[RFC PATCH v5 00/15] Optimizing iommu_[map/unmap] performance

[RFC PATCH v5 00/15] Optimizing iommu_[map/unmap] performance

[Isaac J. Manjarres]

When unmapping a buffer from an IOMMU domain, the IOMMU framework unmaps
the buffer at a granule of the largest page size that is supported by
the IOMMU hardware and fits within the buffer. For every block that
is unmapped, the IOMMU framework will call into the IOMMU driver, and
then the io-pgtable framework to walk the page tables to find the entry
that corresponds to the IOVA, and then unmaps the entry.

This can be suboptimal in scenarios where a buffer or a piece of a
buffer can be split into several contiguous page blocks of the same size.
For example, consider an IOMMU that supports 4 KB page blocks, 2 MB page
blocks, and 1 GB page blocks, and a buffer that is 4 MB in size is being
unmapped at IOVA 0. The current call-flow will result in 4 indirect calls,
and 2 page table walks, to unmap 2 entries that are next to each other in
the page-tables, when both entries could have been unmapped in one shot
by clearing both page table entries in the same call.

The same optimization is applicable to mapping buffers as well, so
these patches implement a set of callbacks called unmap_pages and
map_pages to the io-pgtable code and IOMMU drivers which unmaps or maps
an IOVA range that consists of a number of pages of the same
page size that is supported by the IOMMU hardware, and allows for
manipulating multiple page table entries in the same set of indirect
calls. The reason for introducing these callbacks is to give other IOMMU
drivers/io-pgtable formats time to change to using the new callbacks, so
that the transition to using this approach can be done piecemeal.

Changes since V4:

* Fixed type for addr_merge from phys_addr_t to unsigned long so
  that GENMASK() can be used.
* Hooked up arm_v7s_[unmap/map]_pages to the io-pgtable ops.
* Introduced a macro for calculating the number of page table entries
  for the ARM LPAE io-pgtable format.

Changes since V3:

* Removed usage of ULL variants of bitops from Will's patches, as
  they were not needed.
* Instead of unmapping/mapping pgcount pages, unmap_pages() and
  map_pages() will at most unmap and map pgcount pages, allowing
  for part of the pages in pgcount to be mapped and unmapped. This
  was done to simplify the handling in the io-pgtable layer.
* Extended the existing PTE manipulation methods in io-pgtable-arm
  to handle multiple entries, per Robin's suggestion, eliminating
  the need to add functions to clear multiple PTEs.
* Implemented a naive form of [map/unmap]_pages() for ARM v7s io-pgtable
  format.
* arm_[v7s/lpae]_[map/unmap] will call
  arm_[v7s/lpae]_[map_pages/unmap_pages] with an argument of 1 page.
* The arm_smmu_[map/unmap] functions have been removed, since they
  have been replaced by arm_smmu_[map/unmap]_pages.

Changes since V2:

* Added a check in __iommu_map() to check for the existence
  of either the map or map_pages callback as per Lu's suggestion.

Changes since V1:

* Implemented the map_pages() callbacks
* Integrated Will's patches into this series which
  address several concerns about how iommu_pgsize() partitioned a
  buffer (I made a minor change to the patch which changes
  iommu_pgsize() to use bitmaps by using the ULL variants of
  the bitops)

Isaac J. Manjarres (12):
  iommu/io-pgtable: Introduce unmap_pages() as a page table op
  iommu: Add an unmap_pages() op for IOMMU drivers
  iommu/io-pgtable: Introduce map_pages() as a page table op
  iommu: Add a map_pages() op for IOMMU drivers
  iommu: Add support for the map_pages() callback
  iommu/io-pgtable-arm: Prepare PTE methods for handling multiple
    entries
  iommu/io-pgtable-arm: Implement arm_lpae_unmap_pages()
  iommu/io-pgtable-arm: Implement arm_lpae_map_pages()
  iommu/io-pgtable-arm-v7s: Implement arm_v7s_unmap_pages()
  iommu/io-pgtable-arm-v7s: Implement arm_v7s_map_pages()
  iommu/arm-smmu: Implement the unmap_pages() IOMMU driver callback
  iommu/arm-smmu: Implement the map_pages() IOMMU driver callback

Will Deacon (3):
  iommu: Use bitmap to calculate page size in iommu_pgsize()
  iommu: Split 'addr_merge' argument to iommu_pgsize() into separate
    parts
  iommu: Hook up '->unmap_pages' driver callback

 drivers/iommu/arm/arm-smmu/arm-smmu.c |  18 +--
 drivers/iommu/io-pgtable-arm-v7s.c    |  50 ++++++-
 drivers/iommu/io-pgtable-arm.c        | 189 +++++++++++++++++---------
 drivers/iommu/iommu.c                 | 130 +++++++++++++-----
 include/linux/io-pgtable.h            |   8 ++
 include/linux/iommu.h                 |   9 ++
 6 files changed, 289 insertions(+), 115 deletions(-)

-- 
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[RFC PATCH v5 01/15] iommu/io-pgtable: Introduce unmap_pages() as a page table op

[Isaac J. Manjarres]

The io-pgtable code expects to operate on a single block or
granule of memory that is supported by the IOMMU hardware when
unmapping memory.

This means that when a large buffer that consists of multiple
such blocks is unmapped, the io-pgtable code will walk the page
tables to the correct level to unmap each block, even for blocks
that are virtually contiguous and at the same level, which can
incur an overhead in performance.

Introduce the unmap_pages() page table op to express to the
io-pgtable code that it should unmap a number of blocks of
the same size, instead of a single block. Doing so allows
multiple blocks to be unmapped in one call to the io-pgtable
code, reducing the number of page table walks, and indirect
calls.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
 include/linux/io-pgtable.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index a4c9ca2c31f1..2ed0c057d9e7 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -144,6 +144,7 @@ struct io_pgtable_cfg {
  *
  * @map:          Map a physically contiguous memory region.
  * @unmap:        Unmap a physically contiguous memory region.
+ * @unmap_pages:  Unmap a range of virtually contiguous pages of the same size.
  * @iova_to_phys: Translate iova to physical address.
  *
  * These functions map directly onto the iommu_ops member functions with
@@ -154,6 +155,9 @@ struct io_pgtable_ops {
 		   phys_addr_t paddr, size_t size, int prot, gfp_t gfp);
 	size_t (*unmap)(struct io_pgtable_ops *ops, unsigned long iova,
 			size_t size, struct iommu_iotlb_gather *gather);
+	size_t (*unmap_pages)(struct io_pgtable_ops *ops, unsigned long iova,
+			      size_t pgsize, size_t pgcount,
+			      struct iommu_iotlb_gather *gather);
 	phys_addr_t (*iova_to_phys)(struct io_pgtable_ops *ops,
 				    unsigned long iova);
 };
-- 
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[RFC PATCH v5 02/15] iommu: Add an unmap_pages() op for IOMMU drivers

[Isaac J. Manjarres]

Add a callback for IOMMU drivers to provide a path for the
IOMMU framework to call into an IOMMU driver, which can call
into the io-pgtable code, to unmap a virtually contiguous
range of pages of the same size.

