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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: x86@kernel.org, platform-driver-x86@vger.kernel.org,
	linux-sgx@vger.kernel.org
Cc: 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@linux.intel.com,
	andriy.shevchenko@linux.intel.com, tglx@linutronix.de,
	kai.svahn@intel.com, mark.shanahan@intel.com,
	luto@amacapital.net,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Suresh Siddha <suresh.b.siddha@intel.com>,
	linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT
	AND 64-BIT))
Subject: [PATCH v17 17/23] x86/sgx: Add sgx_einit() for initializing enclaves
Date: Fri, 16 Nov 2018 03:01:24 +0200
Message-ID: <20181116010412.23967-18-jarkko.sakkinen@linux.intel.com> (raw)
In-Reply-To: <20181116010412.23967-1-jarkko.sakkinen@linux.intel.com>

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

Add a helper function to perform ENCLS(EINIT) with the correct LE
hash MSR values.  ENCLS[EINIT] initializes an enclave, verifying the
enclave's measurement and preparing it for execution, i.e. the enclave
cannot be run until it has been initialized.  The measurement aspect
of EINIT references the MSR_IA32_SGXLEPUBKEYHASH* MSRs, with the CPU
comparing CPU compares the key (technically its hash) used to sign the
enclave[1] with the key hash stored in the MSRs, and will reject EINIT
if the keys do not match.

A per-cpu cache is used to avoid writing the MSRs as writing the MSRs
is extraordinarily expensive, e.g. 300-400 cycles per MSR.  Because
the cache may become stale, force update the MSRs and retry EINIT if
the first EINIT fails due to an "invalid token".  An invalid token
error does not necessarily mean the MSRs need to be updated, but the
cost of an unnecessary write is minimal relative to the cost of EINIT
itself.

[1] For EINIT's purposes, the effective signer of the enclave may be
    the enclave's owner, or a separate Launch Enclave that has created
    an EINIT token for the target enclave.  When using an EINIT token,
    the key used to sign the token must match the MSRs in order for
    EINIT to succeed.

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/include/asm/sgx.h      |  2 ++
 arch/x86/kernel/cpu/intel_sgx.c | 50 +++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h
index 372fc378018b..4cdfa1d22c6e 100644
--- a/arch/x86/include/asm/sgx.h
+++ b/arch/x86/include/asm/sgx.h
@@ -310,5 +310,7 @@ static inline int __emodt(struct sgx_secinfo *secinfo, void *addr)
 struct sgx_epc_page *sgx_alloc_page(void);
 int __sgx_free_page(struct sgx_epc_page *page);
 void sgx_free_page(struct sgx_epc_page *page);
+int sgx_einit(struct sgx_sigstruct *sigstruct, struct sgx_einittoken *token,
+	      struct sgx_epc_page *secs, u64 *lepubkeyhash);
 
 #endif /* _ASM_X86_SGX_H */
diff --git a/arch/x86/kernel/cpu/intel_sgx.c b/arch/x86/kernel/cpu/intel_sgx.c
index 59750a5df629..0e5fc8fc6b0d 100644
--- a/arch/x86/kernel/cpu/intel_sgx.c
+++ b/arch/x86/kernel/cpu/intel_sgx.c
@@ -15,6 +15,9 @@ EXPORT_SYMBOL_GPL(sgx_epc_sections);
 
 static int sgx_nr_epc_sections;
 
+/* A per-cpu cache for the last known values of IA32_SGXLEPUBKEYHASHx MSRs. */
+static DEFINE_PER_CPU(u64 [4], sgx_lepubkeyhash_cache);
+
 /**
  * sgx_alloc_page - Allocate an EPC page
  *
@@ -91,6 +94,53 @@ void sgx_free_page(struct sgx_epc_page *page)
 }
 EXPORT_SYMBOL_GPL(sgx_free_page);
 
