[RFC PATCH v2 01/11] x86/cpufeature: Enumerate Key Locker feature

["Chang S. Bae" <chang.seok.bae@intel.com>]

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

The feature accompanies new AES instructions as a successor to Intel's AES
New Instructions (AES-NI). It also follows AES-NI's other feature
dependency.

Here add it to enumerate the hardware capability, shown as 'keylocker' in
/proc/cpuinfo.

Define the feature-specific CPUID leaf and bits for the feature enablement.

Add X86_FEATURE_KEYLOCKER to the disabled features mask for the use of
compile-time configuration.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
Changes from RFC v1:
* Updated the changelog.
---
 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

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index ac37830ae941..578cf3fe7182 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -359,6 +359,7 @@
 #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_BUS_LOCK_DETECT	(16*32+24) /* Bus Lock detect */
 #define X86_FEATURE_CLDEMOTE		(16*32+25) /* CLDEMOTE instruction */
 #define X86_FEATURE_MOVDIRI		(16*32+27) /* MOVDIRI instruction */
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index b7dd944dc867..96acda147a50 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
@@ -88,7 +94,7 @@
 #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_MASK19	0
diff --git a/arch/x86/include/asm/keylocker.h b/arch/x86/include/asm/keylocker.h
new file mode 100644
index 000000000000..0597d6b1cd05
--- /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 defda61f372d..ce2020b9ff4d 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -75,6 +75,7 @@ static const struct cpuid_dep cpuid_deps[] = {
 	{ X86_FEATURE_SGX_LC,			X86_FEATURE_SGX	      },
 	{ X86_FEATURE_SGX1,			X86_FEATURE_SGX       },
 	{ X86_FEATURE_SGX2,			X86_FEATURE_SGX1      },
+	{ X86_FEATURE_KEYLOCKER,		X86_FEATURE_XMM2      },
 	{}
 };
 
-- 
2.17.1