From: Dave Hansen <dave.hansen@intel.com>
To: Kai Huang <kai.huang@intel.com>
Cc: linux-sgx@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org,
seanjc@google.com, jarkko@kernel.org, luto@kernel.org,
haitao.huang@intel.com, pbonzini@redhat.com, bp@alien8.de,
tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com
Subject: Re: [RFC PATCH 03/23] x86/sgx: Introduce virtual EPC for use by KVM guests
Date: Fri, 15 Jan 2021 07:39:44 -0800 [thread overview]
Message-ID: <af302572-96ae-66f5-4922-ef4a8879907f@intel.com> (raw)
In-Reply-To: <20210116030713.276e48c023330172cded174c@intel.com>
On 1/15/21 6:07 AM, Kai Huang wrote:
>>From virtual EPC's perspective, if we don't force this in kernel, then
> *theoretically*, userspace can use fork() to make multiple VMs map to the
> same physical EPC, which will potentially cause enclaves in all VMs to behave
> abnormally. So to me, from this perspective, it's better to enforce in kernel
> so that only first VM can use this virtual EPC instance, because EPC by
> architectural design cannot be shared.
>
> But as Sean said, KVM doesn't support VM across multiple mm structs. And if I
> read code correctly, KVM doesn't support userspace to use fork() to create new
> VM. For instance, when creating VM, KVM grabs current->mm and keeps it in
> 'struct kvm' for bookkeeping, and kvm_vcpu_ioctl() and kvm_device_ioctl() will
> refuse to work if kvm->mm doesn't equal to current->mm. So in practice, I
> believe w/o enforcing this in kernel, we should also have no problem here.
>
> Sean, please correct me if I am wrong.
>
> Dave, if above stands, do you think it is reasonable to keep current->mm in
> epc->mm and enforce in sgx_virt_epc_mmap()?
Everything you wrote above tells me the kernel should not be enforcing
the behavior. You basically said that it's only a theoretical problem,
and old if someone goes and does something with KVM that's nobody can do
today.
You've 100% convinced me that having the kernel enforce this is
*un*reasonable.
next prev parent reply other threads:[~2021-01-15 15:40 UTC|newest]
Thread overview: 111+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-06 1:55 [RFC PATCH 00/23] KVM SGX virtualization support Kai Huang
2021-01-06 1:55 ` [RFC PATCH 01/23] x86/sgx: Split out adding EPC page to free list to separate helper Kai Huang
2021-01-11 22:38 ` Jarkko Sakkinen
2021-01-12 0:19 ` Kai Huang
2021-01-12 21:45 ` Sean Christopherson
2021-01-13 1:15 ` Kai Huang
2021-01-13 17:05 ` Jarkko Sakkinen
2021-01-06 1:55 ` [RFC PATCH 02/23] x86/sgx: Add enum for SGX_CHILD_PRESENT error code Kai Huang
2021-01-06 18:28 ` Dave Hansen
2021-01-06 21:40 ` Kai Huang
2021-01-12 0:26 ` Jarkko Sakkinen
2021-01-11 23:32 ` Jarkko Sakkinen
2021-01-12 0:16 ` Kai Huang
2021-01-12 1:46 ` Jarkko Sakkinen
2021-01-06 1:55 ` [RFC PATCH 03/23] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
2021-01-06 19:35 ` Dave Hansen
2021-01-06 20:35 ` Sean Christopherson
2021-01-07 0:47 ` Kai Huang
2021-01-07 0:52 ` Dave Hansen
2021-01-07 1:38 ` Kai Huang
2021-01-07 5:00 ` Dave Hansen
2021-01-07 1:42 ` Kai Huang
2021-01-07 5:02 ` Dave Hansen
2021-01-15 14:07 ` Kai Huang
2021-01-15 15:39 ` Dave Hansen [this message]
2021-01-15 21:33 ` Kai Huang
2021-01-15 21:45 ` Sean Christopherson
2021-01-15 22:30 ` Kai Huang
2021-01-11 23:38 ` Jarkko Sakkinen
2021-01-12 0:56 ` Kai Huang
2021-01-12 1:50 ` Jarkko Sakkinen
2021-01-12 2:03 ` Kai Huang
2021-01-06 1:55 ` [RFC PATCH 04/23] x86/cpufeatures: Add SGX1 and SGX2 sub-features Kai Huang
2021-01-06 19:39 ` Dave Hansen
2021-01-06 22:12 ` Kai Huang
2021-01-06 22:21 ` Dave Hansen
2021-01-06 22:56 ` Kai Huang
2021-01-06 23:19 ` Sean Christopherson
