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From: Sean Christopherson <seanjc@google.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Kai Huang <kai.huang@intel.com>,
	kvm@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org,
	linux-kernel@vger.kernel.org, jarkko@kernel.org, luto@kernel.org,
	dave.hansen@intel.com, rick.p.edgecombe@intel.com,
	haitao.huang@intel.com, pbonzini@redhat.com, tglx@linutronix.de,
	mingo@redhat.com, hpa@zytor.com
Subject: Re: [PATCH v3 03/25] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()
Date: Tue, 23 Mar 2021 16:21:47 +0000	[thread overview]
Message-ID: <YFoVmxIFjGpqM6Bk@google.com> (raw)
In-Reply-To: <20210323160604.GB4729@zn.tnic>

On Tue, Mar 23, 2021, Borislav Petkov wrote:
> On Tue, Mar 23, 2021 at 03:45:14PM +0000, Sean Christopherson wrote:
> > Practically speaking, "basic" deployments of SGX VMs will be insulated from
> > this bug.  KVM doesn't support EPC oversubscription, so even if all EPC is
> > exhausted, new VMs will fail to launch, but existing VMs will continue to chug
> > along with no ill effects....
> 
> Ok, so it sounds to me like *at* *least* there should be some writeup in
> Documentation/ explaining to the user what to do when she sees such an
> EREMOVE failure, perhaps the gist of this thread and then possibly the
> error message should point to that doc.
> 
> We will of course have to revisit when this hits the wild and people
> start (or not) hitting this. But judging by past experience, if it is
> there, we will hit it. Murphy says so.

I like the idea of pointing at the documentation.  The documentation should
probably emphasize that something is very, very wrong.  E.g. if a kernel bug
triggers EREMOVE failure and isn't detected until the kernel is widely deployed
in a fleet, then the folks deploying the kernel probably _should_ be in all out
panic.  For this variety of bug to escape that far, it means there are huge
holes in test coverage, in both the kernel itself and in the infrasturcture of
whoever is rolling out their new kernel.

  reply	other threads:[~2021-03-23 16:22 UTC|newest]

