linux/arch/x86/kvm/cpuid.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef ARCH_X86_KVM_CPUID_H
#define ARCH_X86_KVM_CPUID_H

#include "x86.h"
#include <asm/cpu.h>
#include <asm/processor.h>

int kvm_update_cpuid(struct kvm_vcpu *vcpu);
struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
					      u32 function, u32 index);
int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
			    struct kvm_cpuid_entry2 __user *entries,
			    unsigned int type);
int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
			     struct kvm_cpuid *cpuid,
			     struct kvm_cpuid_entry __user *entries);
int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
			      struct kvm_cpuid2 *cpuid,
			      struct kvm_cpuid_entry2 __user *entries);
int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
			      struct kvm_cpuid2 *cpuid,
			      struct kvm_cpuid_entry2 __user *entries);
bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
	       u32 *ecx, u32 *edx, bool check_limit);

int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu);

static inline int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
{
	return vcpu->arch.maxphyaddr;
}

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},
};

/*
 * 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 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);
}

/*
 * 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)
{
	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 x86_feature)
{
	unsigned x86_leaf = x86_feature / 32;

	reverse_cpuid_check(x86_leaf);
	return reverse_cpuid[x86_leaf];
}

static __always_inline u32 *guest_cpuid_get_register(struct kvm_vcpu *vcpu, unsigned x86_feature)
{
	struct kvm_cpuid_entry2 *entry;
	const struct cpuid_reg cpuid = x86_feature_cpuid(x86_feature);

	entry = kvm_find_cpuid_entry(vcpu, cpuid.function, cpuid.index);
	if (!entry)
		return NULL;

	switch (cpuid.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 bool guest_cpuid_has(struct kvm_vcpu *vcpu, unsigned x86_feature)
{
	u32 *reg;

	reg = guest_cpuid_get_register(vcpu, x86_feature);
	if (!reg)
		return false;

	return *reg & __feature_bit(x86_feature);
}

static __always_inline void guest_cpuid_clear(struct kvm_vcpu *vcpu, unsigned x86_feature)
{
	u32 *reg;

	reg = guest_cpuid_get_register(vcpu, x86_feature);
	if (reg)
		*reg &= ~__feature_bit(x86_feature);
}

static inline bool guest_cpuid_is_amd(struct kvm_vcpu *vcpu)
{
	struct kvm_cpuid_entry2 *best;

	best = kvm_find_cpuid_entry(vcpu, 0, 0);
	return best && best->ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx;
}

static inline int guest_cpuid_family(struct kvm_vcpu *vcpu)
{
	struct kvm_cpuid_entry2 *best;

	best = kvm_find_cpuid_entry(vcpu, 0x1, 0);
	if (!best)
		return -1;

	return x86_family(best->eax);
}

static inline int guest_cpuid_model(struct kvm_vcpu *vcpu)
{
	struct kvm_cpuid_entry2 *best;

	best = kvm_find_cpuid_entry(vcpu, 0x1, 0);
	if (!best)
		return -1;

	return x86_model(best->eax);
}

static inline int guest_cpuid_stepping(struct kvm_vcpu *vcpu)
{
	struct kvm_cpuid_entry2 *best;

	best = kvm_find_cpuid_entry(vcpu, 0x1, 0);
	if (!best)
		return -1;

	return x86_stepping(best->eax);
}

static inline bool supports_cpuid_fault(struct kvm_vcpu *vcpu)
{
	return vcpu->arch.msr_platform_info & MSR_PLATFORM_INFO_CPUID_FAULT;
}

static inline bool cpuid_fault_enabled(struct kvm_vcpu *vcpu)
{
	return vcpu->arch.msr_misc_features_enables &
		  MSR_MISC_FEATURES_ENABLES_CPUID_FAULT;
}

#endif