be dealt with
later, if desired. For now, the existing IOMMU API behavior is retained
(see: "iommu/intel: announce supported page sizes").

As requested, register_iommu() isn't changed yet, so we can convert
the IOMMU drivers in subsequent patches, and after all the drivers
are converted, register_iommu will be changed (and the temporary
register_iommu_pgsize() will be removed).

Mainline users of the IOMMU API (kvm and omap-iovmm) are adopted
to send the mapping size in bytes instead of in page order.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: David Brown <davidb@codeaurora.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Joerg Roedel <Joerg.Roedel@amd.com>
Cc: Stepan Moskovchenko <stepanm@codeaurora.org>
Cc: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: kvm at vger.kernel.org
---
v1->v2: keep old code around until all drivers are converted

 drivers/iommu/iommu.c      |  158 +++++++++++++++++++++++++++++++++++++++++---
 drivers/iommu/omap-iovmm.c |   12 +---
 include/linux/iommu.h      |    6 +-
 virt/kvm/iommu.c           |    4 +-
 4 files changed, 157 insertions(+), 23 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index c68ff29..c848f14 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -16,6 +16,8 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  */
 
+#define pr_fmt(fmt)    "%s: " fmt, __func__
+
 #include <linux/kernel.h>
 #include <linux/bug.h>
 #include <linux/types.h>
@@ -23,15 +25,73 @@
 #include <linux/slab.h>
 #include <linux/errno.h>
 #include <linux/iommu.h>
+#include <linux/bitmap.h>
 
 static struct iommu_ops *iommu_ops;
 
+/* bitmap of supported page sizes */
+static unsigned long *iommu_pgsize_bitmap;
+
+/* number of bits used to represent the supported pages */
+static unsigned int iommu_nr_page_bits;
+
+/* size of the smallest supported page (in bytes) */
+static unsigned int iommu_min_pagesz;
+
+/* bit number of the smallest supported page */
+static unsigned int iommu_min_page_idx;
+
+/**
+ * register_iommu() - register an IOMMU hardware
+ * @ops: iommu handlers
+ * @pgsize_bitmap: bitmap of page sizes supported by the hardware
+ * @nr_page_bits: size of @pgsize_bitmap (in bits)
+ *
+ * Note: this is a temporary function, which will be removed once
+ * all IOMMU drivers are converted. The only reason it exists is to
+ * allow splitting the pgsizes changes to several patches in order to ease
+ * the review.
+ */
+void register_iommu_pgsize(struct iommu_ops *ops, unsigned long *pgsize_bitmap,
+					unsigned int nr_page_bits)
+{
+	if (iommu_ops || iommu_pgsize_bitmap || !nr_page_bits)
+		BUG();
+
+	iommu_ops = ops;
+	iommu_pgsize_bitmap = pgsize_bitmap;
+	iommu_nr_page_bits = nr_page_bits;
+
+	/* find the minimum page size and its index only once */
+	iommu_min_page_idx = find_first_bit(pgsize_bitmap, nr_page_bits);
+	iommu_min_pagesz = 1 << iommu_min_page_idx;
+}
+
+/*
+ * default pagesize bitmap, will be removed once all IOMMU drivers
+ * are converted
+ */
+static unsigned long default_iommu_pgsizes = ~0xFFFUL;
+
 void register_iommu(struct iommu_ops *ops)
 {
 	if (iommu_ops)
 		BUG();
 
 	iommu_ops = ops;
+
+	/*
+	 * set default pgsize values, which retain the existing
+	 * IOMMU API behavior: drivers will be called to map
+	 * regions that are sized/aligned to order of 4KB pages
+	 */
+	iommu_pgsize_bitmap = &default_iommu_pgsizes;
+	iommu_nr_page_bits = BITS_PER_LONG;
+
+	/* find the minimum page size and its index only once */
+	iommu_min_page_idx = find_first_bit(iommu_pgsize_bitmap,
+						iommu_nr_page_bits);
+	iommu_min_pagesz = 1 << iommu_min_page_idx;
 }
 
 bool iommu_found(void)
@@ -109,26 +169,104 @@ int iommu_domain_has_cap(struct iommu_domain *domain,
 EXPORT_SYMBOL_GPL(iommu_domain_has_cap);
 
