1. Patchew
  2. linux
  3. [PATCH v4 0/6] Preparation to .map_page and .unmap_page removal
  4. View patch

[PATCH v4 5/6] xen: swiotlb: Switch to physical address mapping callbacks

Leon Romanovsky posted 6 patches 1 week, 6 days ago
[PATCH v4 5/6] xen: swiotlb: Switch to physical address mapping callbacks
Posted by Leon Romanovsky 1 week, 6 days ago 
From: Leon Romanovsky <leonro@nvidia.com>

Combine resource and page mappings routines to one function
and remove .map_resource/.unmap_resource callbacks completely.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/xen/swiotlb-xen.c | 63 ++++++++++++++++++---------------------
 1 file changed, 29 insertions(+), 34 deletions(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index dd7747a2de879..48936179c940b 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -200,17 +200,32 @@ xen_swiotlb_free_coherent(struct device *dev, size_t size, void *vaddr,
  * physical address to use is returned.
  *
  * Once the device is given the dma address, the device owns this memory until
- * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
+ * either xen_swiotlb_unmap_phys or xen_swiotlb_dma_sync_single is performed.
  */
-static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
-				unsigned long offset, size_t size,
-				enum dma_data_direction dir,
+static dma_addr_t xen_swiotlb_map_phys(struct device *dev, phys_addr_t phys,
+				size_t size, enum dma_data_direction dir,
 				unsigned long attrs)
 {
-	phys_addr_t map, phys = page_to_phys(page) + offset;
-	dma_addr_t dev_addr = xen_phys_to_dma(dev, phys);
+	dma_addr_t dev_addr;
+	phys_addr_t map;
 
 	BUG_ON(dir == DMA_NONE);
+
+	if (attrs & DMA_ATTR_MMIO) {
+		if (unlikely(!dma_capable(dev, phys, size, false))) {
+			dev_err_once(
+				dev,
+				"DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
+				&dma_addr, size, *dev->dma_mask,
+				dev->bus_dma_limit);
+			WARN_ON_ONCE(1);
+			return DMA_MAPPING_ERROR;
+		}
+		return phys;
+	}
+
+	dev_addr = xen_phys_to_dma(dev, phys);
+
 	/*
 	 * If the address happens to be in the device's DMA window,
 	 * we can safely return the device addr and not worry about bounce
@@ -257,13 +272,13 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
 
 /*
  * Unmap a single streaming mode DMA translation.  The dma_addr and size must
- * match what was provided for in a previous xen_swiotlb_map_page call.  All
+ * match what was provided for in a previous xen_swiotlb_map_phys call.  All
  * other usages are undefined.
  *
  * After this call, reads by the cpu to the buffer are guaranteed to see
  * whatever the device wrote there.
  */
-static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
+static void xen_swiotlb_unmap_phys(struct device *hwdev, dma_addr_t dev_addr,
 		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
 	phys_addr_t paddr = xen_dma_to_phys(hwdev, dev_addr);
@@ -325,7 +340,7 @@ xen_swiotlb_sync_single_for_device(struct device *dev, dma_addr_t dma_addr,
 
 /*
  * Unmap a set of streaming mode DMA translations.  Again, cpu read rules
- * concerning calls here are the same as for swiotlb_unmap_page() above.
+ * concerning calls here are the same as for swiotlb_unmap_phys() above.
  */
 static void
 xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
@@ -337,7 +352,7 @@ xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
 	BUG_ON(dir == DMA_NONE);
 
 	for_each_sg(sgl, sg, nelems, i)
-		xen_swiotlb_unmap_page(hwdev, sg->dma_address, sg_dma_len(sg),
+		xen_swiotlb_unmap_phys(hwdev, sg->dma_address, sg_dma_len(sg),
 				dir, attrs);
 
 }
@@ -352,8 +367,8 @@ xen_swiotlb_map_sg(struct device *dev, struct scatterlist *sgl, int nelems,
 	BUG_ON(dir == DMA_NONE);
 
 	for_each_sg(sgl, sg, nelems, i) {
-		sg->dma_address = xen_swiotlb_map_page(dev, sg_page(sg),
-				sg->offset, sg->length, dir, attrs);
+		sg->dma_address = xen_swiotlb_map_phys(dev, sg_phys(sg),
+				sg->length, dir, attrs);
 		if (sg->dma_address == DMA_MAPPING_ERROR)
 			goto out_unmap;
 		sg_dma_len(sg) = sg->length;
@@ -392,25 +407,6 @@ xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
 	}
 }
 
