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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "Xing, Cedric" <cedric.xing@intel.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Andy Lutomirski <luto@kernel.org>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	James Morris <jmorris@namei.org>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	LSM List <linux-security-module@vger.kernel.org>,
	Paul Moore <paul@paul-moore.com>,
	Eric Paris <eparis@parisplace.org>,
	"selinux@vger.kernel.org" <selinux@vger.kernel.org>,
	Jethro Beekman <jethro@fortanix.com>,
	"Hansen, Dave" <dave.hansen@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
	"linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"nhorman@redhat.com" <nhorman@redhat.com>,
	"npmccallum@redhat.com" <npmccallum@redhat.com>,
	"Ayoun, Serge" <serge.ayoun@intel.com>,
	"Katz-zamir, Shay" <shay.katz-zamir@intel.com>,
	"Huang, Haitao" <haitao.huang@intel.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	"Svahn, Kai" <kai.svahn@intel.com>,
	Borislav Petkov <bp@alien8.de>,
	Josh Triplett <josh@joshtriplett.org>,
	"Huang, Kai" <kai.huang@intel.com>,
	David Rientjes <rientjes@google.com>,
	"Roberts, William C" <william.c.roberts@intel.com>,
	"Tricca, Philip B" <philip.b.tricca@intel.com>
Subject: Re: [RFC PATCH 2/9] x86/sgx: Do not naturally align MAP_FIXED address
Date: Fri, 14 Jun 2019 18:18:28 +0300
Message-ID: <20190614151805.GB11241@linux.intel.com> (raw)
In-Reply-To: <20190613171451.GD5850@linux.intel.com>

On Thu, Jun 13, 2019 at 10:14:51AM -0700, Sean Christopherson wrote:
> > I don't get this. The swapper takes a read lock on mm->mmap_sem, which locks
> > the vma, which in turn reference counts vma->vm_file. Why is the internal
> > refcount still needed? 
> 
> mmap_sem is only held when reclaim is touching PTEs, e.g. to test/clear
> its accessed bit and to zap the PTE.  The liveliness of the enclave needs
> to be guaranteed for the entire duration of reclaim, e.g. we can't have
> the enclave disappearing when we go to do EWB.  It's also worth nothing
> that a single reclaim may operate on more than one mmap_sem, as enclaves
> can be shared across processes (mm_structs).

Anyway, the takeaway I got from this is that encl->refcount does not
need to be updated for VMAs (sent a patch to linux-sgx that I plan
merge).

