From: Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuwamy@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>, Borislav Petkov <bp@alien8.de>
Cc: Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
David Hildenbrand <david@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Juergen Gross <jgross@suse.com>, Deep Shah <sdeep@vmware.com>,
VMware Inc <pv-drivers@vmware.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Peter H Anvin <hpa@zytor.com>,
Dave Hansen <dave.hansen@intel.com>,
Tony Luck <tony.luck@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Andi Kleen <ak@linux.intel.com>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>,
Sean Christopherson <seanjc@google.com>,
Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v10 03/11] x86/cpufeatures: Add TDX Guest CPU feature
Date: Thu, 14 Oct 2021 10:28:10 -0700 [thread overview]
Message-ID: <3f32856b-22b6-f6a4-b125-4921f6106e6f@linux.intel.com> (raw)
In-Reply-To: <87zgrc7clg.ffs@tglx>
On 10/13/21 4:02 PM, Thomas Gleixner wrote:
> On Wed, Oct 13 2021 at 15:28, Sathyanarayanan Kuppuswamy wrote:
>> On 10/13/21 2:37 PM, Borislav Petkov wrote:
>>> On Wed, Oct 13, 2021 at 11:25:35PM +0200, Thomas Gleixner wrote:
>>>> So this ends up in doing:
>>>>
>>>> use();
>>>> init();
>>>>
>>>> Can you spot what's wrong with that?
>>>>
>>>> That's a clear violation of common sense and is simply not going to
>>>> happen. Why? If you think about deep defensive programming then use()
>>>> will look like this:
>>>>
>>>> use()
>>>> {
>>>> assert(initialized);
>>>> }
>>>>
>>>> which is not something made up. It's a fundamental principle of
>>>> programming and some languages enforce that for very good reasons.
>>>>
>>>> Just because it can be done in C is no justification.
>>> Oh, I heartily agree.
>>>
>>>> What's wrong with:
>>>>
>>>> x86_64_start_kernel()
>>>>
>>>> tdx_early_init();
>>>>
>>>> copy_bootdata();
>>>>
>>>> tdx_late_init();
>>>>
>>>> Absolutely nothing. It's clear, simple and well defined.
>>> I like simple more than anyone, so sure, I'd prefer that a lot more.
>>>
>>> And so the options parsing would need to happen early using, say,
>>> cmdline_find_option() or so, like sme_enable() does.
>> Since in tdx_early_init() all we are going to do is to initialize
>> "tdx_guest_detected" using cpuid call, shall we name it
>> tdx_guest_cpuid_init()? (similar to sme_enable call in AMD)
> How is that similar?
>
> Just chose a name which makes sense in the overall scheme. I surely care
> about naming convetions, but what I care more about is correctness.
>
> Whether it ends up being named
>
> tdx_enable() - to match the SME muck
>
> or
>
> tdx_detect()
>
> or whatever makes sense does not really matter. As long as it makes
> sense. That's bikeshed painting realm.
>
> Coming back to your suggestion 'tdx_guest_cpuid_init()'. Just sit back
> and think about what that name says:
>
> tdx_guest_cpuid_init()
>
> For the uniformed reader this says:
>
> If tdx guest then initialize CPUID
>
> which is obviously not what you want to express, right?
>
> So, naming matters but you are free to chose something which makes
> sense.
Makes sense. I agree tdx_guest_cpuid_init() name is bit confusing.
I will use tdx_detect as you have mentioned.