 int iommu_map(struct iommu_domain *domain, unsigned long iova,
-	      phys_addr_t paddr, int gfp_order, int prot)
+	      phys_addr_t paddr, size_t size, int prot)
 {
-	size_t size;
+	int ret = 0;
+
+	/*
+	 * both the virtual address and the physical one, as well as
+	 * the size of the mapping, must be aligned (at least) to the
+	 * size of the smallest page supported by the hardware
+	 */
+	if (!IS_ALIGNED(iova | paddr | size, iommu_min_pagesz)) {
+		pr_err("unaligned: iova 0x%lx pa 0x%lx size 0x%lx min_pagesz "
+			"0x%x\n", iova, (unsigned long)paddr,
+			(unsigned long)size, iommu_min_pagesz);
+		return -EINVAL;
+	}
+
+	pr_debug("map: iova 0x%lx pa 0x%lx size 0x%lx\n", iova,
+				(unsigned long)paddr, (unsigned long)size);
+
+	while (size) {
+		unsigned long pgsize = iommu_min_pagesz;
+		unsigned long idx = iommu_min_page_idx;
+		unsigned long addr_merge = iova | paddr;
+		int order;
+
+		/* find the max page size with which iova, paddr are aligned */
+		for (;;) {
+			unsigned long try_pgsize;
+
+			idx = find_next_bit(iommu_pgsize_bitmap,
+						iommu_nr_page_bits, idx + 1);
+
+			/* no more pages to check ? */
+			if (idx >= iommu_nr_page_bits)
+				break;
+
+			try_pgsize = 1 << idx;
 
-	size         = 0x1000UL << gfp_order;
+			/* page too big ? addresses not aligned ? */
+			if (size < try_pgsize ||
+					!IS_ALIGNED(addr_merge, try_pgsize))
+				break;
 
-	BUG_ON(!IS_ALIGNED(iova | paddr, size));
+			pgsize = try_pgsize;
+		}
 
-	return iommu_ops->map(domain, iova, paddr, gfp_order, prot);
+		order = get_order(pgsize);
+
+		pr_debug("mapping: iova 0x%lx pa 0x%lx order %d\n", iova,
+					(unsigned long)paddr, order);
+
+		ret = iommu_ops->map(domain, iova, paddr, order, prot);
+		if (ret)
+			break;
+
+		size -= pgsize;
+		iova += pgsize;
+		paddr += pgsize;
+	}
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(iommu_map);
 
-int iommu_unmap(struct iommu_domain *domain, unsigned long iova, int gfp_order)
+int iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size)
 {
-	size_t size;
+	int order, unmapped_size, unmapped_order, total_unmapped = 0;
+
+	/*
+	 * The virtual address, as well as the size of the mapping, must be
+	 * aligned (at least) to the size of the smallest page supported
+	 * by the hardware
+	 */
+	if (!IS_ALIGNED(iova | size, iommu_min_pagesz)) {
+		pr_err("unaligned: iova 0x%lx size 0x%lx min_pagesz 0x%x\n",
+				iova, (unsigned long)size, iommu_min_pagesz);
+		return -EINVAL;
+	}
+
+	pr_debug("unmap this: iova 0x%lx size 0x%lx\n", iova,
+							(unsigned long)size);
+
+	while (size > total_unmapped) {
+		order = get_order(size - total_unmapped);
+
+		unmapped_order = iommu_ops->unmap(domain, iova, order);
+		if (unmapped_order < 0)
+			return unmapped_order;
+
+		pr_debug("unmapped: iova 0x%lx order %d\n", iova,
+							unmapped_order);
 
-	size         = 0x1000UL << gfp_order;
+		unmapped_size = 0x1000UL << unmapped_order;
 
-	BUG_ON(!IS_ALIGNED(iova, size));
+		iova += unmapped_size;
+		total_unmapped += unmapped_size;
+	}
 
-	return iommu_ops->unmap(domain, iova, gfp_order);
+	return get_order(total_unmapped);
 }
 EXPORT_SYMBOL_GPL(iommu_unmap);
diff --git a/drivers/iommu/omap-iovmm.c b/drivers/iommu/omap-iovmm.c
index e8fdb88..f4dea5a 100644
--- a/drivers/iommu/omap-iovmm.c
+++ b/drivers/iommu/omap-iovmm.c
@@ -409,7 +409,6 @@ static int map_iovm_area(struct iommu_domain *domain, struct iovm_struct *new,
 	unsigned int i, j;
 	struct scatterlist *sg;
 	u32 da = new->da_start;
-	int order;
 
 	if (!domain || !sgt)
 		return -EINVAL;
@@ -428,12 +427,10 @@ static int map_iovm_area(struct iommu_domain *domain, struct iovm_struct *new,
 		if (bytes_to_iopgsz(bytes) < 0)
 			goto err_out;
 
