Re: [PATCH v2 5/7] arm64: mm: Add confidential computing hook to ioremap_prot()

[Catalin Marinas <catalin.marinas@arm.com>]

On Fri, Aug 30, 2024 at 02:01:48PM +0100, Will Deacon wrote:
> @@ -16,7 +28,16 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
>  	if (WARN_ON(pfn_is_map_memory(__phys_to_pfn(phys_addr))))
>  		return NULL;
>  
> -	return generic_ioremap_prot(phys_addr, size, __pgprot(prot));
> +	/*
> +	 * If a hook is registered (e.g. for confidential computing
> +	 * purposes), call that now and barf if it fails.
> +	 */
> +	if (unlikely(ioremap_prot_hook) &&
> +	    WARN_ON(ioremap_prot_hook(phys_addr, size, &pgprot))) {
> +		return NULL;
> +	}
> +
> +	return generic_ioremap_prot(phys_addr, size, pgprot);
>  }
>  EXPORT_SYMBOL(ioremap_prot);

I mentioned on the CCA series, the patch is all good but we may need
something similar for io_remap_pfn_range() which uses
pgprot_decrypted() (I think it mostly matters for the pKVM case).

-- 
Catalin