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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Borislav Petkov <bp@alien8.de>,
	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,
	haitao.huang@intel.com, andriy.shevchenko@linux.intel.com,
	tglx@linutronix.de, kai.svahn@intel.com, josh@joshtriplett.org,
	luto@kernel.org, kai.huang@intel.com, rientjes@google.com,
	cedric.xing@intel.com, puiterwijk@redhat.com,
	Jethro Beekman <jethro@fortanix.com>
Subject: Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
Date: Fri, 29 May 2020 11:13:42 +0300	[thread overview]
Message-ID: <20200529081342.GB1376838@linux.intel.com> (raw)
In-Reply-To: <20200529081258.GA1376838@linux.intel.com>

On Fri, May 29, 2020 at 11:13:09AM +0300, Jarkko Sakkinen wrote:
> On Thu, May 28, 2020 at 08:37:16PM -0700, Sean Christopherson wrote:
> > On Fri, May 29, 2020 at 06:28:16AM +0300, Jarkko Sakkinen wrote:
> > > On Thu, May 28, 2020 at 12:59:17PM -0700, Sean Christopherson wrote:
> > > > On Thu, May 28, 2020 at 10:07:18PM +0300, Jarkko Sakkinen wrote:
> > > > >  * sgx_grab_page() - Grab a free EPC page
> > > > >  * @owner:	the owner of the EPC page
> > > > >  * @reclaim:	reclaim pages if necessary
> > > > >  *
> > > > >  * Iterate through EPC sections and borrow a free EPC page to the caller. When a
> > > > >  * page is no longer needed it must be released with sgx_free_page(). If
> > > > >  * @reclaim is set to true, directly reclaim pages when we are out of pages. No
> > > > >  * mm's can be locked when @reclaim is set to true.
> > > > >  *
> > > > >  * Finally, wake up ksgxswapd when the number of pages goes below the watermark
> > > > >  * before returning back to the caller.
> > > > >  *
> > > > >  * Return:
> > > > >  *   an EPC page,
> > > > >  *   -errno on error
> > > > >  */
> > > > > 
> > > > > I also rewrote the kdoc.
> > > > > 
> > > > > I do agree that sgx_try_grab_page() should be renamed as __sgx_grab_page().
> > > > 
> > > > FWIW, I really, really dislike "grab".  The nomenclature for normal memory
> > > > and pages uses "alloc" when taking a page off a free list, and "grab" when
> > > > elevating the refcount.  I don't understand the motivation for diverging
> > > > from that.  SGX is weird enough as is, using names that don't align with
> > > > exist norms will only serve to further obfuscate the code.
> > > 
> > > OK, what would be a better name then? The semantics are not standard
> > > memory allocation semantics in the first place. And kdoc in v30 speaks
> > > about grabbing.
> > 
> > In what way are they not standard allocation semantics?  sgx_alloc_page()
> > is an API to allocate (EPC) memory on-demand, sgx_free_page() is its partner
> > to free that memory when it is no longer needed.  There are many different
> > ways to manage and allocate memory, but the basic premise is the same for
> > all and no different than what we're doing.
> 
> I end up to (ignoring unchanged names):
> 
> - __sgx_alloc_epc_page_from_section() (static)
> - __sgx_alloc_epc_page()
> - sgx_alloc_epc_page()
> - sgx_setup_epc_section()

OK, also sgx_free_epc_page (not sgx_free_page() as before).

/Jarkko

  reply	other threads:[~2020-05-29  8:13 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 01/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-05-20 12:16   ` Borislav Petkov
2020-05-20 14:00     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
2020-05-20 12:23   ` Borislav Petkov
2020-05-20 14:04     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 03/20] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-05-20 18:47   ` Borislav Petkov
2020-05-20 21:04     ` Sean Christopherson
2020-05-22 15:54     ` Jarkko Sakkinen
2020-05-22 16:13       ` Sean Christopherson
2020-05-22 19:50         ` Jarkko Sakkinen
2020-05-25  8:20           ` Borislav Petkov
2020-05-27 19:43             ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 05/20] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 06/20] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2020-05-25  9:23   ` Borislav Petkov
2020-05-27  3:56     ` Sean Christopherson
2020-05-27 20:35       ` Borislav Petkov
2020-05-28  7:36         ` Jarkko Sakkinen
2020-05-28  5:25       ` Jarkko Sakkinen
2020-05-28  5:35         ` Jarkko Sakkinen
2020-05-28  6:14           ` Jarkko Sakkinen
2020-05-28  6:16             ` Jarkko Sakkinen
2020-05-28  5:13     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2020-05-26 12:52   ` Borislav Petkov
2020-05-27  4:21     ` Sean Christopherson
2020-05-27 20:46       ` Borislav Petkov
2020-05-28  0:52         ` Sean Christopherson
2020-05-28  6:51           ` Jarkko Sakkinen
2020-05-28  1:23         ` Jarkko Sakkinen
2020-05-28  1:36           ` Sean Christopherson
2020-05-28  6:52             ` Jarkko Sakkinen
2020-05-28 17:16               ` Borislav Petkov
2020-05-28 17:19                 ` Sean Christopherson
2020-05-28 17:27                   ` Borislav Petkov
2020-05-28 17:34                     ` Sean Christopherson
2020-05-28 19:07                 ` Jarkko Sakkinen
2020-05-28 19:59                   ` Sean Christopherson
2020-05-29  3:28                     ` Jarkko Sakkinen
2020-05-29  3:37                       ` Sean Christopherson
2020-05-29  5:07                         ` Jarkko Sakkinen
2020-05-29  8:12                         ` Jarkko Sakkinen
2020-05-29  8:13                           ` Jarkko Sakkinen [this message]
2020-05-29  3:38                       ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2020-05-29 12:10   ` Borislav Petkov
2020-05-29 18:18     ` Jarkko Sakkinen
2020-05-29 18:28   ` Dave Hansen
2020-05-31 23:12     ` Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 10/20] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
2020-05-21 19:12   ` Sean Christopherson
2020-05-22 19:26     ` Jarkko Sakkinen
2020-05-22 19:39     ` Jarkko Sakkinen
2020-05-22  3:33   ` Sean Christopherson
2020-05-15  0:44 ` [PATCH v30 11/20] x86/sgx: Add provisioning Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 12/20] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-05-22  6:58   ` Sean Christopherson
2020-05-22 19:57     ` Jarkko Sakkinen
2020-05-22 21:52       ` Sean Christopherson
2020-05-22  7:15   ` Sean Christopherson
2020-05-22 19:47     ` Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 13/20] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 14/20] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 15/20] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 16/20] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 17/20] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 18/20] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 19/20] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 20/20] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-05-16  8:57 ` [PATCH] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen

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