From: Dave Hansen <dave.hansen@intel.com>
To: Sathyanarayanan Kuppuswamy Natarajan
<sathyanarayanan.nkuppuswamy@gmail.com>,
Randy Dunlap <rdunlap@infradead.org>
Cc: Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
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>, 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>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v8 02/11] x86/tdx: Introduce INTEL_TDX_GUEST config option
Date: Tue, 5 Oct 2021 07:09:59 -0700 [thread overview]
Message-ID: <8a484fb1-21c5-5181-3e77-c818bcc2ffa7@intel.com> (raw)
In-Reply-To: <CAC41dw-U85dCGDm_QzyyOQfhbbaZZ5m9CvLuDjdXjuxEyid8qw@mail.gmail.com>
On 10/5/21 6:29 AM, Sathyanarayanan Kuppuswamy Natarajan wrote:
> On Mon, Oct 4, 2021 at 9:53 PM Randy Dunlap <rdunlap@infradead.org> wrote:
>> On 10/4/21 7:51 PM, Kuppuswamy Sathyanarayanan wrote:
>>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
>>> index 2b2a9639d8ae..c42dd8a2d1f4 100644
>>> --- a/arch/x86/Kconfig
>>> +++ b/arch/x86/Kconfig
>>> @@ -865,6 +865,20 @@ config ACRN_GUEST
>>> IOT with small footprint and real-time features. More details can be
>>> found inhttps://projectacrn.org/.
>>>
>>> +config INTEL_TDX_GUEST
>>> + bool "Intel Trusted Domain eXtensions Guest Support"
>>> + depends on X86_64 && CPU_SUP_INTEL && PARAVIRT
>>> + depends on SECURITY
>>> + select X86_X2APIC
>> Apparently some Intel CPUs don't have the x2apic feature, since the
>> Kconfig help text for X86_X2APIC says:
>>
>> This enables x2apic support on CPUs that have this feature.
>>
>> so how is it safe to set/enable/select that kconfig symbol?
>>
>> Will the x2apic code just safely not work if the h/w feature is
>> missing?
> For the TDX guest, x2apic will be emulated. So it will exist in our
> case. Even if x2apic or TDX guest is not supported by CPU, it will
> boot just fine.
This doesn't really explain the "select X86_X2APIC", though.
You just said that TDX doesn't *require* X2APIC. So, why is it being
selected? What is the specific connection between TDX and X2APIC?
next prev parent reply other threads:[~2021-10-05 14:20 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-05 2:51 [PATCH v8 00/11] Add TDX Guest Support (Initial support) Kuppuswamy Sathyanarayanan
2021-10-05 2:51 ` [PATCH v8 01/11] x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT Kuppuswamy Sathyanarayanan
2021-10-05 20:13 ` Josh Poimboeuf
2021-10-05 2:51 ` [PATCH v8 02/11] x86/tdx: Introduce INTEL_TDX_GUEST config option Kuppuswamy Sathyanarayanan
2021-10-05 4:53 ` Randy Dunlap
2021-10-05 13:29 ` Sathyanarayanan Kuppuswamy Natarajan
2021-10-05 14:09 ` Dave Hansen [this message]
2021-10-05 14:31 ` Sean Christopherson
2021-10-05 14:43 ` Kuppuswamy, Sathyanarayanan
2021-10-05 14:13 ` Borislav Petkov
2021-10-05 14:48 ` Kuppuswamy, Sathyanarayanan
2021-10-05 17:29 ` Borislav Petkov
2021-10-05 20:21 ` Josh Poimboeuf
2021-10-05 20:38 ` Kuppuswamy, Sathyanarayanan
2021-10-05 20:17 ` Josh Poimboeuf
