From: Andy Lutomirski <luto@kernel.org>
To: Jethro Beekman <jethro@fortanix.com>
Cc: "Christopherson, Sean J" <sean.j.christopherson@intel.com>,
"Andrew Lutomirski" <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Rich Felker <dalias@libc.org>, Jann Horn <jannh@google.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
Florian Weimer <fweimer@redhat.com>,
"Linux API" <linux-api@vger.kernel.org>, X86 ML <x86@kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"Peter Zijlstra" <peterz@infradead.org>, <nhorman@redhat.com>,
<npmccallum@redhat.com>, "Ayoun, Serge" <serge.ayoun@intel.com>,
<shay.katz-zamir@intel.com>, <linux-sgx@vger.kernel.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"Carlos O'Donell" <carlos@redhat.com>,
<adhemerval.zanella@linaro.org>
Subject: Re: RFC: userspace exception fixups
Date: Fri, 2 Nov 2018 10:01:08 -0700 [thread overview]
Message-ID: <CALCETrUo8uwnu3dBVSHVtB_z4uQgW=40grVdZWmTt64Tei6WiQ@mail.gmail.com> (raw)
In-Reply-To: <dd455b30-b586-bf5b-2195-cf20c1af9890@fortanix.com>
On Fri, Nov 2, 2018 at 9:56 AM Jethro Beekman <jethro@fortanix.com> wrote:
>
> On 2018-11-02 09:52, Sean Christopherson wrote:
> > On Fri, Nov 02, 2018 at 04:37:10PM +0000, Jethro Beekman wrote:
> >> On 2018-11-02 09:30, Sean Christopherson wrote:
> >>> ... The intended convention for EENTER is to have an ENCLU at the AEX target ...
> >>>
> >>> ... to further enforce that the AEX target needs to be ENCLU.
> >>
> >> Some SGX runtimes may want to use a different AEX target.
> >
> > To what end? Userspace gets no indication as to why the AEX occurred.
> > And if exceptions are getting transfered to userspace the trampoline
> > would effectively be handling only INTR, NMI, #MC and EPC #PF.
> >
>
> Various reasons...
>
> Userspace may have established an exception handling convention with the
> enclave (by setting TCS.NSSA > 1) and may want to call EENTER instead of
> ERESUME.
>
Ugh,
I sincerely hope that a future ISA extension lets the kernel return
directly back to enclave mode so that AEX events become entirely
invisible to user code. It would be nice if user developers didn't
start depending on the rather odd AEX semantics right now. But I
don't think the kernel can sanely do much about it.
WARNING: multiple messages have this Message-ID (diff)
From: Andy Lutomirski <luto@kernel.org>
To: Jethro Beekman <jethro@fortanix.com>
Cc: "Christopherson, Sean J" <sean.j.christopherson@intel.com>,
Andrew Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Rich Felker <dalias@libc.org>, Jann Horn <jannh@google.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
Florian Weimer <fweimer@redhat.com>,
Linux API <linux-api@vger.kernel.org>, X86 ML <x86@kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
nhorman@redhat.com, npmccallum@redhat.com, "Ayoun,
Serge" <serge.ayoun@intel.com>,
shay.katz-zamir@intel.com, linux-sgx@vger.kernel.org,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"Carlos O'Donell" <carlos@redhat.com>,
adhemerval.zanella@linaro.org
Subject: Re: RFC: userspace exception fixups
Date: Fri, 2 Nov 2018 10:01:08 -0700 [thread overview]
Message-ID: <CALCETrUo8uwnu3dBVSHVtB_z4uQgW=40grVdZWmTt64Tei6WiQ@mail.gmail.com> (raw)
Message-ID: <20181102170108.FAy-R8DRyGyX6AS-6QZjvEcmZwzyqR2ZvWtIf3H1cXM@z> (raw)
In-Reply-To: <dd455b30-b586-bf5b-2195-cf20c1af9890@fortanix.com>
On Fri, Nov 2, 2018 at 9:56 AM Jethro Beekman <jethro@fortanix.com> wrote:
>
> On 2018-11-02 09:52, Sean Christopherson wrote:
> > On Fri, Nov 02, 2018 at 04:37:10PM +0000, Jethro Beekman wrote:
> >> On 2018-11-02 09:30, Sean Christopherson wrote:
> >>> ... The intended convention for EENTER is to have an ENCLU at the AEX target ...
> >>>
> >>> ... to further enforce that the AEX target needs to be ENCLU.
> >>
> >> Some SGX runtimes may want to use a different AEX target.
> >
> > To what end? Userspace gets no indication as to why the AEX occurred.
> > And if exceptions are getting transfered to userspace the trampoline
> > would effectively be handling only INTR, NMI, #MC and EPC #PF.
> >
>
> Various reasons...
