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From: Dave Hansen <dave.hansen@intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
	"linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"Huang, Kai" <kai.huang@intel.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"corbet@lwn.net" <corbet@lwn.net>,
	"luto@kernel.org" <luto@kernel.org>,
	"jethro@fortanix.com" <jethro@fortanix.com>,
	"wanpengli@tencent.com" <wanpengli@tencent.com>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"b.thiel@posteo.de" <b.thiel@posteo.de>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"pbonzini@redhat.com" <pbonzini@redhat.com>,
	"jarkko@kernel.org" <jarkko@kernel.org>,
	"joro@8bytes.org" <joro@8bytes.org>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"jmattson@google.com" <jmattson@google.com>,
	"vkuznets@redhat.com" <vkuznets@redhat.com>,
	"bp@alien8.de" <bp@alien8.de>,
	"Huang, Haitao" <haitao.huang@intel.com>
Subject: Re: [RFC PATCH v3 00/27] KVM SGX virtualization support
Date: Wed, 3 Feb 2021 07:10:31 -0800	[thread overview]
Message-ID: <f50ac476-71f2-60d4-5008-672365f4d554@intel.com> (raw)
In-Reply-To: <YBnmow4e8WUkRl2H@google.com>

On 2/2/21 3:56 PM, Sean Christopherson wrote:
>> I seem to remember much stronger language in the SDM about this.  I've
>> always thought of SGX as a big unrecoverable machine-check party waiting
>> to happen.
>>
>> I'll ask around internally at Intel and see what folks say.  Basically,
>> should we be afraid of a big bad EPC access?
> If bad accesses to the EPC can cause machine checks, then EPC should never be
> mapped into userspace, i.e. the SGX driver should never have been merged.

The SDM doesn't define the behavior well enough.  I'll try to get that
fixed.

But, there is some documentation of the abort page semantics:

> https://download.01.org/intel-sgx/sgx-linux/2.10/docs/Intel_SGX_Developer_Reference_Linux_2.10_Open_Source.pdf

Basically, writes get dropped and reads get all 1's on all the
implementations in the wild.  I actually would have much rather gotten a
fault, but oh well.

It sounds like we need to at least modify KVM to make sure not to map
and access EPC addresses.  We might even want to add some VM_WARN_ON()s
in the code that creates kernel mappings to catch these mappings if they
happen anywhere else.

EPC mappings seem like (silent) trouble waiting to happen.

  parent reply	other threads:[~2021-02-03 15:13 UTC|newest]

