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From: Jarkko Sakkinen <jarkko@kernel.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Kai Huang <kai.huang@intel.com>,
	linux-sgx@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org,
	seanjc@google.com, luto@kernel.org, rick.p.edgecombe@intel.com,
	haitao.huang@intel.com, pbonzini@redhat.com, bp@alien8.de,
	tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com
Subject: Re: [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests
Date: Thu, 18 Feb 2021 00:22:48 +0200	[thread overview]
Message-ID: <YC2XOC2bsALZi5NC@kernel.org> (raw)
In-Reply-To: <eafcdcae-ae66-e717-2f8b-2bdfb8e7d0d5@intel.com>

On Tue, Feb 16, 2021 at 10:38:42AM -0800, Dave Hansen wrote:
> On 2/13/21 5:28 AM, Kai Huang wrote:
> > SGX driver uses misc device /dev/sgx_enclave to support userspace to
> > create enclave.  Each file descriptor from opening /dev/sgx_enclave
> > represents an enclave.  
> 
> Is this strictly true?  Does dup(2) create a new enclave?

No.

> > Unlike SGX driver, KVM doesn't control how guest
> > uses EPC, therefore EPC allocated to KVM guest is not associated to an
> > encalve, and /dev/sgx_enclave is not suitable for allocating EPC for KVM
> 
>   ^ enclave
> 
> > guest.
> 
> 
> > Having separate device nodes for SGX driver and KVM virtual EPC also
> > allows separate permission control for running host SGX enclaves and
> > KVM SGX guests.
> 
> Specifically, 'sgx_vepc' is a less restrictive interface.  It would make
> a lot of sense to more tightly control access compared to 'sgx_enclave'.
> 
> > More specifically, to allocate a virtual EPC instance with particular
> > size, the userspace hypervisor opens /dev/sgx_vepc, and uses mmap()
> > with the intended size to get an address range of virtual EPC.  Then
> > it may use the address range to create one KVM memory slot as virtual
> > EPC for guest.
> 
> This paragraph doesn't really explain anything important to me.  Both
> devices require using mmap().
> 
> With typos in the changelog fixed, I'm OK with the rest:
> 
> Acked-by: Dave Hansen <dave.hansen@intel.com>
> 
> BTW...  A lot of this patch is just a skeletal device driver.  I'm a
> horrible device driver writer, so take this ack as "everything seems
> explained well" versus "I promise this will pass muster with the guys
> who review device drivers all day long."
> 

/Jarkko

  parent reply	other threads:[~2021-02-17 22:23 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-13 13:28 [RFC PATCH v5 00/26] KVM SGX virtualization support Kai Huang
2021-02-13 13:28 ` [RFC PATCH v5 01/26] x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit Kai Huang
2021-02-13 13:28 ` [RFC PATCH v5 02/26] x86/cpufeatures: Add SGX1 and SGX2 sub-features Kai Huang
2021-02-13 13:28 ` [RFC PATCH v5 03/26] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Kai Huang
2021-02-16 17:04   ` Dave Hansen
2021-02-16 20:42     ` Huang, Kai
2021-02-13 13:28 ` [RFC PATCH v5 04/26] x86/sgx: Add SGX_CHILD_PRESENT hardware error code Kai Huang
2021-02-13 13:28 ` [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
2021-02-16  2:12   ` Jarkko Sakkinen
2021-02-16 18:38   ` Dave Hansen
2021-02-16 19:25     ` Sean Christopherson
2021-02-16 21:33       ` Huang, Kai
2021-02-16 21:34     ` Huang, Kai
2021-02-17 22:22     ` Jarkko Sakkinen [this message]
2021-02-13 13:29 ` [RFC PATCH v5 06/26] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
2021-02-16  2:15   ` Jarkko Sakkinen
2021-02-16  5:03     ` Huang, Kai
2021-02-16  8:36       ` Jarkko Sakkinen
2021-02-16 10:24         ` Huang, Kai
2021-02-16 18:40   ` Dave Hansen
2021-02-16 20:42     ` Huang, Kai
2021-02-13 13:29 ` [RFC PATCH v5 07/26] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled Kai Huang
2021-02-16 18:41   ` Dave Hansen
2021-02-13 13:29 ` [RFC PATCH v5 08/26] x86/sgx: Expose SGX architectural definitions to the kernel Kai Huang
2021-02-16  2:17   ` Jarkko Sakkinen
2021-02-16 10:30     ` Huang, Kai
2021-02-16 10:32       ` Borislav Petkov
2021-02-16 11:15         ` Huang, Kai
2021-02-16 11:48           ` Borislav Petkov
2021-02-16 11:56             ` Huang, Kai
2021-02-16 15:18             ` Dave Hansen
2021-02-16 18:47               ` Borislav Petkov
2021-02-16 18:53                 ` Dave Hansen
2021-02-16 19:18                   ` Borislav Petkov
2021-02-17 22:20               ` Jarkko Sakkinen
2021-02-18  9:09                 ` Huang, Kai
2021-02-16 16:28         ` Jarkko Sakkinen
2021-02-13 13:29 ` [RFC PATCH v5 09/26] x86/sgx: Move ENCLS leaf definitions to sgx_arch.h Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 10/26] x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT) Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 11/26] x86/sgx: Add encls_faulted() helper Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 12/26] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 13/26] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Kai Huang
2021-02-16  3:08   ` Jarkko Sakkinen
2021-02-16  3:09     ` Jarkko Sakkinen
2021-02-16  4:55       ` Huang, Kai
2021-02-16  8:33         ` Jarkko Sakkinen
2021-02-16  8:35           ` Jarkko Sakkinen
2021-02-16  9:33             ` Huang, Kai
2021-02-13 13:29 ` [RFC PATCH v5 14/26] x86/sgx: Move provisioning device creation out of SGX driver Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 15/26] KVM: VMX: Convert vcpu_vmx.exit_reason to a union Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 16/26] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 17/26] KVM: x86: Define new #PF SGX error code bit Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 18/26] KVM: x86: Add support for reverse CPUID lookup of scattered features Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 19/26] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 20/26] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 21/26] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 22/26] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 23/26] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 24/26] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
2021-02-13 13:29 ` [RFC PATCH v5 25/26] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
2021-02-13 13:30 ` [RFC PATCH v5 26/26] KVM: x86: Add capability to grant VM access to privileged SGX attribute Kai Huang
2021-02-16 18:48 ` [RFC PATCH v5 00/26] KVM SGX virtualization support Dave Hansen
2021-02-16 19:15   ` Sean Christopherson
2021-02-16 20:58   ` Huang, Kai

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