From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
x86@kernel.org, linux-sgx@vger.kernel.org,
akpm@linux-foundation.org, 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, bp@alien8.de, josh@joshtriplett.org,
luto@kernel.org, kai.huang@intel.com, rientjes@google.com,
Andy Lutomirski <luto@amacapital.net>,
Dave Hansen <dave.hansen@linux.intel.com>
Subject: Re: [PATCH v19 07/27] x86/mm: x86/sgx: Signal SIGSEGV for userspace #PFs w/ PF_SGX
Date: Mon, 18 Mar 2019 12:53:42 -0700 [thread overview]
Message-ID: <20190318195342.GB20298@linux.intel.com> (raw)
In-Reply-To: <25682442-e244-7308-e805-9e4960b7b525@intel.com>
On Mon, Mar 18, 2019 at 10:15:18AM -0700, Dave Hansen wrote:
> On 3/17/19 2:14 PM, Jarkko Sakkinen wrote:
> > + /*
> > + * Access is blocked by the Enclave Page Cache Map (EPCM), i.e. the
> > + * access is allowed by the PTE but not the EPCM. This usually happens
> > + * when the EPCM is yanked out from under us, e.g. by hardware after a
> > + * suspend/resume cycle. In any case, software, i.e. the kernel, can't
> > + * fix the source of the fault as the EPCM can't be directly modified
> > + * by software. Handle the fault as an access error in order to signal
> > + * userspace, e.g. so that userspace can rebuild their enclave(s), even
> > + * though userspace may not have actually violated access permissions.
> > + */
> > + if (unlikely(error_code & X86_PF_SGX))
> > + return 1;
>
> A sanitized error_code gets passed up to userspace. Is that how
> userspace figures out that this was a PF_SGX fault instead of something
> more routine?
Yes. Technically userspace can survive without PF_SGX, e.g. assume that
SIGSEGV on EENTER itself indicates an EPCM fault, but the explicit flag
does make things easier and cleaner.
next prev parent reply other threads:[~2019-03-18 19:53 UTC|newest]
Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-17 21:14 [PATCH v19 00/27] Intel SGX1 support Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 01/27] x86/cpufeatures: Add Intel-defined SGX feature bit Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 02/27] x86/cpufeatures: Add SGX sub-features (as Linux-defined bits) Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 03/27] x86/msr: Add IA32_FEATURE_CONTROL.SGX_ENABLE definition Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 04/27] x86/cpufeatures: Add Intel-defined SGX_LC feature bit Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 05/27] x86/msr: Add SGX Launch Control MSR definitions Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 06/27] x86/mm: x86/sgx: Add new 'PF_SGX' page fault error code bit Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 07/27] x86/mm: x86/sgx: Signal SIGSEGV for userspace #PFs w/ PF_SGX Jarkko Sakkinen
2019-03-18 17:15 ` Dave Hansen
2019-03-18 19:53 ` Sean Christopherson [this message]
2019-03-17 21:14 ` [PATCH v19 08/27] x86/cpu/intel: Detect SGX support and update caps appropriately Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 09/27] x86/sgx: Add ENCLS architectural error codes Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 10/27] x86/sgx: Add SGX1 and SGX2 architectural data structures Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 11/27] x86/sgx: Add definitions for SGX's CPUID leaf and variable sub-leafs Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 12/27] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2019-03-18 19:50 ` Sean Christopherson
2019-03-21 14:40 ` Jarkko Sakkinen
