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From: Andy Lutomirski <luto@kernel.org>
To: "Xing, Cedric" <cedric.xing@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>,
	"Christopherson, Sean J" <sean.j.christopherson@intel.com>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"Hansen, Dave" <dave.hansen@intel.com>,
	"nhorman@redhat.com" <nhorman@redhat.com>,
	"npmccallum@redhat.com" <npmccallum@redhat.com>,
	"Ayoun, Serge" <serge.ayoun@intel.com>,
	"Katz-zamir, Shay" <shay.katz-zamir@intel.com>,
	"Huang, Haitao" <haitao.huang@intel.com>,
	"andriy.shevchenko@linux.intel.com" 
	<andriy.shevchenko@linux.intel.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"Svahn, Kai" <kai.svahn@intel.com>, "bp@alien8.de" <bp@alien8.de>,
	"josh@joshtriplett.org" <josh@joshtriplett.org>,
	"Huang, Kai" <kai.huang@intel.com>,
	"rientjes@google.com" <rientjes@google.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Haitao Huang <haitao.huang@linux.intel.com>,
	Jethro Beekman <jethro@fortanix.com>,
	"Dr . Greg Wettstein" <greg@enjellic.com>
Subject: Re: [PATCH v19,RESEND 24/27] x86/vdso: Add __vdso_sgx_enter_enclave() to wrap SGX enclave transitions
Date: Tue, 26 Mar 2019 10:08:31 -0700	[thread overview]
Message-ID: <CALCETrVcR_etAHSVZxvCz7CcPnF4ajpcWiRCtFrOckVWVJByHA@mail.gmail.com> (raw)
In-Reply-To: <960B34DE67B9E140824F1DCDEC400C0F4E85FABF@ORSMSX116.amr.corp.intel.com>

On Mon, Mar 25, 2019 at 9:53 PM Xing, Cedric <cedric.xing@intel.com> wrote:
>
> > On Mon, Mar 25, 2019 at 11:03 AM Sean Christopherson
> > <sean.j.christopherson@intel.com> wrote:
> > >
> > > On Sun, Mar 24, 2019 at 01:59:48AM -0700, Xing, Cedric wrote:
> > > > As said in my previous email, this vDSO API isn't even compliant to
> > > > x86_64 ABI and is absolutely NOT for average developers. Instead,
> > > > host/enclave communications are expected to be handled by SDKs and
> > > > those developers will be very aware of the limitations of their
> > > > targeted environments, and will need the freedom to deploy optimal
> > solutions.
> >
> > > I fully realize that the above approach saddles Cedric and the SDK
> > > team with the extra task of justifying the need for two vDSO
> > > interfaces, and likely reduces the probability of their proposal being
> > > accepted.  But, we don't *force* the SDK to be rewritten, and we gain
> > > a vDSO interface that many people want and is acceptable to the
> > > maintainers (unless I've horribly misread Andy's position).
> >
> > I don't think you've horribly misread it.  I would like to keep the
> > stuff in the vDSO as minimal as possible.  If we need to add a fancier
> > interface down the line, then that's fine.
>
> Andy, I don't know "many people" is how many in Sean's email. I couldn't tell you how long it took us to settle on the current SGX ISA because you would just LAUGH! Why? Because it took insanely ridiculously long. Why that long? Because the h/w and u-code teams would like to trim down the ISA as much as possible. The fact is, whatever new is released, Intel will have to maintain it on all future processors FOREVER! That means significant/on-going cost to Intel. So any addition to ISA has to undergo extensive reviews that involve all kinds of experts from both within Intel and externally, and would usually take years, before you can see what you are seeing today. As I said in my earlier emails, RBP is NOT needed for interrupt/exception handlers, then how did RBP end up being restored at AEX? You can guess how many people were standing behind it! Sean has no clue! I can assure you!
>
> Guess we've talked enough on the technical front. So let's talk about it on the business front. Let me take a step back. Let's say you are right, all enclaves would eventually be coded in the way you want. We (Intel SDK team) were convinced to follow your approach. But there were existing enclaves and a migration path would be needed. Would you like to support us? It'd be only 9 LOC on your side but how much would incur on our side? If you believe you are doing right thing, then acceptance is the next thing you should think of. You should offer an easy path for those who did "wrong" to get on your "right" boat. Don't you think so?
>

I suppose the real question is: are there a significant number of
users who will want to run enclaves created using an old SDK on Linux?
 And will there actually be support for doing this in the software
stack?

