From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "Huang, Kai" <kai.huang@intel.com>,
"platform-driver-x86@vger.kernel.org"
<platform-driver-x86@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"nhorman@redhat.com" <nhorman@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"suresh.b.siddha@intel.com" <suresh.b.siddha@intel.com>,
"Ayoun, Serge" <serge.ayoun@intel.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"npmccallum@redhat.com" <npmccallum@redhat.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
"Hansen, Dave" <dave.hansen@intel.com>
Subject: Re: [PATCH v13 10/13] x86/sgx: Add sgx_einit() for initializing enclaves
Date: Wed, 5 Sep 2018 20:39:40 +0300 [thread overview]
Message-ID: <20180905173940.GG11368@linux.intel.com> (raw)
In-Reply-To: <20180904163546.GA5421@linux.intel.com>
On Tue, Sep 04, 2018 at 09:35:46AM -0700, Sean Christopherson wrote:
> On Tue, Sep 04, 2018 at 06:30:21PM +0300, Jarkko Sakkinen wrote:
> > On Tue, Sep 04, 2018 at 07:54:51AM -0700, Sean Christopherson wrote:
> > > I don't see any value in trying to rule out specific causes of
> > > INVALID_TOKEN, but we should only retry EINIT if ret==INVALID_TOKEN
> > > and RDMSR(HASH0) != sgx_lepubkeyhash[0]. Only the first MSR needs to
> > > be checked for validity as they're a package deal, i.e. they'll all be
> > > valid or all be reset. There shouldn't be a limit on retry attempts,
> > > e.g. the MSRs could theoretically be reset between WRMSR and EINIT.
> >
> > Why is doing rdmsrs necessary? With the INVALID_TOKEN error we know we
> > are out-of-sync i.e. have been sleeping and then one just needs to do
> > wrmsrs.
>
> As Kai mentioned, INVALID_TOKEN is returned for other reasons, e.g. a
> production enclave trying to use a debug token or reserved bits set in
> the token. And in the KVM case, the hash and token are provided by
> the guest, so it's entirely possible the enclave/token is not signed
> with the key specified in the hash. RDMSR is relatively inexpensive
> compared to the overall cost of EINIT. Though of course EINIT failure
> isn't exactly a fast path, so I'm ok if you want to opt for simplicity
> and retry on INVALID_TOKEN without checking the MSRs, just make sure
> to add a comment indicating we're intentionally not checking the MSRs.
Great!
> > I think one retry should be enough given that VMM traps EINIT. One retry
> > is needed to take care of the guest itself (or host if we are running on
> > bare metal) having been in a sleep state.
>
> Assuming we do RDMSR(hash0), that should be sufficient to prevent
> infinite retry and it protects against the MSRs being lost between
> WRMSR and EINIT during retry. That being said, I'm ok retrying only
> once, especially if you want to omit the RDMSR. Disabling preemption
> should prevent the kernel from suspending between WRMSR and EINIT,
> I'm just being paranoid.
But they are in the same preempt-disabled-region already?
/Jarkko
next prev parent reply other threads:[~2018-09-05 17:39 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-27 18:53 [PATCH v13 00/13] Intel SGX1 support Jarkko Sakkinen
2018-08-27 18:53 ` [PATCH v13 01/13] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2018-09-03 12:56 ` Andy Shevchenko
2018-09-03 19:10 ` Jarkko Sakkinen
2018-08-27 18:53 ` [PATCH v13 02/13] x86/cpufeature: Add SGX and SGX_LC CPU features Jarkko Sakkinen
2018-08-28 0:07 ` Huang, Kai
2018-08-28 7:17 ` Jarkko Sakkinen
2018-08-29 7:36 ` Huang, Kai
2018-08-31 12:19 ` Jarkko Sakkinen
2018-08-31 16:18 ` Dr. Greg
2018-08-27 18:53 ` [PATCH v13 03/13] x86/cpufeatures: Add Intel-defined SGX leaf CPUID_12_EAX Jarkko Sakkinen
2018-08-27 19:39 ` Dave Hansen
2018-08-28 7:23 ` Jarkko Sakkinen
2018-08-28 10:21 ` Borislav Petkov
