Date:   Tue, 14 Dec 2021 15:33:03 +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, 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, thomas.lendacky@amd.com,
        Tianyu.Lan@microsoft.com, 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, joro@8bytes.org, parri.andrea@gmail.com,
        dave.hansen@intel.com
Subject: Re: [PATCH V7 2/5] x86/hyper-v: Add hyperv Isolation VM check in the
 cc_platform_has()
Message-ID: <20211214153303.qmhowu4lfpcp4gej@liuwe-devbox-debian-v2>
References: <20211213071407.314309-1-ltykernel@gmail.com>
 <20211213071407.314309-3-ltykernel@gmail.com>
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On Mon, Dec 13, 2021 at 02:14:03AM -0500, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> 
> Hyper-V provides Isolation VM for confidential computing support and
> guest memory is encrypted in it. Places checking cc_platform_has()
> with GUEST_MEM_ENCRYPT attr should return "True" in Isolation vm. e.g,
> swiotlb bounce buffer size needs to adjust according to memory size
> in the sev_setup_arch(). Add GUEST_MEM_ENCRYPT check for Hyper-V Isolation
> VM.
> 
> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>

x86 maintainers, any comment on this patch?

> ---
> Change since v6:
> 	* Change the order in the cc_platform_has() and check sev first.
> 
> Change since v3:
> 	* Change code style of checking GUEST_MEM attribute in the
> 	  hyperv_cc_platform_has().
> ---
>  arch/x86/kernel/cc_platform.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/x86/kernel/cc_platform.c b/arch/x86/kernel/cc_platform.c
> index 03bb2f343ddb..6cb3a675e686 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)
> @@ -58,12 +59,19 @@ static bool amd_cc_platform_has(enum cc_attr attr)
>  #endif
>  }
>  
> +static bool hyperv_cc_platform_has(enum cc_attr attr)
> +{
> +	return attr == CC_ATTR_GUEST_MEM_ENCRYPT;
> +}
>  
>  bool cc_platform_has(enum cc_attr attr)
>  {
>  	if (sme_me_mask)
>  		return amd_cc_platform_has(attr);
>  
> +	if (hv_is_isolation_supported())
> +		return hyperv_cc_platform_has(attr);
> +
>  	return false;
>  }
>  EXPORT_SYMBOL_GPL(cc_platform_has);
> -- 
> 2.25.1
>