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Date:   Tue, 21 May 2019 07:15:07 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        Alexey Kardashevskiy <aik@ozlabs.ru>,
        Anshuman Khandual <anshuman.linux@gmail.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Christoph Hellwig <hch@lst.de>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Mike Anderson <andmike@linux.ibm.com>,
        Paul Mackerras <paulus@samba.org>,
        Ram Pai <linuxram@us.ibm.com>,
        Claudio Carvalho <cclaudio@linux.ibm.com>,
        Anshuman Khandual <khandual@linux.vnet.ibm.com>
Subject: Re: [PATCH 11/12] powerpc/pseries/svm: Force SWIOTLB for secure
 guests
Message-ID: <20190521051507.GD29120@lst.de>
References: <20190521044912.1375-1-bauerman@linux.ibm.com> <20190521044912.1375-12-bauerman@linux.ibm.com>
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> diff --git a/arch/powerpc/include/asm/mem_encrypt.h b/arch/powerpc/include/asm/mem_encrypt.h
> new file mode 100644
> index 000000000000..45d5e4d0e6e0
> --- /dev/null
> +++ b/arch/powerpc/include/asm/mem_encrypt.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * SVM helper functions
> + *
> + * Copyright 2019 IBM Corporation
> + */
> +
> +#ifndef _ASM_POWERPC_MEM_ENCRYPT_H
> +#define _ASM_POWERPC_MEM_ENCRYPT_H
> +
> +#define sme_me_mask	0ULL
> +
> +static inline bool sme_active(void) { return false; }
> +static inline bool sev_active(void) { return false; }
> +
> +int set_memory_encrypted(unsigned long addr, int numpages);
> +int set_memory_decrypted(unsigned long addr, int numpages);
> +
> +#endif /* _ASM_POWERPC_MEM_ENCRYPT_H */

S/390 seems to be adding a stub header just like this.  Can you please
clean up the Kconfig and generic headers bits for memory encryption so
that we don't need all this boilerplate code?

>  config PPC_SVM
>  	bool "Secure virtual machine (SVM) support for POWER"
>  	depends on PPC_PSERIES
> +	select SWIOTLB
> +	select ARCH_HAS_MEM_ENCRYPT
>  	default n

n is the default default, no need to explictly specify it.