[RFC,1/8] x86/cpufeature: Enumerate Key Locker feature

Commit Message

Chang S. Bae Dec. 16, 2020, 5:41 p.m. UTC

Intel's Key Locker is a new security feature providing a mechanism to
protect a data encryption key when processing the Advanced Encryption
Standard algorithm.

Here we add it to the kernel/user ABI by enumerating the hardware
capability. E.g., /proc/cpuinfo: keylocker.

Also, define the feature-specific CPUID leaf and bits for the feature
enablement.

Key Locker is on the disabled list, which is useful for compile-time
configuration later.

Signed-off-by: Chang S. Bae <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
---
 arch/x86/include/asm/cpufeatures.h          |  1 +
 arch/x86/include/asm/disabled-features.h    |  8 +++++++-
 arch/x86/include/asm/keylocker.h            | 18 ++++++++++++++++++
 arch/x86/include/uapi/asm/processor-flags.h |  2 ++
 arch/x86/kernel/cpu/cpuid-deps.c            |  1 +
 5 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 arch/x86/include/asm/keylocker.h

Patch

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index dad350d42ecf..8f2f050023b7 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -352,6 +352,7 @@ 
 #define X86_FEATURE_AVX512_VPOPCNTDQ	(16*32+14) /* POPCNT for vectors of DW/QW */
 #define X86_FEATURE_LA57		(16*32+16) /* 5-level page tables */
 #define X86_FEATURE_RDPID		(16*32+22) /* RDPID instruction */
+#define X86_FEATURE_KEYLOCKER		(16*32+23) /* Key Locker */
 #define X86_FEATURE_CLDEMOTE		(16*32+25) /* CLDEMOTE instruction */
 #define X86_FEATURE_MOVDIRI		(16*32+27) /* MOVDIRI instruction */
 #define X86_FEATURE_MOVDIR64B		(16*32+28) /* MOVDIR64B instruction */
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 5861d34f9771..0ac9414da242 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -44,6 +44,12 @@ 
 # define DISABLE_OSPKE		(1<<(X86_FEATURE_OSPKE & 31))
 #endif /* CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS */
 
+#ifdef CONFIG_X86_KEYLOCKER
+# define DISABLE_KEYLOCKER	0
+#else
+# define DISABLE_KEYLOCKER	(1<<(X86_FEATURE_KEYLOCKER & 31))
+#endif /* CONFIG_X86_KEYLOCKER */
+
 #ifdef CONFIG_X86_5LEVEL
 # define DISABLE_LA57	0
 #else
@@ -82,7 +88,7 @@ 
 #define DISABLED_MASK14	0
 #define DISABLED_MASK15	0
 #define DISABLED_MASK16	(DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP| \
-			 DISABLE_ENQCMD)
+			 DISABLE_ENQCMD|DISABLE_KEYLOCKER)
 #define DISABLED_MASK17	0
 #define DISABLED_MASK18	0
 #define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 19)
diff --git a/arch/x86/include/asm/keylocker.h b/arch/x86/include/asm/keylocker.h
new file mode 100644
index 000000000000..2fe13c21c63f
--- /dev/null
+++ b/arch/x86/include/asm/keylocker.h
@@ -0,0 +1,18 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _ASM_KEYLOCKER_H
+#define _ASM_KEYLOCKER_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/bits.h>
+
+#define KEYLOCKER_CPUID                0x019
+#define KEYLOCKER_CPUID_EAX_SUPERVISOR BIT(0)
+#define KEYLOCKER_CPUID_EBX_AESKLE     BIT(0)
+#define KEYLOCKER_CPUID_EBX_WIDE       BIT(2)
+#define KEYLOCKER_CPUID_EBX_BACKUP     BIT(4)
+#define KEYLOCKER_CPUID_ECX_RAND       BIT(1)
+
+#endif /*__ASSEMBLY__ */
+#endif /* _ASM_KEYLOCKER_H */
diff --git a/arch/x86/include/uapi/asm/processor-flags.h b/arch/x86/include/uapi/asm/processor-flags.h
index bcba3c643e63..b958a95a0908 100644
--- a/arch/x86/include/uapi/asm/processor-flags.h
+++ b/arch/x86/include/uapi/asm/processor-flags.h
@@ -124,6 +124,8 @@ 
 #define X86_CR4_PCIDE		_BITUL(X86_CR4_PCIDE_BIT)
 #define X86_CR4_OSXSAVE_BIT	18 /* enable xsave and xrestore */
 #define X86_CR4_OSXSAVE		_BITUL(X86_CR4_OSXSAVE_BIT)
+#define X86_CR4_KEYLOCKER_BIT	19 /* enable Key Locker */
+#define X86_CR4_KEYLOCKER	_BITUL(X86_CR4_KEYLOCKER_BIT)
 #define X86_CR4_SMEP_BIT	20 /* enable SMEP support */
 #define X86_CR4_SMEP		_BITUL(X86_CR4_SMEP_BIT)
 #define X86_CR4_SMAP_BIT	21 /* enable SMAP support */
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index d502241995a3..b8edcb91fe4f 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -71,6 +71,7 @@  static const struct cpuid_dep cpuid_deps[] = {
 	{ X86_FEATURE_AVX512_BF16,		X86_FEATURE_AVX512VL  },
 	{ X86_FEATURE_ENQCMD,			X86_FEATURE_XSAVES    },
 	{ X86_FEATURE_PER_THREAD_MBA,		X86_FEATURE_MBA       },
+	{ X86_FEATURE_KEYLOCKER,		X86_FEATURE_XMM2      },
 	{}
 };