2021-01-06 23:33 ` Dave Hansen
2021-01-06 23:56 ` Kai Huang
2021-01-06 23:40 ` Kai Huang
2021-01-06 23:43 ` Dave Hansen
2021-01-06 23:56 ` Kai Huang
2021-01-06 22:15 ` Borislav Petkov
2021-01-06 23:09 ` Kai Huang
2021-01-07 6:41 ` Borislav Petkov
2021-01-08 2:00 ` Kai Huang
2021-01-08 5:10 ` Dave Hansen
2021-01-08 7:03 ` Kai Huang
2021-01-08 7:17 ` Borislav Petkov
2021-01-08 8:06 ` Kai Huang
2021-01-08 8:13 ` Borislav Petkov
2021-01-08 9:00 ` Kai Huang
2021-01-08 23:55 ` Sean Christopherson
2021-01-09 0:35 ` Borislav Petkov
2021-01-09 1:01 ` Sean Christopherson
2021-01-09 1:19 ` Borislav Petkov
2021-01-11 17:54 ` Sean Christopherson
2021-01-11 19:09 ` Borislav Petkov
2021-01-11 19:20 ` Sean Christopherson
2021-01-12 2:01 ` Kai Huang
2021-01-12 12:13 ` Borislav Petkov
2021-01-12 17:15 ` Sean Christopherson
2021-01-12 17:51 ` Borislav Petkov
2021-01-12 21:07 ` Kai Huang
2021-01-12 23:17 ` Sean Christopherson
2021-01-13 1:05 ` Kai Huang
2021-01-11 23:39 ` Jarkko Sakkinen
2021-01-06 1:55 ` [RFC PATCH 05/23] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
2021-01-06 19:54 ` Dave Hansen
2021-01-06 22:34 ` Kai Huang
2021-01-06 22:38 ` Dave Hansen
2021-01-06 1:56 ` [RFC PATCH 06/23] x86/sgx: Expose SGX architectural definitions to the kernel Kai Huang
2021-01-06 1:56 ` [RFC PATCH 07/23] x86/sgx: Move ENCLS leaf definitions to sgx_arch.h Kai Huang
2021-01-06 1:56 ` [RFC PATCH 08/23] x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT) Kai Huang
2021-01-06 1:56 ` [RFC PATCH 09/23] x86/sgx: Add encls_faulted() helper Kai Huang
2021-01-06 1:56 ` [RFC PATCH 10/23] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs Kai Huang
2021-01-06 19:56 ` Dave Hansen
2021-01-06 1:56 ` [RFC PATCH 11/23] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Kai Huang
2021-01-06 20:12 ` Dave Hansen
2021-01-06 21:04 ` Sean Christopherson
2021-01-06 21:23 ` Dave Hansen
2021-01-06 22:58 ` Kai Huang
2021-01-06 1:56 ` [RFC PATCH 12/23] x86/sgx: Move provisioning device creation out of SGX driver Kai Huang
2021-01-06 1:56 ` [RFC PATCH 13/23] KVM: VMX: Convert vcpu_vmx.exit_reason to a union Kai Huang
2021-01-06 1:56 ` [RFC PATCH 14/23] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
2021-01-06 1:56 ` [RFC PATCH 15/23] KVM: x86: Define new #PF SGX error code bit Kai Huang
2021-01-06 1:56 ` [RFC PATCH 16/23] KVM: x86: Add SGX feature leaf to reverse CPUID lookup Kai Huang
2021-01-06 1:56 ` [RFC PATCH 17/23] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
2021-01-06 1:56 ` [RFC PATCH 18/23] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
2021-01-06 1:56 ` [RFC PATCH 19/23] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
2021-01-06 1:56 ` [RFC PATCH 20/23] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
2021-01-06 1:56 ` [RFC PATCH 21/23] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
2021-01-06 1:56 ` [RFC PATCH 22/23] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
2021-01-06 1:58 ` [RFC PATCH 23/23] KVM: x86: Add capability to grant VM access to privileged SGX attribute Kai Huang
2021-01-06 2:22 ` [RFC PATCH 00/23] KVM SGX virtualization support Kai Huang
2021-01-06 17:07 ` Dave Hansen
2021-01-07 0:34 ` Kai Huang
2021-01-07 0:48 ` Dave Hansen
2021-01-07 1:50 ` Kai Huang
2021-01-07 16:14 ` Sean Christopherson
2021-01-08 2:16 ` Kai Huang
2021-01-11 17:20 ` Jarkko Sakkinen
2021-01-11 18:37 ` Sean Christopherson
2021-01-12 1:58 ` Jarkko Sakkinen
2021-01-12 1:14 ` Kai Huang
2021-01-12 2:02 ` Jarkko Sakkinen
2021-01-12 2:07 ` Kai Huang
2021-01-15 14:43 ` Kai Huang
2021-01-16 9:31 ` Jarkko Sakkinen
2021-01-16 9:50 ` Jarkko Sakkinen
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