From: Dave Hansen <dave.hansen@intel.com> To: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Jethro Beekman <jethro@fortanix.com>, Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>, Andy Lutomirski <luto@amacapital.net>, Andrew Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>, Platform Driver <platform-driver-x86@vger.kernel.org>, "nhorman@redhat.com" <nhorman@redhat.com>, "npmccallum@redhat.com" <npmccallum@redhat.com>, "Ayoun, Serge" <serge.ayoun@intel.com>, "shay.katz-zamir@intel.com" <shay.katz-zamir@intel.com>, "linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>, Andy Shevchenko <andriy.shevchenko@linux.intel.com>, Dave Hansen <dave.hansen@linux.intel.com>, Peter Zijlstra <peterz@infradead.org>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH v14 09/19] x86/mm: x86/sgx: Signal SEGV_SGXERR for #PFs w/ PF_SGX Date: Wed, 31 Oct 2018 14:35:34 -0700 [thread overview] Message-ID: <a9c23203-476d-875d-9fbb-263716833e17@intel.com> (raw) In-Reply-To: <20181031213036.GA23089@linux.intel.com> On 10/31/18 2:30 PM, Sean Christopherson wrote: > On Mon, Oct 01, 2018 at 03:03:30PM -0700, Dave Hansen wrote: >> On 10/01/2018 02:42 PM, Jethro Beekman wrote: >>> >>> 1) Even though the vDSO function exists, userspace may still call >>> `ENCLU[EENTER]` manually, so the fault handling as described in the >>> current patch should also be maintained. >> >> Why? > > Circling back to this question, what if we take the easy way out and > simply signal SIGSEGV without an SGX-specific code? I.e. treat #PF > with X86_PF_SGX as an access error, no more no less. That should be > sufficient for userspace to function, albeit with a little more effort, > but presumably no more than would be needed to run on SGX1 hardware. There are two sides to this ABI: what the kernel does to support SGX and what userspace does. If we do what you suggest, we remove any (most?) needed kernel changes and foist the burden entirely into userspace. But, we end up with two ABIs: the old one and the new vDSO one. IOW, once we start doing SIGSEGV, we have to do it forever, despite if we have a newer mechanism. > AFAIK there isn't a way to prevent userspace from manually invoking > EENTER, short of doing some really nasty text poking or PTE swizzling. > We could declare using EENTER as unsupported, Yep, userspace can call it all it wants, and we can also say that calling it outside the vdso is "undefined".
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave.hansen@intel.com> To: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Jethro Beekman <jethro@fortanix.com>, Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>, Andy Lutomirski <luto@amacapital.net>, Andrew Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>, Platform Driver <platform-driver-x86@vger.kernel.org>, "nhorman@redhat.com" <nhorman@redhat.com>, "npmccallum@redhat.com" <npmccallum@redhat.com>, "Ayoun, Serge" <serge.ayoun@intel.com>, "shay.katz-zamir@intel.com" <shay.katz-zamir@intel.com>, "linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>, Andy Shevchenko <andriy.shevchenko@linux.intel.com>, Dave Hansen <dave.hansen@linux.intel.com>, Peter Zijlstra <peterz@infradead.org>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com> Subject: Re: [PATCH v14 09/19] x86/mm: x86/sgx: Signal SEGV_SGXERR for #PFs w/ PF_SGX Date: Wed, 31 Oct 2018 14:35:34 -0700 [thread overview] Message-ID: <a9c23203-476d-875d-9fbb-263716833e17@intel.com> (raw) In-Reply-To: <20181031213036.GA23089@linux.intel.com> On 10/31/18 2:30 PM, Sean Christopherson wrote: > On Mon, Oct 01, 2018 at 03:03:30PM -0700, Dave Hansen wrote: >> On 10/01/2018 02:42 PM, Jethro Beekman wrote: >>> >>> 1) Even though the vDSO function exists, userspace may still call >>> `ENCLU[EENTER]` manually, so the fault handling as described in the >>> current patch should also be maintained. >> >> Why? > > Circling back to this question, what if we take the easy way out and > simply signal SIGSEGV without an SGX-specific code? I.e. treat #PF > with X86_PF_SGX as an access error, no more no less. That should be > sufficient for userspace to function, albeit with a little more effort, > but presumably no more than would be needed to run on SGX1 hardware. There are two sides to this ABI: what the kernel does to support SGX and what userspace does. If we do what you suggest, we remove any (most?) needed kernel changes and foist the burden entirely into userspace. But, we end up with two ABIs: the old one and the new vDSO one. IOW, once we start doing SIGSEGV, we have to do it forever, despite if we have a newer mechanism. > AFAIK there isn't a way to prevent userspace from manually invoking > EENTER, short of doing some really nasty text poking or PTE swizzling. > We could declare using EENTER as unsupported, Yep, userspace can call it all it wants, and we can also say that calling it outside the vdso is "undefined".