>
> Thanks,
>
> tglx
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
next prev parent reply other threads:[~2021-10-14 17:47 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-09 5:37 [PATCH v10 00/11] Add TDX Guest Support (Initial support) Kuppuswamy Sathyanarayanan
2021-10-09 5:37 ` [PATCH v10 01/11] x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT Kuppuswamy Sathyanarayanan
2021-10-15 16:59 ` David Hildenbrand
2021-10-09 5:37 ` [PATCH v10 02/11] x86/tdx: Introduce INTEL_TDX_GUEST config option Kuppuswamy Sathyanarayanan
2021-10-11 18:19 ` Josh Poimboeuf
2021-10-11 18:38 ` Andi Kleen
2021-10-11 18:47 ` Kuppuswamy, Sathyanarayanan
2021-10-09 5:37 ` [PATCH v10 03/11] x86/cpufeatures: Add TDX Guest CPU feature Kuppuswamy Sathyanarayanan
2021-10-13 8:18 ` Borislav Petkov
2021-10-13 13:32 ` Sathyanarayanan Kuppuswamy
2021-10-13 19:42 ` Josh Poimboeuf
2021-10-13 23:19 ` Thomas Gleixner
2021-10-14 0:25 ` Josh Poimboeuf
2021-10-14 7:57 ` Borislav Petkov
[not found] ` <1a6220a5-3abd-dea1-4b2f-2acade311236@linux.intel.com>
2021-10-18 21:59 ` Borislav Petkov
2021-10-18 22:04 ` Sathyanarayanan Kuppuswamy
2021-10-13 20:44 ` Thomas Gleixner
2021-10-13 21:05 ` Sathyanarayanan Kuppuswamy
2021-10-13 21:35 ` Thomas Gleixner
2021-10-13 21:07 ` Borislav Petkov
2021-10-13 21:25 ` Thomas Gleixner
2021-10-13 21:37 ` Borislav Petkov
2021-10-13 22:28 ` Sathyanarayanan Kuppuswamy
2021-10-13 23:02 ` Thomas Gleixner
2021-10-14 17:28 ` Sathyanarayanan Kuppuswamy [this message]
2021-10-09 5:37 ` [PATCH v10 04/11] x86/tdx: Add TDX support to intel_cc_platform_has() Kuppuswamy Sathyanarayanan
2021-10-13 15:57 ` Borislav Petkov
2021-10-14 7:12 ` Thomas Gleixner
2021-10-14 17:31 ` Sathyanarayanan Kuppuswamy
2021-10-09 5:37 ` [PATCH v10 05/11] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions Kuppuswamy Sathyanarayanan
2021-10-14 7:28 ` Thomas Gleixner
2021-10-15 0:19 ` Sathyanarayanan Kuppuswamy
2021-10-09 5:37 ` [PATCH v10 06/11] x86/traps: Add #VE support for TDX guest Kuppuswamy Sathyanarayanan
2021-10-14 8:30 ` Thomas Gleixner
2021-10-17 2:45 ` Sathyanarayanan Kuppuswamy
2021-10-17 3:18 ` Dave Hansen
2021-10-17 3:49 ` Sathyanarayanan Kuppuswamy
2021-10-09 5:37 ` [PATCH v10 07/11] x86/tdx: Add HLT " Kuppuswamy Sathyanarayanan
2021-10-14 9:30 ` Thomas Gleixner
2021-10-15 1:33 ` Sathyanarayanan Kuppuswamy
2021-10-15 15:03 ` Sean Christopherson
2021-10-09 5:37 ` [PATCH v10 08/11] x86/tdx: Wire up KVM hypercalls Kuppuswamy Sathyanarayanan
2021-10-14 10:21 ` Thomas Gleixner
2021-10-15 3:03 ` Sathyanarayanan Kuppuswamy
2021-10-09 5:37 ` [PATCH v10 09/11] x86/tdx: Add MSR support for TDX guest Kuppuswamy Sathyanarayanan
2021-10-09 5:37 ` [PATCH v10 10/11] x86/tdx: Don't write CSTAR MSR on Intel Kuppuswamy Sathyanarayanan
2021-10-14 10:47 ` Thomas Gleixner
2021-10-14 13:47 ` Andi Kleen
2021-10-14 14:27 ` Thomas Gleixner
2021-10-09 5:37 ` [PATCH v10 11/11] x86/tdx: Handle CPUID via #VE Kuppuswamy Sathyanarayanan
2021-10-14 12:01 ` Thomas Gleixner
2021-10-14 13:25 ` Dave Hansen
2021-10-09 7:38 ` [PATCH v10 00/11] Add TDX Guest Support (Initial support) Borislav Petkov
2021-10-09 20:56 ` Kuppuswamy, Sathyanarayanan
2021-10-11 13:03 ` Borislav Petkov
2021-10-11 16:33 ` Dave Hansen
2021-10-11 16:48 ` Dave Hansen
2021-10-11 17:04 ` Borislav Petkov
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