> -----Original Message-----
> From: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> Sent: Wednesday, August 10, 2022 6:51 PM
> To: Dhanraj, Vijay <vijay.dhanraj@xxxxxxxxx>
> Cc: linux-sgx@xxxxxxxxxxxxxxx; Chatre, Reinette
> <reinette.chatre@xxxxxxxxx>; dave.hansen@xxxxxxxxxxxxxxx; Huang, Haitao
> <haitao.huang@xxxxxxxxx>
> Subject: Re: [PATCH] Add SGX selftest `augment_via_eaccept_long`
>
> On Thu, Aug 11, 2022 at 04:36:57AM +0300, Jarkko Sakkinen wrote:
> > On Thu, Aug 11, 2022 at 04:01:15AM +0300, Jarkko Sakkinen wrote:
> > > On Wed, Aug 10, 2022 at 12:09:56AM +0000, Dhanraj, Vijay wrote:
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> > > > > Sent: Tuesday, August 9, 2022 11:53 AM
> > > > > To: Dhanraj, Vijay <vijay.dhanraj@xxxxxxxxx>
> > > > > Cc: linux-sgx@xxxxxxxxxxxxxxx; Chatre, Reinette
> > > > > <reinette.chatre@xxxxxxxxx>; dave.hansen@xxxxxxxxxxxxxxx; Huang,
> > > > > Haitao <haitao.huang@xxxxxxxxx>
> > > > > Subject: Re: [PATCH] Add SGX selftest `augment_via_eaccept_long`
> > > > >
> > > > > On Tue, Aug 09, 2022 at 05:08:21PM +0000, Dhanraj, Vijay wrote:
> > > > > >
> > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> > > > > > > Sent: Tuesday, August 9, 2022 9:10 AM
> > > > > > > To: Dhanraj, Vijay <vijay.dhanraj@xxxxxxxxx>
> > > > > > > Cc: linux-sgx@xxxxxxxxxxxxxxx; Chatre, Reinette
> > > > > > > <reinette.chatre@xxxxxxxxx>; dave.hansen@xxxxxxxxxxxxxxx;
> > > > > > > Huang, Haitao <haitao.huang@xxxxxxxxx>
> > > > > > > Subject: Re: [PATCH] Add SGX selftest
> > > > > > > `augment_via_eaccept_long`
> > > > > > >
> > > > > > > On Tue, Aug 09, 2022 at 01:45:35PM +0300, Jarkko Sakkinen wrote:
> > > > > > > > On Mon, Aug 08, 2022 at 06:29:13PM +0300, Jarkko Sakkinen
> wrote:
> > > > > > > > > On Mon, Aug 08, 2022 at 01:00:54PM +0000, Dhanraj, Vijay
> wrote:
> > > > > > > > > >
> > > > > > > > > > > -----Original Message-----
> > > > > > > > > > > From: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> > > > > > > > > > > Sent: Monday, August 8, 2022 5:18 AM
> > > > > > > > > > > To: Dhanraj, Vijay <vijay.dhanraj@xxxxxxxxx>
> > > > > > > > > > > Cc: linux-sgx@xxxxxxxxxxxxxxx; Chatre, Reinette
> > > > > > > > > > > <reinette.chatre@xxxxxxxxx>;
> > > > > > > > > > > dave.hansen@xxxxxxxxxxxxxxx; Huang, Haitao
> > > > > > > > > > > <haitao.huang@xxxxxxxxx>
> > > > > > > > > > > Subject: Re: [PATCH] Add SGX selftest
> > > > > > > > > > > `augment_via_eaccept_long`
> > > > > > > > > > >
> > > > > > > > > > > On Thu, Aug 04, 2022 at 01:14:56PM -0700,
> > > > > > > > > > > vijay.dhanraj@xxxxxxxxx
> > > > > > > wrote:
> > > > > > > > > > > > From: Vijay Dhanraj <vijay.dhanraj@xxxxxxxxx>
> > > > > > > > > > > >
> > > > > > > > > > > > This commit adds a new test case which is same as
> > > > > > > > > > > > `augment_via_eaccept` but adds more number of EPC
> > > > > > > > > > > > pages to stress test
> > > > > > > > > > > `EAUG` via `EACCEPT`.
> > > > > > > > > > > >
> > > > > > > > > > > > Signed-off-by: Vijay Dhanraj
> > > > > > > > > > > > <vijay.dhanraj@xxxxxxxxx>
> > > > > > > > > > > > Signed-off-by: Haitao Huang
> > > > > > > > > > > > <haitao.huang@xxxxxxxxxxxxxxx>
> > > > > > > > > > >
> > > > > > > > > > > Hey, to reproduce the original issue: does it
> > > > > > > > > > > reproduce on VM or should I run baremetal kernel?
> > > > > > > > > > >
> > > > > > > > > > > BR, Jarkko
> > > > > > > > > >
> > > > > > > > > > Hi Jarkko, The issue should be reproducible on baremetal
> kernel.
> > > > > > > > >
> > > > > > > > > Thanks.
> > > > > > > >
> > > > > > > > I need comment out other tests in order to make sane out
> > > > > > > > of this
> > > > > > > > :-)
> > > > > > > >
> > > > > > > > Mentioning this because came into realization that stress
> > > > > > > > tests should be IMHO moved each to a separate binary (so
> > > > > > > > that they can be run separately). Just a note (TODO) to myself.
> > > > > > > >
> > > > > > > > I'll work on this today again and *possibly* split your
> > > > > > > > test to its own application to get a starting point for
> forementioned.
> > > > > > >
> > > > > > > I got
> > > > > > >
> > > > > > > # RUN enclave.augment_via_eaccept_long ...
> > > > > > > # main.c:1241:augment_via_eaccept_long:test enclave:
> > > > > > > total_size = 8192,
> > > > > > > seg->size = 8192 # main.c:1241:augment_via_eaccept_long:test
> enclave:
> > > > > > > total_size = 12288, seg->size = 4096 #
> > > > > > > main.c:1241:augment_via_eaccept_long:test enclave:
> > > > > > > total_size = 36864,
> > > > > > > seg->size = 24576 # main.c:1241:augment_via_eaccept_long:test
> enclave:
> > > > > > > total_size = 40960, seg->size = 4096 #
> > > > > > > main.c:1259:augment_via_eaccept_long:mmaping pages at end of
> > > > > enclave...
> > > > > > > # main.c:1273:augment_via_eaccept_long:Entering enclave to
> > > > > > > run EACCEPT for each page of 8589934592 bytes may take a while
> ...
> > > > > > > # OK enclave.augment_via_eaccept_long
> > > > > > >
> > > > > > > The CPU used for testing was according to /proc/cpuinfo:
> > > > > > >
> > > > > > > model name : Intel(R) Xeon(R) Gold 6338 CPU @ 2.00GHz
> > > > > > >
> > > > > > > I have couple of queries:
> > > > > > >
> > > > > > > 1. Is it possible to get dmesg output?
> > > > > > I did check the dmesg output but couldn't find anything
> > > > > > related to the
> > > > > failure. Just the general log messages.
> > > > > >
> > > > > > > 2. Do I have to repeat the test multiple times, or does it
> > > > > > > occur unconditionaly?
> > > > > > >
> > > > > > I was able to repro every time but it was a bit sporadic for Haitao.
> > > > > >
> > > > > > > BR, Jarkko
> > > > > >
> > > > > > Also, did you set the PRMRR size to 2GB per socket in the
> > > > > > BIOS? The issue is only reproduced for oversubscribed
> > > > > > scenario. When I set my PRMRR to 64GB per socket, I wasn't able to
> repro the issue.
> > > > >
> > > > > I need to revisit this.
> > > > >
> > > > > Can you simply run test_sgx with gdb and see where it hits?
