From: Andi Kleen <ak@linux.intel.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: "Kuppuswamy,
Sathyanarayanan" <sathyanarayanan.kuppuswamy@linux.intel.com>,
Sean Christopherson <seanjc@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>,
Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Raj Ashok <ashok.raj@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 1/1] x86/tdx: Handle MWAIT, MONITOR and WBINVD
Date: Wed, 31 Mar 2021 21:24:36 -0700 [thread overview]
Message-ID: <20210401042436.GJ1285835@tassilo.jf.intel.com> (raw)
In-Reply-To: <92688a68-f4b8-9518-424b-7d967c4c728a@intel.com>
On Wed, Mar 31, 2021 at 08:46:18PM -0700, Dave Hansen wrote:
> On 3/31/21 8:28 PM, Andi Kleen wrote:
> >> The hardware (and VMMs and SEAM) have ways of telling the guest kernel
> >> what is supported: CPUID. If it screws up, and the guest gets an
> >> unexpected #VE, so be it.
> > The main reason for disabling stuff is actually that we don't need
> > to harden it. All these things are potential attack paths.
>
> Wait, MWAIT is an attack path? If it were an attack path, wouldn't it
No MWAIT is not, but lots of other things that can be controlled by the
host are. And that will be a motivation to disable things.
> >> We don't have all kinds of crazy handling in the kernel's #UD handler
> >> just in case a CPU mis-enumerates a feature and we get a #UD. We have
> >> to trust the underlying hardware to be sane. If it isn't, we die a
> >> horrible death as fast as possible. Why should TDX be any different?
> > That's what the original patch did -- no unnecessary checks -- but reviewers
> > keep asking for the extra checks, so Sathya added more. We have the not
> > unusual problem here that reviewers don't agree among themselves.
>
> Getting consensus is a pain in the neck, eh?
Tt seems more like a circular argument currently.
>
> It's too bad all the reviewers in the community aren't like all of the
> engineers at big companies where everyone always agrees. :)
I would propose to go back to the original patch without all the extra
checks. I think that's what you're arguing too. IIRC the person
who originally requested extra checks was Andy, if he's ok with
that too we can do it, so that you guys can finally move on
to the other patches that actually do more than just trivial things.
-Andi
next prev parent reply other threads:[~2021-04-01 4:25 UTC|newest]
Thread overview: 161+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-06 3:02 Test Email sathyanarayanan.kuppuswamy
2021-02-05 23:38 ` [RFC v1 00/26] Add TDX Guest Support Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 01/26] x86/paravirt: Introduce CONFIG_PARAVIRT_XL Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 02/26] x86/cpufeatures: Add TDX Guest CPU feature Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 03/26] x86/cpufeatures: Add is_tdx_guest() interface Kuppuswamy Sathyanarayanan
2021-04-01 21:08 ` Dave Hansen
2021-04-01 21:15 ` Kuppuswamy, Sathyanarayanan
2021-04-01 21:19 ` Dave Hansen
2021-04-01 22:25 ` Kuppuswamy, Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 04/26] x86/tdx: Get TD execution environment information via TDINFO Kuppuswamy Sathyanarayanan
2021-02-08 10:00 ` Peter Zijlstra
2021-02-08 19:10 ` Kuppuswamy, Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 05/26] x86/traps: Add #VE support for TDX guest Kuppuswamy Sathyanarayanan
2021-02-08 10:20 ` Peter Zijlstra
2021-02-08 16:23 ` Andi Kleen
2021-02-08 16:33 ` Peter Zijlstra
2021-02-08 16:46 ` Sean Christopherson