2018-08-28 10:38 ` Jarkko Sakkinen
2018-08-27 18:53 ` [PATCH v13 04/13] x86/sgx: Architectural structures Jarkko Sakkinen
2018-08-27 19:41 ` Dave Hansen
2018-08-28 8:08 ` Jarkko Sakkinen
2018-09-03 13:16 ` Andy Shevchenko
2018-09-03 19:17 ` Jarkko Sakkinen
2018-09-04 16:04 ` Dave Hansen
2018-09-04 16:06 ` Andy Shevchenko
2018-09-05 17:32 ` Jarkko Sakkinen
2018-08-27 18:53 ` [PATCH v13 05/13] x86/msr: Add SGX definitions to msr-index.h Jarkko Sakkinen
2018-08-27 19:42 ` Dave Hansen
2018-08-28 8:11 ` Jarkko Sakkinen
2018-08-27 18:53 ` [PATCH v13 06/13] x86/sgx: Detect Intel SGX Jarkko Sakkinen
2018-08-27 19:53 ` Dave Hansen
2018-08-28 8:28 ` Jarkko Sakkinen
2018-09-03 14:26 ` Andy Shevchenko
2018-09-04 9:56 ` Jarkko Sakkinen
2018-08-27 18:53 ` [PATCH v13 07/13] x86/sgx: Add data structures for tracking the EPC pages Jarkko Sakkinen
2018-08-27 21:07 ` Dave Hansen
2018-08-28 10:30 ` Jarkko Sakkinen
2018-08-28 16:53 ` Dave Hansen
2018-08-28 21:34 ` Sean Christopherson
2018-08-31 11:13 ` Jarkko Sakkinen
2018-08-31 11:10 ` Jarkko Sakkinen
2018-09-03 14:41 ` Andy Shevchenko
2018-09-04 9:59 ` Jarkko Sakkinen
2018-09-04 17:49 ` Sean Christopherson
2018-09-04 18:01 ` Andy Shevchenko
2018-09-04 18:17 ` Sean Christopherson
2018-09-05 17:36 ` Jarkko Sakkinen
2018-08-27 18:53 ` [PATCH v13 08/13] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2018-09-03 15:01 ` Andy Shevchenko
2018-09-04 11:09 ` Jarkko Sakkinen
2018-08-27 18:53 ` [PATCH v13 09/13] x86/sgx: Enclave Page Cache (EPC) memory manager Jarkko Sakkinen
2018-08-27 21:14 ` Dave Hansen
2018-08-28 8:36 ` Jarkko Sakkinen
2018-08-27 21:15 ` Dave Hansen
2018-08-28 8:35 ` Jarkko Sakkinen
2018-08-28 14:07 ` Dave Hansen
2018-08-28 21:22 ` Sean Christopherson
2018-08-28 21:26 ` Dave Hansen
2018-08-28 21:52 ` Sean Christopherson
2018-08-31 11:22 ` Jarkko Sakkinen
2018-09-03 19:02 ` Andy Shevchenko
2018-09-04 15:38 ` Jarkko Sakkinen
2018-09-04 15:45 ` Sean Christopherson
2018-09-11 15:04 ` Sean Christopherson
2018-09-16 11:40 ` Jarkko Sakkinen
2018-08-27 18:53 ` [PATCH v13 10/13] x86/sgx: Add sgx_einit() for initializing enclaves Jarkko Sakkinen
2018-08-27 21:41 ` Huang, Kai
2018-08-28 7:01 ` Jarkko Sakkinen
2018-08-29 7:33 ` Huang, Kai
2018-08-29 20:33 ` Sean Christopherson
2018-08-29 20:58 ` Huang, Kai
2018-08-29 21:09 ` Sean Christopherson
2018-08-30 1:45 ` Huang, Kai
2018-08-31 17:43 ` Sean Christopherson
2018-08-31 21:34 ` Dr. Greg
2018-09-03 19:27 ` Jarkko Sakkinen
2018-09-03 18:15 ` Jarkko Sakkinen
2018-08-31 12:17 ` Jarkko Sakkinen
2018-08-31 18:15 ` Sean Christopherson
2018-09-03 19:19 ` Jarkko Sakkinen
2018-09-03 23:45 ` Huang, Kai
2018-09-04 14:54 ` Sean Christopherson
2018-09-04 15:30 ` Jarkko Sakkinen
2018-09-04 16:35 ` Sean Christopherson
2018-09-04 22:13 ` Huang, Kai
2018-09-05 17:39 ` Jarkko Sakkinen [this message]
2018-09-04 15:26 ` Jarkko Sakkinen
2018-09-03 13:53 ` Jann Horn
2018-09-04 9:55 ` Jarkko Sakkinen
2018-09-04 16:05 ` Andy Shevchenko
2018-08-27 18:53 ` [PATCH v13 11/13] platform/x86: Intel SGX driver Jarkko Sakkinen
2018-09-04 17:59 ` Andy Shevchenko
2018-09-05 17:33 ` Jarkko Sakkinen
2018-09-05 17:36 ` Andy Shevchenko
2018-09-06 9:21 ` Jarkko Sakkinen
2018-09-06 17:35 ` Miguel Ojeda
2018-09-07 0:50 ` Joe Perches
2018-09-07 17:02 ` Sean Christopherson
2018-09-10 18:37 ` Jarkko Sakkinen
2018-09-10 21:22 ` Joe Perches
2018-09-10 18:33 ` Jarkko Sakkinen
2018-08-27 18:53 ` [PATCH v13 12/13] platform/x86: ptrace() support for the " Jarkko Sakkinen
2018-08-27 18:53 ` [PATCH v13 13/13] x86/sgx: Driver documentation Jarkko Sakkinen
2018-08-27 19:40 ` Randy Dunlap
2018-08-28 7:58 ` Jarkko Sakkinen
2018-08-28 8:03 ` Jarkko Sakkinen
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