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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,
	linux-kernel@vger.kernel.org,
	Jethro Beekman <jethro@fortanix.com>,
	Darren Kenny <darren.kenny@oracle.com>,
	akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com,
	asapek@google.com, bp@alien8.de, cedric.xing@intel.com,
	chenalexchen@google.com, conradparker@google.com,
	cyhanish@google.com, haitao.huang@intel.com, kai.huang@intel.com,
	kai.svahn@intel.com, kmoy@google.com, ludloff@google.com,
	luto@kernel.org, nhorman@redhat.com, npmccallum@redhat.com,
	puiterwijk@redhat.com, rientjes@google.com, tglx@linutronix.de,
	yaozhangx@google.com, mikko.ylinen@intel.com
Subject: Re: [PATCH v39 05/24] x86/sgx: Add wrappers for ENCLS leaf functions
Date: Mon, 19 Oct 2020 10:53:53 -0700
Message-ID: <20201019175353.GB22358@linux.intel.com> (raw)
In-Reply-To: <b3224f09-c853-f99a-a0a1-8c983076d25b@intel.com>

On Mon, Oct 19, 2020 at 10:48:35AM -0700, Dave Hansen wrote:
> On 10/19/20 10:38 AM, Sean Christopherson wrote:
> >>> +static inline bool encls_failed(int ret)
> >>> +{
> >>> +	int epcm_trapnr;
> >>> +
> >>> +	if (boot_cpu_has(X86_FEATURE_SGX2))
> >>> +		epcm_trapnr = X86_TRAP_PF;
> >>> +	else
> >>> +		epcm_trapnr = X86_TRAP_GP;
> >> So, the SDM makes it sound like the only thing that changes from
> >> SGX1->SGX2 is the ENCLS leafs supported.  Since the kernel doesn't use
> >> any SGX2 leaf functions, this would imply there is some other
> >> architecture change which is visible.  *But* I don't see any evidence of
> >> this in the SDM, at least from a quick scan.
> >>
> >> Why is this here?
> > SGX1 CPUs take an erratum on the #PF behavior, e.g. "KBW90 Violation of Intel
> > SGX Access-Control Requirements Produce #GP Instead of #PF".
> > 
> > https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/xeon-e3-1200v6-spec-update.pdf
> 
> OK, but that's only for "Intel ® Xeon ® E3-1200 v6 Processor Family",
> specifically stepping B-0.  That's far from a broad erratum.  I *see* it
> in other errata lists, but I still think this is too broad.
> 
> Also, what if a hypervisor masks the SGX2 cpuid bit on SGX2-capable
> hardware?  Won't the hardware still exhibit the erratum?
> 
> I don't think we can control model-specific errata behavior with an
> architectural CPUID bit.

Hmm, true.  Checking for #PF _or_ #GP on SGX1 CPUs would be my first choice.
ENCLS #GPs for other reasons, most of which would indicate a kernel bug.  It'd
be nice to limit the "#GP is expected, sort of" behavior to CPUs that might be
affected by an erratum.

