Commit 01338078 authored by Ricardo Koller's avatar Ricardo Koller Committed by Paolo Bonzini
Browse files

KVM: x86: Move reverse CPUID helpers to separate header file 



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: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarRicardo Koller <ricarkol@google.com>
Message-Id: <20210422005626.564163-2-ricarkol@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 27b4a9c4

arch/x86/kvm/cpuid.h

+1 −176
Original line number Diff line number Diff line
@@ -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,

						 unsigned int leaf)

{

arch/x86/kvm/reverse_cpuid.h

0 → 100644
+185 −0
Original line number Diff line number Diff line 
/* 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 */