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

Wei Liu
2021-12-02T14:39:51Z

On Wed, Dec 01, 2021 at 11:02:53AM -0500, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
>
> 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@microsoft.com>
> ---
> 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.