-		order = get_order(bytes);
-
 		pr_debug("%s: [%d] %08x %08x(%x)\n", __func__,
 			 i, da, pa, bytes);
 
-		err = iommu_map(domain, da, pa, order, flags);
+		err = iommu_map(domain, da, pa, bytes, flags);
 		if (err)
 			goto err_out;
 
@@ -448,10 +445,9 @@ err_out:
 		size_t bytes;
 
 		bytes = sg->length + sg->offset;
-		order = get_order(bytes);
 
 		/* ignore failures.. we're already handling one */
-		iommu_unmap(domain, da, order);
+		iommu_unmap(domain, da, bytes);
 
 		da += bytes;
 	}
@@ -474,12 +470,10 @@ static void unmap_iovm_area(struct iommu_domain *domain, struct omap_iommu *obj,
 	start = area->da_start;
 	for_each_sg(sgt->sgl, sg, sgt->nents, i) {
 		size_t bytes;
-		int order;
 
 		bytes = sg->length + sg->offset;
-		order = get_order(bytes);
 
-		err = iommu_unmap(domain, start, order);
+		err = iommu_unmap(domain, start, bytes);
 		if (err < 0)
 			break;
 
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index d084e87..1806956 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -61,6 +61,8 @@ struct iommu_ops {
 #ifdef CONFIG_IOMMU_API
 
 extern void register_iommu(struct iommu_ops *ops);
+extern void register_iommu_pgsize(struct iommu_ops *ops,
+		unsigned long *pgsize_bitmap, unsigned int nr_page_bits);
 extern bool iommu_found(void);
 extern struct iommu_domain *iommu_domain_alloc(void);
 extern void iommu_domain_free(struct iommu_domain *domain);
@@ -69,9 +71,9 @@ extern int iommu_attach_device(struct iommu_domain *domain,
 extern void iommu_detach_device(struct iommu_domain *domain,
 				struct device *dev);
 extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
-		     phys_addr_t paddr, int gfp_order, int prot);
+		     phys_addr_t paddr, size_t size, int prot);
 extern int iommu_unmap(struct iommu_domain *domain, unsigned long iova,
-		       int gfp_order);
+		       size_t size);
 extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain,
 				      unsigned long iova);
 extern int iommu_domain_has_cap(struct iommu_domain *domain,
diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index 78c80f6..ea142d3 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -111,7 +111,7 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
 
 		/* Map into IO address space */
 		r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
-			      get_order(page_size), flags);
+			      page_size, flags);
 		if (r) {
 			printk(KERN_ERR "kvm_iommu_map_address:"
 			       "iommu failed to map pfn=%llx\n", pfn);
@@ -293,7 +293,7 @@ static void kvm_iommu_put_pages(struct kvm *kvm,
 		pfn  = phys >> PAGE_SHIFT;
 
 		/* Unmap address from IO address space */
-		order       = iommu_unmap(domain, gfn_to_gpa(gfn), 0);
+		order       = iommu_unmap(domain, gfn_to_gpa(gfn), PAGE_SIZE);
 		unmap_pages = 1ULL << order;
 
 		/* Unpin all pages we just unmapped to not leak any memory */
-- 
1.7.4.1

[PATCH v2 2/6] iommu/omap: announce supported page sizes

[Ohad Ben-Cohen]

Let the IOMMU core know we support 4KB, 64KB, 1MB and 16MB page sizes.

This way the IOMMU core can split any arbitrary-sized physically
contiguous regions (that it needs to map) as needed.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
---
 drivers/iommu/omap-iommu.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 7e0188f..403dd6a 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -1202,6 +1202,9 @@ static int omap_iommu_domain_has_cap(struct iommu_domain *domain,
 	return 0;
 }
 
+/* bitmap of the page sizes supported by the OMAP IOMMU hardware */
+static unsigned long omap_iommu_pgsizes = SZ_4K | SZ_64K | SZ_1M | SZ_16M;
+
 static struct iommu_ops omap_iommu_ops = {
 	.domain_init	= omap_iommu_domain_init,
 	.domain_destroy	= omap_iommu_domain_destroy,
@@ -1225,7 +1228,8 @@ static int __init omap_iommu_init(void)
 		return -ENOMEM;
 	iopte_cachep = p;
 
-	register_iommu(&omap_iommu_ops);
+	/* we're only using the first 25 bits of the pgsizes bitmap */
+	register_iommu_pgsize(&omap_iommu_ops, &omap_iommu_pgsizes, 25);
 
 	return platform_driver_register(&omap_iommu_driver);
 }
-- 
1.7.4.1

[PATCH v2 3/6] iommu/msm: announce supported page sizes

[Ohad Ben-Cohen]

Let the IOMMU core know we support 4KB, 64KB, 1MB and 16MB page sizes.

