Date:   Thu, 2 Dec 2021 14:39:46 +0000
From:   Wei Liu <wei.liu@kernel.org>
To:     Tianyu Lan <ltykernel@gmail.com>
Cc:     kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com,
        wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de,
        mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
        x86@kernel.org, hpa@zytor.com, jgross@suse.com,
        sstabellini@kernel.org, boris.ostrovsky@oracle.com,
        joro@8bytes.org, will@kernel.org, davem@davemloft.net,
        kuba@kernel.org, jejb@linux.ibm.com, martin.petersen@oracle.com,
        arnd@arndb.de, hch@infradead.org, m.szyprowski@samsung.com,
        robin.murphy@arm.com, Tianyu.Lan@microsoft.com,
        thomas.lendacky@amd.com, xen-devel@lists.xenproject.org,
        michael.h.kelley@microsoft.com, iommu@lists.linux-foundation.org,
        linux-arch@vger.kernel.org, linux-hyperv@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
        netdev@vger.kernel.org, vkuznets@redhat.com, brijesh.singh@amd.com,
        konrad.wilk@oracle.com, hch@lst.de, parri.andrea@gmail.com,
        dave.hansen@intel.com
Subject: Re: [PATCH V3 2/5] x86/hyper-v: Add hyperv Isolation VM check in the
 cc_platform_has()
Message-ID: <20211202143946.7o7ncwcjq3t6xcrq@liuwe-devbox-debian-v2>
References: <20211201160257.1003912-1-ltykernel@gmail.com>
 <20211201160257.1003912-3-ltykernel@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20211201160257.1003912-3-ltykernel@gmail.com>
Precedence: bulk

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.