next prev parent reply other threads:[~2018-10-31 21:35 UTC|newest] Thread overview: 184+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-09-25 13:06 [PATCH v14 00/19] Intel SGX1 support Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 01/19] x86/sgx: Update MAINTAINERS Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 02/19] x86/sgx: Architectural structures Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 03/19] x86/cpufeature: Add SGX and SGX_LC CPU features Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 04/19] x86/cpufeatures: Add SGX feature bits Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 16:48 ` Borislav Petkov 2018-09-25 16:48 ` Borislav Petkov 2018-09-25 16:48 ` Borislav Petkov 2018-09-26 11:11 ` Jarkko Sakkinen 2018-09-26 11:11 ` Jarkko Sakkinen 2018-09-26 11:11 ` Jarkko Sakkinen 2018-09-26 11:36 ` Borislav Petkov 2018-09-26 11:36 ` Borislav Petkov 2018-09-27 13:16 ` Jarkko Sakkinen 2018-09-27 13:16 ` Jarkko Sakkinen 2018-09-27 13:51 ` Borislav Petkov 2018-09-27 13:51 ` Borislav Petkov 2018-09-27 14:52 ` Jarkko Sakkinen 2018-09-27 14:52 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 05/19] x86/msr: Add SGX definitions to msr-index.h Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 06/19] x86/mm: x86/sgx: Add new 'PF_SGX' page fault error code bit Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 07/19] x86/fault: x86/mm/pkeys: relocate stale comment regarding OSPKE Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 08/19] signal: x86/sgx: Add SIGSEGV siginfo code for SGX EPCM fault Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-26 19:14 ` Sean Christopherson 2018-09-26 19:14 ` Sean Christopherson 2018-09-26 19:14 ` Sean Christopherson 2018-09-27 18:41 ` Eric W. Biederman 2018-09-27 18:41 ` Eric W. Biederman 2018-09-27 18:41 ` Eric W. Biederman 2018-09-25 13:06 ` [PATCH v14 09/19] x86/mm: x86/sgx: Signal SEGV_SGXERR for #PFs w/ PF_SGX Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 22:53 ` Andy Lutomirski 2018-09-25 22:53 ` Andy Lutomirski 2018-09-26 17:35 ` Sean Christopherson 2018-09-26 17:35 ` Sean Christopherson 2018-09-26 18:12 ` Andy Lutomirski 2018-09-26 18:12 ` Andy Lutomirski 2018-09-26 20:16 ` Dave Hansen 2018-09-26 20:16 ` Dave Hansen 2018-09-26 20:44 ` Sean Christopherson 2018-09-26 20:44 ` Sean Christopherson 2018-09-26 20:49 ` Dave Hansen 2018-09-26 20:49 ` Dave Hansen 2018-09-26 21:15 ` Andy Lutomirski 2018-09-26 21:15 ` Andy Lutomirski 2018-09-26 21:45 ` Dave Hansen 2018-09-26 21:45 ` Dave Hansen 2018-09-26 22:37 ` Andy Lutomirski 2018-09-26 22:37 ` Andy Lutomirski 2018-09-27 14:21 ` Jarkko Sakkinen 2018-09-27 14:21 ` Jarkko Sakkinen 2018-09-27 14:41 ` Andy Lutomirski 2018-09-27 14:41 ` Andy Lutomirski 2018-09-27 13:56 ` Jarkko Sakkinen 2018-09-27 13:56 ` Jarkko Sakkinen 2018-10-01 21:42 ` Jethro Beekman 2018-10-01 22:03 ` Dave Hansen 2018-10-31 21:30 ` Sean Christopherson 2018-10-31 21:30 ` Sean Christopherson 2018-10-31 21:35 ` Dave Hansen [this message] 2018-10-31 21:35 ` Dave Hansen 2018-10-31 21:53 ` Jethro Beekman 2018-10-31 21:58 ` Dave Hansen 2018-10-31 22:52 ` Andy Lutomirski 2018-10-31 22:52 ` Andy Lutomirski 2018-11-01 17:51 ` Dave Hansen 2018-11-01 17:52 ` Andy Lutomirski 2018-11-01 17:52 ` Andy Lutomirski 2018-11-01 17:42 ` Jarkko Sakkinen 2018-11-01 17:42 ` Jarkko Sakkinen 2018-11-01 17:42 ` Jarkko Sakkinen 2018-11-01 17:44 ` Jarkko Sakkinen 2018-11-01 17:44 ` Jarkko Sakkinen 2018-11-01 17:44 ` Jarkko Sakkinen 2018-10-02 0:31 ` Jarkko Sakkinen 2018-10-02 0:31 ` Jarkko Sakkinen 2018-10-01 14:29 ` Sean Christopherson 2018-10-01 14:29 ` Sean Christopherson 2018-10-01 14:41 ` Dave Hansen 2018-10-01 14:41 ` Dave Hansen 2018-10-02 0:07 ` Jarkko Sakkinen 2018-10-02 0:07 ` Jarkko