diff mbox series

[v39,01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits

Message ID 20201003045059.665934-2-jarkko.sakkinen@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series Intel SGX foundations | expand

Commit Message

Jarkko Sakkinen Oct. 3, 2020, 4:50 a.m. UTC 
From: Sean Christopherson <sean.j.christopherson@intel.com>

Add X86_FEATURE_SGX from CPUID.(EAX=7, ECX=1), which informs whether the
CPU has SGX.

Add X86_FEATURE_SGX1 and X86_FEATURE_SGX2 from CPUID.(EAX=12H, ECX=0),
which describe the level of SGX support available [1].

Add IA32_FEATURE_CONTROL.SGX_ENABLE. BIOS can use this bit to opt-in SGX
before locking the feature control MSR [2].

[1] Intel SDM: 36.7.2 Intel® SGX Resource Enumeration Leaves
[2] Intel SDM: 36.7.1 Intel® SGX Opt-In Configuration

Reviewed-by: Borislav Petkov <bp@alien8.de>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.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/include/asm/cpufeature.h        |  5 +++--
 arch/x86/include/asm/cpufeatures.h       |  7 ++++++-
 arch/x86/include/asm/disabled-features.h | 18 +++++++++++++++---
 arch/x86/include/asm/msr-index.h         |  1 +
 arch/x86/include/asm/required-features.h |  2 +-
 arch/x86/kernel/cpu/common.c             |  4 ++++
 6 files changed, 30 insertions(+), 7 deletions(-)

Comments

Dave Hansen Oct. 19, 2020, 2:10 p.m. UTC | #1 
On 10/2/20 9:50 PM, Jarkko Sakkinen wrote:
> 
> Add X86_FEATURE_SGX1 and X86_FEATURE_SGX2 from CPUID.(EAX=12H, ECX=0),
> which describe the level of SGX support available [1].

The SDM says there are 6 leaf functions added with SGX2 (SDM Vol 3D
Table 36-2):

ENCLS[EAUG]
ENCLS[EMODPR]
ENCLS[EMODT]
ENCLU[EACCEPT]
ENCLU[EMODPE]
ENCLU[EACCEPTCOPY]

But I don't see *ANY* of those in use in this patch set.  I know we
added a bunch of infrastructure around mitigating if EMODPE got *used*,
but does the kernel need to change its behavior if SGX1 vs. SGX2 is
supported?

BTW, the SG2 bit is defined:

	Bit 01: SGX2. If 1, Indicates Intel SGX supports the collection
	of SGX2 leaf functions.

which makes me think it's for leaf functions only.
Sean Christopherson Oct. 19, 2020, 5:49 p.m. UTC | #2 
On Mon, Oct 19, 2020 at 07:10:58AM -0700, Dave Hansen wrote:
> On 10/2/20 9:50 PM, Jarkko Sakkinen wrote:
> > 
> > Add X86_FEATURE_SGX1 and X86_FEATURE_SGX2 from CPUID.(EAX=12H, ECX=0),
> > which describe the level of SGX support available [1].
> 
> The SDM says there are 6 leaf functions added with SGX2 (SDM Vol 3D
> Table 36-2):
> 
> ENCLS[EAUG]
> ENCLS[EMODPR]
> ENCLS[EMODT]
> ENCLU[EACCEPT]
> ENCLU[EMODPE]
> ENCLU[EACCEPTCOPY]
> 
> But I don't see *ANY* of those in use in this patch set.  I know we
> added a bunch of infrastructure around mitigating if EMODPE got *used*,
> but does the kernel need to change its behavior if SGX1 vs. SGX2 is
> supported?
> 
> BTW, the SG2 bit is defined:
> 
> 	Bit 01: SGX2. If 1, Indicates Intel SGX supports the collection
> 	of SGX2 leaf functions.
> 
> which makes me think it's for leaf functions only.

As mentioned in the other thread, SGX1 hardware takes an erratum on the #PF
behavior of the EPCM, i.e. on SGX2+, EPCM violations generate #PF with
PFEC.SGX=1, whereas SGX1 hardware will #GP.
diff mbox series

Patch

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 59bf91c57aa8..efbdba5170a3 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -30,6 +30,7 @@  enum cpuid_leafs
 	CPUID_7_ECX,
 	CPUID_8000_0007_EBX,
 	CPUID_7_EDX,
+	CPUID_12_EAX,
 };
 
 #ifdef CONFIG_X86_FEATURE_NAMES
@@ -89,7 +90,7 @@  extern const char * const x86_bug_flags[NBUGINTS*32];
 	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) ||	\
 	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) ||	\
 	   REQUIRED_MASK_CHECK					  ||	\
-	   BUILD_BUG_ON_ZERO(NCAPINTS != 19))
+	   BUILD_BUG_ON_ZERO(NCAPINTS != 20))
 
 #define DISABLED_MASK_BIT_SET(feature_bit)				\
 	 ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  0, feature_bit) ||	\
@@ -112,7 +113,7 @@  extern const char * const x86_bug_flags[NBUGINTS*32];
 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) ||	\
 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) ||	\
 	   DISABLED_MASK_CHECK					  ||	\
-	   BUILD_BUG_ON_ZERO(NCAPINTS != 19))
+	   BUILD_BUG_ON_ZERO(NCAPINTS != 20))
 