For IOMMU drivers that do not specify an unmap_pages() callback,
the existing logic of unmapping memory one page block at a time
will be used.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 include/linux/iommu.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 5e7fe519430a..9cf81242581a 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -193,6 +193,7 @@ struct iommu_iotlb_gather {
  * @detach_dev: detach device from an iommu domain
  * @map: map a physically contiguous memory region to an iommu domain
  * @unmap: unmap a physically contiguous memory region from an iommu domain
+ * @unmap_pages: unmap a number of pages of the same size from an iommu domain
  * @flush_iotlb_all: Synchronously flush all hardware TLBs for this domain
  * @iotlb_sync_map: Sync mappings created recently using @map to the hardware
  * @iotlb_sync: Flush all queued ranges from the hardware TLBs and empty flush
@@ -245,6 +246,9 @@ struct iommu_ops {
 		   phys_addr_t paddr, size_t size, int prot, gfp_t gfp);
 	size_t (*unmap)(struct iommu_domain *domain, unsigned long iova,
 		     size_t size, struct iommu_iotlb_gather *iotlb_gather);
+	size_t (*unmap_pages)(struct iommu_domain *domain, unsigned long iova,
+			      size_t pgsize, size_t pgcount,
+			      struct iommu_iotlb_gather *iotlb_gather);
 	void (*flush_iotlb_all)(struct iommu_domain *domain);
 	void (*iotlb_sync_map)(struct iommu_domain *domain, unsigned long iova,
 			       size_t size);
-- 
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[RFC PATCH v5 03/15] iommu/io-pgtable: Introduce map_pages() as a page table op

[Isaac J. Manjarres]

Mapping memory into io-pgtables follows the same semantics
that unmapping memory used to follow (i.e. a buffer will be
mapped one page block per call to the io-pgtable code). This
means that it can be optimized in the same way that unmapping
memory was, so add a map_pages() callback to the io-pgtable
ops structure, so that a range of pages of the same size
can be mapped within the same call.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: Will Deacon <will@kernel.org>
---
 include/linux/io-pgtable.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index 2ed0c057d9e7..019149b204b8 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -143,6 +143,7 @@ struct io_pgtable_cfg {
  * struct io_pgtable_ops - Page table manipulation API for IOMMU drivers.
  *
  * @map:          Map a physically contiguous memory region.
+ * @map_pages:    Map a physically contiguous range of pages of the same size.
  * @unmap:        Unmap a physically contiguous memory region.
  * @unmap_pages:  Unmap a range of virtually contiguous pages of the same size.
  * @iova_to_phys: Translate iova to physical address.
@@ -153,6 +154,9 @@ struct io_pgtable_cfg {
 struct io_pgtable_ops {
 	int (*map)(struct io_pgtable_ops *ops, unsigned long iova,
 		   phys_addr_t paddr, size_t size, int prot, gfp_t gfp);
+	int (*map_pages)(struct io_pgtable_ops *ops, unsigned long iova,
+			 phys_addr_t paddr, size_t pgsize, size_t pgcount,
+			 int prot, gfp_t gfp, size_t *mapped);
 	size_t (*unmap)(struct io_pgtable_ops *ops, unsigned long iova,
 			size_t size, struct iommu_iotlb_gather *gather);
 	size_t (*unmap_pages)(struct io_pgtable_ops *ops, unsigned long iova,
-- 
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[RFC PATCH v5 04/15] iommu: Add a map_pages() op for IOMMU drivers

[Isaac J. Manjarres]

Add a callback for IOMMU drivers to provide a path for the
IOMMU framework to call into an IOMMU driver, which can
call into the io-pgtable code, to map a physically contiguous
rnage of pages of the same size.

For IOMMU drivers that do not specify a map_pages() callback,
the existing logic of mapping memory one page block at a time
will be used.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: Will Deacon <will@kernel.org>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 include/linux/iommu.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 9cf81242581a..528d6a58479e 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -192,6 +192,8 @@ struct iommu_iotlb_gather {
  * @attach_dev: attach device to an iommu domain
  * @detach_dev: detach device from an iommu domain
  * @map: map a physically contiguous memory region to an iommu domain
+ * @map_pages: map a physically contiguous set of pages of the same size to
+ *             an iommu domain.
  * @unmap: unmap a physically contiguous memory region from an iommu domain
  * @unmap_pages: unmap a number of pages of the same size from an iommu domain
  * @flush_iotlb_all: Synchronously flush all hardware TLBs for this domain
@@ -244,6 +246,9 @@ struct iommu_ops {
 	void (*detach_dev)(struct iommu_domain *domain, struct device *dev);
 	int (*map)(struct iommu_domain *domain, unsigned long iova,
 		   phys_addr_t paddr, size_t size, int prot, gfp_t gfp);
+	int (*map_pages)(struct iommu_domain *domain, unsigned long iova,
+			 phys_addr_t paddr, size_t pgsize, size_t pgcount,
+			 int prot, gfp_t gfp, size_t *mapped);
 	size_t (*unmap)(struct iommu_domain *domain, unsigned long iova,
 		     size_t size, struct iommu_iotlb_gather *iotlb_gather);
 	size_t (*unmap_pages)(struct iommu_domain *domain, unsigned long iova,
-- 
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[RFC PATCH v5 05/15] iommu: Use bitmap to calculate page size in iommu_pgsize()

[Isaac J. Manjarres]

From: Will Deacon <will@kernel.org>

Avoid the potential for shifting values by amounts greater than the
width of their type by using a bitmap to compute page size in
iommu_pgsize().

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
---
 drivers/iommu/iommu.c | 31 ++++++++++++-------------------
 1 file changed, 12 insertions(+), 19 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index d0b0a15dba84..bcd623862bf9 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -8,6 +8,7 @@
 
 #include <linux/device.h>
 #include <linux/kernel.h>
+#include <linux/bits.h>
 #include <linux/bug.h>
 #include <linux/types.h>
 #include <linux/init.h>
@@ -2360,30 +2361,22 @@ static size_t iommu_pgsize(struct iommu_domain *domain,
 			   unsigned long addr_merge, size_t size)
 {
 	unsigned int pgsize_idx;
+	unsigned long pgsizes;
 	size_t pgsize;
 
-	/* Max page size that still fits into 'size' */
-	pgsize_idx = __fls(size);
+	/* Page sizes supported by the hardware and small enough for @size */
+	pgsizes = domain->pgsize_bitmap & GENMASK(__fls(size), 0);
 
-	/* need to consider alignment requirements ? */
-	if (likely(addr_merge)) {
-		/* Max page size allowed by address */
-		unsigned int align_pgsize_idx = __ffs(addr_merge);
-		pgsize_idx = min(pgsize_idx, align_pgsize_idx);
-	}
-
-	/* build a mask of acceptable page sizes */
-	pgsize = (1UL << (pgsize_idx + 1)) - 1;
-
-	/* throw away page sizes not supported by the hardware */
-	pgsize &= domain->pgsize_bitmap;
+	/* Constrain the page sizes further based on the maximum alignment */
+	if (likely(addr_merge))
+		pgsizes &= GENMASK(__ffs(addr_merge), 0);
 
-	/* make sure we're still sane */
-	BUG_ON(!pgsize);
+	/* Make sure we have at least one suitable page size */
+	BUG_ON(!pgsizes);
 
-	/* pick the biggest page */
-	pgsize_idx = __fls(pgsize);
-	pgsize = 1UL << pgsize_idx;
+	/* Pick the biggest page size remaining */
+	pgsize_idx = __fls(pgsizes);
+	pgsize = BIT(pgsize_idx);
 
 	return pgsize;
 }
-- 
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[RFC PATCH v5 06/15] iommu: Split 'addr_merge' argument to iommu_pgsize() into separate parts

[Isaac J. Manjarres]

From: Will Deacon <will@kernel.org>

The 'addr_merge' parameter to iommu_pgsize() is a fabricated address
intended to describe the alignment requirements to consider when
choosing an appropriate page size. On the iommu_map() path, this address
is the logical OR of the virtual and physical addresses.

Subsequent improvements to iommu_pgsize() will need to check the
alignment of the virtual and physical components of 'addr_merge'
independently, so pass them in as separate parameters and reconstruct
'addr_merge' locally.

No functional change.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
---
 drivers/iommu/iommu.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index bcd623862bf9..624ce3c7ae33 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2357,12 +2357,13 @@ phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
 }
 EXPORT_SYMBOL_GPL(iommu_iova_to_phys);
 
-static size_t iommu_pgsize(struct iommu_domain *domain,
-			   unsigned long addr_merge, size_t size)
+static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova,
+			   phys_addr_t paddr, size_t size)
 {
 	unsigned int pgsize_idx;
 	unsigned long pgsizes;
 	size_t pgsize;
+	unsigned long addr_merge = paddr | iova;
 
 	/* Page sizes supported by the hardware and small enough for @size */
 	pgsizes = domain->pgsize_bitmap & GENMASK(__fls(size), 0);
@@ -2415,7 +2416,7 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
 	pr_debug("map: iova 0x%lx pa %pa size 0x%zx\n", iova, &paddr, size);
 
 	while (size) {
-		size_t pgsize = iommu_pgsize(domain, iova | paddr, size);
+		size_t pgsize = iommu_pgsize(domain, iova, paddr, size);
 
 		pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
 			 iova, &paddr, pgsize);
@@ -2503,8 +2504,9 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
 	 * or we hit an area that isn't mapped.
 	 */
 	while (unmapped < size) {
-		size_t pgsize = iommu_pgsize(domain, iova, size - unmapped);
+		size_t pgsize;
 
+		pgsize = iommu_pgsize(domain, iova, iova, size - unmapped);
 		unmapped_page = ops->unmap(domain, iova, pgsize, iotlb_gather);
 		if (!unmapped_page)
 			break;
-- 
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[RFC PATCH v5 07/15] iommu: Hook up '->unmap_pages' driver callback

[Isaac J. Manjarres]

From: Will Deacon <will@kernel.org>

Extend iommu_pgsize() to populate an optional 'count' parameter so that
we can direct unmapping operation to the ->unmap_pages callback if it
has been provided by the driver.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
---
 drivers/iommu/iommu.c | 60 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 51 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 624ce3c7ae33..1fc919ea95ac 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2358,11 +2358,11 @@ phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
 EXPORT_SYMBOL_GPL(iommu_iova_to_phys);
 
 static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova,
-			   phys_addr_t paddr, size_t size)
+			   phys_addr_t paddr, size_t size, size_t *count)
 {
-	unsigned int pgsize_idx;
+	unsigned int pgsize_idx, pgsize_idx_next;
 	unsigned long pgsizes;
-	size_t pgsize;
+	size_t offset, pgsize, pgsize_next;
 	unsigned long addr_merge = paddr | iova;
 
 	/* Page sizes supported by the hardware and small enough for @size */
@@ -2378,7 +2378,37 @@ static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova,
 	/* Pick the biggest page size remaining */
 	pgsize_idx = __fls(pgsizes);
 	pgsize = BIT(pgsize_idx);
+	if (!count)
+		return pgsize;
 
+
+	/* Find the next biggest support page size, if it exists */
+	pgsizes = domain->pgsize_bitmap & ~GENMASK(pgsize_idx, 0);
+	if (!pgsizes)
+		goto out_set_count;
+
+	pgsize_idx_next = __ffs(pgsizes);
+	pgsize_next = BIT(pgsize_idx_next);
+
+	/*
+	 * There's no point trying a bigger page size unless the virtual
+	 * and physical addresses are similarly offset within the larger page.
+	 */
+	if ((iova ^ paddr) & (pgsize_next - 1))
+		goto out_set_count;
+
+	/* Calculate the offset to the next page size alignment boundary */
+	offset = pgsize_next - (addr_merge & (pgsize_next - 1));
+
+	/*
+	 * If size is big enough to accommodate the larger page, reduce
+	 * the number of smaller pages.
+	 */
+	if (offset + pgsize_next <= size)
+		size = offset;
+
+out_set_count:
+	*count = size >> pgsize_idx;
 	return pgsize;
 }
 
@@ -2416,7 +2446,7 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
 	pr_debug("map: iova 0x%lx pa %pa size 0x%zx\n", iova, &paddr, size);
 
 	while (size) {
-		size_t pgsize = iommu_pgsize(domain, iova, paddr, size);
+		size_t pgsize = iommu_pgsize(domain, iova, paddr, size, NULL);
 
 		pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
 			 iova, &paddr, pgsize);
@@ -2467,6 +2497,19 @@ int iommu_map_atomic(struct iommu_domain *domain, unsigned long iova,
 }
 EXPORT_SYMBOL_GPL(iommu_map_atomic);
 
+static size_t __iommu_unmap_pages(struct iommu_domain *domain,
+				  unsigned long iova, size_t size,
+				  struct iommu_iotlb_gather *iotlb_gather)
+{
+	const struct iommu_ops *ops = domain->ops;
+	size_t pgsize, count;
+
+	pgsize = iommu_pgsize(domain, iova, iova, size, &count);
+	return ops->unmap_pages ?
+	       ops->unmap_pages(domain, iova, pgsize, count, iotlb_gather) :
+	       ops->unmap(domain, iova, pgsize, iotlb_gather);
+}
+
 static size_t __iommu_unmap(struct iommu_domain *domain,
 			    unsigned long iova, size_t size,
 			    struct iommu_iotlb_gather *iotlb_gather)
@@ -2476,7 +2519,7 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
 	unsigned long orig_iova = iova;
 	unsigned int min_pagesz;
 
-	if (unlikely(ops->unmap == NULL ||
+	if (unlikely(!(ops->unmap || ops->unmap_pages) ||
 		     domain->pgsize_bitmap == 0UL))
 		return 0;
 
@@ -2504,10 +2547,9 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
 	 * or we hit an area that isn't mapped.
 	 */
 	while (unmapped < size) {
-		size_t pgsize;
-
-		pgsize = iommu_pgsize(domain, iova, iova, size - unmapped);
-		unmapped_page = ops->unmap(domain, iova, pgsize, iotlb_gather);
+		unmapped_page = __iommu_unmap_pages(domain, iova,
+						    size - unmapped,
+						    iotlb_gather);
 		if (!unmapped_page)
 			break;
 
-- 
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a Linux Foundation Collaborative Project

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[RFC PATCH v5 08/15] iommu: Add support for the map_pages() callback

[Isaac J. Manjarres]

Since iommu_pgsize can calculate how many pages of the
same size can be mapped/unmapped before the next largest
page size boundary, add support for invoking an IOMMU
driver's map_pages() callback, if it provides one.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: Will Deacon <will@kernel.org>
---
 drivers/iommu/iommu.c | 43 +++++++++++++++++++++++++++++++++++--------
 1 file changed, 35 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 1fc919ea95ac..c94b6b3198b6 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2412,6 +2412,30 @@ static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova,
 	return pgsize;
 }
 
+static int __iommu_map_pages(struct iommu_domain *domain, unsigned long iova,
+			     phys_addr_t paddr, size_t size, int prot,
+			     gfp_t gfp, size_t *mapped)
+{
+	const struct iommu_ops *ops = domain->ops;
+	size_t pgsize, count;
+	int ret;
+
+	pgsize = iommu_pgsize(domain, iova, paddr, size, &count);
+
+	pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx count %ld\n",
+			 iova, &paddr, pgsize, count);
+
+	if (ops->map_pages) {
+		ret = ops->map_pages(domain, iova, paddr, pgsize, count, prot,
+				     gfp, mapped);
+	} else {
+		ret = ops->map(domain, iova, paddr, pgsize, prot, gfp);
+		*mapped = ret ? 0 : pgsize;
+	}
+
+	return ret;
+}
+
 static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
 		       phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
 {
@@ -2422,7 +2446,7 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
 	phys_addr_t orig_paddr = paddr;
 	int ret = 0;
 
-	if (unlikely(ops->map == NULL ||
+	if (unlikely(!(ops->map || ops->map_pages) ||
 		     domain->pgsize_bitmap == 0UL))
 		return -ENODEV;
 
@@ -2446,18 +2470,21 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
 	pr_debug("map: iova 0x%lx pa %pa size 0x%zx\n", iova, &paddr, size);
 
 	while (size) {
-		size_t pgsize = iommu_pgsize(domain, iova, paddr, size, NULL);
+		size_t mapped = 0;
 
-		pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
-			 iova, &paddr, pgsize);
-		ret = ops->map(domain, iova, paddr, pgsize, prot, gfp);
+		ret = __iommu_map_pages(domain, iova, paddr, size, prot, gfp,
+					&mapped);
+		/*
+		 * Some pages may have been mapped, even if an error occurred,
+		 * so we should account for those so they can be unmapped.
+		 */
+		size -= mapped;
 
 		if (ret)
 			break;
 
-		iova += pgsize;
-		paddr += pgsize;
-		size -= pgsize;
+		iova += mapped;
+		paddr += mapped;
 	}
 
 	/* unroll mapping in case something went wrong */
-- 
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a Linux Foundation Collaborative Project

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[RFC PATCH v5 09/15] iommu/io-pgtable-arm: Prepare PTE methods for handling multiple entries

[Isaac J. Manjarres]