Thread overview: 156+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-26 10:10 [RFC PATCH v3 00/27] KVM SGX virtualization support Kai Huang
2021-01-26  9:29 ` Kai Huang
2021-01-26  9:30 ` [RFC PATCH v3 01/27] x86/cpufeatures: Add SGX1 and SGX2 sub-features Kai Huang
2021-01-26 15:34   ` Dave Hansen
2021-01-26 23:18     ` Kai Huang
2021-01-30 13:20       ` Jarkko Sakkinen
2021-02-01  0:01         ` Kai Huang
2021-02-02 17:17           ` Jarkko Sakkinen
2021-02-03  1:09             ` Kai Huang
2021-02-02 17:56           ` Paolo Bonzini
2021-02-02 18:00             ` Dave Hansen
2021-02-02 18:03               ` Paolo Bonzini
2021-02-02 18:42                 ` Sean Christopherson
2021-02-03  1:05                   ` Kai Huang
2021-01-30 13:11   ` Jarkko Sakkinen
2021-01-26  9:30 ` [RFC PATCH v3 02/27] x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit Kai Huang
2021-01-26 15:35   ` Dave Hansen
2021-01-30 13:22   ` Jarkko Sakkinen
2021-02-01  0:08     ` Kai Huang
2021-01-26  9:30 ` [RFC PATCH v3 03/27] x86/sgx: Remove a warn from sgx_free_epc_page() Kai Huang
2021-01-26 15:39   ` Dave Hansen
2021-01-26 16:30     ` Sean Christopherson
2021-01-27  1:08     ` Kai Huang
2021-01-27  1:12       ` Dave Hansen
2021-01-27  1:26         ` Kai Huang
2021-02-01  0:11           ` Kai Huang
2021-02-03 10:03             ` Jarkko Sakkinen
2021-01-26  9:30 ` [RFC PATCH v3 04/27] x86/sgx: Wipe out EREMOVE " Kai Huang
2021-01-26 16:04   ` Dave Hansen
2021-01-27  1:25     ` Kai Huang
2021-02-02 18:00       ` Paolo Bonzini
2021-02-02 19:25         ` Kai Huang
2021-02-02 19:02       ` Dave Hansen
2021-01-26  9:30 ` [RFC PATCH v3 05/27] x86/sgx: Add SGX_CHILD_PRESENT hardware error code Kai Huang
2021-01-26 15:49   ` Dave Hansen
2021-01-27  0:00     ` Kai Huang
2021-01-27  0:21       ` Dave Hansen
2021-01-27  0:52         ` Kai Huang
2021-01-26  9:30 ` [RFC PATCH v3 06/27] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
2021-01-26 16:19   ` Dave Hansen
2021-01-27  0:16     ` Kai Huang
2021-01-27  0:27       ` Dave Hansen
2021-01-27  0:48         ` Kai Huang
2021-01-30 14:41   ` Jarkko Sakkinen
2021-01-26  9:30 ` [RFC PATCH v3 07/27] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
2021-01-26 16:26   ` Dave Hansen
2021-01-26 17:00     ` Sean Christopherson
2021-01-26 23:54       ` Kai Huang
2021-01-26 23:56     ` Kai Huang
2021-01-27  0:18       ` Dave Hansen
2021-01-27  2:02         ` Kai Huang
2021-01-27 17:13           ` Sean Christopherson
2021-01-30 14:42   ` Jarkko Sakkinen
2021-02-01  5:38     ` Kai Huang
2021-01-26  9:31 ` [RFC PATCH v3 08/27] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled Kai Huang
2021-01-26 17:03   ` Dave Hansen
2021-01-26 18:10     ` Andy Lutomirski
2021-01-26 23:25       ` Kai Huang
2021-01-30 14:45   ` Jarkko Sakkinen
2021-02-01  5:40     ` Kai Huang
2021-02-01 15:25       ` Dave Hansen
2021-02-01 17:23         ` Sean Christopherson
2021-02-02  0:12           ` Kai Huang
2021-02-02 23:10             ` Jarkko Sakkinen
2021-02-02 23:07         ` Jarkko Sakkinen
2021-02-02 17:32       ` Jarkko Sakkinen
2021-02-02 18:20         ` Sean Christopherson
2021-02-02 23:16           ` Jarkko Sakkinen
2021-02-03  0:49             ` Kai Huang
2021-02-03 22:02               ` Jarkko Sakkinen
2021-02-03 22:59                 ` Sean Christopherson
2021-02-04  1:39                   ` Jarkko Sakkinen
2021-02-04  2:59                     ` Kai Huang
2021-02-04  3:05                       ` Jarkko Sakkinen
2021-02-04  3:09                         ` Jarkko Sakkinen
2021-02-04  3:20                           ` Kai Huang
2021-02-04 14:51                             ` Jarkko Sakkinen
2021-02-04 22:41                               ` Dave Hansen
2021-02-04 22:56                                 ` Kai Huang
2021-02-05  2:08                                 ` Jarkko Sakkinen
2021-02-05  3:00                                   ` Huang, Kai
2021-02-02 18:49         ` Kai Huang
2021-02-02 23:17           ` Jarkko Sakkinen
2021-01-26  9:31 ` [RFC PATCH v3 09/27] x86/sgx: Expose SGX architectural definitions to the kernel Kai Huang
2021-01-30 14:46   ` Jarkko Sakkinen
2021-01-26  9:31 ` [RFC PATCH v3 10/27] x86/sgx: Move ENCLS leaf definitions to sgx_arch.h Kai Huang
2021-01-26  9:31 ` [RFC PATCH v3 11/27] x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT) Kai Huang
2021-01-26  9:31 ` [RFC PATCH v3 12/27] x86/sgx: Add encls_faulted() helper Kai Huang
2021-01-30 14:48   ` Jarkko Sakkinen
2021-01-26  9:31 ` [RFC PATCH v3 13/27] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs Kai Huang
2021-01-30 14:49   ` Jarkko Sakkinen
2021-02-01  1:17     ` Kai Huang
2021-02-01 21:22       ` Dave Hansen
2021-01-26  9:31 ` [RFC PATCH v3 14/27] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Kai Huang
2021-01-30 14:51   ` Jarkko Sakkinen
2021-02-01  0:17     ` Kai Huang
2021-02-02 17:20       ` Jarkko Sakkinen
2021-02-02 20:35         ` Kai Huang
2021-02-04  3:53   ` Kai Huang
2021-02-05  0:32     ` Sean Christopherson
2021-02-05  1:39       ` Huang, Kai
2021-01-26  9:31 ` [RFC PATCH v3 15/27] x86/sgx: Move provisioning device creation out of SGX driver Kai Huang
2021-01-30 14:52   ` Jarkko Sakkinen
2021-01-26  9:31 ` [RFC PATCH v3 16/27] KVM: VMX: Convert vcpu_vmx.exit_reason to a union Kai Huang
2021-01-30 15:00   ` Jarkko Sakkinen
2021-02-01  0:32     ` Kai Huang
2021-02-02 17:24       ` Jarkko Sakkinen
2021-02-02 19:23         ` Kai Huang
2021-02-02 22:41           ` Jarkko Sakkinen
2021-02-03  0:42             ` Kai Huang
2021-02-01 17:12     ` Sean Christopherson
2021-02-02 22:38       ` Jarkko Sakkinen
2021-01-26  9:31 ` [RFC PATCH v3 17/27] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
2021-01-26  9:31 ` [RFC PATCH v3 18/27] KVM: x86: Define new #PF SGX error code bit Kai Huang
2021-01-26  9:31 ` [RFC PATCH v3 19/27] KVM: x86: Add support for reverse CPUID lookup of scattered features Kai Huang
2021-01-26  9:31 ` [RFC PATCH v3 20/27] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features Kai Huang
2021-01-26  9:31 ` [RFC PATCH v3 21/27] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
2021-01-26  9:31 ` [RFC PATCH v3 22/27] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
2021-01-26  9:31 ` [RFC PATCH v3 23/27] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
2021-02-03  0:52   ` Edgecombe, Rick P
2021-02-03  1:36     ` Sean Christopherson
2021-02-03  9:11       ` Kai Huang
2021-02-03 17:07         ` Sean Christopherson
2021-02-03 23:11           ` Kai Huang
2021-02-03 18:47   ` Edgecombe, Rick P
2021-02-03 19:36     ` Sean Christopherson
2021-02-03 23:29       ` Kai Huang
2021-02-03 23:36         ` Sean Christopherson
2021-02-03 23:45           ` Kai Huang
2021-02-03 23:59             ` Sean Christopherson
2021-02-04  0:11               ` Kai Huang
2021-02-04  2:01                 ` Sean Christopherson
2021-01-26  9:31 ` [RFC PATCH v3 24/27] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
2021-01-26  9:31 ` [RFC PATCH v3 25/27] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
2021-01-26  9:31 ` [RFC PATCH v3 26/27] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
2021-01-26  9:32 ` [RFC PATCH v3 27/27] KVM: x86: Add capability to grant VM access to privileged SGX attribute Kai Huang
2021-02-02 22:21 ` [RFC PATCH v3 00/27] KVM SGX virtualization support Edgecombe, Rick P
2021-02-02 22:33   ` Sean Christopherson
2021-02-02 23:21     ` Dave Hansen
2021-02-02 23:56       ` Sean Christopherson
2021-02-03  0:43         ` Dave Hansen
2021-02-03 15:10         ` Dave Hansen [this message]
2021-02-03 17:36           ` Sean Christopherson
2021-02-03 17:43             ` Paolo Bonzini
2021-02-03 17:46               ` Dave Hansen
2021-02-03 23:09                 ` Kai Huang
2021-02-03 23:32                   ` Sean Christopherson
2021-02-03 23:37                     ` Dave Hansen
2021-02-04  0:04                       ` Kai Huang
2021-02-04  0:28                         ` Sean Christopherson
2021-02-04  3:18                           ` Kai Huang
2021-02-04 16:28                             ` Sean Christopherson
2021-02-04 16:48                               ` Dave Hansen
2021-02-05 12:32                                 ` Kai Huang
2021-02-05 16:51                                   ` Sean Christopherson
2021-02-02 22:36   ` Dave Hansen

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