  reply index

Thread overview: 117+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-03  4:50 [PATCH v39 00/24] Intel SGX foundations Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-10-19 14:10   ` Dave Hansen
2020-10-19 17:49     ` Sean Christopherson
2020-10-03  4:50 ` [PATCH v39 02/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 03/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 04/24] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 05/24] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-10-19 14:30   ` Dave Hansen
2020-10-19 17:38     ` Sean Christopherson
2020-10-19 17:48       ` Dave Hansen
2020-10-19 17:53         ` Sean Christopherson [this message]
2020-10-19 17:58           ` Dave Hansen
2020-10-03  4:50 ` [PATCH v39 06/24] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 07/24] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 08/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-10-19  8:45   ` Jarkko Sakkinen
2020-10-19 12:39     ` Borislav Petkov
2020-10-23  9:01       ` Jarkko Sakkinen
2020-10-19 13:40     ` Dave Hansen
2020-10-23  9:03       ` Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 09/24] x86/sgx: Add __sgx_alloc_epc_page() and sgx_free_epc_page() Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 10/24] mm: Add 'mprotect' hook to struct vm_operations_struct Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 11/24] x86/sgx: Add SGX enclave driver Jarkko Sakkinen
2020-10-03 14:39   ` Greg KH
2020-10-04 14:32     ` Jarkko Sakkinen
2020-10-04 15:01       ` Jarkko Sakkinen
2020-10-05  9:42       ` Greg KH
2020-10-05 12:42         ` Jarkko Sakkinen
2020-10-07 18:09           ` Haitao Huang
2020-10-07 19:26             ` Greg KH
2020-10-09  6:44               ` Jarkko Sakkinen
2020-10-14 20:16                 ` Dave Hansen
2020-10-05  8:45     ` Christoph Hellwig
2020-10-05 11:42       ` Jarkko Sakkinen
2020-10-05 11:50         ` Greg KH
2020-10-05 14:23           ` Jarkko Sakkinen
2020-10-05 15:02             ` Greg KH
2020-10-05 16:40               ` Dave Hansen
2020-10-05 20:02                 ` Jarkko Sakkinen
2020-10-09  7:10     ` Pavel Machek
2020-10-09  7:21       ` Greg KH
2020-10-09  8:21         ` Pavel Machek
2020-10-03 19:54   ` Matthew Wilcox
2020-10-04 21:50     ` Jarkko Sakkinen
2020-10-04 22:02       ` Jarkko Sakkinen
2020-10-04 22:27       ` Matthew Wilcox
2020-10-04 23:41         ` Jarkko Sakkinen
2020-10-05  1:30           ` Matthew Wilcox
2020-10-05  3:06             ` Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE Jarkko Sakkinen
2020-10-16 17:07   ` Dave Hansen
2020-10-18  4:26     ` Jarkko Sakkinen
2020-10-19 20:21       ` Dave Hansen
2020-10-19 20:48         ` Sean Christopherson
2020-10-03  4:50 ` [PATCH v39 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Jarkko Sakkinen
2020-10-16 21:25   ` Dave Hansen
2020-10-18  5:03     ` Jarkko Sakkinen
2020-10-19  7:03       ` Jarkko Sakkinen
2020-10-19 20:48       ` Dave Hansen
2020-10-19 21:15         ` Sean Christopherson
2020-10-19 21:44           ` Dave Hansen
2020-10-23 10:11             ` Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 15/24] x86/sgx: Add SGX_IOC_ENCLAVE_PROVISION Jarkko Sakkinen
2020-10-20 15:48   ` Dave Hansen
2020-10-23 10:14     ` Jarkko Sakkinen
2020-10-20 21:19   ` Dave Hansen
2020-10-23 10:17     ` Jarkko Sakkinen
2020-10-23 14:19       ` Dave Hansen
2020-10-24 11:34         ` Jarkko Sakkinen
2020-10-24 15:47           ` Andy Lutomirski
2020-10-24 20:23             ` Jarkko Sakkinen
2020-10-27 10:38               ` Dr. Greg
2020-10-23 14:23       ` Jethro Beekman
2020-10-24 11:40         ` Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 16/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-10-03  5:22   ` Haitao Huang
2020-10-03 13:32     ` Jarkko Sakkinen
2020-10-03 18:23       ` Haitao Huang
2020-10-04 22:39         ` Jarkko Sakkinen
2020-10-07 17:25           ` Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 17/24] x86/sgx: Add ptrace() support for the SGX driver Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 18/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 19/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 20/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-10-06  2:57   ` Sean Christopherson
2020-10-06  8:30     ` Jethro Beekman
2020-10-06 15:15       ` Sean Christopherson
2020-10-06 17:28         ` Jarkko Sakkinen
2020-10-06 23:21           ` Sean Christopherson
2020-10-07  0:22             ` Jarkko Sakkinen
2020-10-07  1:17               ` Sean Christopherson
2020-10-07  3:14                 ` Jarkko Sakkinen
2020-10-07  4:34                   ` Sean Christopherson
2020-10-07  7:39                     ` Jarkko Sakkinen
2020-10-07  8:04                       ` Jarkko Sakkinen
2020-10-07 15:25                       ` Sean Christopherson
2020-10-07 17:08                         ` Jarkko Sakkinen
2020-10-07 17:13                           ` Jarkko Sakkinen
2020-10-06 15:49       ` Jarkko Sakkinen
2020-10-06 15:36     ` Jarkko Sakkinen
2020-10-06 21:39     ` Jarkko Sakkinen
2020-10-07  0:23       ` Jarkko Sakkinen
2020-10-17  1:48   ` Andy Lutomirski
2020-10-17 21:02     ` Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 22/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-10-12 16:50   ` Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 23/24] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-10-03  4:50 ` [PATCH v39 24/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-10-16 21:04   ` Dave Hansen
2020-10-18  4:27     ` Jarkko Sakkinen
2020-10-03 14:32 ` [PATCH v39 00/24] Intel SGX foundations Greg KH
2020-10-03 14:53   ` Jarkko Sakkinen
2020-10-15 19:06 ` Dave Hansen
2020-10-17 20:43   ` Jarkko Sakkinen

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