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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	linux-sgx@vger.kernel.org, akpm@linux-foundation.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, bp@alien8.de,
	josh@joshtriplett.org, luto@kernel.org, kai.huang@intel.com,
	rientjes@google.com, cedric.xing@intel.com,
	Suresh Siddha <suresh.b.siddha@intel.com>
Subject: Re: [PATCH v21 16/28] x86/sgx: Add the Linux SGX Enclave Driver
Date: Tue, 6 Aug 2019 00:39:46 +0300
Message-ID: <20190805213909.x5wv26zrgwqfrp4d@linux.intel.com> (raw)
In-Reply-To: <20190805161644.GD29275@linux.intel.com>

On Mon, Aug 05, 2019 at 09:16:44AM -0700, Sean Christopherson wrote:
> On Sat, Jul 13, 2019 at 08:07:52PM +0300, Jarkko Sakkinen wrote:
> > +static unsigned long sgx_get_unmapped_area(struct file *file,
> > +					   unsigned long addr,
> > +					   unsigned long len,
> > +					   unsigned long pgoff,
> > +					   unsigned long flags)
> > +{
> > +	if (flags & MAP_PRIVATE)
> > +		return -EINVAL;
> > +
> > +	if (flags & MAP_FIXED)
> > +		return addr;
> > +
> > +	if (len < 2 * PAGE_SIZE || len & (len - 1))
> > +		return -EINVAL;
> > +
> > +	addr = current->mm->get_unmapped_area(file, addr, 2 * len, pgoff,
> > +					      flags);
> > +	if (IS_ERR_VALUE(addr))
> > +		return addr;
> > +
> > +	addr = (addr + (len - 1)) & ~(len - 1);
> > +
> > +	return addr;
> > +}
> 
> Thinking about this more, I don't think the driver should verify or adjust
> @addr and @len during non-fixed mmap().  There is no requirement that
> userspace must map the full ELRANGE, or that an enclave's ELRANGE can
> *never* be mapped to non-EPC.  The architectural requirement is that an
> access that hits ELRANGE must map to the EPC *if* the CPU is executing the
> associated enclave.

Yeah, well, these were done in a quite different "ecosystem" where range
was the enclave and not like now. Can be considered as cruft that we
have simply missed when moving the fd associated enclaves.

In the current framework of things it definitely makes sense to remove
these calculations.

So, I guess we will end up to:

static unsigned long sgx_get_unmapped_area(struct file *file,
					   unsigned long addr,
					   unsigned long len,
					   unsigned long pgoff,
					   unsigned long flags)
{
	if (flags & MAP_PRIVATE)
		return -EINVAL;

	if (flags & MAP_FIXED)
		return addr;

	return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
}

/Jarkko

  reply index

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-13 17:07 [PATCH v21 00/28] Intel SGX foundations Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 01/28] x86/cpufeatures: Add Intel-defined SGX feature bit Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 02/28] x86/cpufeatures: Add SGX sub-features (as Linux-defined bits) Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 03/28] x86/msr: Add IA32_FEATURE_CONTROL.SGX_ENABLE definition Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 04/28] x86/cpufeatures: Add Intel-defined SGX_LC feature bit Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 05/28] x86/msr: Add SGX Launch Control MSR definitions Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 06/28] x86/mm: x86/sgx: Add new 'PF_SGX' page fault error code bit Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 07/28] x86/mm: x86/sgx: Signal SIGSEGV for userspace #PFs w/ PF_SGX Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 08/28] x86/cpu/intel: Detect SGX support and update caps appropriately Jarkko Sakkinen
2019-07-24 19:35   ` Sean Christopherson
2019-08-02 20:48     ` Jarkko Sakkinen
2019-08-07 15:17     ` Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 09/28] x86/sgx: Add ENCLS architectural error codes Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 10/28] x86/sgx: Add SGX1 and SGX2 architectural data structures Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 11/28] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 12/28] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 13/28] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 14/28] x86/sgx: Add sgx_einit() for initializing enclaves Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 15/28] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 16/28] x86/sgx: Add the Linux SGX Enclave Driver Jarkko Sakkinen
2019-07-29 11:17   ` Ayoun, Serge
2019-08-07 15:15     ` Jarkko Sakkinen
2019-08-07 15:17       ` Jarkko Sakkinen
2019-08-07 16:45         ` Jethro Beekman
2019-08-08 15:40       ` Sean Christopherson
2019-08-09 15:02         ` Jarkko Sakkinen
2019-08-09 15:24           ` Sean Christopherson
2019-08-05 16:16   ` Sean Christopherson
2019-08-05 21:39     ` Jarkko Sakkinen [this message]
2019-07-13 17:07 ` [PATCH v21 17/28] x86/sgx: Add provisioning Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 18/28] x86/sgx: Add swapping code to the core and SGX driver Jarkko Sakkinen
2019-08-07  6:33   ` Jethro Beekman
2019-08-07 19:12     ` Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 19/28] x86/sgx: ptrace() support for the " Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 20/28] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 21/28] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 22/28] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2019-07-13 17:07 ` [PATCH v21 23/28] x86/vdso: Add __vdso_sgx_enter_enclave() to wrap SGX enclave transitions Jarkko Sakkinen
2019-07-17 22:07   ` Xing, Cedric
2019-07-13 17:08 ` [PATCH v21 24/28] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2019-07-17 22:37   ` Xing, Cedric
2019-08-02 20:46     ` Jarkko Sakkinen
2019-08-16 15:43     ` Jarkko Sakkinen
2019-08-16 15:51       ` Jarkko Sakkinen
2019-08-16 16:56     ` Jarkko Sakkinen
2019-07-13 17:08 ` [PATCH v21 25/28] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2019-07-13 17:08 ` [PATCH v21 26/28] docs: x86/sgx: Add Architecture documentation Jarkko Sakkinen
2019-07-13 17:08 ` [PATCH v21 27/28] docs: x86/sgx: Document kernel internals Jarkko Sakkinen
2019-07-13 17:08 ` [PATCH v21 28/28] docs: x86/sgx: Document the enclave API Jarkko Sakkinen
2019-07-14 14:36 ` [PATCH v21 00/28] Intel SGX foundations Jarkko Sakkinen
2019-08-07  6:40   ` Jethro Beekman

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