linux-kernel - Re: [PATCH v3 03/26] x86/virt/tdx: Move low level SEAMCALL helpers out of <asm/tdx.h>

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Message-ID: <aXoEQP0jyXgR6ohs@intel.com>
Date: Wed, 28 Jan 2026 20:42:40 +0800
From: Chao Gao <chao.gao@...el.com>
To: Binbin Wu <binbin.wu@...ux.intel.com>
CC: <linux-coco@...ts.linux.dev>, <linux-kernel@...r.kernel.org>,
	<kvm@...r.kernel.org>, <x86@...nel.org>, <reinette.chatre@...el.com>,
	<ira.weiny@...el.com>, <kai.huang@...el.com>, <dan.j.williams@...el.com>,
	<yilun.xu@...ux.intel.com>, <sagis@...gle.com>, <vannapurve@...gle.com>,
	<paulmck@...nel.org>, <nik.borisov@...e.com>, <zhenzhong.duan@...el.com>,
	<seanjc@...gle.com>, <rick.p.edgecombe@...el.com>, <kas@...nel.org>,
	<dave.hansen@...ux.intel.com>, <vishal.l.verma@...el.com>, Thomas Gleixner
	<tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov
	<bp@...en8.de>, "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH v3 03/26] x86/virt/tdx: Move low level SEAMCALL helpers
 out of <asm/tdx.h>

On Wed, Jan 28, 2026 at 09:37:05AM +0800, Binbin Wu wrote:
>
>
>On 1/23/2026 10:55 PM, Chao Gao wrote:
>> From: Kai Huang <kai.huang@...el.com>
>> 
>> TDX host core code implements three seamcall*() helpers to make SEAMCALL
>> to the TDX module.  Currently, they are implemented in <asm/tdx.h> and
>> are exposed to other kernel code which includes <asm/tdx.h>.
>> 
>> However, other than the TDX host core, seamcall*() are not expected to
>> be used by other kernel code directly.  For instance, for all SEAMCALLs
>> that are used by KVM, the TDX host core exports a wrapper function for
>> each of them.
>> 
>> Move seamcall*() and related code out of <asm/tdx.h> and make them only
>> visible to TDX host core.
>> 
>> Since TDX host core tdx.c is already very heavy, don't put low level
>> seamcall*() code there but to a new dedicated "seamcall.h".  Also,
>> currently tdx.c has seamcall_prerr*() helpers which additionally print
>> error message when calling seamcall*() fails.  Move them to "seamcall.h"
>> as well.  In such way all low level SEAMCALL helpers are in a dedicated
>> place, which is much more readable.
>> 
>> Signed-off-by: Kai Huang <kai.huang@...el.com>
>> Signed-off-by: Chao Gao <chao.gao@...el.com>
>> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@...el.com>
>
>Reviewed-by: Binbin Wu <binbin.wu@...ux.intel.com>
>
>One question below.
>
>[...]
>
>> diff --git a/arch/x86/virt/vmx/tdx/seamcall.h b/arch/x86/virt/vmx/tdx/seamcall.h
>> new file mode 100644
>> index 000000000000..0912e03fabfe
>> --- /dev/null
>> +++ b/arch/x86/virt/vmx/tdx/seamcall.h
>> @@ -0,0 +1,99 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/* Copyright (C) 2025 Intel Corporation */
>
>Should this be updated to 2026?

Yes. And I may drop the copyright notice if it is not necessary.

According to [1][2], it seems to be optional or even discouraged.

[1]: https://lwn.net/Articles/912355/
[2]: https://www.linuxfoundation.org/blog/blog/copyright-notices-in-open-source-software-projects