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From: Leon Romanovsky <leon@kernel.org>
To: Christoph Hellwig <hch@lst.de>,
	Robin Murphy <robin.murphy@arm.com>,
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Cc: Leon Romanovsky <leonro@nvidia.com>,
	Jonathan Corbet <corbet@lwn.net>,
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	Keith Busch <kbusch@kernel.org>,
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Subject: [RFC 05/16] iommu/dma: Prepare map/unmap page functions to receive IOVA
Date: Tue,  5 Mar 2024 12:15:15 +0200
Message-ID: <13187a8682ab4f8708ca88cc4363f90e64e14ccc.1709631413.git.leon@kernel.org>
In-Reply-To: <a77609c9c9a09214e38b04133e44eee67fe50ab0.1709631413.git.leon@kernel.org>
References: <a77609c9c9a09214e38b04133e44eee67fe50ab0.1709631413.git.leon@kernel.org>
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From: Leon Romanovsky <leonro@nvidia.com>

Extend the existing map_page/unmap_page function implementations to get
preallocated IOVA. In such case, the IOVA allocation needs to be
skipped, but rest of the code stays the same.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/iommu/dma-iommu.c | 68 ++++++++++++++++++++++++++-------------
 1 file changed, 45 insertions(+), 23 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index e55726783501..dbdd373a609a 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -824,7 +824,7 @@ static void __iommu_dma_free_iova(struct iommu_dma_cookie *cookie,
 }
 
 static void __iommu_dma_unmap(struct device *dev, dma_addr_t dma_addr,
-		size_t size)
+			      size_t size, bool free_iova)
 {
 	struct iommu_domain *domain = iommu_get_dma_domain(dev);
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
@@ -843,17 +843,19 @@ static void __iommu_dma_unmap(struct device *dev, dma_addr_t dma_addr,
 
 	if (!iotlb_gather.queued)
 		iommu_iotlb_sync(domain, &iotlb_gather);
-	__iommu_dma_free_iova(cookie, dma_addr, size, &iotlb_gather);
+	if (free_iova)
+		__iommu_dma_free_iova(cookie, dma_addr, size, &iotlb_gather);
 }
 
 static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
-		size_t size, int prot, u64 dma_mask)
+				  dma_addr_t iova, size_t size, int prot,
+				  u64 dma_mask)
 {
 	struct iommu_domain *domain = iommu_get_dma_domain(dev);
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
 	struct iova_domain *iovad = &cookie->iovad;
 	size_t iova_off = iova_offset(iovad, phys);
-	dma_addr_t iova;
+	bool no_iova = !iova;
 
 	if (static_branch_unlikely(&iommu_deferred_attach_enabled) &&
 	    iommu_deferred_attach(dev, domain))
@@ -861,12 +863,14 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
 
 	size = iova_align(iovad, size + iova_off);
 
-	iova = __iommu_dma_alloc_iova(domain, size, dma_mask, dev);
+	if (no_iova)
+		iova = __iommu_dma_alloc_iova(domain, size, dma_mask, dev);
 	if (!iova)
 		return DMA_MAPPING_ERROR;
 
 	if (iommu_map(domain, iova, phys - iova_off, size, prot, GFP_ATOMIC)) {
-		__iommu_dma_free_iova(cookie, iova, size, NULL);
+		if (no_iova)
+			__iommu_dma_free_iova(cookie, iova, size, NULL);
 		return DMA_MAPPING_ERROR;
 	}
 	return iova + iova_off;
@@ -1031,7 +1035,7 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
 	return vaddr;
 
 out_unmap:
-	__iommu_dma_unmap(dev, *dma_handle, size);
+	__iommu_dma_unmap(dev, *dma_handle, size, true);
 	__iommu_dma_free_pages(pages, PAGE_ALIGN(size) >> PAGE_SHIFT);
 	return NULL;
 }
@@ -1060,7 +1064,7 @@ static void iommu_dma_free_noncontiguous(struct device *dev, size_t size,
 {
 	struct dma_sgt_handle *sh = sgt_handle(sgt);
 
-	__iommu_dma_unmap(dev, sgt->sgl->dma_address, size);
+	__iommu_dma_unmap(dev, sgt->sgl->dma_address, size, true);
 	__iommu_dma_free_pages(sh->pages, PAGE_ALIGN(size) >> PAGE_SHIFT);
 	sg_free_table(&sh->sgt);
 	kfree(sh);
@@ -1131,9 +1135,11 @@ static void iommu_dma_sync_sg_for_device(struct device *dev,
 			arch_sync_dma_for_device(sg_phys(sg), sg->length, dir);
 }
 
