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From: Thomas Gleixner <tglx@linutronix.de>
To: isaku.yamahata@intel.com, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	erdemaktas@google.com, Connor Kuehl <ckuehl@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: isaku.yamahata@intel.com, isaku.yamahata@gmail.com,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Kai Huang <kai.huang@linux.intel.com>
Subject: Re: [RFC PATCH v3 18/59] KVM: x86: Add flag to mark TSC as immutable (for TDX)
Date: Thu, 25 Nov 2021 20:40:22 +0100	[thread overview]
Message-ID: <87ilwgja6x.ffs@tglx> (raw)
In-Reply-To: <00772535f09b2bf98e6bc7008e81c6ffb381ed84.1637799475.git.isaku.yamahata@intel.com>

On Wed, Nov 24 2021 at 16:20, isaku yamahata wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
>
> The TSC for TDX1 guests is fixed at TD creation time.  Add tsc_immutable

What's a TDX1 guest?

> to reflect that the TSC of the guest cannot be changed in any way, and
> use it to short circuit all paths that lead to one of the myriad TSC
> adjustment flows.

I can kinda see the reason for this being valuable on it's own, but in
general why does TDX need a gazillion flags to disable tons of different
things if _ALL_ these flags are going to be set by for TDX guests
anyway?

Seperate flags make only sense when they have a value on their own,
i.e. are useful for things outside of TDX. If not they are just useless
ballast.

Thanks,

        tglx

  reply	other threads:[~2021-11-25 19:42 UTC|newest]

