[PATCH v7 1/7] x86/cpu, kvm: Add support for cpuid leaf 80000021/EAX (FeatureExt2Eax)

Kim Phillips
2023-01-16T23:02:48Z

Add the 80000021/EAX leaf that advertises features in later Zen
processors. The majority of the features will be used in the kernel
and thus a separate leaf is appropriate.

Include KVM's reverse_cpuid entry because features are used by VM
guests, too.

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
---
arch/x86/include/asm/cpufeature.h | 7 +++++--
arch/x86/include/asm/cpufeatures.h | 2 +-
arch/x86/include/asm/disabled-features.h | 3 ++-
arch/x86/include/asm/required-features.h | 3 ++-
arch/x86/kernel/cpu/common.c | 3 +++
arch/x86/kvm/reverse_cpuid.h | 1 +
6 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 1a85e1fb0922..ce0c8f7d3218 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -32,6 +32,7 @@ enum cpuid_leafs
CPUID_8000_0007_EBX,
CPUID_7_EDX,
CPUID_8000_001F_EAX,
+ CPUID_8000_0021_EAX,
};

#define X86_CAP_FMT_NUM "%d:%d"
@@ -94,8 +95,9 @@ 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) || \
CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 19, feature_bit) || \
+ CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 20, feature_bit) || \
REQUIRED_MASK_CHECK || \
- BUILD_BUG_ON_ZERO(NCAPINTS != 20))
+ BUILD_BUG_ON_ZERO(NCAPINTS != 21))

#define DISABLED_MASK_BIT_SET(feature_bit) \
( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 0, feature_bit) || \
@@ -118,8 +120,9 @@ 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) || \
CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 19, feature_bit) || \
+ CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 20, feature_bit) || \
DISABLED_MASK_CHECK || \
- BUILD_BUG_ON_ZERO(NCAPINTS != 20))
+ BUILD_BUG_ON_ZERO(NCAPINTS != 21))

#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 6cfa7143c316..a84536876794 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 20 /* N 32-bit words worth of info */
+#define NCAPINTS 21 /* N 32-bit words worth of info */
#define NBUGINTS 1 /* N 32-bit bug flags */

/*
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index c44b56f7ffba..5dfa4fb76f4b 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -124,6 +124,7 @@
#define DISABLED_MASK17 0
#define DISABLED_MASK18 0
#define DISABLED_MASK19 0
-#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 20)
+#define DISABLED_MASK20 0
+#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 21)

#endif /* _ASM_X86_DISABLED_FEATURES_H */
diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
index aff774775c67..7ba1726b71c7 100644
--- a/arch/x86/include/asm/required-features.h
+++ b/arch/x86/include/asm/required-features.h
@@ -98,6 +98,7 @@
#define REQUIRED_MASK17 0
#define REQUIRED_MASK18 0
#define REQUIRED_MASK19 0
-#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 20)
+#define REQUIRED_MASK20 0
+#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 21)

#endif /* _ASM_X86_REQUIRED_FEATURES_H */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index ce40e7caa555..d762654d16a0 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1093,6 +1093,9 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
if (c->extended_cpuid_level >= 0x8000001f)
c->x86_capability[CPUID_8000_001F_EAX] = cpuid_eax(0x8000001f);

+ if (c->extended_cpuid_level >= 0x80000021)
+ c->x86_capability[CPUID_8000_0021_EAX] = cpuid_eax(0x80000021);
+
init_scattered_cpuid_features(c);
init_speculation_control(c);

diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h
index 042d0aca3c92..81f4e9ce0c77 100644
--- a/arch/x86/kvm/reverse_cpuid.h
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -68,6 +68,7 @@ static const struct cpuid_reg reverse_cpuid[] = {
[CPUID_12_EAX] = {0x00000012, 0, CPUID_EAX},
[CPUID_8000_001F_EAX] = {0x8000001f, 0, CPUID_EAX},
[CPUID_7_1_EDX] = { 7, 1, CPUID_EDX},
+ [CPUID_8000_0021_EAX] = {0x80000021, 0, CPUID_EAX},
};

/*
--
2.34.1