2021-10-05 20:33 ` Sean Christopherson
2021-10-05 20:42 ` Dave Hansen
2021-10-05 20:37 ` Kuppuswamy, Sathyanarayanan
2021-10-05 2:51 ` [PATCH v8 03/11] x86/cpufeatures: Add TDX Guest CPU feature Kuppuswamy Sathyanarayanan
2021-10-05 21:04 ` Josh Poimboeuf
2021-10-05 21:19 ` Borislav Petkov
2021-10-05 21:41 ` Kuppuswamy, Sathyanarayanan
2021-10-06 3:42 ` Josh Poimboeuf
2021-10-06 4:33 ` Kuppuswamy, Sathyanarayanan
2021-10-06 5:03 ` Josh Poimboeuf
2021-10-06 12:47 ` Borislav Petkov
2021-10-06 14:11 ` Josh Poimboeuf
2021-10-06 14:26 ` Borislav Petkov
2021-10-06 14:25 ` Josh Poimboeuf
2021-10-06 15:26 ` Borislav Petkov
2021-10-06 15:43 ` Kuppuswamy, Sathyanarayanan
2021-10-06 16:20 ` Borislav Petkov
2021-10-05 2:51 ` [PATCH v8 04/11] x86/tdx: Add Intel ARCH support to cc_platform_has() Kuppuswamy Sathyanarayanan
2021-10-05 4:47 ` Randy Dunlap
2021-10-05 12:29 ` Kuppuswamy, Sathyanarayanan
2021-10-05 21:16 ` Josh Poimboeuf
2021-10-05 21:42 ` Kuppuswamy, Sathyanarayanan
2021-10-06 18:02 ` Borislav Petkov
2021-10-06 18:14 ` Kuppuswamy, Sathyanarayanan
2021-10-05 2:51 ` [PATCH v8 05/11] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions Kuppuswamy Sathyanarayanan
2021-10-06 5:53 ` Josh Poimboeuf
2021-10-06 16:52 ` Kuppuswamy, Sathyanarayanan
2021-10-07 9:33 ` Borislav Petkov
2021-10-07 16:55 ` Kuppuswamy, Sathyanarayanan
2021-10-05 2:52 ` [PATCH v8 06/11] x86/traps: Add #VE support for TDX guest Kuppuswamy Sathyanarayanan
2021-10-06 18:40 ` Josh Poimboeuf
2021-10-07 17:06 ` Borislav Petkov
2021-10-07 17:22 ` Kuppuswamy, Sathyanarayanan
2021-10-07 17:32 ` Borislav Petkov
2021-10-17 17:15 ` Dave Hansen
2021-10-18 10:53 ` Borislav Petkov
2021-10-18 14:05 ` Dave Hansen
2021-10-18 14:09 ` Borislav Petkov
2021-10-09 3:56 ` Lai Jiangshan
2021-10-11 15:06 ` Sean Christopherson
2021-10-11 16:49 ` Andi Kleen
2021-10-05 2:52 ` [PATCH v8 07/11] x86/tdx: Add HLT " Kuppuswamy Sathyanarayanan
2021-10-06 19:17 ` Josh Poimboeuf
2021-10-07 19:25 ` Kuppuswamy, Sathyanarayanan
2021-10-08 17:31 ` Borislav Petkov
2021-10-08 17:38 ` Kuppuswamy, Sathyanarayanan
2021-10-08 17:59 ` Borislav Petkov
2021-10-05 2:52 ` [PATCH v8 08/11] x86/tdx: Wire up KVM hypercalls Kuppuswamy Sathyanarayanan
2021-10-06 19:34 ` Josh Poimboeuf
2021-10-06 19:40 ` Borislav Petkov
2021-11-05 20:59 ` Sean Christopherson
2021-11-12 16:17 ` Sathyanarayanan Kuppuswamy
2021-10-05 2:52 ` [PATCH v8 09/11] x86/tdx: Add MSR support for TDX guest Kuppuswamy Sathyanarayanan
2021-10-05 23:22 ` Josh Poimboeuf
2021-10-06 0:48 ` Kuppuswamy, Sathyanarayanan
2021-10-06 19:49 ` Josh Poimboeuf
2021-10-08 2:16 ` Kuppuswamy, Sathyanarayanan
2021-10-05 2:52 ` [PATCH v8 10/11] x86/tdx: Don't write CSTAR MSR on Intel Kuppuswamy Sathyanarayanan
2021-10-05 2:52 ` [PATCH v8 11/11] x86/tdx: Handle CPUID via #VE Kuppuswamy Sathyanarayanan
2021-10-06 20:26 ` Josh Poimboeuf
2021-10-08 2:25 ` Kuppuswamy, Sathyanarayanan
2021-10-11 18:16 ` Josh Poimboeuf
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