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From: Andy Lutomirski <luto@kernel.org>
To: Nathaniel McCallum <npmccallum@redhat.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	X86 ML <x86@kernel.org>,
	linux-sgx@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Jethro Beekman <jethro@fortanix.com>,
	Cedric Xing <cedric.xing@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	asapek@google.com, Borislav Petkov <bp@alien8.de>,
	chenalexchen@google.com, Conrad Parker <conradparker@google.com>,
	cyhanish@google.com, Dave Hansen <dave.hansen@intel.com>,
	"Huang, Haitao" <haitao.huang@intel.com>,
	Josh Triplett <josh@joshtriplett.org>,
	"Huang, Kai" <kai.huang@intel.com>,
	"Svahn, Kai" <kai.svahn@intel.com>, Keith Moyer <kmoy@google.com>,
	Christian Ludloff <ludloff@google.com>,
	Andrew Lutomirski <luto@kernel.org>,
	Neil Horman <nhorman@redhat.com>,
	Patrick Uiterwijk <puiterwijk@redhat.com>,
	David Rientjes <rientjes@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	yaozhangx@google.com
Subject: Re: [PATCH v36 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call
Date: Mon, 10 Aug 2020 16:08:46 -0700
Message-ID: <CALCETrVch_XW-oc_-LR8Dbgat9DpSKtCYTV9YZaU7tfu61FHEw@mail.gmail.com> (raw)
In-Reply-To: <CAOASepOqRfUafSv_qjUv-jW_6n8G7kZ9yh-2z_Z9sjL_2zqNCg@mail.gmail.com>

On Thu, Aug 6, 2020 at 7:55 AM Nathaniel McCallum <npmccallum@redhat.com> wrote:
>
> In a past revision of this patch, I had requested a void *misc
> parameter that could be passed through vdso_sgx_enter_enclave_t into
> sgx_enclave_exit_handler_t. This request encountered some push back
> and I dropped the issue. However, I'd like to revisit it or something
> similar.

Why do you need an exit handler at all?  IIRC way back when I
suggested that we simply not support it at all.  If you want to
call__vdso_sgx_enter_enclave() in a loop, call it in a loop.  If you
want to wrap it intelligently in Rust, you don't want a callback
anyway -- that forces you have an FFI (or non-Rust, anyway) frame on
the stack, which interacts poorly with panic handling and prevents you
from using await in your Rust callback handler.  If, on the other
hand, you just call __vdso_sg_enter_enclave() in a loop, all these
problems go away and, if you really want, you can pass in a callback
in Rust and call the callback from Rust.

What am I missing?  I still don't really understand why we are
supporting this mechanism at all.  Just the asm code to invoke the
callback seems to be about half of the entire function.

  parent reply index

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-16 13:52 [PATCH v36 00/24] Intel SGX foundations Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-08-06 13:13   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 02/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-08-06 13:14   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 03/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-08-06 13:16   ` Darren Kenny
2020-08-20 15:31   ` Borislav Petkov
2020-08-21 17:35     ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 04/24] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-08-06 13:14   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 05/24] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-08-07  9:37   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 06/24] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-08-06 13:17   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 07/24] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-08-06 13:18   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 08/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-08-06 13:27   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 09/24] x86/sgx: Add __sgx_alloc_epc_page() and sgx_free_epc_page() Jarkko Sakkinen
2020-08-06 13:29   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 10/24] mm: Add vm_ops->mprotect() Jarkko Sakkinen
2020-08-06 13:35   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 11/24] x86/sgx: Add SGX enclave driver Jarkko Sakkinen
2020-08-06 13:59   ` Darren Kenny
2020-08-25 16:44   ` Borislav Petkov
2020-08-26 13:46     ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE Jarkko Sakkinen
2020-08-06 15:40   ` Darren Kenny
2020-08-26 14:52   ` Borislav Petkov
2020-08-27 13:24     ` Jarkko Sakkinen
2020-08-27 16:15       ` Borislav Petkov
2020-08-28 23:39         ` Jarkko Sakkinen
2020-08-29  0:21       ` Jarkko Sakkinen
2020-09-01 16:41   ` Haitao Huang
2020-09-04 11:55     ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Jarkko Sakkinen
2020-08-06 16:29   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT Jarkko Sakkinen
2020-08-06 16:40   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 15/24] x86/sgx: Allow a limited use of ATTRIBUTE.PROVISIONKEY for attestation Jarkko Sakkinen
2020-08-06 17:00   ` Darren Kenny
2020-08-18 13:30     ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 16/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 17/24] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 18/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 19/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 20/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-08-06 14:55   ` Nathaniel McCallum
2020-08-10 22:23     ` Sean Christopherson
2020-08-11  7:16       ` Jethro Beekman
2020-08-11 14:54         ` Sean Christopherson
2020-08-18 14:52       ` Jarkko Sakkinen
2020-08-18 15:06         ` Jarkko Sakkinen
2020-08-18 15:15           ` Nathaniel McCallum
2020-08-18 16:43             ` Jarkko Sakkinen
2020-08-19 13:33               ` Nathaniel McCallum
2020-08-19 14:00                 ` Jethro Beekman
2020-08-19 21:23                 ` Jarkko Sakkinen
2020-08-10 23:08     ` Andy Lutomirski [this message]
2020-08-10 23:48       ` Sean Christopherson
2020-08-11  0:52         ` Andy Lutomirski
2020-08-11 15:16           ` Andy Lutomirski
2020-08-13 19:38             ` Sean Christopherson
2020-08-17 13:12       ` Nathaniel McCallum
2020-08-17 15:01         ` Andy Lutomirski
2020-08-18 15:15       ` Jarkko Sakkinen
2020-08-20  0:19         ` Andy Lutomirski
2020-08-18 14:26     ` Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 22/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-08-27  4:47   ` Nathaniel McCallum
2020-08-27 15:20     ` Sean Christopherson
2020-08-28 23:27       ` Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 23/24] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-07-28 21:35   ` Pavel Machek
2020-08-06 10:21     ` Dr. Greg
2020-08-08 22:18       ` Pavel Machek
2020-08-19 20:55     ` Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 24/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen

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