From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: linux-kernel@vger.kernel.org, intel-sgx-kernel-dev@lists.01.org,
platform-driver-x86@vger.kernel.org
Subject: Re: [intel-sgx-kernel-dev] [PATCH RFC v3 07/12] intel_sgx: driver for Intel Software Guard Extensions
Date: Tue, 14 Nov 2017 23:05:05 +0200 [thread overview]
Message-ID: <20171114210505.wu7kf5wef5l7ujhj@linux.intel.com> (raw)
In-Reply-To: <20171114193334.26fj2txyptd5se5c@linux.intel.com>
On Tue, Nov 14, 2017 at 09:33:34PM +0200, Jarkko Sakkinen wrote:
> On Tue, Nov 07, 2017 at 11:05:08AM -0800, Dave Hansen wrote:
> > On 11/07/2017 10:47 AM, Jarkko Sakkinen wrote:
> > > On Mon, Nov 06, 2017 at 07:54:00AM -0800, Dave Hansen wrote:
> > >> On 10/10/2017 07:32 AM, Jarkko Sakkinen wrote:
> > >>> +static LIST_HEAD(sgx_free_list);
> > >>> +static DEFINE_SPINLOCK(sgx_free_list_lock);
> > >>
> > >> Is this a global list? Will this be a scalability problem on larger
> > >> systems?
> > >
> > > It will be need to be refined for NUMA.
> > >
> > > In addition, per-CPU caches would probably make sense.
> > >
> > > For simplicity, I would keep it as it is up until the driver is in the
> > > mainline.
> >
> > FWIW, I don't think we should merge things that aren't performant.
> > Global locks like this are just intolerable. You can add this as a
> > later patch, but please don't merge stuff like this.
>
> The back pointer to struct sgx_encl_page from struct sgx_epc_page is
> useless. I've had this in backlog already long time ago but had forgot
> it as I've been mostly working with the launch infrastructure lately.
>
> Your comment worked as kind of a reminder of that. Thank you.
>
> Once that field is removed the whole struct is useless and EPC bank
> converges to an array. With an array the driver should be able reserve
> pages without a global lock.
>
> I've started writing a patch to make all this happen and it is
> progressing really well. I'm planning to include this change to v6.
> As it simplifies code I'm going to squash it as part of the initial
> driver patch.
>
> How does this sound?
Every sgx_epc_bank will have a bitmap array for reserved EPC.
Every unswapped sgx_encl_page will have a pointer containing physical
address of the EPC page in the upper bits and bank number in the lower
bits (like sgx_epc_page has now in the 'pa' field).
This layout does not require a global lock.
/Jarkko
next prev parent reply other threads:[~2017-11-14 21:05 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-10 14:32 [PATCH RFC v3 00/12] Intel(R) SGX Driver Jarkko Sakkinen
2017-10-10 14:32 ` [PATCH RFC v3 01/12] intel_sgx: updated MAINTAINERS Jarkko Sakkinen
2017-10-10 14:32 ` [PATCH RFC v3 02/12] x86: add SGX definition to cpufeature Jarkko Sakkinen
2017-10-10 14:32 ` [PATCH RFC v3 03/12] x86: define the feature control MSR's SGX enable bit Jarkko Sakkinen
2017-10-10 14:32 ` [PATCH RFC v3 04/12] x86: define the feature control MSR's SGX launch control bit Jarkko Sakkinen
2017-10-10 14:32 ` [PATCH RFC v3 05/12] x86: add SGX MSRs to msr-index.h Jarkko Sakkinen
2017-10-10 14:32 ` [PATCH RFC v3 06/12] fs/pipe.c: export create_pipe_files() and replace_fd() Jarkko Sakkinen
2017-10-10 14:32 ` [PATCH RFC v3 08/12] intel_sgx: ptrace() support Jarkko Sakkinen
2017-10-10 14:32 ` [PATCH RFC v3 09/12] intel_sgx: driver documentation Jarkko Sakkinen
2017-10-10 14:32 ` [PATCH RFC v3 10/12] intel_sgx: in-kernel launch enclave Jarkko Sakkinen
2017-11-08 20:07 ` [intel-sgx-kernel-dev] " Sean Christopherson
2017-11-14 14:22 ` Jarkko Sakkinen
2017-10-10 14:32 ` [PATCH RFC v3 11/12] intel_sgx: glue code for in-kernel LE Jarkko Sakkinen
2017-10-10 14:32 ` [PATCH RFC v3 12/12] intel_sgx: update IA32_SGXLEPUBKEYHASH* MSRs Jarkko Sakkinen
[not found] ` <20171010143258.21623-8-jarkko.sakkinen@linux.intel.com>
2017-10-10 15:41 ` [intel-sgx-kernel-dev] [PATCH RFC v3 07/12] intel_sgx: driver for Intel Software Guard Extensions Sean Christopherson
2017-10-11 11:46 ` Jarkko Sakkinen
2017-10-11 15:56 ` Sean Christopherson
2017-10-10 18:26 ` Sean Christopherson
2017-10-13 19:58 ` Jarkko Sakkinen
2017-10-13 20:02 ` Jarkko Sakkinen
2017-10-13 20:08 ` Jarkko Sakkinen
2017-10-13 20:13 ` Jarkko Sakkinen
2017-10-12 16:48 ` Sean Christopherson
2017-10-13 19:16 ` Jarkko Sakkinen
2017-11-02 19:48 ` Sean Christopherson
2017-11-06 7:23 ` Jarkko Sakkinen
2017-11-02 20:10 ` Sean Christopherson
2017-11-06 11:08 ` Jarkko Sakkinen
2017-11-06 11:33 ` Jarkko Sakkinen
2017-11-06 14:56 ` Sean Christopherson
2017-11-08 6:25 ` Jarkko Sakkinen
2017-11-06 11:39 ` Jarkko Sakkinen
2017-11-06 14:54 ` Sean Christopherson
2017-11-07 18:43 ` Jarkko Sakkinen
2017-11-06 15:54 ` Dave Hansen
2017-11-07 18:47 ` Jarkko Sakkinen
2017-11-07 19:05 ` Dave Hansen
2017-11-14 19:33 ` Jarkko Sakkinen
2017-11-14 21:05 ` Jarkko Sakkinen [this message]
2017-11-14 21:12 ` Dave Hansen
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