This way the IOMMU core can split any arbitrary-sized physically
contiguous regions (that it needs to map) as needed.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: David Brown <davidb@codeaurora.org>
Cc: Stepan Moskovchenko <stepanm@codeaurora.org>
---
 drivers/iommu/msm_iommu.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
index d1733f6..a4ed116 100644
--- a/drivers/iommu/msm_iommu.c
+++ b/drivers/iommu/msm_iommu.c
@@ -676,6 +676,9 @@ fail:
 	return 0;
 }
 
+/* bitmap of the page sizes currently supported */
+static unsigned long msm_iommu_pgsizes = SZ_4K | SZ_64K | SZ_1M | SZ_16M;
+
 static struct iommu_ops msm_iommu_ops = {
 	.domain_init = msm_iommu_domain_init,
 	.domain_destroy = msm_iommu_domain_destroy,
@@ -728,7 +731,10 @@ static void __init setup_iommu_tex_classes(void)
 static int __init msm_iommu_init(void)
 {
 	setup_iommu_tex_classes();
-	register_iommu(&msm_iommu_ops);
+
+	/* we're only using the first 25 bits of the pgsizes bitmap */
+	register_iommu_pgsize(&msm_iommu_ops, &msm_iommu_pgsizes, 25);
+
 	return 0;
 }
 
-- 
1.7.4.1

[PATCH v2 4/6] iommu/amd: announce supported page sizes

[Ohad Ben-Cohen]

Let the IOMMU core know we support arbitrary page sizes (as long as
they're an order of 4KB).

This way the IOMMU core will retain the existing behavior we're used to;
it will let us map regions that:
- their size is an order of 4KB
- they are naturally aligned

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Joerg Roedel <Joerg.Roedel@amd.com>
---
 drivers/iommu/amd_iommu.c |   21 ++++++++++++++++++++-
 1 files changed, 20 insertions(+), 1 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index a14f8dc..17fa0fc 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2488,12 +2488,31 @@ static unsigned device_dma_ops_init(void)
 }
 
 /*
+ * This bitmap is used to advertise the page sizes our hardware support
+ * to the IOMMU core, which will then use this information to split
+ * physically contiguous memory regions it is mapping into page sizes
+ * that we support.
+ *
+ * Traditionally the IOMMU core just handed us the mappings directly,
+ * after making sure the size is an order of a 4KB page and that the
+ * mapping has natural alignment.
+ *
+ * To retain this behavior, we currently advertise that we support
+ * all page sizes that are an order of 4KB.
+ *
+ * If at some point we'd like to utilize the IOMMU core's new behavior,
+ * we could change this to advertise the real page sizes we support.
+ */
+static unsigned long amd_iommu_pgsizes = ~0xFFFUL;
+
+/*
  * The function which clues the AMD IOMMU driver into dma_ops.
  */
 
 void __init amd_iommu_init_api(void)
 {
-	register_iommu(&amd_iommu_ops);
+	register_iommu_pgsize(&amd_iommu_ops, &amd_iommu_pgsizes,
+						BITS_PER_LONG);
 }
 
 int __init amd_iommu_init_dma_ops(void)
-- 
1.7.4.1

[PATCH v2 5/6] iommu/intel: announce supported page sizes

[Ohad Ben-Cohen]

Let the IOMMU core know we support arbitrary page sizes (as long as
they're an order of 4KB).

This way the IOMMU core will retain the existing behavior we're used to;
it will let us map regions that:
- their size is an order of 4KB
- they are naturally aligned

Note: Intel IOMMU hardware doesn't support arbitrary page sizes,
but the driver does (it splits arbitrary-sized mappings into
the pages supported by the hardware).

To make everything simpler for now, though, this patch effectively tells
the IOMMU core to keep giving this driver the same memory regions it did
before, so nothing is changed as far as it's concerned.

