dma-mapping fixes for 5.8:

- fix dma coherent mmap in nommu (me)
  - more AMD SEV fallout (David Rientjes, me)
  - fix alignment in dma_common_*_remap (Eric Auger)
 -----BEGIN PGP SIGNATURE-----
 
 iQI/BAABCgApFiEEgdbnc3r/njty3Iq9D55TZVIEUYMFAl72+VsLHGhjaEBsc3Qu
 ZGUACgkQD55TZVIEUYMVaw//VgQbKUfTsuCZt+ZZqIY5nd6YajexoC+X051yC7/8
 YtdGqAa2RuutoHwUhTcqzvrSsCqthNCeeZ3yBUS/SQwyoQy3szrEwNXnRboNdwgq
 xebuTOra3MIRSWJzFHL+PNQjkaGSoQroSJHEeVZOUdYchE+sNh/pZxQoPU8ImcOe
 iVB+6nDJga+CpbKVi6oaGs8EISHtYkt1yHOeAhTxlqPkmP1tvsOZFgvMQBPCq4Rz
 QlqcVilDb0fPl2pnLy1LTbgAC8yPs7phrf9KBVUqCptfTLAv1nkwI9WpX8zFmkDo
 KapepEr9bkAHcq+gNcUOSiKr3K1bMF41numZ5zi6PnEJ/bHsPEotzwf05GrKY0Ci
 vMNpWL5QIcaMECe8Q8jrelgoDK0614vp8k7U+1CXmgpyF3lf5+zXwJyYLSgcf2PI
 2ryJnnib3jYORe80VVHc76CpX5Z5Ez6IaaDP/3rNsexLW/Ip3mhwqUDEYNCvMN+P
 qYJ8GrmqGAbMrhifvxVRL0ur73kIKE2s4l7xznd7p0Nj6ToAdMYnmrKUZEhMTPD9
 UcpzK9omgT51qAsByEggT97eDYzQSqYfh0OxAUJwML/8AXa7nJVdFo9ipHCVal6x
 tEuWpAMBe9YRBDaPUgu3vf8VNagv7YCzJmLnPFS7KvYJ0siw5r6ZxdXfkE2cG9o2
 DyI=
 =qAJQ
 -----END PGP SIGNATURE-----

Merge tag 'dma-mapping-5.8-4' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping fixes from Christoph Hellwig:

 - fix dma coherent mmap in nommu (me)

 - more AMD SEV fallout (David Rientjes, me)

 - fix alignment in dma_common_*_remap (Eric Auger)

* tag 'dma-mapping-5.8-4' of git://git.infradead.org/users/hch/dma-mapping:
  dma-remap: align the size in dma_common_*_remap()
  dma-mapping: DMA_COHERENT_POOL should select GENERIC_ALLOCATOR
  dma-direct: add missing set_memory_decrypted() for coherent mapping
  dma-direct: check return value when encrypting or decrypting memory
  dma-direct: re-encrypt memory if dma_direct_alloc_pages() fails
  dma-direct: always align allocation size in dma_direct_alloc_pages()
  dma-direct: mark __dma_direct_alloc_pages static
  dma-direct: re-enable mmap for !CONFIG_MMU

include/linux/dma-direct.h

@@ -77,8 +77,6 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
 		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs);
 void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
 		dma_addr_t dma_addr, unsigned long attrs);
-struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
-		gfp_t gfp, unsigned long attrs);
 int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt,
 		void *cpu_addr, dma_addr_t dma_addr, size_t size,
 		unsigned long attrs);

kernel/dma/Kconfig

@@ -71,15 +71,16 @@ config SWIOTLB
 # in the pagetables
 #
 config DMA_NONCOHERENT_MMAP
+	default y if !MMU
 	bool
 
 config DMA_COHERENT_POOL
+	select GENERIC_ALLOCATOR
 	bool
 
 config DMA_REMAP
 	bool
 	depends on MMU
-	select GENERIC_ALLOCATOR
 	select DMA_NONCOHERENT_MMAP
 
 config DMA_DIRECT_REMAP

kernel/dma/direct.c

@@ -109,14 +109,15 @@ static inline bool dma_should_free_from_pool(struct device *dev,
 	return false;
 }
 
-struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
+static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
 		gfp_t gfp, unsigned long attrs)
 {
-	size_t alloc_size = PAGE_ALIGN(size);
 	int node = dev_to_node(dev);
 	struct page *page = NULL;
 	u64 phys_limit;
 
+	WARN_ON_ONCE(!PAGE_ALIGNED(size));
+
 	if (attrs & DMA_ATTR_NO_WARN)
 		gfp |= __GFP_NOWARN;
 
