Re: [PATCH 01/10] dma-direct: factor out dma_set_{de,en}crypted helpers

[Robin Murphy <robin.murphy@arm.com>]

On 2021-10-21 10:06, Christoph Hellwig wrote:
> Factor out helpers the make dealing with memory encryption a little less
> cumbersome.

Reviewed-by: Robin Murphy <robin.murphy@arm.com>

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   kernel/dma/direct.c | 56 ++++++++++++++++++++-------------------------
>   1 file changed, 25 insertions(+), 31 deletions(-)
> 
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 4c6c5e0635e34..d4d54af31a341 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -75,6 +75,20 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
>   		min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
>   }
>   
> +static int dma_set_decrypted(struct device *dev, void *vaddr, size_t size)
> +{
> +	if (!force_dma_unencrypted(dev))
> +		return 0;
> +	return set_memory_decrypted((unsigned long)vaddr, 1 << get_order(size));
> +}
> +
> +static int dma_set_encrypted(struct device *dev, void *vaddr, size_t size)
> +{
> +	if (!force_dma_unencrypted(dev))
> +		return 0;
> +	return set_memory_encrypted((unsigned long)vaddr, 1 << get_order(size));
> +}
> +
>   static void __dma_direct_free_pages(struct device *dev, struct page *page,
>   				    size_t size)
>   {
> @@ -154,7 +168,6 @@ void *dma_direct_alloc(struct device *dev, size_t size,
>   {
>   	struct page *page;
>   	void *ret;
> -	int err;
>   
>   	size = PAGE_ALIGN(size);
>   	if (attrs & DMA_ATTR_NO_WARN)
> @@ -216,12 +229,8 @@ void *dma_direct_alloc(struct device *dev, size_t size,
>   				__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;
> -		}
> +		if (dma_set_decrypted(dev, ret, size))
> +			goto out_free_pages;
>   		memset(ret, 0, size);
>   		goto done;
>   	}
> @@ -238,13 +247,8 @@ void *dma_direct_alloc(struct device *dev, size_t size,
>   	}
>   
>   	ret = page_address(page);
> -	if (force_dma_unencrypted(dev)) {
> -		err = set_memory_decrypted((unsigned long)ret,
> -					   1 << get_order(size));
> -		if (err)
> -			goto out_free_pages;
> -	}
> -
> +	if (dma_set_decrypted(dev, ret, size))
> +		goto out_free_pages;
>   	memset(ret, 0, size);
>   
>   	if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
> @@ -259,13 +263,9 @@ void *dma_direct_alloc(struct device *dev, size_t size,
>   	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;
> -	}
> +	/* If memory cannot be re-encrypted, it must be leaked */
> +	if (dma_set_encrypted(dev, page_address(page), size))
> +		return NULL;
>   out_free_pages:
>   	__dma_direct_free_pages(dev, page, size);
>   	return NULL;
> @@ -304,8 +304,7 @@ void dma_direct_free(struct device *dev, size_t size,
>   	    dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size)))
>   		return;
>   
> -	if (force_dma_unencrypted(dev))
> -		set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
> +	dma_set_encrypted(dev, cpu_addr, 1 << page_order);
>   
>   	if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr))
>   		vunmap(cpu_addr);
> @@ -341,11 +340,8 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
>   	}
>   
>   	ret = page_address(page);
> -	if (force_dma_unencrypted(dev)) {
> -		if (set_memory_decrypted((unsigned long)ret,
> -				1 << get_order(size)))
> -			goto out_free_pages;
> -	}
> +	if (dma_set_decrypted(dev, ret, size))
> +		goto out_free_pages;
>   	memset(ret, 0, size);
>   	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
>   	return page;
> @@ -366,9 +362,7 @@ void dma_direct_free_pages(struct device *dev, size_t size,
>   	    dma_free_from_pool(dev, vaddr, size))
>   		return;
>   
> -	if (force_dma_unencrypted(dev))
> -		set_memory_encrypted((unsigned long)vaddr, 1 << page_order);
> -
> +	dma_set_encrypted(dev, vaddr, 1 << page_order);
>   	__dma_direct_free_pages(dev, page, size);
>   }
>   
> 
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