Message-ID: <3bfbbaa1-69f8-0f33-a4dc-5a10758e603a@gmail.com>
Date:   Fri, 3 Feb 2023 13:23:02 +0800
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Subject: Re: [RFC PATCH V3 07/16] drivers: hv: Decrypt percpu hvcall input arg
 page in sev-snp enlightened guest
To:     "Michael Kelley (LINUX)" <mikelley@microsoft.com>,
        "luto@kernel.org" <luto@kernel.org>,
        "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>,
        "seanjc@google.com" <seanjc@google.com>,
        "pbonzini@redhat.com" <pbonzini@redhat.com>,
        "jgross@suse.com" <jgross@suse.com>,
        Tianyu Lan <Tianyu.Lan@microsoft.com>,
        "kirill@shutemov.name" <kirill@shutemov.name>,
        "jiangshan.ljs@antgroup.com" <jiangshan.ljs@antgroup.com>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "ashish.kalra@amd.com" <ashish.kalra@amd.com>,
        "srutherford@google.com" <srutherford@google.com>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
        "anshuman.khandual@arm.com" <anshuman.khandual@arm.com>,
        "pawan.kumar.gupta@linux.intel.com" 
        <pawan.kumar.gupta@linux.intel.com>,
        "adrian.hunter@intel.com" <adrian.hunter@intel.com>,
        "daniel.sneddon@linux.intel.com" <daniel.sneddon@linux.intel.com>,
        "alexander.shishkin@linux.intel.com" 
        <alexander.shishkin@linux.intel.com>,
        "sandipan.das@amd.com" <sandipan.das@amd.com>,
        "ray.huang@amd.com" <ray.huang@amd.com>,
        "brijesh.singh@amd.com" <brijesh.singh@amd.com>,
        "michael.roth@amd.com" <michael.roth@amd.com>,
        "thomas.lendacky@amd.com" <thomas.lendacky@amd.com>,
        "venu.busireddy@oracle.com" <venu.busireddy@oracle.com>,
        "sterritt@google.com" <sterritt@google.com>,
        "tony.luck@intel.com" <tony.luck@intel.com>,
        "samitolvanen@google.com" <samitolvanen@google.com>,
        "fenghua.yu@intel.com" <fenghua.yu@intel.com>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>
References: <20230122024607.788454-1-ltykernel@gmail.com>
 <20230122024607.788454-8-ltykernel@gmail.com>
 <BYAPR21MB16880F982D51474B0911D528D7D09@BYAPR21MB1688.namprd21.prod.outlook.com>
From:   Tianyu Lan <ltykernel@gmail.com>
In-Reply-To: <BYAPR21MB16880F982D51474B0911D528D7D09@BYAPR21MB1688.namprd21.prod.outlook.com>
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On 2/1/2023 2:02 AM, Michael Kelley (LINUX) wrote:
>> @@ -134,6 +136,17 @@ int hv_common_cpu_init(unsigned int cpu)
>>   	if (!(*inputarg))
>>   		return -ENOMEM;
>>
>> +	if (hv_isolation_type_en_snp()) {
>> +		ret = set_memory_decrypted((unsigned long)*inputarg, pgcount);
> You used "pgcount" here in response to a comment on v2 of the
> patch.  But the corresponding re-encryption in hv_common_cpu_die()
> uses a fixed value of "1".   The two cases should be consistent.  Either
> assert that hv_root_partition will never be true in an SNP VM, in which
> case hard coding "1" is OK.  Or properly calculate the number of pages
> in both cases so they are consistent.
> 

Agree. We should keep the logic in both hv_common_cpu_init() and 
hv_common_cpu_die(). Will fix it.