/Jarkko

  reply index

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-31 23:31 [RFC PATCH 0/9] security: x86/sgx: SGX vs. LSM Sean Christopherson
2019-05-31 23:31 ` [RFC PATCH 1/9] x86/sgx: Remove unused local variable in sgx_encl_release() Sean Christopherson
2019-06-04 11:41   ` Jarkko Sakkinen
2019-05-31 23:31 ` [RFC PATCH 2/9] x86/sgx: Do not naturally align MAP_FIXED address Sean Christopherson
2019-06-04 11:49   ` Jarkko Sakkinen
2019-06-04 20:16     ` Andy Lutomirski
2019-06-04 22:10       ` Xing, Cedric
2019-06-05 14:08         ` Sean Christopherson
2019-06-05 15:17         ` Jarkko Sakkinen
2019-06-05 20:14           ` Andy Lutomirski
2019-06-06 15:37             ` Jarkko Sakkinen
2019-06-13 13:48               ` Jarkko Sakkinen
2019-06-13 16:47                 ` Xing, Cedric
2019-06-13 17:14                   ` Sean Christopherson
2019-06-14 15:18                     ` Jarkko Sakkinen [this message]
2019-06-05 15:15       ` Jarkko Sakkinen
2019-05-31 23:31 ` [RFC PATCH 3/9] x86/sgx: Allow userspace to add multiple pages in single ioctl() Sean Christopherson
2019-06-03  6:26   ` Xing, Cedric
2019-06-03 20:08     ` Sean Christopherson
2019-06-03 20:39       ` Sean Christopherson
2019-06-03 23:45         ` Xing, Cedric
2019-06-04  0:54           ` Sean Christopherson
2019-06-04 20:18         ` Andy Lutomirski
2019-06-04 22:02           ` Xing, Cedric
2019-06-03 20:14   ` Dave Hansen
2019-06-03 20:37     ` Sean Christopherson
2019-06-03 20:39       ` Dave Hansen
2019-06-03 23:48       ` Xing, Cedric
2019-06-04  0:55         ` Sean Christopherson
2019-06-04 11:55   ` Jarkko Sakkinen
2019-05-31 23:31 ` [RFC PATCH 4/9] mm: Introduce vm_ops->mprotect() Sean Christopherson
2019-06-03  6:27   ` Xing, Cedric
2019-06-04 12:24   ` Jarkko Sakkinen
2019-06-04 14:51   ` Andy Lutomirski
2019-05-31 23:31 ` [RFC PATCH 5/9] x86/sgx: Restrict mapping without an enclave page to PROT_NONE Sean Christopherson
2019-06-03  6:28   ` Xing, Cedric
2019-06-04 15:32   ` Jarkko Sakkinen
2019-05-31 23:31 ` [RFC PATCH 6/9] x86/sgx: Require userspace to provide allowed prots to ADD_PAGES Sean Christopherson
2019-06-03  6:28   ` Xing, Cedric
2019-06-04 16:23   ` Jarkko Sakkinen
2019-06-04 16:45     ` Sean Christopherson
2019-06-05 15:06       ` Jarkko Sakkinen
2019-06-04 20:23   ` Andy Lutomirski
2019-06-05 11:10   ` Ayoun, Serge
2019-06-05 23:58     ` Sean Christopherson
2019-05-31 23:31 ` [RFC PATCH 7/9] x86/sgx: Enforce noexec filesystem restriction for enclaves Sean Christopherson
2019-06-03  6:29   ` Xing, Cedric
2019-06-04 20:26     ` Andy Lutomirski
2019-06-04 16:25   ` Jarkko Sakkinen
2019-06-04 20:25     ` Andy Lutomirski
2019-06-04 20:34       ` Sean Christopherson
2019-06-04 21:54       ` Xing, Cedric
2019-06-05 15:10       ` Jarkko Sakkinen
2019-06-06  1:01         ` Sean Christopherson
2019-05-31 23:31 ` [RFC PATCH 8/9] LSM: x86/sgx: Introduce ->enclave_load() hook for Intel SGX Sean Christopherson
2019-06-03  6:28   ` Xing, Cedric
2019-06-03 14:19   ` Stephen Smalley
2019-06-03 14:42     ` Sean Christopherson
2019-06-03 18:38       ` Stephen Smalley
2019-06-03 18:45         ` Dave Hansen
2019-06-04 20:29   ` Andy Lutomirski
2019-06-04 20:36     ` Sean Christopherson
2019-06-04 21:43       ` Xing, Cedric
2019-06-06  2:04         ` Sean Christopherson
2019-05-31 23:31 ` [RFC PATCH 9/9] security/selinux: Add enclave_load() implementation Sean Christopherson
2019-06-03 15:01   ` Stephen Smalley
2019-06-03 15:50     ` Sean Christopherson
2019-06-02  7:29 ` [RFC PATCH 0/9] security: x86/sgx: SGX vs. LSM Xing, Cedric
2019-06-03 17:15   ` Sean Christopherson
2019-06-03 18:30     ` Xing, Cedric
2019-06-04  1:36       ` Sean Christopherson
2019-06-04 15:33       ` Stephen Smalley
2019-06-04 16:30         ` Sean Christopherson
2019-06-04 21:38         ` Xing, Cedric
2019-06-03 17:47   ` Stephen Smalley
2019-06-03 18:02     ` Xing, Cedric
2019-06-04 11:15 ` Jarkko Sakkinen

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