-static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
-		unsigned long offset, size_t size, enum dma_data_direction dir,
-		unsigned long attrs)
+static dma_addr_t __iommu_dma_map_pages(struct device *dev, struct page *page,
+					unsigned long offset, dma_addr_t iova,
+					size_t size,
+					enum dma_data_direction dir,
+					unsigned long attrs)
 {
 	phys_addr_t phys = page_to_phys(page) + offset;
 	bool coherent = dev_is_dma_coherent(dev);
@@ -1141,7 +1147,7 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
 	struct iommu_domain *domain = iommu_get_dma_domain(dev);
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
 	struct iova_domain *iovad = &cookie->iovad;
-	dma_addr_t iova, dma_mask = dma_get_mask(dev);
+	dma_addr_t addr, dma_mask = dma_get_mask(dev);
 
 	/*
 	 * If both the physical buffer start address and size are
@@ -1182,14 +1188,23 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
 	if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 		arch_sync_dma_for_device(phys, size, dir);
 
-	iova = __iommu_dma_map(dev, phys, size, prot, dma_mask);
-	if (iova == DMA_MAPPING_ERROR && is_swiotlb_buffer(dev, phys))
+	addr = __iommu_dma_map(dev, phys, iova, size, prot, dma_mask);
+	if (addr == DMA_MAPPING_ERROR && is_swiotlb_buffer(dev, phys))
 		swiotlb_tbl_unmap_single(dev, phys, size, dir, attrs);
-	return iova;
+	return addr;
 }
 
-static void iommu_dma_unmap_page(struct device *dev, dma_addr_t dma_handle,
-		size_t size, enum dma_data_direction dir, unsigned long attrs)
+static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
+				     unsigned long offset, size_t size,
+				     enum dma_data_direction dir,
+				     unsigned long attrs)
+{
+	return __iommu_dma_map_pages(dev, page, offset, 0, size, dir, attrs);
+}
+
+static void __iommu_dma_unmap_pages(struct device *dev, dma_addr_t dma_handle,
+				    size_t size, enum dma_data_direction dir,
+				    unsigned long attrs, bool free_iova)
 {
 	struct iommu_domain *domain = iommu_get_dma_domain(dev);
 	phys_addr_t phys;
@@ -1201,12 +1216,19 @@ static void iommu_dma_unmap_page(struct device *dev, dma_addr_t dma_handle,
 	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) && !dev_is_dma_coherent(dev))
 		arch_sync_dma_for_cpu(phys, size, dir);
 
-	__iommu_dma_unmap(dev, dma_handle, size);
+	__iommu_dma_unmap(dev, dma_handle, size, free_iova);
 
 	if (unlikely(is_swiotlb_buffer(dev, phys)))
 		swiotlb_tbl_unmap_single(dev, phys, size, dir, attrs);
 }
 
+static void iommu_dma_unmap_page(struct device *dev, dma_addr_t dma_handle,
+				 size_t size, enum dma_data_direction dir,
+				 unsigned long attrs)
+{
+	__iommu_dma_unmap_pages(dev, dma_handle, size, dir, attrs, true);
+}
+
 /*
  * Prepare a successfully-mapped scatterlist to give back to the caller.
  *
@@ -1509,13 +1531,13 @@ static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 	}
 
 	if (end)
-		__iommu_dma_unmap(dev, start, end - start);
+		__iommu_dma_unmap(dev, start, end - start, true);
 }
 
 static dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
 		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
-	return __iommu_dma_map(dev, phys, size,
+	return __iommu_dma_map(dev, phys, 0, size,
 			dma_info_to_prot(dir, false, attrs) | IOMMU_MMIO,
 			dma_get_mask(dev));
 }
@@ -1523,7 +1545,7 @@ static dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
 static void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
 		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
-	__iommu_dma_unmap(dev, handle, size);
+	__iommu_dma_unmap(dev, handle, size, true);
 }
 
 static void __iommu_dma_free(struct device *dev, size_t size, void *cpu_addr)
@@ -1560,7 +1582,7 @@ static void __iommu_dma_free(struct device *dev, size_t size, void *cpu_addr)
 static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,
 		dma_addr_t handle, unsigned long attrs)
 {
-	__iommu_dma_unmap(dev, handle, size);
+	__iommu_dma_unmap(dev, handle, size, true);
 	__iommu_dma_free(dev, size, cpu_addr);
 }
 
@@ -1626,7 +1648,7 @@ static void *iommu_dma_alloc(struct device *dev, size_t size,
 	if (!cpu_addr)
 		return NULL;
 
-	*handle = __iommu_dma_map(dev, page_to_phys(page), size, ioprot,
+	*handle = __iommu_dma_map(dev, page_to_phys(page), 0, size, ioprot,
 			dev->coherent_dma_mask);
 	if (*handle == DMA_MAPPING_ERROR) {
 		__iommu_dma_free(dev, size, cpu_addr);
-- 
2.44.0