+static void sgx_update_lepubkeyhash_msrs(u64 *lepubkeyhash, bool enforce)
+{
+	u64 __percpu *cache;
+	int i;
+
+	cache = per_cpu(sgx_lepubkeyhash_cache, smp_processor_id());
+	for (i = 0; i < 4; i++) {
+		if (enforce || (lepubkeyhash[i] != cache[i])) {
+			wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
+			cache[i] = lepubkeyhash[i];
+		}
+	}
+}
+
+/**
+ * sgx_einit - initialize an enclave
+ * @sigstruct:		a pointer a SIGSTRUCT
+ * @token:		a pointer an EINITTOKEN (optional)
+ * @secs:		a pointer a SECS
+ * @lepubkeyhash:	the desired value for IA32_SGXLEPUBKEYHASHx MSRs
+ *
+ * Execute ENCLS[EINIT], writing the IA32_SGXLEPUBKEYHASHx MSRs according
+ * to @lepubkeyhash (if possible and necessary).
+ *
+ * Return:
+ *   0 on success,
+ *   -errno or SGX error on failure
+ */
+int sgx_einit(struct sgx_sigstruct *sigstruct, struct sgx_einittoken *token,
+	      struct sgx_epc_page *secs, u64 *lepubkeyhash)
+{
+	int ret;
+
+	if (!boot_cpu_has(X86_FEATURE_SGX_LC))
+		return __einit(sigstruct, token, sgx_epc_addr(secs));
+
+	preempt_disable();
+	sgx_update_lepubkeyhash_msrs(lepubkeyhash, false);
+	ret = __einit(sigstruct, token, sgx_epc_addr(secs));
+	if (ret == SGX_INVALID_EINITTOKEN) {
+		sgx_update_lepubkeyhash_msrs(lepubkeyhash, true);
+		ret = __einit(sigstruct, token, sgx_epc_addr(secs));
+	}
+	preempt_enable();
+	return ret;
+}
+EXPORT_SYMBOL(sgx_einit);
 
 static __init void sgx_free_epc_section(struct sgx_epc_section *section)
 {
-- 
2.19.1


  parent reply index

Thread overview: 161+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20181116010412.23967-1-jarkko.sakkinen@linux.intel.com>
2018-11-16  1:01 ` [PATCH v17 01/23] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2018-11-16 14:22   ` Borislav Petkov
2018-11-16 15:07     ` Jarkko Sakkinen
2018-11-16 20:24       ` Borislav Petkov
2018-11-18  8:20         ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 02/23] x86/cpufeatures: Add Intel-defined SGX feature bit Jarkko Sakkinen
2018-11-16 14:28   ` Borislav Petkov
2018-11-16 15:13     ` Jarkko Sakkinen
2018-11-16 15:18       ` Jarkko Sakkinen
2018-11-16 20:53         ` Borislav Petkov
2018-11-16  1:01 ` [PATCH v17 03/23] x86/cpufeatures: Add SGX sub-features (as Linux-defined bits) Jarkko Sakkinen
2018-11-16 14:37   ` Borislav Petkov
2018-11-16 15:38     ` Sean Christopherson
2018-11-16 23:31   ` Dave Hansen
2018-11-18  8:36     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 04/23] x86/msr: Add IA32_FEATURE_CONTROL.SGX_ENABLE definition Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 05/23] x86/cpufeatures: Add Intel-defined SGX_LC feature bit Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 06/23] x86/cpu/intel: Detect SGX support and update caps appropriately Jarkko Sakkinen
2018-11-16 23:32   ` Dave Hansen
2018-11-18  8:37     ` Jarkko Sakkinen
2018-11-21 18:17   ` Borislav Petkov
2018-11-24 13:54     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 07/23] x86/mm: x86/sgx: Add new 'PF_SGX' page fault error code bit Jarkko Sakkinen
2018-11-16 23:33   ` Dave Hansen
2018-11-18  8:38     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 08/23] x86/mm: x86/sgx: Signal SIGSEGV for userspace #PFs w/ PF_SGX Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 09/23] x86/sgx: Define SGX1 and SGX2 ENCLS leafs Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 10/23] x86/sgx: Add ENCLS architectural error codes Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 11/23] x86/sgx: Add SGX1 and SGX2 architectural data structures Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 12/23] x86/sgx: Add definitions for SGX's CPUID leaf and variable sub-leafs Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 13/23] x86/msr: Add SGX Launch Control MSR definitions Jarkko Sakkinen
2018-11-16 17:29   ` Sean Christopherson
2018-11-18  8:19     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 14/23] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 15/23] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 16/23] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2018-11-16  1:01 ` Jarkko Sakkinen [this message]
2018-11-16  1:01 ` [PATCH v17 18/23] platform/x86: Intel SGX driver Jarkko Sakkinen
2018-11-16  1:37   ` Randy Dunlap
2018-11-16 11:23     ` Jarkko Sakkinen
2018-11-19 15:06   ` Jarkko Sakkinen
2018-11-19 16:22     ` Jethro Beekman
2018-11-19 17:19       ` Jarkko Sakkinen
2018-11-19 17:39         ` Jethro Beekman
2018-11-20 10:58           ` Jarkko Sakkinen
2018-11-21 15:24             ` Jarkko Sakkinen
2018-11-19 18:18         ` Andy Lutomirski
2018-11-20 11:00           ` Jarkko Sakkinen
2018-11-19 15:29   ` Andy Lutomirski
2018-11-19 16:19     ` Jarkko Sakkinen
2018-11-19 16:59       ` Andy Lutomirski
2018-11-20 12:04         ` Jarkko Sakkinen
2018-11-22 11:12           ` Dr. Greg
2018-11-22 15:21             ` Andy Lutomirski
2018-11-24 17:21               ` Jarkko Sakkinen
2018-11-24 20:13                 ` Dr. Greg
2018-11-26 21:15                   ` Jarkko Sakkinen
2018-11-25 14:53                 ` Jarkko Sakkinen
2018-11-25 16:22                   ` Andy Lutomirski
2018-11-25 18:55                     ` Dr. Greg
2018-11-25 23:51                       ` Jarkko Sakkinen
     [not found]                       ` <D45BC005-5064-4C75-B486-4E43C454E2F6@amacapital.net>
2018-11-26  0:37                         ` Andy Lutomirski
2018-11-26 11:00                           ` Dr. Greg
2018-11-26 18:22                             ` Andy Lutomirski
2018-11-26 22:16                             ` Jarkko Sakkinen
2018-11-26 21:51                     ` Jarkko Sakkinen
2018-11-26 23:04                       ` Jarkko Sakkinen
2018-11-27  8:55                         ` Dr. Greg
2018-11-27 16:41                           ` Jarkko Sakkinen
2018-11-27 17:55                             ` Andy Lutomirski
2018-11-28 10:49                               ` Dr. Greg
2018-11-28 19:22                                 ` Jarkko Sakkinen
2018-12-10 10:49                                   ` Dr. Greg
2018-12-12 18:00                                     ` Jarkko Sakkinen
2018-12-14 23:59                                       ` Dr. Greg
2018-12-15  0:06                                         ` Sean Christopherson
2018-12-15 23:22                                           ` Dr. Greg
2018-12-17 14:27                                             ` Sean Christopherson