 #define cpu_has(c, bit)							\
 	(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :	\
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index dad350d42ecf..7150001d5232 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -13,7 +13,7 @@ 
 /*
  * Defines x86 CPU feature bits
  */
-#define NCAPINTS			19	   /* N 32-bit words worth of info */
+#define NCAPINTS			20	   /* N 32-bit words worth of info */
 #define NBUGINTS			1	   /* N 32-bit bug flags */
 
 /*
@@ -241,6 +241,7 @@ 
 /* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
 #define X86_FEATURE_FSGSBASE		( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
 #define X86_FEATURE_TSC_ADJUST		( 9*32+ 1) /* TSC adjustment MSR 0x3B */
+#define X86_FEATURE_SGX			( 9*32+ 2) /* Software Guard Extensions */
 #define X86_FEATURE_BMI1		( 9*32+ 3) /* 1st group bit manipulation extensions */
 #define X86_FEATURE_HLE			( 9*32+ 4) /* Hardware Lock Elision */
 #define X86_FEATURE_AVX2		( 9*32+ 5) /* AVX2 instructions */
@@ -381,6 +382,10 @@ 
 #define X86_FEATURE_CORE_CAPABILITIES	(18*32+30) /* "" IA32_CORE_CAPABILITIES MSR */
 #define X86_FEATURE_SPEC_CTRL_SSBD	(18*32+31) /* "" Speculative Store Bypass Disable */
 
+/* Intel-defined SGX features, CPUID level 0x00000012:0 (EAX), word 19 */
+#define X86_FEATURE_SGX1		(19*32+ 0) /* SGX1 leaf functions */
+#define X86_FEATURE_SGX2		(19*32+ 1) /* SGX2 leaf functions */
+
 /*
  * BUG word(s)
  */
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 5861d34f9771..689a100948eb 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -28,13 +28,18 @@ 
 # define DISABLE_CYRIX_ARR	(1<<(X86_FEATURE_CYRIX_ARR & 31))
 # define DISABLE_CENTAUR_MCR	(1<<(X86_FEATURE_CENTAUR_MCR & 31))
 # define DISABLE_PCID		0
+# define DISABLE_SGX1		0
+# define DISABLE_SGX2		0
 #else
 # define DISABLE_VME		0
 # define DISABLE_K6_MTRR	0
 # define DISABLE_CYRIX_ARR	0
 # define DISABLE_CENTAUR_MCR	0
 # define DISABLE_PCID		(1<<(X86_FEATURE_PCID & 31))
-#endif /* CONFIG_X86_64 */
+# define DISABLE_SGX1		(1<<(X86_FEATURE_SGX1 & 31))
+# define DISABLE_SGX2		(1<<(X86_FEATURE_SGX2 & 31))
+ #endif /* CONFIG_X86_64 */
+
 
 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
 # define DISABLE_PKU		0
@@ -62,6 +67,12 @@ 
 # define DISABLE_ENQCMD (1 << (X86_FEATURE_ENQCMD & 31))
 #endif
 
+#ifdef CONFIG_INTEL_SGX
+# define DISABLE_SGX	0
+#else
+# define DISABLE_SGX	(1 << (X86_FEATURE_SGX & 31))
+#endif
+
 /*
  * Make sure to add features to the correct mask
  */
@@ -74,7 +85,7 @@ 
 #define DISABLED_MASK6	0
 #define DISABLED_MASK7	(DISABLE_PTI)
 #define DISABLED_MASK8	0
-#define DISABLED_MASK9	(DISABLE_SMAP)
+#define DISABLED_MASK9	(DISABLE_SMAP|DISABLE_SGX)
 #define DISABLED_MASK10	0
 #define DISABLED_MASK11	0
 #define DISABLED_MASK12	0
@@ -85,6 +96,7 @@ 
 			 DISABLE_ENQCMD)
 #define DISABLED_MASK17	0
 #define DISABLED_MASK18	0
-#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 19)
+#define DISABLED_MASK19	(DISABLE_SGX1|DISABLE_SGX2)
+#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 20)
 
 #endif /* _ASM_X86_DISABLED_FEATURES_H */
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 972a34d93505..258d555d22f2 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -609,6 +609,7 @@ 
 #define FEAT_CTL_LOCKED				BIT(0)
 #define FEAT_CTL_VMX_ENABLED_INSIDE_SMX		BIT(1)
 #define FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX	BIT(2)
+#define FEAT_CTL_SGX_ENABLED			BIT(18)
 #define FEAT_CTL_LMCE_ENABLED			BIT(20)
 
 #define MSR_IA32_TSC_ADJUST             0x0000003b
diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
index 3ff0d48469f2..6a02e04c90fb 100644
--- a/arch/x86/include/asm/required-features.h
+++ b/arch/x86/include/asm/required-features.h
@@ -101,6 +101,6 @@ 
 #define REQUIRED_MASK16	0
 #define REQUIRED_MASK17	0
 #define REQUIRED_MASK18	0
-#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 19)
+#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 20)
 
 #endif /* _ASM_X86_REQUIRED_FEATURES_H */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 6220fae87263..d940db176901 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -932,6 +932,10 @@  void get_cpu_cap(struct cpuinfo_x86 *c)
 		c->x86_capability[CPUID_D_1_EAX] = eax;
 	}
 
+	/* Additional Intel-defined SGX flags: level 0x00000012 */
+	if (c->cpuid_level >= 0x00000012)
+		c->x86_capability[CPUID_12_EAX] = cpuid_eax(0x00000012);
+
 	/* AMD-defined flags: level 0x80000001 */
 	eax = cpuid_eax(0x80000000);
 	c->extended_cpuid_level = eax;