Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <4875ea9c-593a-e669-889a-1e809a50a570@linux.intel.com>
Date:   Tue, 19 Apr 2022 07:19:41 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Firefox/91.0 Thunderbird/91.7.0
Subject: Re: [PATCH v3 4/4] platform/x86: intel_tdx_attest: Add TDX Guest
 attestation interface driver
Content-Language: en-US
To:     Dave Hansen <dave.hansen@intel.com>,
        Kai Huang <kai.huang@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        Hans de Goede <hdegoede@redhat.com>,
        Mark Gross <mgross@linux.intel.com>
Cc:     "H . Peter Anvin" <hpa@zytor.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Tony Luck <tony.luck@intel.com>,
        Andi Kleen <ak@linux.intel.com>, linux-kernel@vger.kernel.org,
        platform-driver-x86@vger.kernel.org
References: <20220415220109.282834-1-sathyanarayanan.kuppuswamy@linux.intel.com>
 <20220415220109.282834-5-sathyanarayanan.kuppuswamy@linux.intel.com>
 <bd83067542a3519ee4c91f9d50e9bd4fac27e4bb.camel@intel.com>
 <975b5050-2108-9ace-cc71-46f17db0a731@intel.com>
From:   Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@linux.intel.com>
In-Reply-To: <975b5050-2108-9ace-cc71-46f17db0a731@intel.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 4/19/22 7:13 AM, Dave Hansen wrote:
>> >From this perspective, I am not sure what's the value of having a dedicated
>> INTEL_TDX_ATTESTATION Kconfig.  The attestation support code should be turned on
>> unconditionally when CONFIG_INTEL_TDX_GUEST is on.  The code can also be just
>> under arch/x86/coco/tdx/ I guess?
> How much code are we talking about?  What's the difference in the size
> of the binaries with this compiled in?

Current driver size is ~300 lines. It adds ~500 bytes to the kernel
binary if it is built-in.

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer