Re: [PATCH V3 2/5] x86/hyper-v: Add hyperv Isolation VM check in the cc_platform_has()

[Wei Liu]

On Wed, Dec 01, 2021 at 11:02:53AM -0500, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
> 
> Hyper-V provides Isolation VM which has memory encrypt support. Add
> hyperv_cc_platform_has() and return true for check of GUEST_MEM_ENCRYPT
> attribute.
> 
> Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
> ---
>  arch/x86/kernel/cc_platform.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/arch/x86/kernel/cc_platform.c b/arch/x86/kernel/cc_platform.c
> index 03bb2f343ddb..f3bb0431f5c5 100644
> --- a/arch/x86/kernel/cc_platform.c
> +++ b/arch/x86/kernel/cc_platform.c
> @@ -11,6 +11,7 @@
>  #include <linux/cc_platform.h>
>  #include <linux/mem_encrypt.h>
>  
> +#include <asm/mshyperv.h>
>  #include <asm/processor.h>
>  
>  static bool __maybe_unused intel_cc_platform_has(enum cc_attr attr)
> @@ -58,9 +59,23 @@ static bool amd_cc_platform_has(enum cc_attr attr)
>  #endif
>  }
>  
> +static bool hyperv_cc_platform_has(enum cc_attr attr)
> +{
> +#ifdef CONFIG_HYPERV
> +	if (attr == CC_ATTR_GUEST_MEM_ENCRYPT)
> +		return true;
> +	else
> +		return false;

This can be simplified as

	return attr == CC_ATTR_GUEST_MEM_ENCRYPT;


Wei.