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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: x86@kernel.org, linux-sgx@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Jethro Beekman <jethro@fortanix.com>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.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, dave.hansen@intel.com,
	haitao.huang@intel.com, josh@joshtriplett.org,
	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
Subject: [PATCH v33 06/21] x86/cpu/intel: Detect SGX support
Date: Thu, 18 Jun 2020 01:08:28 +0300
Message-ID: <20200617220844.57423-7-jarkko.sakkinen@linux.intel.com> (raw)
In-Reply-To: <20200617220844.57423-1-jarkko.sakkinen@linux.intel.com>

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

Configure SGX as part of feature control MSR initialization and update
the associated X86_FEATURE flags accordingly.  Because the kernel will
require the LE hash MSRs to be writable when running native enclaves,
disable X86_FEATURE_SGX (and all derivatives) if SGX Launch Control is
not (or cannot) be fully enabled via feature control MSR.

The check is done for every CPU, not just BSP, in order to verify that
MSR_IA32_FEATURE_CONTROL is correctly configured on all CPUs. The other
parts of the kernel, like the enclave driver, expect the same
configuration from all CPUs.

Note, unlike VMX, clear the X86_FEATURE_SGX* flags for all CPUs if any
CPU lacks SGX support as the kernel expects SGX to be available on all
CPUs.  X86_FEATURE_VMX is intentionally cleared only for the current CPU
so that KVM can provide additional information if KVM fails to load,
e.g. print which CPU doesn't support VMX.  KVM/VMX requires additional
per-CPU enabling, e.g. to set CR4.VMXE and do VMXON, and so already has
the necessary infrastructure to do per-CPU checks.  SGX on the other
hand doesn't require additional enabling, so clearing the feature flags
on all CPUs means the SGX subsystem doesn't need to manually do support
checks on a per-CPU basis.

Acked-by: Jethro Beekman <jethro@fortanix.com>
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/feat_ctl.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index 29a3bedabd06..c3afcd2e4342 100644
--- a/arch/x86/kernel/cpu/feat_ctl.c
+++ b/arch/x86/kernel/cpu/feat_ctl.c
@@ -93,16 +93,35 @@ static void init_vmx_capabilities(struct cpuinfo_x86 *c)
 }
 #endif /* CONFIG_X86_VMX_FEATURE_NAMES */
 
+static void clear_sgx_caps(void)
+{
+	setup_clear_cpu_cap(X86_FEATURE_SGX);
+	setup_clear_cpu_cap(X86_FEATURE_SGX_LC);
+	setup_clear_cpu_cap(X86_FEATURE_SGX1);
+	setup_clear_cpu_cap(X86_FEATURE_SGX2);
+}
+
 void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 {
 	bool tboot = tboot_enabled();
+	bool enable_sgx;
 	u64 msr;
 
 	if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) {
 		clear_cpu_cap(c, X86_FEATURE_VMX);
+		clear_sgx_caps();
 		return;
 	}
 
+	/*
+	 * Enable SGX if and only if the kernel supports SGX and Launch Control
+	 * is supported, i.e. disable SGX if the LE hash MSRs can't be written.
+	 */
+	enable_sgx = cpu_has(c, X86_FEATURE_SGX) &&
+		     cpu_has(c, X86_FEATURE_SGX1) &&
+		     cpu_has(c, X86_FEATURE_SGX_LC) &&
+		     IS_ENABLED(CONFIG_INTEL_SGX);
+
 	if (msr & FEAT_CTL_LOCKED)
 		goto update_caps;
 
@@ -124,13 +143,16 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 			msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
 	}
 
+	if (enable_sgx)
+		msr |= FEAT_CTL_SGX_ENABLED | FEAT_CTL_SGX_LC_ENABLED;
+
 	wrmsrl(MSR_IA32_FEAT_CTL, msr);
 
 update_caps:
 	set_cpu_cap(c, X86_FEATURE_MSR_IA32_FEAT_CTL);
 
 	if (!cpu_has(c, X86_FEATURE_VMX))
-		return;
+		goto update_sgx;
 
 	if ( (tboot && !(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX)) ||
 	    (!tboot && !(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX))) {
@@ -143,4 +165,12 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 		init_vmx_capabilities(c);
 #endif
 	}
+
+update_sgx:
+	if (!(msr & FEAT_CTL_SGX_ENABLED) ||
+	    !(msr & FEAT_CTL_SGX_LC_ENABLED) || !enable_sgx) {
+		if (enable_sgx)
+			pr_err_once("SGX disabled by BIOS\n");
+		clear_sgx_caps();
+	}
 }
-- 
2.25.1