Thread overview: 134+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-19  7:29 [PATCH v3 00/25] KVM SGX virtualization support Kai Huang
2021-03-19  7:22 ` [PATCH v3 01/25] x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Kai Huang
2021-03-19  7:22 ` [PATCH v3 02/25] x86/cpufeatures: Add SGX1 and SGX2 sub-features Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Sean Christopherson
2021-03-19  7:22 ` [PATCH v3 03/25] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Kai Huang
2021-03-22 18:16   ` Borislav Petkov
2021-03-22 18:56     ` Sean Christopherson
2021-03-22 19:11       ` Paolo Bonzini
2021-03-22 20:43         ` Kai Huang
2021-03-23 16:40           ` Paolo Bonzini
2021-03-22 19:15       ` Borislav Petkov
2021-03-22 19:37         ` Sean Christopherson
2021-03-22 20:36           ` Kai Huang
2021-03-22 21:06           ` Borislav Petkov
2021-03-22 22:06             ` Kai Huang
2021-03-22 22:37               ` Borislav Petkov
2021-03-22 23:16                 ` Kai Huang
2021-03-23 15:45                   ` Sean Christopherson
2021-03-23 16:06                     ` Borislav Petkov
2021-03-23 16:21                       ` Sean Christopherson [this message]
2021-03-23 16:32                         ` Borislav Petkov
2021-03-23 16:51                           ` Sean Christopherson
2021-03-24  9:38                           ` Kai Huang
2021-03-24 10:09                             ` Paolo Bonzini
2021-03-24 10:48                               ` Kai Huang
2021-03-24 11:24                                 ` Paolo Bonzini
2021-03-24 23:23                               ` Kai Huang
2021-03-24 23:39                                 ` Paolo Bonzini
2021-03-24 23:46                                   ` Kai Huang
2021-03-25  8:42                                     ` Borislav Petkov
2021-03-25  9:38                                       ` Kai Huang
2021-03-25 16:52                                         ` Borislav Petkov
2021-03-24  9:28                         ` Jarkko Sakkinen
2021-03-23 16:38                       ` Paolo Bonzini
2021-03-23 17:02                         ` Sean Christopherson
2021-03-23 17:06                           ` Paolo Bonzini
2021-03-23 17:16                             ` Sean Christopherson
2021-03-23 18:16                             ` Borislav Petkov
2021-03-24  9:26                       ` Jarkko Sakkinen
2021-03-22 22:23             ` Kai Huang
2021-03-25  9:30   ` [PATCH v4 " Kai Huang
2021-03-26 19:48     ` Jarkko Sakkinen
2021-03-26 20:38       ` Kai Huang
2021-03-26 21:39       ` Jarkko Sakkinen
2021-04-07 10:03     ` [tip: x86/sgx] " tip-bot2 for Kai Huang
2021-03-19  7:22 ` [PATCH v3 04/25] x86/sgx: Add SGX_CHILD_PRESENT hardware error code Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Sean Christopherson
2021-03-19  7:22 ` [PATCH v3 05/25] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
2021-03-25  9:36   ` Kai Huang
2021-03-26 15:03   ` Borislav Petkov
2021-03-26 15:17     ` Dave Hansen
2021-03-26 15:29       ` Borislav Petkov
2021-03-26 15:35         ` Dave Hansen
2021-03-26 17:02           ` Borislav Petkov
2021-03-31  1:10     ` Kai Huang
2021-03-31  6:44       ` Boris Petkov
2021-03-31  6:51         ` Kai Huang
2021-03-31  7:44           ` Boris Petkov
2021-03-31  8:53             ` Kai Huang
2021-03-31 12:20               ` Kai Huang
2021-04-01 18:31                 ` Borislav Petkov
2021-04-01 23:38                   ` Kai Huang
2021-04-01  9:45               ` Kai Huang
2021-04-01  9:42   ` [PATCH v4 " Kai Huang
2021-04-05  9:01   ` [PATCH v3 " Borislav Petkov
2021-04-05 21:46     ` Kai Huang
2021-04-06  8:28       ` Borislav Petkov
2021-04-06  9:04         ` Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Sean Christopherson
2021-03-19  7:22 ` [PATCH v3 06/25] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Sean Christopherson
2021-03-19  7:23 ` [PATCH v3 07/25] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled Kai Huang
2021-04-02  9:48   ` Borislav Petkov
2021-04-02 11:08     ` Kai Huang
2021-04-02 11:22       ` Borislav Petkov
2021-04-02 11:38         ` Kai Huang
2021-04-02 15:42     ` Sean Christopherson
2021-04-02 19:08       ` Kai Huang
2021-04-02 19:19       ` Borislav Petkov
2021-04-02 19:30         ` Sean Christopherson
2021-04-02 19:46           ` Borislav Petkov
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Kai Huang
2021-03-19  7:23 ` [PATCH v3 08/25] x86/sgx: Expose SGX architectural definitions to the kernel Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Sean Christopherson
2021-03-19  7:23 ` [PATCH v3 09/25] x86/sgx: Move ENCLS leaf definitions to sgx.h Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Sean Christopherson
2021-03-19  7:23 ` [PATCH v3 10/25] x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT) Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Sean Christopherson
2021-03-19  7:23 ` [PATCH v3 11/25] x86/sgx: Add encls_faulted() helper Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Sean Christopherson
2021-03-19  7:23 ` [PATCH v3 12/25] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Kai Huang
2021-03-19  7:23 ` [PATCH v3 13/25] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Kai Huang
2021-04-05  9:07   ` Borislav Petkov
2021-04-05 21:44     ` Kai Huang
2021-04-06  7:40       ` Borislav Petkov
2021-04-06  8:59         ` Kai Huang
2021-04-06  9:09           ` Borislav Petkov
2021-04-06  9:24             ` Kai Huang
2021-04-06  9:32               ` Borislav Petkov
2021-04-06  9:41                 ` Kai Huang
2021-04-06 17:08                   ` Borislav Petkov
2021-04-06 20:33                     ` Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Sean Christopherson
2021-03-19  7:23 ` [PATCH v3 14/25] x86/sgx: Move provisioning device creation out of SGX driver Kai Huang
2021-04-07 10:03   ` [tip: x86/sgx] " tip-bot2 for Sean Christopherson
2021-03-19  7:23 ` [PATCH v3 15/25] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
2021-03-19  7:23 ` [PATCH v3 16/25] KVM: x86: Define new #PF SGX error code bit Kai Huang
2021-03-19  7:23 ` [PATCH v3 17/25] KVM: x86: Add support for reverse CPUID lookup of scattered features Kai Huang
2021-03-19  7:23 ` [PATCH v3 18/25] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features Kai Huang
2021-03-19  7:23 ` [PATCH v3 19/25] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
2021-03-19  7:23 ` [PATCH v3 20/25] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
2021-03-19  7:23 ` [PATCH v3 21/25] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
2021-03-19  7:23 ` [PATCH v3 22/25] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
2021-03-19  7:23 ` [PATCH v3 23/25] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
2021-03-19  7:23 ` [PATCH v3 24/25] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
2021-03-19  7:24 ` [PATCH v3 25/25] KVM: x86: Add capability to grant VM access to privileged SGX attribute Kai Huang
2021-03-19 14:52 ` [PATCH v3 00/25] KVM SGX virtualization support Jarkko Sakkinen
2021-03-22 10:03   ` Kai Huang
2021-03-22 10:31     ` Borislav Petkov
2021-03-26 22:46 ` Jarkko Sakkinen
2021-03-28 21:01   ` Huang, Kai
2021-03-31 23:23     ` Jarkko Sakkinen
  -- strict thread matches above, loose matches on Subject: below --
2021-03-09  1:39 [PATCH v2 03/25] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Kai Huang
2021-03-11  2:01 ` [PATCH v3 " Kai Huang
2021-03-12 21:21   ` Sean Christopherson
2021-03-13 10:45     ` Jarkko Sakkinen
2021-03-15  7:12       ` Kai Huang
2021-03-15 13:18         ` Jarkko Sakkinen
2021-03-15 13:19           ` Jarkko Sakkinen
2021-03-15 20:29             ` Kai Huang
2021-03-15 22:59               ` Jarkko Sakkinen
2021-03-15 23:50                 ` Kai Huang
2021-03-15 23:11               ` Jarkko Sakkinen

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