Thread overview: 123+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-25  0:19 [RFC PATCH v3 00/59] KVM: X86: TDX support isaku.yamahata
2021-11-25  0:19 ` [RFC PATCH v3 01/59] x86/mktme: move out MKTME related constatnts/macro to msr-index.h isaku.yamahata
2021-11-25  0:19 ` [RFC PATCH v3 02/59] x86/mtrr: mask out keyid bits from variable mtrr mask register isaku.yamahata
2021-11-25  0:19 ` [RFC PATCH v3 03/59] KVM: TDX: Define TDX architectural definitions isaku.yamahata
2021-11-25  0:19 ` [RFC PATCH v3 04/59] KVM: TDX: Add TDX "architectural" error codes isaku.yamahata
2021-11-25  0:19 ` [RFC PATCH v3 05/59] KVM: TDX: add a helper function for kvm to call seamcall isaku.yamahata
2021-11-25  0:19 ` [RFC PATCH v3 06/59] KVM: TDX: Add C wrapper functions for TDX SEAMCALLs isaku.yamahata
2021-11-25  0:19 ` [RFC PATCH v3 07/59] KVM: TDX: Add helper functions to print TDX SEAMCALL error isaku.yamahata
2021-11-25  0:19 ` [RFC PATCH v3 08/59] KVM: Export kvm_io_bus_read for use by TDX for PV MMIO isaku.yamahata
2021-11-25 17:14   ` Thomas Gleixner
2021-11-25  0:19 ` [RFC PATCH v3 09/59] KVM: Enable hardware before doing arch VM initialization isaku.yamahata
2021-11-25 19:02   ` Thomas Gleixner
2021-11-25  0:19 ` [RFC PATCH v3 10/59] KVM: x86: Split core of hypercall emulation to helper function isaku.yamahata
2021-11-25  0:19 ` [RFC PATCH v3 11/59] KVM: x86: Export kvm_mmio tracepoint for use by TDX for PV MMIO isaku.yamahata
2021-11-25  0:19 ` [RFC PATCH v3 12/59] KVM: x86/mmu: Zap only leaf SPTEs for deleted/moved memslot by default isaku.yamahata
2021-11-25 19:04   ` Thomas Gleixner
2021-11-25  0:19 ` [RFC PATCH v3 13/59] KVM: Add max_vcpus field in common 'struct kvm' isaku.yamahata
2021-11-25 19:06   ` Thomas Gleixner
2021-11-25  0:19 ` [RFC PATCH v3 14/59] KVM: x86: Add vm_type to differentiate legacy VMs from protected VMs isaku.yamahata
2021-11-25 19:08   ` Thomas Gleixner
2021-11-29 17:35     ` Sean Christopherson
2021-12-01 19:37       ` Isaku Yamahata
2021-12-03 16:14         ` Sean Christopherson
2021-11-25  0:19 ` [RFC PATCH v3 15/59] KVM: x86: Introduce "protected guest" concept and block disallowed ioctls isaku.yamahata
2021-11-25 19:26   ` Thomas Gleixner
2021-11-25  0:19 ` [RFC PATCH v3 16/59] KVM: x86: Add per-VM flag to disable direct IRQ injection isaku.yamahata
2021-11-25 19:31   ` Thomas Gleixner
2021-11-29  2:49   ` Lai Jiangshan
2021-11-25  0:20 ` [RFC PATCH v3 17/59] KVM: x86: Add flag to disallow #MC injection / KVM_X86_SETUP_MCE isaku.yamahata
2021-11-25 19:33   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 18/59] KVM: x86: Add flag to mark TSC as immutable (for TDX) isaku.yamahata
2021-11-25 19:40   ` Thomas Gleixner [this message]
2021-11-29 18:05     ` Sean Christopherson
2021-11-25  0:20 ` [RFC PATCH v3 19/59] KVM: Add per-VM flag to mark read-only memory as unsupported isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 20/59] KVM: Add per-VM flag to disable dirty logging of memslots for TDs isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 21/59] KVM: x86: Add per-VM flag to disable in-kernel I/O APIC and level routes isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 22/59] KVM: x86: add per-VM flags to disable SMI/INIT/SIPI isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 23/59] KVM: x86: Allow host-initiated WRMSR to set X2APIC regardless of CPUID isaku.yamahata
2021-11-25 19:41   ` Thomas Gleixner
2021-11-26  8:18     ` Paolo Bonzini
2021-11-29 21:21       ` Sean Christopherson
2021-11-25  0:20 ` [RFC PATCH v3 24/59] KVM: x86: Add kvm_x86_ops .cache_gprs() and .flush_gprs() isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 25/59] KVM: x86: Add support for vCPU and device-scoped KVM_MEMORY_ENCRYPT_OP isaku.yamahata
2021-11-25 19:42   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 26/59] KVM: x86: Introduce vm_teardown() hook in kvm_arch_vm_destroy() isaku.yamahata
2021-11-25 19:46   ` Thomas Gleixner
2021-11-25 20:54     ` Paolo Bonzini
2021-11-25 21:11       ` Thomas Gleixner
2021-11-29 18:16         ` Sean Christopherson
2021-11-25  0:20 ` [RFC PATCH v3 27/59] KVM: x86: Add a switch_db_regs flag to handle TDX's auto-switched behavior isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 28/59] KVM: x86: Check for pending APICv interrupt in kvm_vcpu_has_events() isaku.yamahata
2021-11-25 20:50   ` Paolo Bonzini
2021-11-29 19:20     ` Sean Christopherson
2021-11-25  0:20 ` [RFC PATCH v3 29/59] KVM: x86: Add option to force LAPIC expiration wait isaku.yamahata
2021-11-25 19:53   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 30/59] KVM: x86: Add guest_supported_xss placholder isaku.yamahata
2021-11-25 19:55   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 31/59] KVM: x86: Add infrastructure for stolen GPA bits isaku.yamahata