2021-02-08 16:59 ` Peter Zijlstra
2021-02-08 19:05 ` Kuppuswamy, Sathyanarayanan
2021-02-08 16:46 ` Andi Kleen
2021-02-12 19:20 ` Dave Hansen
2021-02-12 19:47 ` Andy Lutomirski
2021-02-12 20:06 ` Sean Christopherson
2021-02-12 20:17 ` Dave Hansen
2021-02-12 20:37 ` Sean Christopherson
2021-02-12 20:46 ` Dave Hansen
2021-02-12 20:54 ` Sean Christopherson
2021-02-12 21:06 ` Dave Hansen
2021-02-12 21:37 ` Sean Christopherson
2021-02-12 21:47 ` Andy Lutomirski
2021-02-12 21:48 ` Dave Hansen
2021-02-14 19:33 ` Andi Kleen
2021-02-14 19:54 ` Andy Lutomirski
2021-02-12 20:20 ` Andy Lutomirski
2021-02-12 20:44 ` Sean Christopherson
2021-02-05 23:38 ` [RFC v1 06/26] x86/tdx: Add HLT " Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 07/26] x86/tdx: Wire up KVM hypercalls Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 08/26] x86/tdx: Add MSR support for TDX guest Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 09/26] x86/tdx: Handle CPUID via #VE Kuppuswamy Sathyanarayanan
2021-02-05 23:42 ` Andy Lutomirski
2021-02-07 14:13 ` Kirill A. Shutemov
2021-02-07 16:01 ` Dave Hansen
2021-02-07 20:29 ` Kirill A. Shutemov
2021-02-07 22:31 ` Dave Hansen
2021-02-07 22:45 ` Andy Lutomirski
2021-02-08 17:10 ` Sean Christopherson
2021-02-08 17:35 ` Andy Lutomirski
2021-02-08 17:47 ` Sean Christopherson
2021-03-18 21:30 ` [PATCH v1 1/1] x86/tdx: Add tdcall() and tdvmcall() helper functions Kuppuswamy Sathyanarayanan
2021-03-19 16:55 ` Sean Christopherson
2021-03-19 17:42 ` Kuppuswamy, Sathyanarayanan
2021-03-19 18:22 ` Dave Hansen
2021-03-19 19:58 ` Kuppuswamy, Sathyanarayanan
2021-03-26 23:38 ` [PATCH v2 1/1] x86/tdx: Add __tdcall() and __tdvmcall() " Kuppuswamy Sathyanarayanan
2021-04-20 17:36 ` Dave Hansen
2021-04-20 19:20 ` Kuppuswamy, Sathyanarayanan
2021-04-20 19:59 ` Dave Hansen
2021-04-20 23:12 ` Kuppuswamy, Sathyanarayanan
2021-04-20 23:42 ` Dave Hansen
2021-04-23 1:09 ` Kuppuswamy, Sathyanarayanan
2021-04-23 1:21 ` Dave Hansen
2021-04-23 1:35 ` Andi Kleen
2021-04-23 15:15 ` Sean Christopherson
2021-04-23 15:28 ` Dan Williams
2021-04-23 15:38 ` Andi Kleen
2021-04-23 15:50 ` Sean Christopherson
2021-04-23 15:47 ` Andi Kleen
2021-04-23 18:18 ` Kuppuswamy, Sathyanarayanan
2021-04-20 23:53 ` Dan Williams
2021-04-20 23:59 ` Kuppuswamy, Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 10/26] x86/io: Allow to override inX() and outX() implementation Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 11/26] x86/tdx: Handle port I/O Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 12/26] x86/tdx: Handle in-kernel MMIO Kuppuswamy Sathyanarayanan
2021-04-01 19:56 ` Dave Hansen
2021-04-01 22:26 ` Sean Christopherson
2021-04-01 22:53 ` Dave Hansen
2021-02-05 23:38 ` [RFC v1 13/26] x86/tdx: Handle MWAIT, MONITOR and WBINVD Kuppuswamy Sathyanarayanan
2021-02-05 23:43 ` Andy Lutomirski
2021-02-05 23:54 ` Kuppuswamy, Sathyanarayanan
2021-02-06 1:05 ` Andy Lutomirski
2021-03-27 0:18 ` [PATCH v1 1/1] " Kuppuswamy Sathyanarayanan
2021-03-27 2:40 ` Andy Lutomirski
2021-03-27 3:40 ` Kuppuswamy, Sathyanarayanan
2021-03-27 16:03 ` Andy Lutomirski
2021-03-27 22:54 ` [PATCH v2 " Kuppuswamy Sathyanarayanan
2021-03-29 17:14 ` Dave Hansen
2021-03-29 21:55 ` Kuppuswamy, Sathyanarayanan
2021-03-29 22:02 ` Dave Hansen
2021-03-29 22:09 ` Kuppuswamy, Sathyanarayanan
2021-03-29 22:12 ` Dave Hansen
2021-03-29 22:42 ` Kuppuswamy, Sathyanarayanan
2021-03-29 23:16 ` [PATCH v3 " Kuppuswamy Sathyanarayanan
2021-03-29 23:23 ` Andy Lutomirski
2021-03-29 23:37 ` Kuppuswamy, Sathyanarayanan