If the answer to both questions is yes, then it seems like it could be
reasonable to support it in the vDSO.  But I still think it should
probably be a different vDSO entry point so that the normal case
doesn't become more complicated.

  reply	other threads:[~2019-03-26 17:08 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-20 16:20 [PATCH v19,RESEND 00/27] Intel SGX1 support Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 01/27] x86/cpufeatures: Add Intel-defined SGX feature bit Jarkko Sakkinen
2019-03-20 19:41   ` Neil Horman
2019-03-21 14:16     ` Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 02/27] x86/cpufeatures: Add SGX sub-features (as Linux-defined bits) Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 03/27] x86/msr: Add IA32_FEATURE_CONTROL.SGX_ENABLE definition Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 04/27] x86/cpufeatures: Add Intel-defined SGX_LC feature bit Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 05/27] x86/msr: Add SGX Launch Control MSR definitions Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 06/27] x86/mm: x86/sgx: Add new 'PF_SGX' page fault error code bit Jarkko Sakkinen
2019-03-20 16:20 ` [PATCH v19,RESEND 07/27] x86/mm: x86/sgx: Signal SIGSEGV for userspace #PFs w/ PF_SGX Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 08/27] x86/cpu/intel: Detect SGX support and update caps appropriately Jarkko Sakkinen
2019-03-26 12:17   ` Huang, Kai
2019-03-26 14:27     ` Sean Christopherson
2019-03-26 21:25       ` Huang, Kai
2019-03-26 21:57         ` Sean Christopherson
2019-03-26 23:19           ` Huang, Kai
2019-03-20 16:21 ` [PATCH v19,RESEND 09/27] x86/sgx: Add ENCLS architectural error codes Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 10/27] x86/sgx: Add SGX1 and SGX2 architectural data structures Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 11/27] x86/sgx: Add definitions for SGX's CPUID leaf and variable sub-leafs Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 12/27] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 13/27] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 14/27] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 15/27] x86/sgx: Add sgx_einit() for initializing enclaves Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 16/27] x86/sgx: Add the Linux SGX Enclave Driver Jarkko Sakkinen
2019-03-26 12:01   ` Huang, Kai
2019-03-26 12:40     ` Thomas Gleixner
2019-03-26 14:54       ` Sean Christopherson
2019-03-26 21:11         ` Huang, Kai
2019-03-27  5:02     ` Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 17/27] x86/sgx: Add provisioning Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 18/27] x86/sgx: Add swapping code to the core and SGX driver Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 19/27] x86/sgx: ptrace() support for the " Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 20/27] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 21/27] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 22/27] x86/fault: Attempt to fixup unhandled #PF in vDSO before signaling Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 23/27] x86/traps: Attempt to fixup exceptions " Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 24/27] x86/vdso: Add __vdso_sgx_enter_enclave() to wrap SGX enclave transitions Jarkko Sakkinen
2019-03-20 18:30   ` Xing, Cedric
2019-03-20 18:52     ` Andy Lutomirski
2019-03-20 19:57       ` Xing, Cedric
2019-03-20 21:03         ` Sean Christopherson
2019-03-21  0:17           ` Xing, Cedric
2019-03-22 21:20             ` Sean Christopherson
2019-03-21 17:17         ` Andy Lutomirski
2019-03-22 20:31           ` Xing, Cedric
2019-03-20 19:02     ` Jethro Beekman
2019-03-20 20:10       ` Xing, Cedric
2019-03-20 19:13     ` Sean Christopherson
2019-03-20 20:38       ` Xing, Cedric
2019-03-22 21:59         ` Sean Christopherson
2019-03-23 17:36           ` Xing, Cedric
2019-03-23 21:38             ` Andy Lutomirski
2019-03-24  8:59               ` Xing, Cedric
2019-03-25 18:03                 ` Sean Christopherson
2019-03-25 23:59                   ` Andy Lutomirski
2019-03-26  4:53                     ` Xing, Cedric
2019-03-26 17:08                       ` Andy Lutomirski [this message]
2019-03-28  4:23                         ` Xing, Cedric
2019-03-28 19:18                           ` Andy Lutomirski
2019-03-28 23:19                             ` Xing, Cedric
2019-03-29  9:48                               ` Jarkko Sakkinen
2019-03-31  8:43                                 ` Dr. Greg
2019-04-03 23:03                             ` Sean Christopherson
2019-03-25 23:54                 ` Andy Lutomirski
2019-03-26  4:16                   ` Xing, Cedric
2019-03-20 16:21 ` [PATCH v19,RESEND 25/27] x86/sgx: SGX documentation Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 26/27] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2019-03-20 16:21 ` [PATCH v19,RESEND 27/27] x86/sgx: Update MAINTAINERS Jarkko Sakkinen

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