82fef0ad811f "x86/mm: unencrypted non-blocking DMA allocations use coherent pools" was Re: next-0519 on thinkpad x60: sound related? window manager crash

[Alex Xu (Hello71)]

Excerpts from David Rientjes's message of June 7, 2020 8:57 pm:
> Thanks for trying it out, Alex.  Would you mind sending your .config and 
> command line?  I assume either mem_encrypt=on or 
> CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT is enabled.
> 
> Could you also give this a try?
> 
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -99,10 +99,11 @@ static inline bool dma_should_alloc_from_pool(struct device *dev, gfp_t gfp,
>  static inline bool dma_should_free_from_pool(struct device *dev,
>  					     unsigned long attrs)
>  {
> -	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL))
> +	if (!IS_ENABLED(CONFIG_DMA_COHERENT_POOL))
> +		return false;
> +	if (force_dma_unencrypted(dev))
>  		return true;
> -	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
> -	    !force_dma_unencrypted(dev))
> +	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)
>  		return false;
>  	if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP))
>  		return true;
> 

This patch doesn't work for me either. It has since occurred to me that 
while I do have CONFIG_AMD_MEM_ENCYRPT=y, I have 
CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=n, because it was broken with 
amdgpu (unfortunately a downgrade from radeon in this respect). Tried it 
again just now and it looks like it's now able to enable KMS, but all it 
displays is serious-looking errors.

Sorry for not mentioning that earlier. I'll send you my .config and 
command line off-list.

Thanks,
Alex.