>
> Userspace may have established an exception handling convention with the
> enclave (by setting TCS.NSSA > 1) and may want to call EENTER instead of
> ERESUME.
>
Ugh,
I sincerely hope that a future ISA extension lets the kernel return
directly back to enclave mode so that AEX events become entirely
invisible to user code. It would be nice if user developers didn't
start depending on the rather odd AEX semantics right now. But I
don't think the kernel can sanely do much about it.
next prev parent reply other threads:[~2018-11-03 2:09 UTC|newest]
Thread overview: 163+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-01 17:53 RFC: userspace exception fixups Andy Lutomirski
2018-11-01 17:53 ` Andy Lutomirski
2018-11-01 18:09 ` Florian Weimer
2018-11-01 18:09 ` Florian Weimer
2018-11-01 18:30 ` Rich Felker
2018-11-01 18:30 ` Rich Felker
2018-11-01 19:00 ` Jarkko Sakkinen
2018-11-01 19:00 ` Jarkko Sakkinen
2018-11-01 18:27 ` Rich Felker
2018-11-01 18:27 ` Rich Felker
2018-11-01 18:33 ` Jann Horn
2018-11-01 18:33 ` Jann Horn
2018-11-01 18:52 ` Rich Felker
2018-11-01 18:52 ` Rich Felker
2018-11-01 19:10 ` Linus Torvalds
2018-11-01 19:10 ` Linus Torvalds
2018-11-01 19:31 ` Rich Felker
2018-11-01 19:31 ` Rich Felker
2018-11-01 21:24 ` Linus Torvalds
2018-11-01 21:24 ` Linus Torvalds
2018-11-01 23:22 ` Andy Lutomirski
2018-11-01 23:22 ` Andy Lutomirski
2018-11-02 16:30 ` Sean Christopherson
2018-11-02 16:30 ` Sean Christopherson
2018-11-02 16:37 ` Jethro Beekman
2018-11-02 16:37 ` Jethro Beekman
2018-11-02 16:52 ` Sean Christopherson
2018-11-02 16:52 ` Sean Christopherson
2018-11-02 16:56 ` Jethro Beekman
2018-11-02 16:56 ` Jethro Beekman
2018-11-02 17:01 ` Andy Lutomirski [this message]
2018-11-02 17:01 ` Andy Lutomirski
2018-11-02 17:05 ` Jethro Beekman
2018-11-02 17:05 ` Jethro Beekman
2018-11-02 17:16 ` Andy Lutomirski
2018-11-02 17:16 ` Andy Lutomirski
2018-11-02 17:32 ` Rich Felker
2018-11-02 17:32 ` Rich Felker
2018-11-02 17:12 ` Sean Christopherson
2018-11-02 17:12 ` Sean Christopherson
2018-11-02 22:42 ` Jarkko Sakkinen
2018-11-02 22:42 ` Jarkko Sakkinen
2018-11-02 16:56 ` Dave Hansen
2018-11-02 16:56 ` Dave Hansen
2018-11-02 17:06 ` Sean Christopherson
2018-11-02 17:06 ` Sean Christopherson
2018-11-02 17:13 ` Dave Hansen
2018-11-02 17:13 ` Dave Hansen
2018-11-02 17:33 ` Sean Christopherson
2018-11-02 17:33 ` Sean Christopherson
2018-11-02 17:48 ` Andy Lutomirski
2018-11-02 17:48 ` Andy Lutomirski
2018-11-02 18:27 ` Sean Christopherson
2018-11-02 18:27 ` Sean Christopherson
2018-11-02 19:02 ` Jann Horn
2018-11-02 19:02 ` Jann Horn
2018-11-02 22:04 ` Sean Christopherson
2018-11-02 22:04 ` Sean Christopherson
2018-11-02 23:27 ` Jann Horn
2018-11-02 23:27 ` Jann Horn
2018-11-02 23:32 ` Andy Lutomirski
2018-11-02 23:32 ` Andy Lutomirski
2018-11-02 23:36 ` Jann Horn
2018-11-02 23:36 ` Jann Horn
2018-11-06 15:37 ` Sean Christopherson
2018-11-06 15:37 ` Sean Christopherson
2018-11-06 16:57 ` Andy Lutomirski
2018-11-06 16:57 ` Andy Lutomirski
2018-11-06 17:03 ` Dave Hansen
2018-11-06 17:03 ` Dave Hansen
2018-11-06 17:19 ` Sean Christopherson
2018-11-06 17:19 ` Sean Christopherson
2018-11-06 18:20 ` Andy Lutomirski
2018-11-06 18:20 ` Andy Lutomirski