Note: at this point, the page sizes announced remain static within the IOMMU
core. To correctly utilize the pgsize-splitting of the IOMMU core by
this driver, it seems that some core changes should still be done,
because Intel's IOMMU page size capabilities seem to have the potential
to be different between different DMA remapping devices.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: David Woodhouse <dwmw2@infradead.org>
---
 drivers/iommu/intel-iommu.c |   21 ++++++++++++++++++++-
 1 files changed, 20 insertions(+), 1 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index c621c98..333a9cb 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3426,6 +3426,24 @@ static struct notifier_block device_nb = {
 	.notifier_call = device_notifier,
 };
 
+/*
+ * This bitmap is used to advertise the page sizes our hardware support
+ * to the IOMMU core, which will then use this information to split
+ * physically contiguous memory regions it is mapping into page sizes
+ * that we support.
+ *
+ * Traditionally the IOMMU core just handed us the mappings directly,
+ * after making sure the size is an order of a 4KB page and that the
+ * mapping has natural alignment.
+ *
+ * To retain this behavior, we currently advertise that we support
+ * all page sizes that are an order of 4KB.
+ *
+ * If at some point we'd like to utilize the IOMMU core's new behavior,
+ * we could change this to advertise the real page sizes we support.
+ */
+static unsigned long intel_iommu_pgsizes = ~0xFFFUL;
+
 int __init intel_iommu_init(void)
 {
 	int ret = 0;
@@ -3486,7 +3504,8 @@ int __init intel_iommu_init(void)
 
 	init_iommu_pm_ops();
 
-	register_iommu(&intel_iommu_ops);
+	register_iommu_pgsize(&intel_iommu_ops, &intel_iommu_pgsizes,
+							BITS_PER_LONG);
 
 	bus_register_notifier(&pci_bus_type, &device_nb);
 
-- 
1.7.4.1

[PATCH v2 6/6] iommu/core: remove the temporary register_iommu_pgsize API

[Ohad Ben-Cohen]

Now that all IOMMU drivers are converted to the new
register_iommu_pgsize() API, the old code can be removed, and
we can s/register_iommu_pgsize/register_iommu/.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Joerg Roedel <Joerg.Roedel@amd.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: David Brown <davidb@codeaurora.org>
Cc: Stepan Moskovchenko <stepanm@codeaurora.org>
---
 drivers/iommu/amd_iommu.c   |    3 +--
 drivers/iommu/intel-iommu.c |    3 +--
 drivers/iommu/iommu.c       |   34 +---------------------------------
 drivers/iommu/msm_iommu.c   |    2 +-
 drivers/iommu/omap-iommu.c  |    2 +-
 include/linux/iommu.h       |    5 ++---
 6 files changed, 7 insertions(+), 42 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 17fa0fc..5cdfa91 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2511,8 +2511,7 @@ static unsigned long amd_iommu_pgsizes = ~0xFFFUL;
 
 void __init amd_iommu_init_api(void)
 {
-	register_iommu_pgsize(&amd_iommu_ops, &amd_iommu_pgsizes,
-						BITS_PER_LONG);
+	register_iommu(&amd_iommu_ops, &amd_iommu_pgsizes, BITS_PER_LONG);
 }
 
 int __init amd_iommu_init_dma_ops(void)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 333a9cb..a8c91a6 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3504,8 +3504,7 @@ int __init intel_iommu_init(void)
 
 	init_iommu_pm_ops();
 
-	register_iommu_pgsize(&intel_iommu_ops, &intel_iommu_pgsizes,
-							BITS_PER_LONG);
+	register_iommu(&intel_iommu_ops, &intel_iommu_pgsizes, BITS_PER_LONG);
 
 	bus_register_notifier(&pci_bus_type, &device_nb);
 
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index c848f14..8bbd1aa 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -46,13 +46,8 @@ static unsigned int iommu_min_page_idx;
  * @ops: iommu handlers
  * @pgsize_bitmap: bitmap of page sizes supported by the hardware
  * @nr_page_bits: size of @pgsize_bitmap (in bits)
- *
- * Note: this is a temporary function, which will be removed once
- * all IOMMU drivers are converted. The only reason it exists is to
- * allow splitting the pgsizes changes to several patches in order to ease
- * the review.
  */
-void register_iommu_pgsize(struct iommu_ops *ops, unsigned long *pgsize_bitmap,
+void register_iommu(struct iommu_ops *ops, unsigned long *pgsize_bitmap,
 					unsigned int nr_page_bits)
 {
 	if (iommu_ops || iommu_pgsize_bitmap || !nr_page_bits)
@@ -67,33 +62,6 @@ void register_iommu_pgsize(struct iommu_ops *ops, unsigned long *pgsize_bitmap,
 	iommu_min_pagesz = 1 << iommu_min_page_idx;
 }
 