2021-11-25 20:00   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 32/59] KVM: x86/mmu: Explicitly check for MMIO spte in fast page fault isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 33/59] KVM: x86/mmu: Ignore bits 63 and 62 when checking for "present" SPTEs isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 34/59] KVM: x86/mmu: Allow non-zero init value for shadow PTE isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 35/59] KVM: x86/mmu: Return old SPTE from mmu_spte_clear_track_bits() isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 36/59] KVM: x86/mmu: Frame in support for private/inaccessible shadow pages isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 37/59] KVM: x86/mmu: Introduce kvm_mmu_map_tdp_page() for use by TDX isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 38/59] KVM: x86/mmu: Allow per-VM override of the TDP max page level isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 39/59] KVM: VMX: Modify NMI and INTR handlers to take intr_info as param isaku.yamahata
2021-11-25 20:06   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 40/59] KVM: VMX: Move NMI/exception handler to common helper isaku.yamahata
2021-11-25 20:06   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 41/59] KVM: VMX: Split out guts of EPT violation to common/exposed function isaku.yamahata
2021-11-25 20:07   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 42/59] KVM: VMX: Define EPT Violation architectural bits isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 43/59] KVM: VMX: Define VMCS encodings for shared EPT pointer isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 44/59] KVM: VMX: Add 'main.c' to wrap VMX and TDX isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 45/59] KVM: VMX: Move setting of EPT MMU masks to common VT-x code isaku.yamahata
2021-11-25 20:08   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 46/59] KVM: VMX: Move register caching logic to common code isaku.yamahata
2021-11-25 20:11   ` Thomas Gleixner
2021-11-25 20:17     ` Paolo Bonzini
2021-11-29 18:23       ` Sean Christopherson
2021-11-29 18:28         ` Paolo Bonzini
2021-11-25  0:20 ` [RFC PATCH v3 47/59] KVM: TDX: Define TDCALL exit reason isaku.yamahata
2021-11-25 20:19   ` Thomas Gleixner
2021-11-29 18:36     ` Sean Christopherson
2021-11-25  0:20 ` [RFC PATCH v3 48/59] KVM: TDX: Stub in tdx.h with structs, accessors, and VMCS helpers isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 49/59] KVM: VMX: Add macro framework to read/write VMCS for VMs and TDs isaku.yamahata
2021-11-25 20:24   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 50/59] KVM: VMX: Move AR_BYTES encoder/decoder helpers to common.h isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 51/59] KVM: VMX: MOVE GDT and IDT accessors to common code isaku.yamahata
2021-11-25 20:25   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 52/59] KVM: VMX: Move .get_interrupt_shadow() implementation to common VMX code isaku.yamahata
2021-11-25 20:26   ` Thomas Gleixner
2021-11-25  0:20 ` [RFC PATCH v3 53/59] KVM: x86: Add a helper function to restore 4 host MSRs on exit to user space isaku.yamahata
2021-11-25 20:34   ` Thomas Gleixner
2021-11-26  9:19     ` Chao Gao
2021-11-26  9:40       ` Paolo Bonzini
2021-11-29  7:08       ` Lai Jiangshan
2021-11-29  9:26         ` Chao Gao
2021-11-30  4:58           ` Lai Jiangshan
2021-11-30  8:19             ` Chao Gao
2021-11-30 11:18               ` Lai Jiangshan
2021-11-25  0:20 ` [RFC PATCH v3 54/59] KVM: X86: Introduce initial_tsc_khz in struct kvm_arch isaku.yamahata
2021-11-25 20:48   ` Paolo Bonzini
2021-11-25 21:05   ` Thomas Gleixner
2021-11-25 22:13     ` Paolo Bonzini
2021-11-25 22:59       ` Thomas Gleixner
2021-11-25 23:26       ` Thomas Gleixner
2021-11-26  7:56         ` Paolo Bonzini
2021-11-29 23:38       ` Sean Christopherson
2021-11-25  0:20 ` [RFC PATCH v3 55/59] KVM: TDX: Add "basic" support for building and running Trust Domains isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 56/59] KVM: TDX: Protect private mapping related SEAMCALLs with spinlock isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 57/59] KVM, x86/mmu: Support TDX private mapping for TDP MMU isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 58/59] KVM: TDX: exit to user space on GET_QUOTE, SETUP_EVENT_NOTIFY_INTERRUPT isaku.yamahata
2021-11-25  0:20 ` [RFC PATCH v3 59/59] Documentation/virtual/kvm: Add Trust Domain Extensions(TDX) isaku.yamahata
2021-11-25  2:12 ` [RFC PATCH v3 00/59] KVM: X86: TDX support Xiaoyao Li
2021-11-30 18:51 ` Sean Christopherson
2021-12-01 13:22   ` Kai Huang
2021-12-01 19:08     ` Isaku Yamahata
2021-12-01 19:32       ` Sean Christopherson
2021-12-01 20:28         ` Kai Huang
2021-12-01 15:05   ` Paolo Bonzini
2021-12-01 20:16     ` Kai Huang

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