> > > > > HOST_CFLAGS has apparently "-g" already.
> > > > >
> > > > > > Regards, Vijay
> > > > >
> > > > > BR, Jarkko
> > > >
> > > > I am able to repro the issue when I reduce the PRMRR to 2B/socket but
> not but not able to break on the assertion failure with gdb. I also enabled
> debug attribute in the secs but still no avail. Anything I am missing here?
> > > >
> > > > diff --git a/tools/testing/selftests/sgx/load.c
> > > > b/tools/testing/selftests/sgx/load.c
> > > > index 7de1b15c90b1..c4bccd3f5f17 100644
> > > > --- a/tools/testing/selftests/sgx/load.c
> > > > +++ b/tools/testing/selftests/sgx/load.c
> > > > @@ -87,7 +87,7 @@ static bool encl_ioc_create(struct encl *encl)
> > > >
> > > > memset(secs, 0, sizeof(*secs));
> > > > secs->ssa_frame_size = 1;
> > > > - secs->attributes = SGX_ATTR_MODE64BIT;
> > > > + secs->attributes = SGX_ATTR_MODE64BIT | SGX_ATTR_DEBUG;
> > > > secs->xfrm = 3;
> > > > secs->base = encl->encl_base;
> > > > secs->size = encl->encl_size;
> > > >
> > > > Regards, Vijay
> > >
> > > I get also full pass with 2GB configuration (and also observed that
> > > kselftest runs much faster with this configuration).
> > >
> > > But I looked at sgx_alloc_epc_page() and saw this:
> > >
> > > if (list_empty(&sgx_active_page_list))
> > > return ERR_PTR(-ENOMEM);
> > >
> > > if (!reclaim) {
> > > page = ERR_PTR(-EBUSY);
> > > break;
> > > }
> > >
> > > In sgx_vma_fault(), when running completely out of reclaimable
> > > pages, this causes VM_FAULT_SIGBUS returned instead of
> VM_FAULT_NOPAGE:
> > >
> > > entry = sgx_encl_load_page(encl, addr, vma->vm_flags);
> > > if (IS_ERR(entry)) {
> > > mutex_unlock(&encl->lock);
> > >
> > > if (PTR_ERR(entry) == -EBUSY)
> > > return VM_FAULT_NOPAGE;
> > >
> > > return VM_FAULT_SIGBUS;
> > > }
> > >
> > > Not sure if those should be re-ordered that would keep the process
> > > stuck up until there is something to reclaim. Now we use NOPAGE to
> > > address situation when there is actually something to reclaim but
> > > because of locking side of things we pass reclaim=false to
> sgx_alloc_epc_page().
> > >
> > > So this is kind of OOM behaviour how it works now instead of
> > > stalling processes.
> >
> > Right, I looked at the original email at was really a page fault that
> > was catched. The above theory cannot possibly hold, as the process
> > does not exit with a bus error.
> >
> > I looked next to sgx_encl_eaug_page(), and found this:
> >
> > encl_page = sgx_encl_page_alloc(encl, addr - encl->base,
> secinfo_flags);
> > if (IS_ERR(encl_page))
> > return VM_FAULT_OOM;
> >
> > This is AFAIK the only code path in sgx_vma_fault() flow that
> > allocates non-EPC memory, and the code paths where EPC allocation
> > fails the result would be SIGBUS.
> >
> > So perhaps allocation is failing here. You could pretty easily trace
> > allocations with bpftrace and kretprobe to see if this is what is
> > happening, e.g. in one terminal:
> >
> > sudo bpftrace -e 'kr:sgx_encl_page_alloc /retval != 0/ { printf("%d\n",
> retval); }'
>
> Should be
>
> sudo bpftrace -e 'kr:sgx_encl_page_alloc /(long)retval < 0/ { printf("%d\n",
> retval); }'
>
> BR, Jarkko
Thanks let me check and get back to you.
Regards, Vijay
