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From: Borislav Petkov <bp@alien8.de>
To: Thomas Gleixner <tglx@linutronix.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: Wed, 13 Oct 2021 23:37:44 +0200	[thread overview]
Message-ID: <YWdRqAqedkhVA2lD@zn.tnic> (raw)
In-Reply-To: <877deg8vn4.ffs@tglx>

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.

Hmmm.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2021-10-13 21:37 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 [this message]
2021-10-13 22:28           ` Sathyanarayanan Kuppuswamy
2021-10-13 23:02             ` Thomas Gleixner
2021-10-14 17:28               ` Sathyanarayanan Kuppuswamy
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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