2018-11-06 18:41 ` Dave Hansen
2018-11-06 18:41 ` Dave Hansen
2018-11-06 19:02 ` Andy Lutomirski
2018-11-06 19:02 ` Andy Lutomirski
2018-11-06 19:22 ` Dave Hansen
2018-11-06 19:22 ` Dave Hansen
2018-11-06 20:12 ` Andy Lutomirski
2018-11-06 20:12 ` Andy Lutomirski
2018-11-06 21:00 ` Dave Hansen
2018-11-06 21:00 ` Dave Hansen
2018-11-06 21:07 ` Andy Lutomirski
2018-11-06 21:07 ` Andy Lutomirski
2018-11-06 21:41 ` Andy Lutomirski
2018-11-06 21:41 ` Andy Lutomirski
2018-11-06 21:59 ` Sean Christopherson
2018-11-06 21:59 ` Sean Christopherson
2018-11-06 23:00 ` Andy Lutomirski
2018-11-06 23:00 ` Andy Lutomirski
2018-11-06 23:35 ` Sean Christopherson
2018-11-06 23:35 ` Sean Christopherson
2018-11-06 23:39 ` Andy Lutomirski
2018-11-06 23:39 ` Andy Lutomirski
2018-11-07 0:02 ` Sean Christopherson
2018-11-07 0:02 ` Sean Christopherson
2018-11-07 1:17 ` Andy Lutomirski
2018-11-07 1:17 ` Andy Lutomirski
2018-11-07 6:47 ` Jethro Beekman
2018-11-07 6:47 ` Jethro Beekman
2018-11-07 15:34 ` Sean Christopherson
2018-11-07 15:34 ` Sean Christopherson
2018-11-07 19:01 ` Sean Christopherson
2018-11-07 19:01 ` Sean Christopherson
2018-11-07 20:56 ` Dave Hansen
2018-11-07 20:56 ` Dave Hansen
2018-11-08 15:04 ` Jarkko Sakkinen
2018-11-08 15:04 ` Jarkko Sakkinen
2018-11-08 19:54 ` Sean Christopherson
2018-11-08 19:54 ` Sean Christopherson
2018-11-08 20:05 ` Andy Lutomirski
2018-11-08 20:05 ` Andy Lutomirski
2018-11-08 20:10 ` Dave Hansen
2018-11-08 20:10 ` Dave Hansen
2018-11-08 21:16 ` Sean Christopherson
2018-11-08 21:16 ` Sean Christopherson
2018-11-08 21:50 ` Dave Hansen
2018-11-08 21:50 ` Dave Hansen
2018-11-08 22:04 ` Sean Christopherson
2018-11-08 22:04 ` Sean Christopherson
2018-11-09 7:12 ` Christoph Hellwig
2018-11-09 7:12 ` Christoph Hellwig
2018-11-06 23:17 ` Rich Felker
2018-11-06 23:17 ` Rich Felker
2018-11-06 23:26 ` Sean Christopherson
2018-11-06 23:26 ` Sean Christopherson
2018-11-07 21:27 ` Rich Felker
2018-11-07 21:27 ` Rich Felker
2018-11-07 21:33 ` Andy Lutomirski
2018-11-07 21:33 ` Andy Lutomirski
2018-11-07 21:40 ` Sean Christopherson
2018-11-07 21:40 ` Sean Christopherson
2018-11-08 15:11 ` Jarkko Sakkinen
2018-11-08 15:11 ` Jarkko Sakkinen
2018-11-06 17:00 ` Dave Hansen
2018-11-06 17:00 ` Dave Hansen
2018-11-02 22:37 ` Jarkko Sakkinen
2018-11-02 22:37 ` Jarkko Sakkinen
2018-11-01 19:06 ` Linus Torvalds
2018-11-01 19:06 ` Linus Torvalds
2018-11-02 22:07 ` Jarkko Sakkinen
2018-11-02 22:07 ` Jarkko Sakkinen
2018-11-18 7:15 ` Jarkko Sakkinen
2018-11-18 7:18 ` Jarkko Sakkinen
2018-11-18 13:02 ` Jarkko Sakkinen
2018-11-19 5:17 ` Jethro Beekman
2018-11-19 14:05 ` Jarkko Sakkinen
2018-11-19 14:59 ` Jarkko Sakkinen
2018-11-19 15:29 ` Andy Lutomirski
2018-11-19 16:02 ` Jarkko Sakkinen
2018-11-19 17:00 ` Andy Lutomirski
2018-11-20 10:11 ` Jarkko Sakkinen
2018-11-20 15:19 ` Andy Lutomirski
2018-11-20 22:55 ` Jarkko Sakkinen
2018-11-21 5:17 ` Jethro Beekman
2018-11-21 15:17 ` Jarkko Sakkinen
2018-11-24 17:07 ` Jarkko Sakkinen
2018-11-26 14:35 ` Sean Christopherson
2018-11-26 22:06 ` Jarkko Sakkinen
2018-11-20 18:09 ` Sean Christopherson
2018-11-20 22:46 ` Jarkko Sakkinen
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