2018-12-17 13:28                                           ` Jarkko Sakkinen
2018-12-17 13:39                                             ` Jarkko Sakkinen
2018-12-17 14:08                                               ` Jarkko Sakkinen
2018-12-17 14:13                                                 ` Jarkko Sakkinen
2018-12-17 16:34                                                   ` Dr. Greg
2018-12-17 17:31                                                 ` Sean Christopherson
2018-12-17 17:49                                                   ` Jarkko Sakkinen
2018-12-17 18:09                                                     ` Sean Christopherson
2018-12-17 18:23                                                       ` Jarkko Sakkinen
2018-12-17 18:46                                                         ` Sean Christopherson
2018-12-17 19:36                                                           ` Jarkko Sakkinen
2018-11-27 16:46                           ` Jarkko Sakkinen
2018-11-28 21:52                           ` Andy Lutomirski
2018-11-27  7:46                       ` Jethro Beekman
2018-11-27 16:36                         ` Jarkko Sakkinen
2018-11-22 20:56             ` Andy Lutomirski
2018-11-23 10:39               ` Dr. Greg
2018-11-24 16:45                 ` Jarkko Sakkinen
2018-11-28  5:08                   ` Jarkko Sakkinen
2018-11-28  5:38                     ` Jethro Beekman
2018-12-09 17:01         ` Pavel Machek
2018-11-20 11:15     ` Dr. Greg
2018-11-24 16:15       ` Jarkko Sakkinen
2018-11-24 19:24         ` Dr. Greg
2018-11-26 19:39           ` Jarkko Sakkinen
2018-12-09 17:01     ` Pavel Machek
2018-12-10 14:46       ` Dr. Greg
2018-12-17 17:45   ` Dave Hansen
2018-12-17 18:01     ` Jarkko Sakkinen
2018-12-17 18:07       ` Dave Hansen
2018-12-17 18:31         ` Jarkko Sakkinen
2018-12-17 18:36       ` Sean Christopherson
2018-12-17 18:43         ` Jarkko Sakkinen
2018-12-17 18:47           ` Dave Hansen
2018-12-17 19:12             ` Andy Lutomirski
2018-12-17 19:17               ` Dave Hansen
2018-12-17 19:25                 ` Andy Lutomirski
2018-12-17 19:54                   ` Jarkko Sakkinen
2018-12-17 19:49                 ` Jarkko Sakkinen
2018-12-17 19:53                   ` Dave Hansen
2018-12-17 19:55                     ` Andy Lutomirski
2018-12-17 20:03                       ` Dave Hansen
2018-12-17 20:10                         ` Andy Lutomirski
2018-12-17 20:15                           ` Dave Hansen
2018-12-17 22:36                             ` Sean Christopherson
2018-12-18  1:40                           ` Jarkko Sakkinen
2018-12-17 22:20               ` Sean Christopherson
2018-12-18  1:39                 ` Jarkko Sakkinen
2018-12-18  3:27                   ` Jarkko Sakkinen
2018-12-18  5:02                     ` Andy Lutomirski
2018-12-18 13:27                       ` Jarkko Sakkinen
2018-12-18  4:55                   ` Andy Lutomirski
2018-12-18 13:18                     ` Jarkko Sakkinen
2018-12-18  4:59                 ` Andy Lutomirski
2018-12-18 13:11                   ` Jarkko Sakkinen
2018-12-18 15:44                   ` Sean Christopherson
2018-12-18 18:53                     ` Sean Christopherson
2018-12-19  5:00                       ` Jarkko Sakkinen
2018-12-19  5:13                         ` Jarkko Sakkinen
2018-12-21 18:28                         ` Sean Christopherson
2018-12-22  0:01                           ` Jarkko Sakkinen
2018-12-19  4:47                     ` Jarkko Sakkinen
2018-12-19  5:24                       ` Jarkko Sakkinen
2018-12-18  1:17               ` Jarkko Sakkinen
2018-12-18  1:31                 ` Jarkko Sakkinen
2018-12-17 18:48           ` Sean Christopherson
2018-12-17 19:09             ` Dave Hansen
2018-12-17 19:37               ` Jarkko Sakkinen
2018-12-17 19:40                 ` Dave Hansen
2018-12-17 19:33             ` Jarkko Sakkinen
2018-12-17 20:21               ` Jarkko Sakkinen
2018-12-18 13:13                 ` Jarkko Sakkinen
2018-12-18 15:46                   ` Sean Christopherson
2018-12-18  5:55   ` Andy Lutomirski
2018-12-19  5:22     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 19/23] platform/x86: sgx: Add swapping functionality to the " Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 20/23] x86/sgx: Add a simple swapper for the EPC memory manager Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 21/23] platform/x86: ptrace() support for the SGX driver Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 22/23] x86/sgx: SGX documentation Jarkko Sakkinen
2018-12-03  3:28   ` Randy Dunlap
2018-12-03  9:32     ` Jarkko Sakkinen
2018-11-16  1:01 ` [PATCH v17 23/23] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2018-11-16 11:17 ` [PATCH v17 00/23] Intel SGX1 support Jarkko Sakkinen

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