Propagate force_dma_unencrypted() into DMA_ATTR_CC_SHARED in the
dma-direct allocation path and use the attribute to drive the related
decisions.

This updates dma_direct_alloc(), dma_direct_free(), and
dma_direct_alloc_pages() to fold the forced unencrypted case into attrs.

Tested-by: Jiri Pirko <redacted>
Tested-by: Michael Kelley <redacted>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
  kernel/dma/direct.c | 53 +++++++++++++++++++++++++++++++++++++--------
  1 file changed, 44 insertions(+), 9 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index a741c8a2ee66..90dc5057a0c0 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c

@@ -193,16 +193,31 @@ void *dma_direct_alloc(struct device *dev, size_t size,
  		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
  {
  	bool remap = false, set_uncached = false;
-	bool mark_mem_decrypt = true;
+	bool mark_mem_decrypt = false;
  	struct page *page;
  	void *ret;
  
+	/*
+	 * DMA_ATTR_CC_SHARED is not a caller-visible dma_alloc_*()
+	 * attribute. The direct allocator uses it internally after it has
+	 * decided that the backing pages must be shared/decrypted, so the
+	 * rest of the allocation path can consistently select DMA addresses,
+	 * choose compatible pools and restore encryption on free.

+	 */
+	if (attrs & DMA_ATTR_CC_SHARED)
+		return NULL;
+
+	if (force_dma_unencrypted(dev)) {
+		attrs |= DMA_ATTR_CC_SHARED;
+		mark_mem_decrypt = true;
+	}
+
  	size = PAGE_ALIGN(size);
  	if (attrs & DMA_ATTR_NO_WARN)
  		gfp |= __GFP_NOWARN;
  
-	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
-	    !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev))
+	if (((attrs & (DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_CC_SHARED)) ==
+	     DMA_ATTR_NO_KERNEL_MAPPING) && !is_swiotlb_for_alloc(dev))
  		return dma_direct_alloc_no_mapping(dev, size, dma_handle, gfp);
  
  	if (!dev_is_dma_coherent(dev)) {

@@ -236,7 +251,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
  	 * Remapping or decrypting memory may block, allocate the memory from
  	 * the atomic pools instead if we aren't allowed block.
  	 */
-	if ((remap || force_dma_unencrypted(dev)) &&
+	if ((remap || (attrs & DMA_ATTR_CC_SHARED)) &&
  	    dma_direct_use_pool(dev, gfp))
  		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
  

@@ -312,12 +327,24 @@ void dma_direct_free(struct device *dev, size_t size,
  		void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs)
  {
  	phys_addr_t phys;
-	bool mark_mem_encrypted = true;
+	bool mark_mem_encrypted = false;
  	struct io_tlb_pool *swiotlb_pool;
  	unsigned int page_order = get_order(size);
  
-	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
-	    !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev)) {
+	/* see dma_direct_alloc() for details */
+	WARN_ON(attrs & DMA_ATTR_CC_SHARED);
+
+	/*
+	 * if the device had requested for an unencrypted buffer,
+	 * convert it to encrypted on free
+	 */
+	if (force_dma_unencrypted(dev)) {
+		attrs |= DMA_ATTR_CC_SHARED;
+		mark_mem_encrypted = true;
+	}
+
+	if (((attrs & (DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_CC_SHARED)) ==
+	     DMA_ATTR_NO_KERNEL_MAPPING) && !is_swiotlb_for_alloc(dev)) {
  		/* cpu_addr is a struct page cookie, not a kernel address */
  		dma_free_contiguous(dev, cpu_addr, size);
  		return;

@@ -366,10 +393,14 @@ void dma_direct_free(struct device *dev, size_t size,
  struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
  		dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
  {
+	unsigned long attrs = 0;
  	struct page *page;
  	void *ret;
  
-	if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp))
+	if (force_dma_unencrypted(dev))
+		attrs |= DMA_ATTR_CC_SHARED;
+
+	if ((attrs & DMA_ATTR_CC_SHARED) && dma_direct_use_pool(dev, gfp))
  		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
  
  	if (is_swiotlb_for_alloc(dev)) {

@@ -403,7 +434,11 @@ void dma_direct_free_pages(struct device *dev, size_t size,
  	phys_addr_t phys;
  	void *vaddr = page_address(page);
  	struct io_tlb_pool *swiotlb_pool;
-	bool mark_mem_encrypted = true;
+	/*
+	 * if the device had requested for an unencrypted buffer,
+	 * convert it to encrypted on free
+	 */
+	bool mark_mem_encrypted = force_dma_unencrypted(dev);
  
  	/* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */
  	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&