The PTE methods currently operate on a single entry. In preparation
for manipulating multiple PTEs in one map or unmap call, allow them
to handle multiple PTEs.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: Robin Murphy <robin.murphy@arm.com>
---
 drivers/iommu/io-pgtable-arm.c | 78 +++++++++++++++++++---------------
 1 file changed, 44 insertions(+), 34 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 87def58e79b5..ea66b10c04c4 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -232,20 +232,23 @@ static void __arm_lpae_free_pages(void *pages, size_t size,
 	free_pages((unsigned long)pages, get_order(size));
 }
 
-static void __arm_lpae_sync_pte(arm_lpae_iopte *ptep,
+static void __arm_lpae_sync_pte(arm_lpae_iopte *ptep, int num_entries,
 				struct io_pgtable_cfg *cfg)
 {
 	dma_sync_single_for_device(cfg->iommu_dev, __arm_lpae_dma_addr(ptep),
-				   sizeof(*ptep), DMA_TO_DEVICE);
+				   sizeof(*ptep) * num_entries, DMA_TO_DEVICE);
 }
 
 static void __arm_lpae_set_pte(arm_lpae_iopte *ptep, arm_lpae_iopte pte,
-			       struct io_pgtable_cfg *cfg)
+			       int num_entries, struct io_pgtable_cfg *cfg)
 {
-	*ptep = pte;
+	int i;
+
+	for (i = 0; i < num_entries; i++)
+		ptep[i] = pte;
 
 	if (!cfg->coherent_walk)
-		__arm_lpae_sync_pte(ptep, cfg);
+		__arm_lpae_sync_pte(ptep, num_entries, cfg);
 }
 
 static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
@@ -255,47 +258,54 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
 
 static void __arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
 				phys_addr_t paddr, arm_lpae_iopte prot,
-				int lvl, arm_lpae_iopte *ptep)
+				int lvl, int num_entries, arm_lpae_iopte *ptep)
 {
 	arm_lpae_iopte pte = prot;
+	struct io_pgtable_cfg *cfg = &data->iop.cfg;
+	size_t sz = ARM_LPAE_BLOCK_SIZE(lvl, data);
+	int i;
 
 	if (data->iop.fmt != ARM_MALI_LPAE && lvl == ARM_LPAE_MAX_LEVELS - 1)
 		pte |= ARM_LPAE_PTE_TYPE_PAGE;
 	else
 		pte |= ARM_LPAE_PTE_TYPE_BLOCK;
 
-	pte |= paddr_to_iopte(paddr, data);
+	for (i = 0; i < num_entries; i++)
+		ptep[i] = pte | paddr_to_iopte(paddr + i * sz, data);
 
-	__arm_lpae_set_pte(ptep, pte, &data->iop.cfg);
+	if (!cfg->coherent_walk)
+		__arm_lpae_sync_pte(ptep, num_entries, cfg);
 }
 
 static int arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
 			     unsigned long iova, phys_addr_t paddr,
-			     arm_lpae_iopte prot, int lvl,
+			     arm_lpae_iopte prot, int lvl, int num_entries,
 			     arm_lpae_iopte *ptep)
 {
-	arm_lpae_iopte pte = *ptep;
-
-	if (iopte_leaf(pte, lvl, data->iop.fmt)) {
-		/* We require an unmap first */
-		WARN_ON(!selftest_running);
-		return -EEXIST;
-	} else if (iopte_type(pte) == ARM_LPAE_PTE_TYPE_TABLE) {
-		/*
-		 * We need to unmap and free the old table before
-		 * overwriting it with a block entry.
-		 */
-		arm_lpae_iopte *tblp;
-		size_t sz = ARM_LPAE_BLOCK_SIZE(lvl, data);
-
-		tblp = ptep - ARM_LPAE_LVL_IDX(iova, lvl, data);
-		if (__arm_lpae_unmap(data, NULL, iova, sz, lvl, tblp) != sz) {
-			WARN_ON(1);
-			return -EINVAL;
+	int i;
+
+	for (i = 0; i < num_entries; i++)
+		if (iopte_leaf(ptep[i], lvl, data->iop.fmt)) {
+			/* We require an unmap first */
+			WARN_ON(!selftest_running);
+			return -EEXIST;
+		} else if (iopte_type(ptep[i]) == ARM_LPAE_PTE_TYPE_TABLE) {
+			/*
+			 * We need to unmap and free the old table before
+			 * overwriting it with a block entry.
+			 */
+			arm_lpae_iopte *tblp;
+			size_t sz = ARM_LPAE_BLOCK_SIZE(lvl, data);
+
+			tblp = ptep - ARM_LPAE_LVL_IDX(iova, lvl, data);
+			if (__arm_lpae_unmap(data, NULL, iova + i * sz, sz,
+					     lvl, tblp) != sz) {
+				WARN_ON(1);
+				return -EINVAL;
+			}
 		}
-	}
 
-	__arm_lpae_init_pte(data, paddr, prot, lvl, ptep);
+	__arm_lpae_init_pte(data, paddr, prot, lvl, num_entries, ptep);
 	return 0;
 }
 
@@ -323,7 +333,7 @@ static arm_lpae_iopte arm_lpae_install_table(arm_lpae_iopte *table,
 		return old;
 
 	/* Even if it's not ours, there's no point waiting; just kick it */
-	__arm_lpae_sync_pte(ptep, cfg);
+	__arm_lpae_sync_pte(ptep, 1, cfg);
 	if (old == curr)
 		WRITE_ONCE(*ptep, new | ARM_LPAE_PTE_SW_SYNC);
 
@@ -344,7 +354,7 @@ static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
 
 	/* If we can install a leaf entry at this level, then do so */
 	if (size == block_size)
-		return arm_lpae_init_pte(data, iova, paddr, prot, lvl, ptep);
+		return arm_lpae_init_pte(data, iova, paddr, prot, lvl, 1, ptep);
 
 	/* We can't allocate tables at the final level */
 	if (WARN_ON(lvl >= ARM_LPAE_MAX_LEVELS - 1))
@@ -361,7 +371,7 @@ static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
 		if (pte)
 			__arm_lpae_free_pages(cptep, tblsz, cfg);
 	} else if (!cfg->coherent_walk && !(pte & ARM_LPAE_PTE_SW_SYNC)) {
-		__arm_lpae_sync_pte(ptep, cfg);
+		__arm_lpae_sync_pte(ptep, 1, cfg);
 	}
 
 	if (pte && !iopte_leaf(pte, lvl, data->iop.fmt)) {
@@ -543,7 +553,7 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
 		if (i == unmap_idx)
 			continue;
 
-		__arm_lpae_init_pte(data, blk_paddr, pte, lvl, &tablep[i]);
+		__arm_lpae_init_pte(data, blk_paddr, pte, lvl, 1, &tablep[i]);
 	}
 
 	pte = arm_lpae_install_table(tablep, ptep, blk_pte, cfg);
@@ -585,7 +595,7 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
 
 	/* If the size matches this level, we're in the right place */
 	if (size == ARM_LPAE_BLOCK_SIZE(lvl, data)) {
-		__arm_lpae_set_pte(ptep, 0, &iop->cfg);
+		__arm_lpae_set_pte(ptep, 0, 1, &iop->cfg);
 
 		if (!iopte_leaf(pte, lvl, iop->fmt)) {
 			/* Also flush any partial walks */
-- 
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a Linux Foundation Collaborative Project

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[RFC PATCH v5 10/15] iommu/io-pgtable-arm: Implement arm_lpae_unmap_pages()

[Isaac J. Manjarres]

Implement the unmap_pages() callback for the ARM LPAE io-pgtable
format.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: Will Deacon <will@kernel.org>
---
 drivers/iommu/io-pgtable-arm.c | 75 ++++++++++++++++++++++------------
 1 file changed, 49 insertions(+), 26 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index ea66b10c04c4..1b690911995a 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -46,6 +46,9 @@
 #define ARM_LPAE_PGD_SIZE(d)						\
 	(sizeof(arm_lpae_iopte) << (d)->pgd_bits)
 
