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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 22:04:06 +0200
Message-ID: <20181115200406.GA24299@linux.intel.com> (raw)
In-Reply-To: <20181115200002.GA24006@linux.intel.com>

On Thu, Nov 15, 2018 at 10:00:02PM +0200, Jarkko Sakkinen wrote:
> 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.

I wonder if you can map shmem file to process address space so that you
get it accounted for the process? That would be optimal for us. This way
this won't become an API issue.

Yeah, as I started to implement this I realized these issues with the
API side that will arise. Even doing vm_mmap() in the kernel code would
be better than taking addresses through the ioctl. That is another
option.

/Jarkko

  reply index

Thread overview: 61+ 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 ` Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 01/22] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2018-11-06 13:45   ` 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   ` 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   ` 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   ` 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   ` 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 13:45   ` Jarkko Sakkinen
2018-11-06 13:58   ` Sean Christopherson
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   ` 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   ` 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   ` 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   ` 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   ` 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   ` 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   ` 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   ` 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   ` 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   ` 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   ` Jarkko Sakkinen
2018-11-06 13:45 ` [PATCH v16 18/22] platform/x86: Intel SGX driver Jarkko Sakkinen
2018-11-06 13:45   ` 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
2018-11-07 18:00         ` Sean Christopherson
2018-11-08 14:46         ` Jarkko Sakkinen
2018-11-15 20:00           ` Jarkko Sakkinen
2018-11-15 20:04             ` Jarkko Sakkinen [this message]
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   ` 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 13:45   ` 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   ` Jarkko Sakkinen
2018-11-06 13:46 ` [PATCH v16 22/22] x86/sgx: SGX documentation Jarkko Sakkinen
2018-11-06 13:46   ` Jarkko Sakkinen
2018-11-27 20:13   ` Pavel Machek

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