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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: x86@kernel.org, linux-sgx@vger.kernel.org
Cc: akpm@linux-foundation.org, dave.hansen@intel.com,
	sean.j.christopherson@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, bp@alien8.de, josh@joshtriplett.org,
	luto@kernel.org, kai.huang@intel.com, rientjes@google.com,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Subject: [PATCH v19 08/27] x86/cpu/intel: Detect SGX support and update caps appropriately
Date: Sun, 17 Mar 2019 23:14:37 +0200
Message-ID: <20190317211456.13927-9-jarkko.sakkinen@linux.intel.com> (raw)
In-Reply-To: <20190317211456.13927-1-jarkko.sakkinen@linux.intel.com>

From: Sean Christopherson <sean.j.christopherson@intel.com>

Similar to other large Intel features such as VMX and TXT, SGX must be
explicitly enabled in IA32_FEATURE_CONTROL MSR to be truly usable.
Clear all SGX related capabilities if SGX is not fully enabled in
IA32_FEATURE_CONTROL or if the SGX1 instruction set isn't supported
(impossible on bare metal, theoretically possible in a VM if the VMM is
doing something weird).

Like SGX itself, SGX Launch Control must be explicitly enabled via a
flag in IA32_FEATURE_CONTROL. Clear the SGX_LC capability if Launch
Control is not fully enabled (or obviously if SGX itself is disabled).

Note that clearing X86_FEATURE_SGX_LC creates a bit of a conundrum
regarding the SGXLEPUBKEYHASH MSRs, as it may be desirable to read the
MSRs even if they are not writable, e.g. to query the configured key,
but clearing the capability leaves no breadcrum for discerning whether
or not the MSRs exist.  But, such usage will be rare (KVM is the only
known case at this time) and not performance critical, so it's not
unreasonable to require the use of rdmsr_safe().  Clearing the cap bit
eliminates the need for an additional flag to track whether or not
Launch Control is truly enabled, which is what we care about the vast
majority of the time.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/kernel/cpu/intel.c | 39 +++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index fc3c07fe7df5..702497f34a96 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -596,6 +596,42 @@ static void detect_tme(struct cpuinfo_x86 *c)
 	c->x86_phys_bits -= keyid_bits;
 }
 
+static void __maybe_unused detect_sgx(struct cpuinfo_x86 *c)
+{
+	unsigned long long fc;
+
+	rdmsrl(MSR_IA32_FEATURE_CONTROL, fc);
+	if (!(fc & FEATURE_CONTROL_LOCKED)) {
+		pr_err_once("sgx: The feature control MSR is not locked\n");
+		goto err_unsupported;
+	}
+
+	if (!(fc & FEATURE_CONTROL_SGX_ENABLE)) {
+		pr_err_once("sgx: SGX is not enabled in IA32_FEATURE_CONTROL MSR\n");
+		goto err_unsupported;
+	}
+
+	if (!cpu_has(c, X86_FEATURE_SGX1)) {
+		pr_err_once("sgx: SGX1 instruction set is not supported\n");
+		goto err_unsupported;
+	}
+
+	if (!(fc & FEATURE_CONTROL_SGX_LE_WR)) {
+		pr_info_once("sgx: The launch control MSRs are not writable\n");
+		goto err_msrs_rdonly;
+	}
+
+	return;
+
+err_unsupported:
+	setup_clear_cpu_cap(X86_FEATURE_SGX);
+	setup_clear_cpu_cap(X86_FEATURE_SGX1);
+	setup_clear_cpu_cap(X86_FEATURE_SGX2);
+
+err_msrs_rdonly:
+	setup_clear_cpu_cap(X86_FEATURE_SGX_LC);
+}
+
 static void init_intel_energy_perf(struct cpuinfo_x86 *c)
 {
 	u64 epb;
@@ -763,6 +799,9 @@ static void init_intel(struct cpuinfo_x86 *c)
 	if (cpu_has(c, X86_FEATURE_TME))
 		detect_tme(c);
 
+	if (IS_ENABLED(CONFIG_INTEL_SGX) && cpu_has(c, X86_FEATURE_SGX))
+		detect_sgx(c);
+
 	init_intel_energy_perf(c);
 
 	init_intel_misc_features(c);
-- 
2.19.1


  parent reply index

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
2019-03-17 21:14 ` Jarkko Sakkinen [this message]
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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