+#define ARM_LPAE_PTES_PER_TABLE(d)					\
+	(ARM_LPAE_GRANULE(d) >> ilog2(sizeof(arm_lpae_iopte)))
+
 /*
  * Calculate the index at level l used to map virtual address a using the
  * pagetable in d.
@@ -253,8 +256,8 @@ static void __arm_lpae_set_pte(arm_lpae_iopte *ptep, arm_lpae_iopte pte,
 
 static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
 			       struct iommu_iotlb_gather *gather,
-			       unsigned long iova, size_t size, int lvl,
-			       arm_lpae_iopte *ptep);
+			       unsigned long iova, size_t size, size_t pgcount,
+			       int lvl, arm_lpae_iopte *ptep);
 
 static void __arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
 				phys_addr_t paddr, arm_lpae_iopte prot,
@@ -298,7 +301,7 @@ static int arm_lpae_init_pte(struct arm_lpae_io_pgtable *data,
 			size_t sz = ARM_LPAE_BLOCK_SIZE(lvl, data);
 
 			tblp = ptep - ARM_LPAE_LVL_IDX(iova, lvl, data);
-			if (__arm_lpae_unmap(data, NULL, iova + i * sz, sz,
+			if (__arm_lpae_unmap(data, NULL, iova + i * sz, sz, 1,
 					     lvl, tblp) != sz) {
 				WARN_ON(1);
 				return -EINVAL;
@@ -526,14 +529,15 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
 				       struct iommu_iotlb_gather *gather,
 				       unsigned long iova, size_t size,
 				       arm_lpae_iopte blk_pte, int lvl,
-				       arm_lpae_iopte *ptep)
+				       arm_lpae_iopte *ptep, size_t pgcount)
 {
 	struct io_pgtable_cfg *cfg = &data->iop.cfg;
 	arm_lpae_iopte pte, *tablep;
 	phys_addr_t blk_paddr;
 	size_t tablesz = ARM_LPAE_GRANULE(data);
 	size_t split_sz = ARM_LPAE_BLOCK_SIZE(lvl, data);
-	int i, unmap_idx = -1;
+	int ptes_per_table = ARM_LPAE_PTES_PER_TABLE(data);
+	int i, unmap_idx_start = -1, num_entries = 0, max_entries;
 
 	if (WARN_ON(lvl == ARM_LPAE_MAX_LEVELS))
 		return 0;
@@ -542,15 +546,18 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
 	if (!tablep)
 		return 0; /* Bytes unmapped */
 
-	if (size == split_sz)
-		unmap_idx = ARM_LPAE_LVL_IDX(iova, lvl, data);
+	if (size == split_sz) {
+		unmap_idx_start = ARM_LPAE_LVL_IDX(iova, lvl, data);
+		max_entries = ptes_per_table - unmap_idx_start;
+		num_entries = min_t(int, pgcount, max_entries);
+	}
 
 	blk_paddr = iopte_to_paddr(blk_pte, data);
 	pte = iopte_prot(blk_pte);
 
-	for (i = 0; i < tablesz / sizeof(pte); i++, blk_paddr += split_sz) {
+	for (i = 0; i < ptes_per_table; i++, blk_paddr += split_sz) {
 		/* Unmap! */
-		if (i == unmap_idx)
+		if (i >= unmap_idx_start && i < (unmap_idx_start + num_entries))
 			continue;
 
 		__arm_lpae_init_pte(data, blk_paddr, pte, lvl, 1, &tablep[i]);
@@ -568,38 +575,44 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
 			return 0;
 
 		tablep = iopte_deref(pte, data);
-	} else if (unmap_idx >= 0) {
-		io_pgtable_tlb_add_page(&data->iop, gather, iova, size);
-		return size;
+	} else if (unmap_idx_start >= 0) {
+		for (i = 0; i < num_entries; i++)
+			io_pgtable_tlb_add_page(&data->iop, gather, iova + i * size, size);
+
+		return num_entries * size;
 	}
 
-	return __arm_lpae_unmap(data, gather, iova, size, lvl, tablep);
+	return __arm_lpae_unmap(data, gather, iova, size, pgcount, lvl, tablep);
 }
 
 static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
 			       struct iommu_iotlb_gather *gather,
-			       unsigned long iova, size_t size, int lvl,
-			       arm_lpae_iopte *ptep)
+			       unsigned long iova, size_t size, size_t pgcount,
+			       int lvl, arm_lpae_iopte *ptep)
 {
 	arm_lpae_iopte pte;
 	struct io_pgtable *iop = &data->iop;
+	int i, num_entries, max_entries, unmap_idx_start;
 
 	/* Something went horribly wrong and we ran out of page table */
 	if (WARN_ON(lvl == ARM_LPAE_MAX_LEVELS))
 		return 0;
 
-	ptep += ARM_LPAE_LVL_IDX(iova, lvl, data);
+	unmap_idx_start = ARM_LPAE_LVL_IDX(iova, lvl, data);
+	ptep += unmap_idx_start;
 	pte = READ_ONCE(*ptep);
 	if (WARN_ON(!pte))
 		return 0;
 
 	/* If the size matches this level, we're in the right place */
 	if (size == ARM_LPAE_BLOCK_SIZE(lvl, data)) {
-		__arm_lpae_set_pte(ptep, 0, 1, &iop->cfg);
+		max_entries = ARM_LPAE_PTES_PER_TABLE(data) - unmap_idx_start;
+		num_entries = min_t(int, pgcount, max_entries);
+		__arm_lpae_set_pte(ptep, 0, num_entries, &iop->cfg);
 
 		if (!iopte_leaf(pte, lvl, iop->fmt)) {
 			/* Also flush any partial walks */
-			io_pgtable_tlb_flush_walk(iop, iova, size,
+			io_pgtable_tlb_flush_walk(iop, iova, num_entries * size,
 						  ARM_LPAE_GRANULE(data));
 			ptep = iopte_deref(pte, data);
 			__arm_lpae_free_pgtable(data, lvl + 1, ptep);
@@ -611,33 +624,35 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
 			 */
 			smp_wmb();
 		} else {
-			io_pgtable_tlb_add_page(iop, gather, iova, size);
+			for (i = 0; i < num_entries; i++)
+				io_pgtable_tlb_add_page(iop, gather, iova + i * size, size);
 		}
 
-		return size;
+		return num_entries * size;
 	} else if (iopte_leaf(pte, lvl, iop->fmt)) {
 		/*
 		 * Insert a table at the next level to map the old region,
 		 * minus the part we want to unmap
 		 */
 		return arm_lpae_split_blk_unmap(data, gather, iova, size, pte,
-						lvl + 1, ptep);
+						lvl + 1, ptep, pgcount);
 	}
 
 	/* Keep on walkin' */
 	ptep = iopte_deref(pte, data);
-	return __arm_lpae_unmap(data, gather, iova, size, lvl + 1, ptep);
+	return __arm_lpae_unmap(data, gather, iova, size, pgcount, lvl + 1, ptep);
 }
 
-static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
-			     size_t size, struct iommu_iotlb_gather *gather)
+static size_t arm_lpae_unmap_pages(struct io_pgtable_ops *ops, unsigned long iova,
+				   size_t pgsize, size_t pgcount,
+				   struct iommu_iotlb_gather *gather)
 {
 	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
 	struct io_pgtable_cfg *cfg = &data->iop.cfg;
 	arm_lpae_iopte *ptep = data->pgd;
 	long iaext = (s64)iova >> cfg->ias;
 
-	if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
+	if (WARN_ON(!pgsize || (pgsize & cfg->pgsize_bitmap) != pgsize || !pgcount))
 		return 0;
 
 	if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1)
@@ -645,7 +660,14 @@ static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
 	if (WARN_ON(iaext))
 		return 0;
 
-	return __arm_lpae_unmap(data, gather, iova, size, data->start_level, ptep);
+	return __arm_lpae_unmap(data, gather, iova, pgsize, pgcount,
+				data->start_level, ptep);
+}
+
+static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
+			     size_t size, struct iommu_iotlb_gather *gather)
+{
+	return arm_lpae_unmap_pages(ops, iova, size, 1, gather);
 }
 
 static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
@@ -761,6 +783,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
 	data->iop.ops = (struct io_pgtable_ops) {
 		.map		= arm_lpae_map,
 		.unmap		= arm_lpae_unmap,
+		.unmap_pages	= arm_lpae_unmap_pages,
 		.iova_to_phys	= arm_lpae_iova_to_phys,
 	};
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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[RFC PATCH v5 11/15] iommu/io-pgtable-arm: Implement arm_lpae_map_pages()

