Re: Unable to load large enclave

From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Jethro Beekman <jethro@fortanix.com>
Cc: "linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
	dave.hansen@intel.com, sean.j.christopherson@intel.com
Subject: Re: Unable to load large enclave
Date: Sat, 3 Oct 2020 16:12:49 +0300	[thread overview]
Message-ID: <20201003131249.GA5025@linux.intel.com> (raw)
In-Reply-To: <20200930114554.GA7612@linux.intel.com>

On Wed, Sep 30, 2020 at 02:45:54PM +0300, Jarkko Sakkinen wrote:
> On Wed, Sep 30, 2020 at 09:12:06AM +0200, Jethro Beekman wrote:
> > On 2020-09-30 03:16, Jarkko Sakkinen wrote:
> > > On Tue, Sep 29, 2020 at 05:52:48PM +0200, Jethro Beekman wrote:
> > >> Since the latest API changes, I'm unable to load a large enclave. The
> > >> test program at
> > >> https://github.com/fortanix/rust-sgx/blob/sgx-load-large-enclave-test/src/main.rs
> > >> always fails with ENOMEM after loading 0xffd6 pages.
> > >>
> > >> I've tested this with v36, if there's reason to believe it has been
> > >> fixed I'd be happy to try it out on a newer patch set.
> > > 
> > > I recommend using v39-rc1 tag that I created for testing because API is
> > > reverted back to be compatible with v36.
> > 
> > Not sure what you're saying. I tested with v36. You're saying v39-rc1
> > will be the same? Or did you fix the issue since v36?
> 
> v37 and v38 has an API change that is reverted in v39:
> 
> https://lore.kernel.org/linux-sgx/20200921195822.GA58176@linux.intel.com/
> 
> I'm not sure of the root cause yet but you asked to try to out a newer
> patch set and v39-rc1 is the best option.
> 
> There was off-by-one error in enclave maximum size calculation fixed in
> v37 (it was actually a bug in SDM inherited to the code) but that should
> not result the situation you just described.

Jethro,

I'll try to set up your environment and start looking into this, but in
the mean time can you provide a trivial ftrace dump?

Here's what you shoud do:

1. Install trace-cmd. It's tool that works as frontend for ftrace
   among other things. ftrace is one of the many tracing frameworks
   in the Linux kernel.
2. Run trace-cmd start -p function -l 'sgx*'. This will start
   to trace exported sgx prefixed functions.
3. Run your test.
4. Dump trace-cmd show output to a text file and send that to me.
5. trace-cmd stop stops the tracing framework.

Thank you.

/Jarkko