Sakkinen 2018-09-27 13:42 ` Jarkko Sakkinen 2018-09-27 13:42 ` Jarkko Sakkinen 2018-09-27 14:58 ` Dave Hansen 2018-09-27 14:58 ` Dave Hansen 2018-09-27 15:39 ` Jarkko Sakkinen 2018-09-27 15:39 ` Jarkko Sakkinen 2018-09-27 15:53 ` Dave Hansen 2018-09-27 15:53 ` Dave Hansen 2018-09-27 13:14 ` Jarkko Sakkinen 2018-09-27 13:14 ` Jarkko Sakkinen 2018-09-27 19:43 ` Eric W. Biederman 2018-09-27 19:43 ` Eric W. Biederman 2018-09-27 19:43 ` Eric W. Biederman 2018-09-28 12:17 ` Jarkko Sakkinen 2018-09-28 12:17 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 10/19] x86/sgx: Detect Intel SGX Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 20:02 ` Randy Dunlap 2018-09-25 20:02 ` Randy Dunlap 2018-09-25 20:02 ` Randy Dunlap 2018-09-27 13:13 ` Jarkko Sakkinen 2018-09-27 13:13 ` Jarkko Sakkinen 2018-09-27 13:13 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 11/19] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 20:01 ` Randy Dunlap 2018-09-25 20:01 ` Randy Dunlap 2018-09-25 20:01 ` Randy Dunlap 2018-09-27 13:12 ` Jarkko Sakkinen 2018-09-27 13:12 ` Jarkko Sakkinen 2018-09-27 13:12 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 12/19] x86/sgx: Add data structures for tracking the EPC pages Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 20:00 ` Randy Dunlap 2018-09-25 20:00 ` Randy Dunlap 2018-09-25 20:00 ` Randy Dunlap 2018-09-27 13:11 ` Jarkko Sakkinen 2018-09-27 13:11 ` Jarkko Sakkinen 2018-09-27 13:11 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 13/19] x86/sgx: Enclave Page Cache (EPC) memory manager Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 14/19] x86/sgx: Add sgx_einit() for initializing enclaves Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 15/19] platform/x86: Intel SGX driver Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-10-04 18:01 ` Sean Christopherson 2018-10-04 18:01 ` Sean Christopherson 2018-10-04 18:01 ` Sean Christopherson 2018-10-05 11:32 ` Jarkko Sakkinen 2018-10-05 11:32 ` Jarkko Sakkinen 2018-10-05 11:32 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 16/19] platform/x86: Add swapping functionality to the " Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 17/19] x86/sgx: Add a simple swapper for the EPC memory manager Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 18/19] platform/x86: ptrace() support for the SGX driver Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` [PATCH v14 19/19] x86/sgx: Driver documentation Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:06 ` Jarkko Sakkinen 2018-09-25 13:27 ` Jonathan Corbet 2018-09-25 13:27 ` Jonathan Corbet 2018-09-25 13:27 ` Jonathan Corbet 2018-10-15 20:54 ` Pavel Machek 2018-10-15 20:54 ` Pavel Machek 2018-10-17 23:45 ` Jarkko Sakkinen 2018-10-17 23:45 ` Jarkko Sakkinen 2018-10-18 9:57 ` Pavel Machek 2018-10-18 9:57 ` Pavel Machek 2018-10-19 23:59 ` Jarkko Sakkinen 2018-10-19 23:59 ` Jarkko Sakkinen 2018-10-17 23:56 ` Dave Hansen 2018-10-17 23:56 ` Dave Hansen
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=a9c23203-476d-875d-9fbb-263716833e17@intel.com \ --to=dave.hansen@intel.com \ --cc=andriy.shevchenko@linux.intel.com \ --cc=bp@alien8.de \ --cc=dave.hansen@linux.intel.com \ --cc=hpa@zytor.com \ --cc=jarkko.sakkinen@linux.intel.com \ --cc=jethro@fortanix.com \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-sgx@vger.kernel.org \ --cc=luto@amacapital.net \ --cc=luto@kernel.org \ --cc=mingo@redhat.com \ --cc=nhorman@redhat.com \ --cc=npmccallum@redhat.com \ --cc=peterz@infradead.org \ --cc=platform-driver-x86@vger.kernel.org \ --cc=sean.j.christopherson@intel.com \ --cc=serge.ayoun@intel.com \ --cc=shay.katz-zamir@intel.com \ --cc=tglx@linutronix.de \ --cc=x86@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.