2021-03-29 23:42 ` Sean Christopherson
2021-03-29 23:58 ` Andy Lutomirski
2021-03-30 2:04 ` Andi Kleen
2021-03-30 2:58 ` Andy Lutomirski
2021-03-30 15:14 ` Sean Christopherson
2021-03-30 16:37 ` Andy Lutomirski
2021-03-30 16:57 ` Sean Christopherson
2021-04-07 15:24 ` Andi Kleen
2021-03-31 21:09 ` [PATCH v4 " Kuppuswamy Sathyanarayanan
2021-03-31 21:49 ` Dave Hansen
2021-03-31 22:29 ` Kuppuswamy, Sathyanarayanan
2021-03-31 21:53 ` Sean Christopherson
2021-03-31 22:00 ` Dave Hansen
2021-03-31 22:06 ` Sean Christopherson
2021-03-31 22:11 ` Dave Hansen
2021-03-31 22:28 ` Kuppuswamy, Sathyanarayanan
2021-03-31 22:32 ` Sean Christopherson
2021-03-31 22:34 ` Dave Hansen
2021-04-01 3:28 ` Andi Kleen
2021-04-01 3:46 ` Dave Hansen
2021-04-01 4:24 ` Andi Kleen [this message]
2021-04-01 4:51 ` [PATCH v5 " Kuppuswamy Sathyanarayanan
2021-03-29 23:39 ` [PATCH v3 " Sean Christopherson
2021-03-29 23:38 ` Dave Hansen
2021-03-30 4:56 ` [PATCH v1 " Xiaoyao Li
2021-03-30 15:00 ` Andi Kleen
2021-03-30 15:10 ` Dave Hansen
2021-03-30 17:02 ` Kuppuswamy, Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 14/26] ACPI: tables: Add multiprocessor wake-up support Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 15/26] x86/boot: Add a trampoline for APs booting in 64-bit mode Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 16/26] x86/boot: Avoid #VE during compressed boot for TDX platforms Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 17/26] x86/boot: Avoid unnecessary #VE during boot process Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 18/26] x86/topology: Disable CPU hotplug support for TDX platforms Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 19/26] x86/tdx: Forcefully disable legacy PIC for TDX guests Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 20/26] x86/tdx: Introduce INTEL_TDX_GUEST config option Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 21/26] x86/mm: Move force_dma_unencrypted() to common code Kuppuswamy Sathyanarayanan
2021-04-01 20:06 ` Dave Hansen
2021-04-06 15:37 ` Kirill A. Shutemov
2021-04-06 16:11 ` Dave Hansen
2021-04-06 16:37 ` Kirill A. Shutemov
2021-02-05 23:38 ` [RFC v1 22/26] x86/tdx: Exclude Shared bit from __PHYSICAL_MASK Kuppuswamy Sathyanarayanan
2021-04-01 20:13 ` Dave Hansen
2021-04-06 15:54 ` Kirill A. Shutemov
2021-04-06 16:12 ` Dave Hansen
2021-02-05 23:38 ` [RFC v1 23/26] x86/tdx: Make pages shared in ioremap() Kuppuswamy Sathyanarayanan
2021-04-01 20:26 ` Dave Hansen
2021-04-06 16:00 ` Kirill A. Shutemov
2021-04-06 16:14 ` Dave Hansen
2021-02-05 23:38 ` [RFC v1 24/26] x86/tdx: Add helper to do MapGPA TDVMALL Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 25/26] x86/tdx: Make DMA pages shared Kuppuswamy Sathyanarayanan
2021-04-01 21:01 ` Dave Hansen
2021-04-06 16:31 ` Kirill A. Shutemov
2021-04-06 16:38 ` Dave Hansen
2021-04-06 17:16 ` Sean Christopherson
2021-02-05 23:38 ` [RFC v1 26/26] x86/kvm: Use bounce buffers for TD guest Kuppuswamy Sathyanarayanan
2021-04-01 21:17 ` Dave Hansen
2021-02-06 3:04 ` Test Email sathyanarayanan.kuppuswamy
2021-02-06 6:24 ` [RFC v1 00/26] Add TDX Guest Support sathyanarayanan.kuppuswamy
2021-03-31 21:38 ` Kuppuswamy, Sathyanarayanan
2021-04-02 0:02 ` Dave Hansen
2021-04-02 2:48 ` Andi Kleen
2021-04-02 15:27 ` Dave Hansen
2021-04-02 21:32 ` Andi Kleen
2021-04-03 16:26 ` Dave Hansen
2021-04-03 17:28 ` Andi Kleen
2021-04-04 15:02 ` Dave Hansen
2021-04-12 17:24 ` Dan Williams
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