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From: Xiaoyao Li <xiaoyao.li@intel.com>
To: Kuppuswamy Sathyanarayanan 
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andy Lutomirski <luto@kernel.org>
Cc: 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>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 03/11] x86/cpufeatures: Add TDX Guest CPU feature
Date: Thu, 15 Jul 2021 19:56:32 +0800	[thread overview]
Message-ID: <64bf7394-ff82-86f7-7a52-ed12508276ac@intel.com> (raw)
In-Reply-To: <20210618225755.662725-4-sathyanarayanan.kuppuswamy@linux.intel.com>

On 6/19/2021 6:57 AM, Kuppuswamy Sathyanarayanan wrote:
> Add CPU feature detection for Trusted Domain Extensions support. TDX
> feature adds capabilities to keep guest register state and memory
> isolated from hypervisor.
> 
> For TDX guest platforms, executing CPUID(eax=0x21, ecx=0) will return
> following values in EAX, EBX, ECX and EDX.
> 
> EAX:  Maximum sub-leaf number:  0
> EBX/EDX/ECX:  Vendor string:
> 
> EBX =  "Inte"
> EDX =  "lTDX"
> ECX =  "    "
> 
> So when above condition is true, set X86_FEATURE_TDX_GUEST feature cap
> bit.
> 

...

> +static inline bool cpuid_has_tdx_guest(void)
> +{
> +	u32 eax, sig[3];
> +
> +	if (cpuid_eax(0) < TDX_CPUID_LEAF_ID)
> +		return false;
> +
> +	cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[1], &sig[2]);

As change log describes, EBX + EDX + ECX is "IntelTDX    ", not EBX + 
ECX + EDX. So it should be

	cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2], &sig[1]);

Please also correct early_cpuid_has_tdx_guest()

> +
> +	return !memcmp("IntelTDX    ", sig, 12);
> +}
> +
> +void __init tdx_early_init(void)
> +{
> +	if (!cpuid_has_tdx_guest())
> +		return;
> +
> +	setup_force_cpu_cap(X86_FEATURE_TDX_GUEST);
> +
> +	pr_info("Guest initialized\n");
> +}
> 


  parent reply	other threads:[~2021-07-15 11:56 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-18 22:57 [PATCH v3 00/11] Add TDX Guest Support (Initial support) Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 01/11] x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 02/11] x86/tdx: Introduce INTEL_TDX_GUEST config option Kuppuswamy Sathyanarayanan
2021-06-19 11:59   ` Juergen Gross
2021-06-19 17:11     ` Kuppuswamy, Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 03/11] x86/cpufeatures: Add TDX Guest CPU feature Kuppuswamy Sathyanarayanan
2021-06-18 23:39   ` Borislav Petkov
2021-06-19  0:13     ` Kuppuswamy, Sathyanarayanan
2021-06-19  6:38       ` Borislav Petkov
2021-07-15 11:56   ` Xiaoyao Li [this message]
2021-07-19  5:10     ` Kuppuswamy, Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 04/11] x86: Introduce generic protected guest abstraction Kuppuswamy Sathyanarayanan
2021-06-24 15:01   ` Borislav Petkov
2021-06-24 17:58     ` Kuppuswamy, Sathyanarayanan
2021-06-28 17:52   ` Tom Lendacky
2021-06-28 18:59     ` Tom Lendacky
2021-06-28 19:14     ` Kuppuswamy, Sathyanarayanan
2021-06-29 19:47       ` Tom Lendacky
2021-06-18 22:57 ` [PATCH v3 05/11] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 06/11] x86/tdx: Get TD execution environment information via TDINFO Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 07/11] x86/traps: Add #VE support for TDX guest Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 08/11] x86/tdx: Add HLT " Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 09/11] x86/tdx: Wire up KVM hypercalls Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 10/11] x86/tdx: Add MSR support for TDX guest Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 11/11] x86/tdx: Handle CPUID via #VE Kuppuswamy Sathyanarayanan
2021-06-30 23:22 ` [PATCH v3 00/11] Add TDX Guest Support (Initial support) Sathyanarayanan Kuppuswamy Natarajan

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