-static dma_addr_t xen_swiotlb_direct_map_resource(struct device *dev,
-						  phys_addr_t paddr,
-						  size_t size,
-						  enum dma_data_direction dir,
-						  unsigned long attrs)
-{
-	dma_addr_t dma_addr = paddr;
-
-	if (unlikely(!dma_capable(dev, dma_addr, size, false))) {
-		dev_err_once(dev,
-			     "DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
-			     &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
-		WARN_ON_ONCE(1);
-		return DMA_MAPPING_ERROR;
-	}
-
-	return dma_addr;
-}
-
 /*
  * Return whether the given device DMA address mask can be supported
  * properly.  For example, if your device can only drive the low 24-bits
@@ -437,13 +433,12 @@ const struct dma_map_ops xen_swiotlb_dma_ops = {
 	.sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
 	.map_sg = xen_swiotlb_map_sg,
 	.unmap_sg = xen_swiotlb_unmap_sg,
-	.map_page = xen_swiotlb_map_page,
-	.unmap_page = xen_swiotlb_unmap_page,
+	.map_phys = xen_swiotlb_map_phys,
+	.unmap_phys = xen_swiotlb_unmap_phys,
 	.dma_supported = xen_swiotlb_dma_supported,
 	.mmap = dma_common_mmap,
 	.get_sgtable = dma_common_get_sgtable,
 	.alloc_pages_op = dma_common_alloc_pages,
 	.free_pages = dma_common_free_pages,
 	.max_mapping_size = swiotlb_max_mapping_size,
-	.map_resource = xen_swiotlb_direct_map_resource,
 };
-- 
2.51.0
Re: [PATCH v4 5/6] xen: swiotlb: Switch to physical address mapping callbacks
Posted by Jason Gunthorpe 2 days, 15 hours ago 
On Thu, Sep 18, 2025 at 05:09:28PM +0300, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@nvidia.com>
> 
> Combine resource and page mappings routines to one function
> and remove .map_resource/.unmap_resource callbacks completely.
> 
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  drivers/xen/swiotlb-xen.c | 63 ++++++++++++++++++---------------------
>  1 file changed, 29 insertions(+), 34 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason
Re: [PATCH v4 5/6] xen: swiotlb: Switch to physical address mapping callbacks
Posted by Leon Romanovsky 1 week, 5 days ago 
On Thu, Sep 18, 2025 at 05:09:28PM +0300, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@nvidia.com>
> 
> Combine resource and page mappings routines to one function
> and remove .map_resource/.unmap_resource callbacks completely.
> 
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  drivers/xen/swiotlb-xen.c | 63 ++++++++++++++++++---------------------
>  1 file changed, 29 insertions(+), 34 deletions(-)

<...>

> +	if (attrs & DMA_ATTR_MMIO) {
> +		if (unlikely(!dma_capable(dev, phys, size, false))) {
> +			dev_err_once(
> +				dev,
> +				"DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
> +				&dma_addr, size, *dev->dma_mask,
> +				dev->bus_dma_limit);
> +			WARN_ON_ONCE(1);
> +			return DMA_MAPPING_ERROR;
> +		}
> +		return phys;
> +	}

This need to be fixed by the following change (dma_addr->phys):

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 48936179c940b..ccf25027bec19 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -215,8 +215,8 @@ static dma_addr_t xen_swiotlb_map_phys(struct device *dev, phys_addr_t phys,
                if (unlikely(!dma_capable(dev, phys, size, false))) {
                        dev_err_once(
                                dev,
-                               "DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
-                               &dma_addr, size, *dev->dma_mask,
+                               "DMA addr %pa+%zu overflow (mask %llx, bus limit %llx).\n",
+                               &phys, size, *dev->dma_mask,
                                dev->bus_dma_limit);
                        WARN_ON_ONCE(1);
                        return DMA_MAPPING_ERROR;

Thanks

Patchew 2.1-devel-b67e4c2

© 2016 - 2025 Red Hat, Inc.