[Isaac J. Manjarres]

Implement the map_pages() callback for the ARM LPAE io-pgtable
format.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
---
 drivers/iommu/io-pgtable-arm.c | 42 ++++++++++++++++++++++++++--------
 1 file changed, 32 insertions(+), 10 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 1b690911995a..92978dd9c885 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -344,20 +344,30 @@ static arm_lpae_iopte arm_lpae_install_table(arm_lpae_iopte *table,
 }
 
 static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
-			  phys_addr_t paddr, size_t size, arm_lpae_iopte prot,
-			  int lvl, arm_lpae_iopte *ptep, gfp_t gfp)
+			  phys_addr_t paddr, size_t size, size_t pgcount,
+			  arm_lpae_iopte prot, int lvl, arm_lpae_iopte *ptep,
+			  gfp_t gfp, size_t *mapped)
 {
 	arm_lpae_iopte *cptep, pte;
 	size_t block_size = ARM_LPAE_BLOCK_SIZE(lvl, data);
 	size_t tblsz = ARM_LPAE_GRANULE(data);
 	struct io_pgtable_cfg *cfg = &data->iop.cfg;
+	int ret = 0, num_entries, max_entries, map_idx_start;
 
 	/* Find our entry at the current level */
-	ptep += ARM_LPAE_LVL_IDX(iova, lvl, data);
+	map_idx_start = ARM_LPAE_LVL_IDX(iova, lvl, data);
+	ptep += map_idx_start;
 
 	/* If we can install a leaf entry at this level, then do so */
-	if (size == block_size)
-		return arm_lpae_init_pte(data, iova, paddr, prot, lvl, 1, ptep);
+	if (size == block_size) {
+		max_entries = ARM_LPAE_PTES_PER_TABLE(data) - map_idx_start;
+		num_entries = min_t(int, pgcount, max_entries);
+		ret = arm_lpae_init_pte(data, iova, paddr, prot, lvl, num_entries, ptep);
+		if (!ret && mapped)
+			*mapped += num_entries * size;
+
+		return ret;
+	}
 
 	/* We can't allocate tables at the final level */
 	if (WARN_ON(lvl >= ARM_LPAE_MAX_LEVELS - 1))
@@ -386,7 +396,8 @@ static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
 	}
 
 	/* Rinse, repeat */
-	return __arm_lpae_map(data, iova, paddr, size, prot, lvl + 1, cptep, gfp);
+	return __arm_lpae_map(data, iova, paddr, size, pgcount, prot, lvl + 1,
+			      cptep, gfp, mapped);
 }
 
 static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
@@ -453,8 +464,9 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
 	return pte;
 }
 
-static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
-			phys_addr_t paddr, size_t size, int iommu_prot, gfp_t gfp)
+static int arm_lpae_map_pages(struct io_pgtable_ops *ops, unsigned long iova,
+			      phys_addr_t paddr, size_t pgsize, size_t pgcount,
+			      int iommu_prot, gfp_t gfp, size_t *mapped)
 {
 	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
 	struct io_pgtable_cfg *cfg = &data->iop.cfg;
@@ -463,7 +475,7 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
 	arm_lpae_iopte prot;
 	long iaext = (s64)iova >> cfg->ias;
 
-	if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
+	if (WARN_ON(!pgsize || (pgsize & cfg->pgsize_bitmap) != pgsize))
 		return -EINVAL;
 
 	if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1)
@@ -476,7 +488,8 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
 		return 0;
 
 	prot = arm_lpae_prot_to_pte(data, iommu_prot);
-	ret = __arm_lpae_map(data, iova, paddr, size, prot, lvl, ptep, gfp);
+	ret = __arm_lpae_map(data, iova, paddr, pgsize, pgcount, prot, lvl,
+			     ptep, gfp, NULL);
 	/*
 	 * Synchronise all PTE updates for the new mapping before there's
 	 * a chance for anything to kick off a table walk for the new iova.
@@ -486,6 +499,14 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
 	return ret;
 }
 
+
+static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
+			phys_addr_t paddr, size_t size, int iommu_prot, gfp_t gfp)
+{
+	return arm_lpae_map_pages(ops, iova, paddr, size, 1, iommu_prot, gfp,
+				  NULL);
+}
+
 static void __arm_lpae_free_pgtable(struct arm_lpae_io_pgtable *data, int lvl,
 				    arm_lpae_iopte *ptep)
 {
@@ -782,6 +803,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
 
 	data->iop.ops = (struct io_pgtable_ops) {
 		.map		= arm_lpae_map,
+		.map_pages	= arm_lpae_map_pages,
 		.unmap		= arm_lpae_unmap,
 		.unmap_pages	= arm_lpae_unmap_pages,
 		.iova_to_phys	= arm_lpae_iova_to_phys,
-- 
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a Linux Foundation Collaborative Project

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[RFC PATCH v5 12/15] iommu/io-pgtable-arm-v7s: Implement arm_v7s_unmap_pages()

[Isaac J. Manjarres]

Implement the unmap_pages() callback for the ARM v7s io-pgtable
format.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
---
 drivers/iommu/io-pgtable-arm-v7s.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index d4004bcf333a..1af060686985 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -710,15 +710,32 @@ static size_t __arm_v7s_unmap(struct arm_v7s_io_pgtable *data,
 	return __arm_v7s_unmap(data, gather, iova, size, lvl + 1, ptep);
 }
 
-static size_t arm_v7s_unmap(struct io_pgtable_ops *ops, unsigned long iova,
-			    size_t size, struct iommu_iotlb_gather *gather)
+static size_t arm_v7s_unmap_pages(struct io_pgtable_ops *ops, unsigned long iova,
+				  size_t pgsize, size_t pgcount,
+				  struct iommu_iotlb_gather *gather)
 {
 	struct arm_v7s_io_pgtable *data = io_pgtable_ops_to_data(ops);
+	size_t unmapped = 0, ret;
 
 	if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias)))
 		return 0;
 
-	return __arm_v7s_unmap(data, gather, iova, size, 1, data->pgd);
+	while (pgcount--) {
+		ret = __arm_v7s_unmap(data, gather, iova, pgsize, 1, data->pgd);
+		if (!ret)
+			break;
+
+		unmapped += pgsize;
+		iova += pgsize;
+	}
+
+	return unmapped;
+}
+
+static size_t arm_v7s_unmap(struct io_pgtable_ops *ops, unsigned long iova,
+			    size_t size, struct iommu_iotlb_gather *gather)
+{
+	return arm_v7s_unmap_pages(ops, iova, size, 1, gather);
 }
 
 static phys_addr_t arm_v7s_iova_to_phys(struct io_pgtable_ops *ops,
@@ -781,6 +798,7 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
 	data->iop.ops = (struct io_pgtable_ops) {
 		.map		= arm_v7s_map,
 		.unmap		= arm_v7s_unmap,
+		.unmap_pages	= arm_v7s_unmap_pages,
 		.iova_to_phys	= arm_v7s_iova_to_phys,
 	};
 
-- 
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[RFC PATCH v5 13/15] iommu/io-pgtable-arm-v7s: Implement arm_v7s_map_pages()

[Isaac J. Manjarres]

Implement the map_pages() callback for the ARM v7s io-pgtable
format.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
---
 drivers/iommu/io-pgtable-arm-v7s.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index 1af060686985..3331caafb273 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -519,11 +519,12 @@ static int __arm_v7s_map(struct arm_v7s_io_pgtable *data, unsigned long iova,
 	return __arm_v7s_map(data, iova, paddr, size, prot, lvl + 1, cptep, gfp);
 }
 
-static int arm_v7s_map(struct io_pgtable_ops *ops, unsigned long iova,
-			phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
+static int arm_v7s_map_pages(struct io_pgtable_ops *ops, unsigned long iova,
+			     phys_addr_t paddr, size_t pgsize, size_t pgcount,
+			     int prot, gfp_t gfp, size_t *mapped)
 {
 	struct arm_v7s_io_pgtable *data = io_pgtable_ops_to_data(ops);
-	int ret;
+	int ret = -EINVAL;
 
 	if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias) ||
 		    paddr >= (1ULL << data->iop.cfg.oas)))
@@ -533,7 +534,17 @@ static int arm_v7s_map(struct io_pgtable_ops *ops, unsigned long iova,
 	if (!(prot & (IOMMU_READ | IOMMU_WRITE)))
 		return 0;
 
