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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: x86@kernel.org, platform-driver-x86@vger.kernel.org,
	linux-sgx@vger.kernel.org, dave.hansen@intel.com,
	nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com,
	shay.katz-zamir@intel.com, haitao.huang@intel.com,
	andriy.shevchenko@linux.intel.com, tglx@linutronix.de,
	kai.svahn@intel.com, Suresh Siddha <suresh.b.siddha@intel.com>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Darren Hart <dvhart@infradead.org>,
	Andy Shevchenko <andy@infradead.org>,
	"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" 
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v16 18/22] platform/x86: Intel SGX driver
Date: Thu, 15 Nov 2018 22:00:02 +0200	[thread overview]
Message-ID: <20181115200002.GA24006@linux.intel.com> (raw)
In-Reply-To: <20181108144603.GA14072@linux.intel.com>

On Thu, Nov 08, 2018 at 04:46:03PM +0200, Jarkko Sakkinen wrote:
> On Wed, Nov 07, 2018 at 10:00:57AM -0800, Sean Christopherson wrote:
> > What do we gain by a single buffer vs. separate buffers?  The ioctl()
> > would be slightly smaller but it seems like the actual code would be
> > more complex.
> 
> I'm fine with either. It was just a suggestion.
> 
> > The enclave build process also utilizes the backing as temp storage
> > to avoid having to alloc kernel memory when queueing pages to be added
> > by the worker thread (which reminds me that I wanted to document why a
> > worker thread is used).  Keeping this behavior would effectively make
> > providing backing mandatory.
> 
> Would it be a problem just allocate those pages with alloc_page() and
> free them in the worker thread?
> 
> > Are there any potential complications with ENCLS consuming userspace
> > pointers?  We'd have to wrap them with user_access_{begin,end}() and
> > probably tweak the fixup, but I assume having the fixup handler means
> > we're generally ok?
> 
> Last time I did it I used get_user_pages() for pinning. I'm not sure
> why I should do anything but just re-use that.

What about VA page swapping? Not saying that it'd have to be done right
now but we need to answer whether it is enclave local or a global asset.
If it is local it would also require an argument.

I will most likely won't fix this for v17 because this detail needs
careful consideration.

/Jarkko

  reply	other threads:[~2018-11-15 20:00 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-06 13:45 [PATCH v16 00/22] Intel SGX1 support Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 01/22] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 02/22] x86/cpufeatures: Add Intel-defined SGX feature bit Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 03/22] x86/cpufeatures: Add SGX sub-features (as Linux-defined bits) Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 04/22] x86/msr: Add IA32_FEATURE_CONTROL.SGX_ENABLE definition Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 05/22] x86/cpufeatures: Add Intel-defined SGX_LC feature bit Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 06/22] x86/cpu/intel: Detect SGX support and update caps appropriately Jarkko Sakkinen
2018-11-06 13:58   ` Sean Christopherson
2018-11-07 15:58     ` Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 07/22] x86/mm: x86/sgx: Add new 'PF_SGX' page fault error code bit Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 08/22] x86/mm: x86/sgx: Signal SIGSEGV for userspace #PFs w/ PF_SGX Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 09/22] x86/sgx: Define SGX1 and SGX2 ENCLS leafs Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 10/22] x86/sgx: Add ENCLS architectural error codes Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 11/22] x86/sgx: Add SGX1 and SGX2 architectural data structures Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 12/22] x86/sgx: Add definitions for SGX's CPUID leaf and variable sub-leafs Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 13/22] x86/msr: Add SGX Launch Control MSR definitions Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 14/22] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 15/22] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 16/22] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 17/22] x86/sgx: Add sgx_einit() for initializing enclaves Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 18/22] platform/x86: Intel SGX driver Jarkko Sakkinen
2018-11-06 16:40   ` Sean Christopherson
2018-11-06 16:57     ` Dave Hansen
2018-11-07 16:37     ` Jarkko Sakkinen
2018-11-07 18:00       ` Sean Christopherson
2018-11-08 14:46         ` Jarkko Sakkinen
2018-11-15 20:00           ` Jarkko Sakkinen [this message]
2018-11-15 20:04             ` Jarkko Sakkinen
2018-11-15 20:16               ` Jarkko Sakkinen
2018-11-21 11:46                 ` Jarkko Sakkinen
2018-11-07 10:29   ` David Laight
2018-11-06 13:45 ` [PATCH v16 19/22] platform/x86: sgx: Add swapping functionality to the " Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 20/22] x86/sgx: Add a simple swapper for the EPC memory manager Jarkko Sakkinen
2018-11-06 13:46 ` [PATCH v16 21/22] platform/x86: ptrace() support for the SGX driver Jarkko Sakkinen
2018-11-06 13:46 ` [PATCH v16 22/22] x86/sgx: SGX documentation Jarkko Sakkinen
2018-11-27 20:13   ` Pavel Machek

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