2019-03-21 15:28 ` Sean Christopherson
2019-03-22 10:19 ` Jarkko Sakkinen
2019-03-22 10:50 ` Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 13/27] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2019-03-19 19:59 ` Sean Christopherson
2019-03-21 14:51 ` Jarkko Sakkinen
2019-03-21 15:40 ` Sean Christopherson
2019-03-22 11:00 ` Jarkko Sakkinen
2019-03-22 16:43 ` Sean Christopherson
2019-03-17 21:14 ` [PATCH v19 16/27] x86/sgx: Add the Linux SGX Enclave Driver Jarkko Sakkinen
2019-03-19 21:19 ` Sean Christopherson
2019-03-21 15:51 ` Jarkko Sakkinen
2019-03-21 16:47 ` Sean Christopherson
2019-03-22 11:10 ` Jarkko Sakkinen
2019-03-26 13:26 ` Jarkko Sakkinen
2019-03-26 23:58 ` Sean Christopherson
2019-03-27 5:28 ` Jarkko Sakkinen
2019-03-27 17:57 ` Sean Christopherson
2019-03-27 18:38 ` Jethro Beekman
2019-03-27 20:06 ` Sean Christopherson
2019-03-28 1:21 ` Jethro Beekman
2019-03-28 13:19 ` Jarkko Sakkinen
2019-03-28 19:05 ` Andy Lutomirski
2019-03-29 9:43 ` Jarkko Sakkinen
2019-03-29 16:20 ` Sean Christopherson
2019-04-01 10:01 ` Jarkko Sakkinen
2019-04-01 17:25 ` Jethro Beekman
2019-04-01 22:57 ` Jarkko Sakkinen
2019-03-28 13:15 ` Jarkko Sakkinen
2019-03-19 23:00 ` Sean Christopherson
2019-03-21 16:18 ` Jarkko Sakkinen
2019-03-21 17:38 ` Sean Christopherson
2019-03-22 11:17 ` Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 17/27] x86/sgx: Add provisioning Jarkko Sakkinen
2019-03-19 20:09 ` Sean Christopherson
2019-03-21 2:08 ` Huang, Kai
2019-03-21 14:32 ` Jarkko Sakkinen
2019-03-21 21:41 ` Huang, Kai
2019-03-22 11:31 ` Jarkko Sakkinen
2019-03-21 14:30 ` Jarkko Sakkinen
2019-03-21 14:38 ` Nathaniel McCallum
2019-03-22 11:22 ` Jarkko Sakkinen
2019-03-21 16:50 ` Andy Lutomirski
2019-03-22 11:29 ` Jarkko Sakkinen
2019-03-22 11:43 ` Jarkko Sakkinen
2019-03-22 18:20 ` Andy Lutomirski
2019-03-25 14:55 ` Jarkko Sakkinen
2019-03-27 0:14 ` Sean Christopherson
2019-04-05 10:18 ` Jarkko Sakkinen
2019-04-05 13:53 ` Andy Lutomirski
2019-04-05 14:20 ` Jarkko Sakkinen
2019-04-05 14:34 ` Greg KH
2019-04-09 13:37 ` Jarkko Sakkinen
2019-04-05 14:21 ` Greg KH
2019-03-17 21:14 ` [PATCH v19 19/27] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2019-03-19 22:22 ` Sean Christopherson
2019-03-21 15:02 ` Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 20/27] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 21/27] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 22/27] x86/fault: Attempt to fixup unhandled #PF in vDSO before signaling Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 23/27] x86/traps: Attempt to fixup exceptions " Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 25/27] x86/sgx: SGX documentation Jarkko Sakkinen
2019-03-20 17:14 ` Sean Christopherson
2019-03-21 16:24 ` Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 26/27] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2019-03-17 21:14 ` [PATCH v19 27/27] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2019-03-19 17:12 ` Sean Christopherson
2019-03-21 14:42 ` Jarkko Sakkinen
[not found] ` <20190317211456.13927-19-jarkko.sakkinen@linux.intel.com>
2019-03-19 22:09 ` [PATCH v19 18/27] x86/sgx: Add swapping code to the core and SGX driver Sean Christopherson
2019-03-21 14:59 ` Jarkko Sakkinen
2019-03-19 23:41 ` [PATCH v19 00/27] Intel SGX1 support Sean Christopherson
2019-03-19 23:52 ` Jethro Beekman
2019-03-20 0:22 ` Sean Christopherson
2019-03-21 16:20 ` Jarkko Sakkinen
2019-03-21 16:00 ` Jarkko Sakkinen
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