From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-sgx@vger.kernel.org, akpm@linux-foundation.org,
dave.hansen@intel.com, nhorman@redhat.com, npmccallum@redhat.com,
serge.ayoun@intel.com, shay.katz-zamir@intel.com,
haitao.huang@intel.com, andriy.shevchenko@linux.intel.com,
tglx@linutronix.de, kai.svahn@intel.com, josh@joshtriplett.org,
luto@kernel.org, kai.huang@intel.com, rientjes@google.com,
cedric.xing@intel.com, Kai Huang <kai.huang@linux.intel.com>,
Haim Cohen <haim.cohen@intel.com>
Subject: Re: [PATCH v22 02/24] x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
Date: Wed, 25 Sep 2019 12:08:26 -0700 [thread overview]
Message-ID: <20190925190825.GK31852@linux.intel.com> (raw)
In-Reply-To: <20190925183136.GH3891@zn.tnic>
On Wed, Sep 25, 2019 at 08:31:36PM +0200, Borislav Petkov wrote:
> On Wed, Sep 25, 2019 at 10:18:24AM -0700, Sean Christopherson wrote:
> > Realistically, there will likely be a non-trivial number of systems with
> > SGX_LE_WR=0 but SGX enabled.
>
> Well no. We won't support those. I remember very vividly at Tech Days a
> couple of years ago where we said we won't support locked down systems.
Yep, that's our intent as well.
> > It's inevitable that some systems will lock down the LE hash MSRs, either
> > intentionally or due to lack of support for SGX_LE_WR. The latter is
> > probably going to be more common than OEMs intentionally locking the MSRs,
> > because some Intel reference BIOSes simply don't support SGX_LE_WR, e.g. I
> > have a Coffee Lake SDP that has hardware support for SGX_LC, but the BIOS
> > doesn't provide any way to set SGX_LE_WR or leave FEATURE_CONTROL unlocked.
>
> We won't support those too. Nothing changes since a couple of years ago.
> We won't support locked down systems and unfinished BIOS systems.
Yep.
> ... reading your other mail about KVM...
>
> I guess KVM could be an exception here if people wanna run different
> OSes in the guest. IMHO.
>
> For that, though, we should still clear all SGX feature bits in the
> host, I'd say, and let the kvm module rediscover everything itself
> through CPUID directly and not using *cpu_has*
>
> Why, you ask? Because otherwise users will start asking why do they have
> "sgx" in /proc/cpuinfo but they can't run their own enclaves.
That makes sense. I was thinking it'd be helpful to leave the bits set,
e.g. for users to differentiate between "I don't have SGX" and "I can't
use SGX because SGX_LC is disabled". But I'm probably being slightly
optomistic...
> But maybe someone has a better idea.
>
> In any case, I think it would be bad idea to show only a subset of
> features in /proc/cpuinfo of a locked-down system and have to explain it
> to users why they can't do own enclaves.
>
> But again, someone might have a better idea.
I'm 99% certain this won't even require a change to the proposed KVM
patches, as KVM mostly pulls SGX support directly from CPUID. The only
thing it checks via cpu_has() is SGX_LC to query whether or not the MSRs
are fully writable.
Keeping the SGX feature bits set was more about reflecting hardware
capabilities than it was a functional requirement.