-	ret = __arm_v7s_map(data, iova, paddr, size, prot, 1, data->pgd, gfp);
+	while (pgcount--) {
+		ret = __arm_v7s_map(data, iova, paddr, pgsize, prot, 1, data->pgd,
+				    gfp);
+		if (ret)
+			break;
+
+		iova += pgsize;
+		paddr += pgsize;
+		if (mapped)
+			*mapped += pgsize;
+	}
 	/*
 	 * Synchronise all PTE updates for the new mapping before there's
 	 * a chance for anything to kick off a table walk for the new iova.
@@ -543,6 +554,12 @@ static int arm_v7s_map(struct io_pgtable_ops *ops, unsigned long iova,
 	return ret;
 }
 
+static int arm_v7s_map(struct io_pgtable_ops *ops, unsigned long iova,
+			phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
+{
+	return arm_v7s_map_pages(ops, iova, paddr, size, 1, prot, gfp, NULL);
+}
+
 static void arm_v7s_free_pgtable(struct io_pgtable *iop)
 {
 	struct arm_v7s_io_pgtable *data = io_pgtable_to_data(iop);
@@ -797,6 +814,7 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
 
 	data->iop.ops = (struct io_pgtable_ops) {
 		.map		= arm_v7s_map,
+		.map_pages	= arm_v7s_map_pages,
 		.unmap		= arm_v7s_unmap,
 		.unmap_pages	= arm_v7s_unmap_pages,
 		.iova_to_phys	= arm_v7s_iova_to_phys,
-- 
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[RFC PATCH v5 14/15] iommu/arm-smmu: Implement the unmap_pages() IOMMU driver callback

[Isaac J. Manjarres]

Implement the unmap_pages() callback for the ARM SMMU driver
to allow calls from iommu_unmap to unmap multiple pages of
the same size in one call. Also, remove the unmap() callback
for the SMMU driver, as it will no longer be used.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: Will Deacon <will@kernel.org>
---
 drivers/iommu/arm/arm-smmu/arm-smmu.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index d8c6bfde6a61..188e506d75e1 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -1208,8 +1208,9 @@ static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
 	return ret;
 }
 
-static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova,
-			     size_t size, struct iommu_iotlb_gather *gather)
+static size_t arm_smmu_unmap_pages(struct iommu_domain *domain, unsigned long iova,
+				   size_t pgsize, size_t pgcount,
+				   struct iommu_iotlb_gather *iotlb_gather)
 {
 	struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops;
 	struct arm_smmu_device *smmu = to_smmu_domain(domain)->smmu;
@@ -1219,7 +1220,7 @@ static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova,
 		return 0;
 
 	arm_smmu_rpm_get(smmu);
-	ret = ops->unmap(ops, iova, size, gather);
+	ret = ops->unmap_pages(ops, iova, pgsize, pgcount, iotlb_gather);
 	arm_smmu_rpm_put(smmu);
 
 	return ret;
@@ -1624,7 +1625,7 @@ static struct iommu_ops arm_smmu_ops = {
 	.domain_free		= arm_smmu_domain_free,
 	.attach_dev		= arm_smmu_attach_dev,
 	.map			= arm_smmu_map,
-	.unmap			= arm_smmu_unmap,
+	.unmap_pages		= arm_smmu_unmap_pages,
 	.flush_iotlb_all	= arm_smmu_flush_iotlb_all,
 	.iotlb_sync		= arm_smmu_iotlb_sync,
 	.iova_to_phys		= arm_smmu_iova_to_phys,
-- 
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a Linux Foundation Collaborative Project

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[RFC PATCH v5 15/15] iommu/arm-smmu: Implement the map_pages() IOMMU driver callback

[Isaac J. Manjarres]

Implement the map_pages() callback for the ARM SMMU driver
to allow calls from iommu_map to map multiple pages of
the same size in one call. Also, remove the map() callback
for the ARM SMMU driver, as it will no longer be used.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Suggested-by: Will Deacon <will@kernel.org>
---
 drivers/iommu/arm/arm-smmu/arm-smmu.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 188e506d75e1..8fcc422e2f2f 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -1191,8 +1191,9 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	return ret;
 }
 
-static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
-			phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
+static int arm_smmu_map_pages(struct iommu_domain *domain, unsigned long iova,
+			      phys_addr_t paddr, size_t pgsize, size_t pgcount,
+			      int prot, gfp_t gfp, size_t *mapped)
 {
 	struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops;
 	struct arm_smmu_device *smmu = to_smmu_domain(domain)->smmu;
@@ -1202,7 +1203,7 @@ static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
 		return -ENODEV;
 
 	arm_smmu_rpm_get(smmu);
-	ret = ops->map(ops, iova, paddr, size, prot, gfp);
+	ret = ops->map_pages(ops, iova, paddr, pgsize, pgcount, prot, gfp, mapped);
 	arm_smmu_rpm_put(smmu);
 
 	return ret;
@@ -1624,7 +1625,7 @@ static struct iommu_ops arm_smmu_ops = {
 	.domain_alloc		= arm_smmu_domain_alloc,
 	.domain_free		= arm_smmu_domain_free,
 	.attach_dev		= arm_smmu_attach_dev,
-	.map			= arm_smmu_map,
+	.map_pages		= arm_smmu_map_pages,
 	.unmap_pages		= arm_smmu_unmap_pages,
 	.flush_iotlb_all	= arm_smmu_flush_iotlb_all,
 	.iotlb_sync		= arm_smmu_iotlb_sync,
-- 
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Re: [RFC PATCH v5 11/15] iommu/io-pgtable-arm: Implement arm_lpae_map_pages()

[chenxiang (M)]

Hi Isaac,


在 2021/4/9 1:13, Isaac J. Manjarres 写道:
> Implement the map_pages() callback for the ARM LPAE io-pgtable
> format.
>
> Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
> ---
>   drivers/iommu/io-pgtable-arm.c | 42 ++++++++++++++++++++++++++--------
>   1 file changed, 32 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> index 1b690911995a..92978dd9c885 100644
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -344,20 +344,30 @@ static arm_lpae_iopte arm_lpae_install_table(arm_lpae_iopte *table,
>   }
>   
>   static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
> -			  phys_addr_t paddr, size_t size, arm_lpae_iopte prot,
> -			  int lvl, arm_lpae_iopte *ptep, gfp_t gfp)
> +			  phys_addr_t paddr, size_t size, size_t pgcount,
> +			  arm_lpae_iopte prot, int lvl, arm_lpae_iopte *ptep,
> +			  gfp_t gfp, size_t *mapped)
>   {
>   	arm_lpae_iopte *cptep, pte;
>   	size_t block_size = ARM_LPAE_BLOCK_SIZE(lvl, data);
>   	size_t tblsz = ARM_LPAE_GRANULE(data);
>   	struct io_pgtable_cfg *cfg = &data->iop.cfg;
> +	int ret = 0, num_entries, max_entries, map_idx_start;
>   
>   	/* Find our entry at the current level */
> -	ptep += ARM_LPAE_LVL_IDX(iova, lvl, data);
> +	map_idx_start = ARM_LPAE_LVL_IDX(iova, lvl, data);
> +	ptep += map_idx_start;
>   
>   	/* If we can install a leaf entry at this level, then do so */
> -	if (size == block_size)
> -		return arm_lpae_init_pte(data, iova, paddr, prot, lvl, 1, ptep);
> +	if (size == block_size) {
> +		max_entries = ARM_LPAE_PTES_PER_TABLE(data) - map_idx_start;
> +		num_entries = min_t(int, pgcount, max_entries);
> +		ret = arm_lpae_init_pte(data, iova, paddr, prot, lvl, num_entries, ptep);
> +		if (!ret && mapped)
> +			*mapped += num_entries * size;
> +
> +		return ret;
> +	}
>   
>   	/* We can't allocate tables at the final level */
>   	if (WARN_ON(lvl >= ARM_LPAE_MAX_LEVELS - 1))
> @@ -386,7 +396,8 @@ static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
>   	}
>   
>   	/* Rinse, repeat */
> -	return __arm_lpae_map(data, iova, paddr, size, prot, lvl + 1, cptep, gfp);
> +	return __arm_lpae_map(data, iova, paddr, size, pgcount, prot, lvl + 1,
> +			      cptep, gfp, mapped);
>   }
>   
>   static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
> @@ -453,8 +464,9 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
>   	return pte;
>   }
>   
> -static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
> -			phys_addr_t paddr, size_t size, int iommu_prot, gfp_t gfp)
> +static int arm_lpae_map_pages(struct io_pgtable_ops *ops, unsigned long iova,
> +			      phys_addr_t paddr, size_t pgsize, size_t pgcount,
> +			      int iommu_prot, gfp_t gfp, size_t *mapped)
>   {
>   	struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
>   	struct io_pgtable_cfg *cfg = &data->iop.cfg;
> @@ -463,7 +475,7 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
>   	arm_lpae_iopte prot;
>   	long iaext = (s64)iova >> cfg->ias;
>   
> -	if (WARN_ON(!size || (size & cfg->pgsize_bitmap) != size))
> +	if (WARN_ON(!pgsize || (pgsize & cfg->pgsize_bitmap) != pgsize))
>   		return -EINVAL;
>   
>   	if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_TTBR1)
> @@ -476,7 +488,8 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
>   		return 0;
>   
>   	prot = arm_lpae_prot_to_pte(data, iommu_prot);
> -	ret = __arm_lpae_map(data, iova, paddr, size, prot, lvl, ptep, gfp);
> +	ret = __arm_lpae_map(data, iova, paddr, pgsize, pgcount, prot, lvl,
> +			     ptep, gfp, NULL);

