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Subject: Re: [RFC v2-fix-v2 1/1] x86: Introduce generic protected guest
 abstractionn
To:     Tom Lendacky <thomas.lendacky@amd.com>,
        Borislav Petkov <bp@alien8.de>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Tony Luck <tony.luck@intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Kirill Shutemov <kirill.shutemov@linux.intel.com>,
        Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Raj Ashok <ashok.raj@intel.com>,
        Sean Christopherson <seanjc@google.com>,
        linux-kernel@vger.kernel.org
References: <20210527042356.3983284-2-sathyanarayanan.kuppuswamy@linux.intel.com>
 <20210601211417.2177598-1-sathyanarayanan.kuppuswamy@linux.intel.com>
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 <1c8938fb-c9e9-af51-5224-70fc869eedea@amd.com>
From:   "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@linux.intel.com>
Message-ID: <df3fdcfb-a0e4-b2ce-0123-ba3cdbc7e76f@linux.intel.com>
Date:   Fri, 4 Jun 2021 15:13:50 -0700
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On 6/4/21 3:01 PM, Tom Lendacky wrote:
>>   	 */
>> -	if (sme_active())
>> +	if (protected_guest_has(VM_HOST_MEM_ENCRYPT))
>>   		swiotlb = 1;
> I still feel this is confusing. SME is a host/bare-metal technology, so
> calling protected_guest_has() seems odd and using VM_HOST_MEM_ENCRYPT,
> where I assume VM is short for virtual machine, also seems odd.
> 
> How about just protected_os_has()? Then you could have
> - HOST_MEM_ENCRYPT  for host memory encryption
> - GUEST_MEM_ENCRYPT for guest memory encryption
> - MEM_ENCRYPT       for either host or guest memory encryption.
> 
> The first is analogous to sme_active(), the second to sev_active() and the
> third to mem_encrypt_active(). Just my opinion, though...
> 

I am not sure whether OS makes sense here. But I am fine with it if
it is maintainers choice.

Other option could be protected_boot_has()?

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer