[PATCH 1/5] KVM: x86: Move reverse CPUID helpers to separate header file
From: Ricardo Koller
Date: Wed Apr 21 2021 - 20:56:45 EST
Split out the reverse CPUID machinery to a dedicated header file
so that KVM selftests can reuse the reverse CPUID definitions without
introducing any '#ifdef __KERNEL__' pollution.
Co-developed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Ricardo Koller <ricarkol@xxxxxxxxxx>
---
arch/x86/kvm/cpuid.h | 177 +--------------------------------
arch/x86/kvm/reverse_cpuid.h | 185 +++++++++++++++++++++++++++++++++++
2 files changed, 186 insertions(+), 176 deletions(-)
create mode 100644 arch/x86/kvm/reverse_cpuid.h
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 888e88b42e8d..6132ed3c6ebf 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -3,28 +3,11 @@
#define ARCH_X86_KVM_CPUID_H
#include "x86.h"
+#include "reverse_cpuid.h"
#include <asm/cpu.h>
#include <asm/processor.h>
#include <uapi/asm/kvm_para.h>
-/*
- * Hardware-defined CPUID leafs that are scattered in the kernel, but need to
- * be directly used by KVM. Note, these word values conflict with the kernel's
- * "bug" caps, but KVM doesn't use those.
- */
-enum kvm_only_cpuid_leafs {
- CPUID_12_EAX = NCAPINTS,
- NR_KVM_CPU_CAPS,
-
- NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS,
-};
-
-#define KVM_X86_FEATURE(w, f) ((w)*32 + (f))
-
-/* Intel-defined SGX sub-features, CPUID level 0x12 (EAX). */
-#define KVM_X86_FEATURE_SGX1 KVM_X86_FEATURE(CPUID_12_EAX, 0)
-#define KVM_X86_FEATURE_SGX2 KVM_X86_FEATURE(CPUID_12_EAX, 1)
-
extern u32 kvm_cpu_caps[NR_KVM_CPU_CAPS] __read_mostly;
void kvm_set_cpu_caps(void);
@@ -76,164 +59,6 @@ static inline bool page_address_valid(struct kvm_vcpu *vcpu, gpa_t gpa)
return kvm_vcpu_is_legal_aligned_gpa(vcpu, gpa, PAGE_SIZE);
}
-struct cpuid_reg {
- u32 function;
- u32 index;
- int reg;
-};
-
-static const struct cpuid_reg reverse_cpuid[] = {
- [CPUID_1_EDX] = { 1, 0, CPUID_EDX},
- [CPUID_8000_0001_EDX] = {0x80000001, 0, CPUID_EDX},
- [CPUID_8086_0001_EDX] = {0x80860001, 0, CPUID_EDX},
- [CPUID_1_ECX] = { 1, 0, CPUID_ECX},
- [CPUID_C000_0001_EDX] = {0xc0000001, 0, CPUID_EDX},
- [CPUID_8000_0001_ECX] = {0x80000001, 0, CPUID_ECX},
- [CPUID_7_0_EBX] = { 7, 0, CPUID_EBX},
- [CPUID_D_1_EAX] = { 0xd, 1, CPUID_EAX},
- [CPUID_8000_0008_EBX] = {0x80000008, 0, CPUID_EBX},
- [CPUID_6_EAX] = { 6, 0, CPUID_EAX},
- [CPUID_8000_000A_EDX] = {0x8000000a, 0, CPUID_EDX},
- [CPUID_7_ECX] = { 7, 0, CPUID_ECX},
- [CPUID_8000_0007_EBX] = {0x80000007, 0, CPUID_EBX},
- [CPUID_7_EDX] = { 7, 0, CPUID_EDX},
- [CPUID_7_1_EAX] = { 7, 1, CPUID_EAX},
- [CPUID_12_EAX] = {0x00000012, 0, CPUID_EAX},
-};
-
-/*
- * Reverse CPUID and its derivatives can only be used for hardware-defined
- * feature words, i.e. words whose bits directly correspond to a CPUID leaf.
- * Retrieving a feature bit or masking guest CPUID from a Linux-defined word
- * is nonsensical as the bit number/mask is an arbitrary software-defined value
- * and can't be used by KVM to query/control guest capabilities. And obviously
- * the leaf being queried must have an entry in the lookup table.
- */
-static __always_inline void reverse_cpuid_check(unsigned int x86_leaf)
-{
- BUILD_BUG_ON(x86_leaf == CPUID_LNX_1);
- BUILD_BUG_ON(x86_leaf == CPUID_LNX_2);
- BUILD_BUG_ON(x86_leaf == CPUID_LNX_3);
- BUILD_BUG_ON(x86_leaf == CPUID_LNX_4);
- BUILD_BUG_ON(x86_leaf >= ARRAY_SIZE(reverse_cpuid));
- BUILD_BUG_ON(reverse_cpuid[x86_leaf].function == 0);
-}
-
-/*
- * Translate feature bits that are scattered in the kernel's cpufeatures word
- * into KVM feature words that align with hardware's definitions.
- */
-static __always_inline u32 __feature_translate(int x86_feature)
-{
- if (x86_feature == X86_FEATURE_SGX1)
- return KVM_X86_FEATURE_SGX1;
- else if (x86_feature == X86_FEATURE_SGX2)
- return KVM_X86_FEATURE_SGX2;
-
- return x86_feature;
-}
-
-static __always_inline u32 __feature_leaf(int x86_feature)
-{
- return __feature_translate(x86_feature) / 32;
-}
-
-/*
- * Retrieve the bit mask from an X86_FEATURE_* definition. Features contain
- * the hardware defined bit number (stored in bits 4:0) and a software defined
- * "word" (stored in bits 31:5). The word is used to index into arrays of
- * bit masks that hold the per-cpu feature capabilities, e.g. this_cpu_has().
- */
-static __always_inline u32 __feature_bit(int x86_feature)
-{
- x86_feature = __feature_translate(x86_feature);
-
- reverse_cpuid_check(x86_feature / 32);
- return 1 << (x86_feature & 31);
-}
-
-#define feature_bit(name) __feature_bit(X86_FEATURE_##name)
-
-static __always_inline struct cpuid_reg x86_feature_cpuid(unsigned int x86_feature)
-{
- unsigned int x86_leaf = __feature_leaf(x86_feature);
-
- reverse_cpuid_check(x86_leaf);
- return reverse_cpuid[x86_leaf];
-}
-
-static __always_inline u32 *__cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry,
- u32 reg)
-{
- switch (reg) {
- case CPUID_EAX:
- return &entry->eax;
- case CPUID_EBX:
- return &entry->ebx;
- case CPUID_ECX:
- return &entry->ecx;
- case CPUID_EDX:
- return &entry->edx;
- default:
- BUILD_BUG();
- return NULL;
- }
-}
-
-static __always_inline u32 *cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry,
- unsigned int x86_feature)
-{
- const struct cpuid_reg cpuid = x86_feature_cpuid(x86_feature);
-
- return __cpuid_entry_get_reg(entry, cpuid.reg);
-}
-
-static __always_inline u32 cpuid_entry_get(struct kvm_cpuid_entry2 *entry,
- unsigned int x86_feature)
-{
- u32 *reg = cpuid_entry_get_reg(entry, x86_feature);
-
- return *reg & __feature_bit(x86_feature);
-}
-
-static __always_inline bool cpuid_entry_has(struct kvm_cpuid_entry2 *entry,
- unsigned int x86_feature)
-{
- return cpuid_entry_get(entry, x86_feature);
-}
-
-static __always_inline void cpuid_entry_clear(struct kvm_cpuid_entry2 *entry,
- unsigned int x86_feature)
-{
- u32 *reg = cpuid_entry_get_reg(entry, x86_feature);
-
- *reg &= ~__feature_bit(x86_feature);
-}
-
-static __always_inline void cpuid_entry_set(struct kvm_cpuid_entry2 *entry,
- unsigned int x86_feature)
-{
- u32 *reg = cpuid_entry_get_reg(entry, x86_feature);
-
- *reg |= __feature_bit(x86_feature);
-}
-
-static __always_inline void cpuid_entry_change(struct kvm_cpuid_entry2 *entry,
- unsigned int x86_feature,
- bool set)
-{
- u32 *reg = cpuid_entry_get_reg(entry, x86_feature);
-
- /*
- * Open coded instead of using cpuid_entry_{clear,set}() to coerce the
- * compiler into using CMOV instead of Jcc when possible.
- */
- if (set)
- *reg |= __feature_bit(x86_feature);
- else
- *reg &= ~__feature_bit(x86_feature);
-}
-
static __always_inline void cpuid_entry_override(struct kvm_cpuid_entry2 *entry,
enum cpuid_leafs leaf)
{
diff --git a/arch/x86/kvm/reverse_cpuid.h b/arch/x86/kvm/reverse_cpuid.h
new file mode 100644
index 000000000000..8e0756ddab1a
--- /dev/null
+++ b/arch/x86/kvm/reverse_cpuid.h
@@ -0,0 +1,185 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef ARCH_X86_KVM_REVERSE_CPUID_H
+#define ARCH_X86_KVM_REVERSE_CPUID_H
+
+#include <uapi/asm/kvm.h>
+#include <asm/cpufeature.h>
+#include <asm/cpufeatures.h>
+
+/*
+ * Hardware-defined CPUID leafs that are scattered in the kernel, but need to
+ * be directly used by KVM. Note, these word values conflict with the kernel's
+ * "bug" caps, but KVM doesn't use those.
+ */
+enum kvm_only_cpuid_leafs {
+ CPUID_12_EAX = NCAPINTS,
+ NR_KVM_CPU_CAPS,
+
+ NKVMCAPINTS = NR_KVM_CPU_CAPS - NCAPINTS,
+};
+
+#define KVM_X86_FEATURE(w, f) ((w)*32 + (f))
+
+/* Intel-defined SGX sub-features, CPUID level 0x12 (EAX). */
+#define KVM_X86_FEATURE_SGX1 KVM_X86_FEATURE(CPUID_12_EAX, 0)
+#define KVM_X86_FEATURE_SGX2 KVM_X86_FEATURE(CPUID_12_EAX, 1)
+
+struct cpuid_reg {
+ u32 function;
+ u32 index;
+ int reg;
+};
+
+static const struct cpuid_reg reverse_cpuid[] = {
+ [CPUID_1_EDX] = { 1, 0, CPUID_EDX},
+ [CPUID_8000_0001_EDX] = {0x80000001, 0, CPUID_EDX},
+ [CPUID_8086_0001_EDX] = {0x80860001, 0, CPUID_EDX},
+ [CPUID_1_ECX] = { 1, 0, CPUID_ECX},
+ [CPUID_C000_0001_EDX] = {0xc0000001, 0, CPUID_EDX},
+ [CPUID_8000_0001_ECX] = {0x80000001, 0, CPUID_ECX},
+ [CPUID_7_0_EBX] = { 7, 0, CPUID_EBX},
+ [CPUID_D_1_EAX] = { 0xd, 1, CPUID_EAX},
+ [CPUID_8000_0008_EBX] = {0x80000008, 0, CPUID_EBX},
+ [CPUID_6_EAX] = { 6, 0, CPUID_EAX},
+ [CPUID_8000_000A_EDX] = {0x8000000a, 0, CPUID_EDX},
+ [CPUID_7_ECX] = { 7, 0, CPUID_ECX},
+ [CPUID_8000_0007_EBX] = {0x80000007, 0, CPUID_EBX},
+ [CPUID_7_EDX] = { 7, 0, CPUID_EDX},
+ [CPUID_7_1_EAX] = { 7, 1, CPUID_EAX},
+ [CPUID_12_EAX] = {0x00000012, 0, CPUID_EAX},
+};
+
+/*
+ * Reverse CPUID and its derivatives can only be used for hardware-defined
+ * feature words, i.e. words whose bits directly correspond to a CPUID leaf.
+ * Retrieving a feature bit or masking guest CPUID from a Linux-defined word
+ * is nonsensical as the bit number/mask is an arbitrary software-defined value
+ * and can't be used by KVM to query/control guest capabilities. And obviously
+ * the leaf being queried must have an entry in the lookup table.
+ */
+static __always_inline void reverse_cpuid_check(unsigned int x86_leaf)
+{
+ BUILD_BUG_ON(x86_leaf == CPUID_LNX_1);
+ BUILD_BUG_ON(x86_leaf == CPUID_LNX_2);
+ BUILD_BUG_ON(x86_leaf == CPUID_LNX_3);
+ BUILD_BUG_ON(x86_leaf == CPUID_LNX_4);
+ BUILD_BUG_ON(x86_leaf >= ARRAY_SIZE(reverse_cpuid));
+ BUILD_BUG_ON(reverse_cpuid[x86_leaf].function == 0);
+}
+
+/*
+ * Translate feature bits that are scattered in the kernel's cpufeatures word
+ * into KVM feature words that align with hardware's definitions.
+ */
+static __always_inline u32 __feature_translate(int x86_feature)
+{
+ if (x86_feature == X86_FEATURE_SGX1)
+ return KVM_X86_FEATURE_SGX1;
+ else if (x86_feature == X86_FEATURE_SGX2)
+ return KVM_X86_FEATURE_SGX2;
+
+ return x86_feature;
+}
+
+static __always_inline u32 __feature_leaf(int x86_feature)
+{
+ return __feature_translate(x86_feature) / 32;
+}
+
+/*
+ * Retrieve the bit mask from an X86_FEATURE_* definition. Features contain
+ * the hardware defined bit number (stored in bits 4:0) and a software defined
+ * "word" (stored in bits 31:5). The word is used to index into arrays of
+ * bit masks that hold the per-cpu feature capabilities, e.g. this_cpu_has().
+ */
+static __always_inline u32 __feature_bit(int x86_feature)
+{
+ x86_feature = __feature_translate(x86_feature);
+
+ reverse_cpuid_check(x86_feature / 32);
+ return 1 << (x86_feature & 31);
+}
+
+#define feature_bit(name) __feature_bit(X86_FEATURE_##name)
+
+static __always_inline struct cpuid_reg x86_feature_cpuid(unsigned int x86_feature)
+{
+ unsigned int x86_leaf = __feature_leaf(x86_feature);
+
+ reverse_cpuid_check(x86_leaf);
+ return reverse_cpuid[x86_leaf];
+}
+
+static __always_inline u32 *__cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry,
+ u32 reg)
+{
+ switch (reg) {
+ case CPUID_EAX:
+ return &entry->eax;
+ case CPUID_EBX:
+ return &entry->ebx;
+ case CPUID_ECX:
+ return &entry->ecx;
+ case CPUID_EDX:
+ return &entry->edx;
+ default:
+ BUILD_BUG();
+ return NULL;
+ }
+}
+
+static __always_inline u32 *cpuid_entry_get_reg(struct kvm_cpuid_entry2 *entry,
+ unsigned int x86_feature)
+{
+ const struct cpuid_reg cpuid = x86_feature_cpuid(x86_feature);
+
+ return __cpuid_entry_get_reg(entry, cpuid.reg);
+}
+
+static __always_inline u32 cpuid_entry_get(struct kvm_cpuid_entry2 *entry,
+ unsigned int x86_feature)
+{
+ u32 *reg = cpuid_entry_get_reg(entry, x86_feature);
+
+ return *reg & __feature_bit(x86_feature);
+}
+
+static __always_inline bool cpuid_entry_has(struct kvm_cpuid_entry2 *entry,
+ unsigned int x86_feature)
+{
+ return cpuid_entry_get(entry, x86_feature);
+}
+
+static __always_inline void cpuid_entry_clear(struct kvm_cpuid_entry2 *entry,
+ unsigned int x86_feature)
+{
+ u32 *reg = cpuid_entry_get_reg(entry, x86_feature);
+
+ *reg &= ~__feature_bit(x86_feature);
+}
+
+static __always_inline void cpuid_entry_set(struct kvm_cpuid_entry2 *entry,
+ unsigned int x86_feature)
+{
+ u32 *reg = cpuid_entry_get_reg(entry, x86_feature);
+
+ *reg |= __feature_bit(x86_feature);
+}
+
+static __always_inline void cpuid_entry_change(struct kvm_cpuid_entry2 *entry,
+ unsigned int x86_feature,
+ bool set)
+{
+ u32 *reg = cpuid_entry_get_reg(entry, x86_feature);
+
+ /*
+ * Open coded instead of using cpuid_entry_{clear,set}() to coerce the
+ * compiler into using CMOV instead of Jcc when possible.
+ */
+ if (set)
+ *reg |= __feature_bit(x86_feature);
+ else
+ *reg &= ~__feature_bit(x86_feature);
+}
+
+#endif /* ARCH_X86_KVM_REVERSE_CPUID_H */
--
2.31.1.368.gbe11c130af-goog