The last input parameter should be mapped instead of NULL.

>   	/*
>   	 * Synchronise all PTE updates for the new mapping before there's
>   	 * a chance for anything to kick off a table walk for the new iova.
> @@ -486,6 +499,14 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
>   	return ret;
>   }
>   
> +
> +static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
> +			phys_addr_t paddr, size_t size, int iommu_prot, gfp_t gfp)
> +{
> +	return arm_lpae_map_pages(ops, iova, paddr, size, 1, iommu_prot, gfp,
> +				  NULL);
> +}
> +
>   static void __arm_lpae_free_pgtable(struct arm_lpae_io_pgtable *data, int lvl,
>   				    arm_lpae_iopte *ptep)
>   {
> @@ -782,6 +803,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
>   
>   	data->iop.ops = (struct io_pgtable_ops) {
>   		.map		= arm_lpae_map,
> +		.map_pages	= arm_lpae_map_pages,
>   		.unmap		= arm_lpae_unmap,
>   		.unmap_pages	= arm_lpae_unmap_pages,
>   		.iova_to_phys	= arm_lpae_iova_to_phys,


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Re: [RFC PATCH v5 00/15] Optimizing iommu_[map/unmap] performance

[Lu Baolu]

Hi Isaac,

Any update for this series? The iommu core part looks good to me and I
also have some patches for Intel IOMMU implementation of [un]map_pages.
Just wonder when could iommu core have this optimization.

Best regards,
baolu

On 4/9/21 1:13 AM, Isaac J. Manjarres wrote:
> When unmapping a buffer from an IOMMU domain, the IOMMU framework unmaps
> the buffer at a granule of the largest page size that is supported by
> the IOMMU hardware and fits within the buffer. For every block that
> is unmapped, the IOMMU framework will call into the IOMMU driver, and
> then the io-pgtable framework to walk the page tables to find the entry
> that corresponds to the IOVA, and then unmaps the entry.
> 
> This can be suboptimal in scenarios where a buffer or a piece of a
> buffer can be split into several contiguous page blocks of the same size.
> For example, consider an IOMMU that supports 4 KB page blocks, 2 MB page
> blocks, and 1 GB page blocks, and a buffer that is 4 MB in size is being
> unmapped at IOVA 0. The current call-flow will result in 4 indirect calls,
> and 2 page table walks, to unmap 2 entries that are next to each other in
> the page-tables, when both entries could have been unmapped in one shot
> by clearing both page table entries in the same call.
> 
> The same optimization is applicable to mapping buffers as well, so
> these patches implement a set of callbacks called unmap_pages and
> map_pages to the io-pgtable code and IOMMU drivers which unmaps or maps
> an IOVA range that consists of a number of pages of the same
> page size that is supported by the IOMMU hardware, and allows for
> manipulating multiple page table entries in the same set of indirect
> calls. The reason for introducing these callbacks is to give other IOMMU
> drivers/io-pgtable formats time to change to using the new callbacks, so
> that the transition to using this approach can be done piecemeal.
> 
> Changes since V4:
> 
> * Fixed type for addr_merge from phys_addr_t to unsigned long so
>    that GENMASK() can be used.
> * Hooked up arm_v7s_[unmap/map]_pages to the io-pgtable ops.
> * Introduced a macro for calculating the number of page table entries
>    for the ARM LPAE io-pgtable format.
> 
> Changes since V3:
> 
> * Removed usage of ULL variants of bitops from Will's patches, as
>    they were not needed.
> * Instead of unmapping/mapping pgcount pages, unmap_pages() and
>    map_pages() will at most unmap and map pgcount pages, allowing
>    for part of the pages in pgcount to be mapped and unmapped. This
>    was done to simplify the handling in the io-pgtable layer.
> * Extended the existing PTE manipulation methods in io-pgtable-arm
>    to handle multiple entries, per Robin's suggestion, eliminating
>    the need to add functions to clear multiple PTEs.
> * Implemented a naive form of [map/unmap]_pages() for ARM v7s io-pgtable
>    format.
> * arm_[v7s/lpae]_[map/unmap] will call
>    arm_[v7s/lpae]_[map_pages/unmap_pages] with an argument of 1 page.
> * The arm_smmu_[map/unmap] functions have been removed, since they
>    have been replaced by arm_smmu_[map/unmap]_pages.
> 
> Changes since V2:
> 
> * Added a check in __iommu_map() to check for the existence
>    of either the map or map_pages callback as per Lu's suggestion.
> 
> Changes since V1:
> 
> * Implemented the map_pages() callbacks
> * Integrated Will's patches into this series which
>    address several concerns about how iommu_pgsize() partitioned a
>    buffer (I made a minor change to the patch which changes
>    iommu_pgsize() to use bitmaps by using the ULL variants of
>    the bitops)
> 
> Isaac J. Manjarres (12):
>    iommu/io-pgtable: Introduce unmap_pages() as a page table op
>    iommu: Add an unmap_pages() op for IOMMU drivers
>    iommu/io-pgtable: Introduce map_pages() as a page table op
>    iommu: Add a map_pages() op for IOMMU drivers
>    iommu: Add support for the map_pages() callback
>    iommu/io-pgtable-arm: Prepare PTE methods for handling multiple
>      entries
>    iommu/io-pgtable-arm: Implement arm_lpae_unmap_pages()
>    iommu/io-pgtable-arm: Implement arm_lpae_map_pages()
>    iommu/io-pgtable-arm-v7s: Implement arm_v7s_unmap_pages()
>    iommu/io-pgtable-arm-v7s: Implement arm_v7s_map_pages()
>    iommu/arm-smmu: Implement the unmap_pages() IOMMU driver callback
>    iommu/arm-smmu: Implement the map_pages() IOMMU driver callback
> 
> Will Deacon (3):
>    iommu: Use bitmap to calculate page size in iommu_pgsize()
>    iommu: Split 'addr_merge' argument to iommu_pgsize() into separate
>      parts
>    iommu: Hook up '->unmap_pages' driver callback
> 
>   drivers/iommu/arm/arm-smmu/arm-smmu.c |  18 +--
>   drivers/iommu/io-pgtable-arm-v7s.c    |  50 ++++++-
>   drivers/iommu/io-pgtable-arm.c        | 189 +++++++++++++++++---------
>   drivers/iommu/iommu.c                 | 130 +++++++++++++-----
>   include/linux/io-pgtable.h            |   8 ++
>   include/linux/iommu.h                 |   9 ++
>   6 files changed, 289 insertions(+), 115 deletions(-)
> 
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