  parent reply index

Thread overview: 93+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-17 22:08 [PATCH v33 00/21] Intel SGX foundations Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 01/21] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-06-22 17:37   ` Borislav Petkov
2020-06-25  1:25     ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 02/21] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-06-24 13:04   ` Borislav Petkov
2020-06-24 14:34     ` Sean Christopherson
2020-06-25  1:28       ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 03/21] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-06-25  8:59   ` Borislav Petkov
2020-06-25 15:34     ` Sean Christopherson
2020-06-25 16:49       ` Borislav Petkov
2020-06-25 20:52     ` Jarkko Sakkinen
2020-06-25 21:11       ` Borislav Petkov
2020-06-26 13:34         ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 04/21] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 05/21] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-06-17 22:08 ` Jarkko Sakkinen [this message]
2020-06-17 22:08 ` [PATCH v33 07/21] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 08/21] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-06-25 10:14   ` Borislav Petkov
2020-06-25 20:11     ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 09/21] x86/sgx: Add __sgx_alloc_epc_page() and sgx_free_epc_page() Jarkko Sakkinen
2020-06-25 17:06   ` Borislav Petkov
2020-06-25 20:55     ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 10/21] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2020-06-25 17:14   ` Borislav Petkov
2020-06-25 17:30     ` Matthew Wilcox
2020-06-25 18:06       ` Sean Christopherson
2020-06-25 22:40         ` Jarkko Sakkinen
2020-06-25 22:26     ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 11/21] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
2020-06-25 17:23   ` Borislav Petkov
2020-06-25 18:34     ` Sean Christopherson
2020-06-25 18:45       ` Borislav Petkov
2020-06-26 14:19       ` Jarkko Sakkinen
2020-06-25 20:21     ` Jarkko Sakkinen
2020-06-25 20:25       ` Borislav Petkov
2020-06-26 13:40         ` Jarkko Sakkinen
2020-06-25 18:53   ` Borislav Petkov
2020-06-26 14:17     ` Jarkko Sakkinen
2020-06-26  9:14   ` Borislav Petkov
2020-06-26 14:16     ` Sean Christopherson
2020-06-26 14:20       ` Borislav Petkov
2020-07-03 23:04         ` Jarkko Sakkinen
2020-07-03  3:09     ` Jarkko Sakkinen
2020-06-26 15:34   ` Borislav Petkov
2020-07-04  0:13     ` Jarkko Sakkinen
2020-10-26 21:26     ` Dave Hansen
2020-10-27  1:52       ` Jarkko Sakkinen
2020-10-27 10:05       ` Borislav Petkov
2020-10-27 15:20         ` Dave Hansen
2020-10-27 15:37           ` Borislav Petkov
2020-06-27 17:43   ` Borislav Petkov
2020-06-29 15:27     ` Sean Christopherson
2020-06-29 15:37       ` Borislav Petkov
2020-07-04  1:43       ` Jarkko Sakkinen
2020-07-07  1:38         ` Sean Christopherson
2020-07-07  3:29           ` Jarkko Sakkinen
2020-07-04  1:42     ` Jarkko Sakkinen
2020-07-02  3:59   ` Sean Christopherson
2020-07-04  3:31     ` Jarkko Sakkinen
2020-09-02  3:06       ` Haitao Huang
2020-09-02 16:10         ` Sean Christopherson
2020-09-02 18:40           ` Haitao Huang
2020-09-04 12:01         ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 12/21] x86/sgx: Allow a limited use of ATTRIBUTE.PROVISIONKEY for attestation Jarkko Sakkinen
2020-06-29 16:02   ` Borislav Petkov
2020-06-29 22:04     ` Sean Christopherson
2020-06-30  8:49       ` Borislav Petkov
2020-06-30 14:20         ` Sean Christopherson
2020-06-30 17:13           ` Andy Lutomirski
2020-07-02 20:47         ` Dr. Greg
2020-07-03  2:43         ` Jarkko Sakkinen
2020-07-03  2:38       ` Jarkko Sakkinen
2020-07-03  2:32     ` Jarkko Sakkinen
2020-07-03  2:55       ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 13/21] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 14/21] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 15/21] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-06-29 17:10   ` Borislav Petkov
2020-06-30  6:00     ` Sean Christopherson
2020-06-30  8:41       ` Borislav Petkov
2020-06-30 14:55         ` Sean Christopherson
2020-06-30 16:48         ` Andy Lutomirski
2020-06-30 17:23           ` Sean Christopherson
2020-07-02 12:52           ` Thomas Gleixner
2020-06-17 22:08 ` [PATCH v33 16/21] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 17/21] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 18/21] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 19/21] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 20/21] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 21/21] x86/sgx: Update MAINTAINERS Jarkko Sakkinen

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