-/*
- * default pagesize bitmap, will be removed once all IOMMU drivers
- * are converted
- */
-static unsigned long default_iommu_pgsizes = ~0xFFFUL;
-
-void register_iommu(struct iommu_ops *ops)
-{
-	if (iommu_ops)
-		BUG();
-
-	iommu_ops = ops;
-
-	/*
-	 * set default pgsize values, which retain the existing
-	 * IOMMU API behavior: drivers will be called to map
-	 * regions that are sized/aligned to order of 4KB pages
-	 */
-	iommu_pgsize_bitmap = &default_iommu_pgsizes;
-	iommu_nr_page_bits = BITS_PER_LONG;
-
-	/* find the minimum page size and its index only once */
-	iommu_min_page_idx = find_first_bit(iommu_pgsize_bitmap,
-						iommu_nr_page_bits);
-	iommu_min_pagesz = 1 << iommu_min_page_idx;
-}
-
 bool iommu_found(void)
 {
 	return iommu_ops != NULL;
diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
index a4ed116..e59ced9 100644
--- a/drivers/iommu/msm_iommu.c
+++ b/drivers/iommu/msm_iommu.c
@@ -733,7 +733,7 @@ static int __init msm_iommu_init(void)
 	setup_iommu_tex_classes();
 
 	/* we're only using the first 25 bits of the pgsizes bitmap */
-	register_iommu_pgsize(&msm_iommu_ops, &msm_iommu_pgsizes, 25);
+	register_iommu(&msm_iommu_ops, &msm_iommu_pgsizes, 25);
 
 	return 0;
 }
diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 403dd6a..3d8ad87 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -1229,7 +1229,7 @@ static int __init omap_iommu_init(void)
 	iopte_cachep = p;
 
 	/* we're only using the first 25 bits of the pgsizes bitmap */
-	register_iommu_pgsize(&omap_iommu_ops, &omap_iommu_pgsizes, 25);
+	register_iommu(&omap_iommu_ops, &omap_iommu_pgsizes, 25);
 
 	return platform_driver_register(&omap_iommu_driver);
 }
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 1806956..297893f 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -60,9 +60,8 @@ struct iommu_ops {
 
 #ifdef CONFIG_IOMMU_API
 
-extern void register_iommu(struct iommu_ops *ops);
-extern void register_iommu_pgsize(struct iommu_ops *ops,
-		unsigned long *pgsize_bitmap, unsigned int nr_page_bits);
+extern void register_iommu(struct iommu_ops *ops, unsigned long *pgsize_bitmap,
+					unsigned int nr_page_bits);
 extern bool iommu_found(void);
 extern struct iommu_domain *iommu_domain_alloc(void);
 extern void iommu_domain_free(struct iommu_domain *domain);
-- 
1.7.4.1

[PATCH v2 5/6] iommu/intel: announce supported page sizes

[David Woodhouse]

On Tue, 2011-09-13 at 22:31 +0300, Ohad Ben-Cohen wrote:
> + * Traditionally the IOMMU core just handed us the mappings directly,
> + * after making sure the size is an order of a 4KB page and that the
> + * mapping has natural alignment.
> + *
> + * To retain this behavior, we currently advertise that we support
> + * all page sizes that are an order of 4KB. 

This is wrong. We do not support 4000-byte pages. We only support
4096-byte pages. 4KiB, not 4kB.

Please fix.

-- 
dwmw2
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[PATCH v2 5/6] iommu/intel: announce supported page sizes

[Ohad Ben-Cohen]

On Wed, Sep 14, 2011 at 12:32 AM, David Woodhouse <dwmw2@infradead.org> wrote:
> On Tue, 2011-09-13 at 22:31 +0300, Ohad Ben-Cohen wrote:
>> + * Traditionally the IOMMU core just handed us the mappings directly,
>> + * after making sure the size is an order of a 4KB page and that the
>> + * mapping has natural alignment.
>> + *
>> + * To retain this behavior, we currently advertise that we support
>> + * all page sizes that are an order of 4KB.
>
> This is wrong. We do not support 4000-byte pages. We only support
> 4096-byte pages. 4KiB, not 4kB.
>
> Please fix.

Sure thing; I'll s/KB/KiB throughout the patch set.

Do I have your ACK otherwise ?

Thanks,
Ohad.