From: Jarkko Sakkinen <jarkko@kernel.org>
To: Reinette Chatre <reinette.chatre@intel.com>
Cc: mtk.manpages@gmail.com, linux-man@vger.kernel.org,
linux-sgx@vger.kernel.org, dave.hansen@linux.intel.com
Subject: Re: [PATCH v5] sgx.7: New page with overview of Software Guard eXtensions (SGX)
Date: Wed, 12 May 2021 04:16:27 +0300 [thread overview]
Message-ID: <YJssa9DyboM8nWXL@kernel.org> (raw)
In-Reply-To: <7ea35a75-a75d-4071-cbf7-f43c672a5a45@intel.com>
On Tue, May 11, 2021 at 01:22:10PM -0700, Reinette Chatre wrote:
> Hi Jarkko,
>
> On 5/10/2021 7:52 AM, Jarkko Sakkinen wrote:
>
> ...
>
> > +There is a hardware constraint that the enclave size must be a power of two,
> > +and the base address must be a multiple of the size.
> > +This can lead to reserving a large region than required by the payload,
>
> a large region than required -> a larger region than required ?
>
> > +but the address space can be obviously trimmed after the enclave has been
>
> can be obviously trimmed -> can be trimmed ?
>
> > +constructed on,
>
> constructed on -> constructed ?
>
> > +with a sequence of
> > +.BR mmap(MAP_FIXED)
> > +calls.
> > +.PP
> > +A process can access enclave by entering into its address space through
> > +a set of entry points,
> > +which must be defined during the construction process.
> > +This requires a complex sequence of CPU instructions,
> > +and kernel assisted exception handling,
> > +encapsulated into
> > +.BR vsgx_enter_enclave
> > +vDSO interface,
> > +provided and documented by
> > +.IR <asm/sgx.h>.
>
> This is not clear to me. This is written as though vsgx_enter_enclave is
> something very specific that is documented in <asm/sgx.h>. Should it perhaps
> be vdso_sgx_enter_enclave_t instead? Am I missing where vsgx_enter_enclave
> is defined? I expect a reader of this man page may want to search for the
> term "vsgx_enter_enclave" after reading the above.
Yeah, it's now incorrect. I'll fix this. Thanks for pointing out.
>
> > +.SS Permissions
> > +In order to build an enclave, a process must be able to call
> > +.IR mmap (2)
> > +with
> > +.IR PROT_EXEC
> > +set.
> > +Like for any other type of executable,
> > +the page permissions must be set appropriately.
> > +For this reason,
> > +.I /dev/sgx_enclave
> > +must reside in a partition,
> > +which is not mounted as no-exec,
> > +in order to be usable,
> > +as
> > +.IR mmap(2)
> > +denies
> > +.IR PROT_EXEC
> > +otherwise.
> > +.SH VERSIONS
> > +The SGX feature was added in Linux 5.11.
> > +.SH SEE ALSO
> > +.BR ioctl (2),
> > +.BR mmap() (2),
>
> mmap() (2) -> mmap (2) ?
>
> > +.BR mprotect (2)
> >
>
> Reinette
Also, other remarks make sense to me, thanks.
/Jarkko
prev parent reply other threads:[~2021-05-12 1:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-10 14:52 [PATCH v5] sgx.7: New page with overview of Software Guard eXtensions (SGX) Jarkko Sakkinen
2021-05-10 14:58 ` Dave Hansen
2021-05-10 17:33 ` Jarkko Sakkinen
2021-05-11 20:22 ` Reinette Chatre
2021-05-12 1:16 ` Jarkko Sakkinen [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YJssa9DyboM8nWXL@kernel.org \
--to=jarkko@kernel.org \
--cc=dave.hansen@linux.intel.com \
--cc=linux-man@vger.kernel.org \
--cc=linux-sgx@vger.kernel.org \
--cc=mtk.manpages@gmail.com \
--cc=reinette.chatre@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).