next prev parent reply other threads:[~2019-09-25 19:08 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-03 14:26 [PATCH v22 00/24] Intel SGX foundations Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2019-09-24 15:28 ` Borislav Petkov
2019-09-24 16:11 ` Sean Christopherson
2019-09-24 16:25 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 02/24] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
2019-09-24 15:52 ` Borislav Petkov
2019-09-24 20:22 ` Sean Christopherson
2019-09-25 8:51 ` Borislav Petkov
2019-09-25 17:18 ` Sean Christopherson
2019-09-25 18:31 ` Borislav Petkov
2019-09-25 19:08 ` Sean Christopherson [this message]
2019-09-27 16:11 ` Jarkko Sakkinen
2019-09-25 14:09 ` Jarkko Sakkinen
2019-09-25 14:10 ` Jarkko Sakkinen
2019-09-25 14:38 ` Jarkko Sakkinen
2019-09-25 15:19 ` Borislav Petkov
2019-09-25 16:49 ` Sean Christopherson
2019-09-25 17:28 ` Borislav Petkov
2019-09-25 18:18 ` Sean Christopherson
2019-09-03 14:26 ` [PATCH v22 03/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2019-09-24 16:04 ` Borislav Petkov
2019-09-25 14:16 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 04/24] x86/cpu/intel: Detect SGX supprt Jarkko Sakkinen
2019-09-24 16:13 ` Borislav Petkov
2019-09-24 17:43 ` Sean Christopherson
2019-09-24 18:21 ` Borislav Petkov
2019-09-25 14:46 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 05/24] x86/sgx: Add ENCLS architectural error codes Jarkko Sakkinen
2019-09-27 10:20 ` Borislav Petkov
2019-09-27 16:08 ` Jarkko Sakkinen
2019-09-27 17:20 ` Sean Christopherson
2019-10-01 20:23 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 06/24] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2019-09-27 16:27 ` Borislav Petkov
2019-10-01 19:10 ` Jarkko Sakkinen
2019-10-01 20:39 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 07/24] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2019-10-04 9:45 ` Borislav Petkov
2019-10-04 18:56 ` Jarkko Sakkinen
2019-10-08 4:04 ` Sean Christopherson
2019-10-08 7:18 ` Borislav Petkov
2019-10-08 13:35 ` Sean Christopherson
2019-10-08 14:56 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 08/24] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2019-10-05 9:26 ` Borislav Petkov
2019-10-07 11:58 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 09/24] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2019-10-05 16:44 ` Borislav Petkov
2019-10-07 14:50 ` Sean Christopherson
2019-10-08 9:09 ` Borislav Petkov
2019-10-08 13:31 ` Sean Christopherson
2019-10-07 17:55 ` Jarkko Sakkinen
2019-10-07 18:09 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 10/24] x86/sgx: Add sgx_einit() for wrapping ENCLS[EINIT] Jarkko Sakkinen
2019-10-08 17:30 ` Borislav Petkov
2019-10-08 17:45 ` Sean Christopherson
2019-10-08 17:46 ` Sean Christopherson
2019-10-08 17:53 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 11/24] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2019-10-08 17:41 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 12/24] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
2019-10-08 17:59 ` Borislav Petkov
2019-10-08 18:17 ` Sean Christopherson
2019-10-08 19:19 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 13/24] x86/sgx: Add provisioning Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 14/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 15/24] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 16/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2019-10-02 23:18 ` Jarkko Sakkinen
2019-10-02 23:45 ` Jarkko Sakkinen
2019-10-04 0:03 ` Sean Christopherson
2019-10-04 18:49 ` Jarkko Sakkinen
2019-10-04 0:15 ` Sean Christopherson
2019-10-04 18:52 ` Jarkko Sakkinen
2019-10-05 15:54 ` Sean Christopherson
2019-10-07 7:57 ` Jarkko Sakkinen
2019-10-07 8:10 ` Jarkko Sakkinen
2019-10-07 12:04 ` Jarkko Sakkinen
2019-10-08 4:54 ` Sean Christopherson
2019-10-05 18:39 ` Sean Christopherson
2019-10-07 8:01 ` Jarkko Sakkinen
2019-10-06 23:38 ` Jarkko Sakkinen
2019-10-06 23:40 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 17/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 18/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 19/24] x86/vdso: Add __vdso_sgx_enter_enclave() to wrap SGX enclave transitions Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 20/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 21/24] selftests/x86: Recurse into subdirectories Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 22/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 23/24] docs: x86/sgx: Document microarchitecture Jarkko Sakkinen
2019-09-27 18:15 ` Randy Dunlap
2019-09-03 14:26 ` [PATCH v22 24/24] docs: x86/sgx: Document kernel internals Jarkko Sakkinen
2019-09-27 17:07 ` Randy Dunlap
2019-10-01 19:34 ` Jarkko Sakkinen
2019-09-13 20:38 ` [PATCH v22 00/24] Intel SGX foundations Dave Hansen
2019-09-14 13:41 ` Jarkko Sakkinen
2019-09-14 15:32 ` Dave Hansen
2019-09-16 5:23 ` Jarkko Sakkinen
2019-09-24 17:20 ` Andy Lutomirski
2019-09-25 14:32 ` Jarkko Sakkinen
2019-10-02 23:42 ` Jarkko Sakkinen
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