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Date:   Tue, 9 Jul 2019 19:18:08 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     Sean Christopherson <sean.j.christopherson@intel.com>
Cc:     linux-sgx@vger.kernel.org, linux-security-module@vger.kernel.org,
        selinux@vger.kernel.org,
        Bill Roberts <william.c.roberts@intel.com>,
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        Jethro Beekman <jethro@fortanix.com>,
        "Dr . Greg Wettstein" <greg@enjellic.com>,
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Subject: Re: [RFC PATCH v4 01/12] x86/sgx: Use mmu_notifier.release() instead
 of per-vma refcounting
Message-ID: <20190709161808.vx6qsnuhzoc4obzk@linux.intel.com>
References: <20190619222401.14942-1-sean.j.christopherson@intel.com>
 <20190619222401.14942-2-sean.j.christopherson@intel.com>
 <20190620210324.GF15383@linux.intel.com>
 <20190708145707.GC20433@linux.intel.com>
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On Mon, Jul 08, 2019 at 07:57:07AM -0700, Sean Christopherson wrote:
> On Fri, Jun 21, 2019 at 12:03:36AM +0300, Jarkko Sakkinen wrote:
> > On Wed, Jun 19, 2019 at 03:23:50PM -0700, Sean Christopherson wrote:
> > > Using per-vma refcounting to track mm_structs associated with an enclave
> > > requires hooking .vm_close(), which in turn prevents the mm from merging
> > > vmas (precisely to allow refcounting).
> > 
> > Why having sgx_vma_close() prevents that? I do not understand the
> > problem statement.
> 
> vmas that define .vm_close() cannot be merged.

Ugh, did not know that :-) Thank you.

/Jarkko