Re: [PATCH v3 4/8] powerpc/pseries/svm: Add a powerpc version of cc_platform_has()

[Christophe Leroy]

On 9/8/21 10:58 PM, Tom Lendacky wrote:
> Introduce a powerpc version of the cc_platform_has() function. This will
> be used to replace the powerpc mem_encrypt_active() implementation, so
> the implementation will initially only support the CC_ATTR_MEM_ENCRYPT
> attribute.
>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
>   arch/powerpc/platforms/pseries/Kconfig       |  1 +
>   arch/powerpc/platforms/pseries/Makefile      |  2 ++
>   arch/powerpc/platforms/pseries/cc_platform.c | 26 ++++++++++++++++++++
>   3 files changed, 29 insertions(+)
>   create mode 100644 arch/powerpc/platforms/pseries/cc_platform.c
>
> diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
> index 5e037df2a3a1..2e57391e0778 100644
> --- a/arch/powerpc/platforms/pseries/Kconfig
> +++ b/arch/powerpc/platforms/pseries/Kconfig
> @@ -159,6 +159,7 @@ config PPC_SVM
>   	select SWIOTLB
>   	select ARCH_HAS_MEM_ENCRYPT
>   	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
> +	select ARCH_HAS_CC_PLATFORM
>   	help
>   	 There are certain POWER platforms which support secure guests using
>   	 the Protected Execution Facility, with the help of an Ultravisor
> diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
> index 4cda0ef87be0..41d8aee98da4 100644
> --- a/arch/powerpc/platforms/pseries/Makefile
> +++ b/arch/powerpc/platforms/pseries/Makefile
> @@ -31,3 +31,5 @@ obj-$(CONFIG_FA_DUMP)		+= rtas-fadump.o
>   
>   obj-$(CONFIG_SUSPEND)		+= suspend.o
>   obj-$(CONFIG_PPC_VAS)		+= vas.o
> +
> +obj-$(CONFIG_ARCH_HAS_CC_PLATFORM)	+= cc_platform.o
> diff --git a/arch/powerpc/platforms/pseries/cc_platform.c b/arch/powerpc/platforms/pseries/cc_platform.c
> new file mode 100644
> index 000000000000..e8021af83a19
> --- /dev/null
> +++ b/arch/powerpc/platforms/pseries/cc_platform.c
> @@ -0,0 +1,26 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Confidential Computing Platform Capability checks
> + *
> + * Copyright (C) 2021 Advanced Micro Devices, Inc.
> + *
> + * Author: Tom Lendacky <thomas.lendacky@xxxxxxx>
> + */
> +
> +#include <linux/export.h>
> +#include <linux/cc_platform.h>
> +
> +#include <asm/machdep.h>
> +#include <asm/svm.h>
> +
> +bool cc_platform_has(enum cc_attr attr)
> +{

Please keep this function inline as mem_encrypt_active() is


> +	switch (attr) {
> +	case CC_ATTR_MEM_ENCRYPT:
> +		return is_secure_guest();
> +
> +	default:
> +		return false;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(cc_platform_has);