@@ -124,14 +125,14 @@ struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
 	gfp &= ~__GFP_ZERO;
 	gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
 					   &phys_limit);
-	page = dma_alloc_contiguous(dev, alloc_size, gfp);
+	page = dma_alloc_contiguous(dev, size, gfp);
 	if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
-		dma_free_contiguous(dev, page, alloc_size);
+		dma_free_contiguous(dev, page, size);
 		page = NULL;
 	}
 again:
 	if (!page)
-		page = alloc_pages_node(node, gfp, get_order(alloc_size));
+		page = alloc_pages_node(node, gfp, get_order(size));
 	if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
 		dma_free_contiguous(dev, page, size);
 		page = NULL;
@@ -157,9 +158,12 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
 {
 	struct page *page;
 	void *ret;
+	int err;
+
+	size = PAGE_ALIGN(size);
 
 	if (dma_should_alloc_from_pool(dev, gfp, attrs)) {
-		ret = dma_alloc_from_pool(dev, PAGE_ALIGN(size), &page, gfp);
+		ret = dma_alloc_from_pool(dev, size, &page, gfp);
 		if (!ret)
 			return NULL;
 		goto done;
@@ -183,14 +187,20 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
 	     dma_alloc_need_uncached(dev, attrs)) ||
 	    (IS_ENABLED(CONFIG_DMA_REMAP) && PageHighMem(page))) {
 		/* remove any dirty cache lines on the kernel alias */
-		arch_dma_prep_coherent(page, PAGE_ALIGN(size));
+		arch_dma_prep_coherent(page, size);
 
 		/* create a coherent mapping */
-		ret = dma_common_contiguous_remap(page, PAGE_ALIGN(size),
+		ret = dma_common_contiguous_remap(page, size,
 				dma_pgprot(dev, PAGE_KERNEL, attrs),
 				__builtin_return_address(0));
 		if (!ret)
 			goto out_free_pages;
+		if (force_dma_unencrypted(dev)) {
+			err = set_memory_decrypted((unsigned long)ret,
+						   1 << get_order(size));
+			if (err)
+				goto out_free_pages;
+		}
 		memset(ret, 0, size);
 		goto done;
 	}
@@ -207,8 +217,12 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
 	}
 
 	ret = page_address(page);
-	if (force_dma_unencrypted(dev))
-		set_memory_decrypted((unsigned long)ret, 1 << get_order(size));
+	if (force_dma_unencrypted(dev)) {
+		err = set_memory_decrypted((unsigned long)ret,
+					   1 << get_order(size));
+		if (err)
+			goto out_free_pages;
+	}
 
 	memset(ret, 0, size);
 
@@ -217,7 +231,7 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
 		arch_dma_prep_coherent(page, size);
 		ret = arch_dma_set_uncached(ret, size);
 		if (IS_ERR(ret))
-			goto out_free_pages;
+			goto out_encrypt_pages;
 	}
 done:
 	if (force_dma_unencrypted(dev))
@@ -225,6 +239,15 @@ done:
 	else
 		*dma_handle = phys_to_dma(dev, page_to_phys(page));
 	return ret;
+
+out_encrypt_pages:
+	if (force_dma_unencrypted(dev)) {
+		err = set_memory_encrypted((unsigned long)page_address(page),
+					   1 << get_order(size));
+		/* If memory cannot be re-encrypted, it must be leaked */
+		if (err)
+			return NULL;
+	}
 out_free_pages:
 	dma_free_contiguous(dev, page, size);
 	return NULL;
@@ -459,7 +482,6 @@ int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt,
 	return ret;
 }
 
-#ifdef CONFIG_MMU
 bool dma_direct_can_mmap(struct device *dev)
 {
 	return dev_is_dma_coherent(dev) ||
@@ -485,19 +507,6 @@ int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma,
 	return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff,
 			user_count << PAGE_SHIFT, vma->vm_page_prot);
 }
-#else /* CONFIG_MMU */
-bool dma_direct_can_mmap(struct device *dev)
-{
-	return false;
-}
-
-int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma,
-		void *cpu_addr, dma_addr_t dma_addr, size_t size,
-		unsigned long attrs)
-{
-	return -ENXIO;
-}
-#endif /* CONFIG_MMU */
 
 int dma_direct_supported(struct device *dev, u64 mask)
 {

kernel/dma/remap.c

@@ -24,7 +24,8 @@ void *dma_common_pages_remap(struct page **pages, size_t size,
 {
 	void *vaddr;
 
-	vaddr = vmap(pages, size >> PAGE_SHIFT, VM_DMA_COHERENT, prot);
+	vaddr = vmap(pages, PAGE_ALIGN(size) >> PAGE_SHIFT,
+		     VM_DMA_COHERENT, prot);
 	if (vaddr)
 		find_vm_area(vaddr)->pages = pages;
 	return vaddr;
@@ -37,7 +38,7 @@ void *dma_common_pages_remap(struct page **pages, size_t size,
 void *dma_common_contiguous_remap(struct page *page, size_t size,
 			pgprot_t prot, const void *caller)
 {
-	int count = size >> PAGE_SHIFT;
+	int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	struct page **pages;
 	void *vaddr;
 	int i;