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Message-ID: <f3d994c1-852e-dee7-e1ed-7b9ef307cb4f@gmail.com>
Date:   Thu, 8 Jun 2023 21:17:24 +0800
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Subject: Re: [PATCH 1/9] x86/hyperv: Add sev-snp enlightened guest static key
To:     "Michael Kelley (LINUX)" <mikelley@microsoft.com>,
        KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        "wei.liu@kernel.org" <wei.liu@kernel.org>,
        Dexuan Cui <decui@microsoft.com>,
        "tglx@linutronix.de" <tglx@linutronix.de>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "bp@alien8.de" <bp@alien8.de>,
        "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
        "x86@kernel.org" <x86@kernel.org>, "hpa@zytor.com" <hpa@zytor.com>,
        "daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
        "arnd@arndb.de" <arnd@arndb.de>
Cc:     Tianyu Lan <Tianyu.Lan@microsoft.com>,
        "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "vkuznets@redhat.com" <vkuznets@redhat.com>
References: <20230601151624.1757616-1-ltykernel@gmail.com>
 <20230601151624.1757616-2-ltykernel@gmail.com>
 <BYAPR21MB168808E653CDCE3585EB8858D750A@BYAPR21MB1688.namprd21.prod.outlook.com>
From:   Tianyu Lan <ltykernel@gmail.com>
In-Reply-To: <BYAPR21MB168808E653CDCE3585EB8858D750A@BYAPR21MB1688.namprd21.prod.outlook.com>
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On 6/8/2023 8:56 PM, Michael Kelley (LINUX) wrote:
>> @ -473,7 +477,7 @@ static void __init ms_hyperv_init_platform(void)
>>
>>   #if IS_ENABLED(CONFIG_HYPERV)
>>   	if ((hv_get_isolation_type() == HV_ISOLATION_TYPE_VBS) ||
>> -	    (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP))
>> +	    ms_hyperv.paravisor_present)
> This test needs to be:
> 
>    	if ((hv_get_isolation_type() == HV_ISOLATION_TYPE_VBS) ||
> 	    ((hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) &&
> 	    ms_hyperv.paravisor_present)
> 
> We want to call hv_vtom_init() only when running with VBS, or
> with SEV-SNP*and*  we have a paravisor present.  Testing only for
> paravisor_present risks confusion with future TDX scenarios.

Yes, current paravisor is only available for VBS and SEV-SNP vTOM cases.
TDX may also have paravisor support. Will update.

Thanks.