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linux/arch/x86/kvm/cpuid.h
Guang Zeng be50b2065d kvm: x86: Add support for getting/setting expanded xstate buffer 
With KVM_CAP_XSAVE, userspace uses a hardcoded 4KB buffer to get/set
xstate data from/to KVM. This doesn't work when dynamic xfeatures
(e.g. AMX) are exposed to the guest as they require a larger buffer
size.

Introduce a new capability (KVM_CAP_XSAVE2). Userspace VMM gets the
required xstate buffer size via KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2).
KVM_SET_XSAVE is extended to work with both legacy and new capabilities
by doing properly-sized memdup_user() based on the guest fpu container.
KVM_GET_XSAVE is kept for backward-compatible reason. Instead,
KVM_GET_XSAVE2 is introduced under KVM_CAP_XSAVE2 as the preferred
interface for getting xstate buffer (4KB or larger size) from KVM
(Link: https://lkml.org/lkml/2021/12/15/510)

Also, update the api doc with the new KVM_GET_XSAVE2 ioctl.

Signed-off-by: Guang Zeng <guang.zeng@intel.com>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20220105123532.12586-19-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-01-14 13:44:41 -05:00

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef ARCH_X86_KVM_CPUID_H
#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>
extern u32 kvm_cpu_caps[NR_KVM_CPU_CAPS] __read_mostly;
void kvm_set_cpu_caps(void);
void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu);
void kvm_update_pv_runtime(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 exact_only);
u32 xstate_required_size(u64 xstate_bv, bool compacted);
int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu);
u64 kvm_vcpu_reserved_gpa_bits_raw(struct kvm_vcpu *vcpu);
static inline int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
{
return vcpu->arch.maxphyaddr;
}
static inline bool kvm_vcpu_is_legal_gpa(struct kvm_vcpu *vcpu, gpa_t gpa)
{
return !(gpa & vcpu->arch.reserved_gpa_bits);
}
static inline bool kvm_vcpu_is_illegal_gpa(struct kvm_vcpu *vcpu, gpa_t gpa)
{
return !kvm_vcpu_is_legal_gpa(vcpu, gpa);
}
static inline bool kvm_vcpu_is_legal_aligned_gpa(struct kvm_vcpu *vcpu,
gpa_t gpa, gpa_t alignment)
{
return IS_ALIGNED(gpa, alignment) && kvm_vcpu_is_legal_gpa(vcpu, gpa);
}
static inline bool page_address_valid(struct kvm_vcpu *vcpu, gpa_t gpa)
{
return kvm_vcpu_is_legal_aligned_gpa(vcpu, gpa, PAGE_SIZE);
}
static __always_inline void cpuid_entry_override(struct kvm_cpuid_entry2 *entry,
unsigned int leaf)
{
u32 *reg = cpuid_entry_get_reg(entry, leaf * 32);
BUILD_BUG_ON(leaf >= ARRAY_SIZE(kvm_cpu_caps));
*reg = kvm_cpu_caps[leaf];
}
static __always_inline u32 *guest_cpuid_get_register(struct kvm_vcpu *vcpu,
unsigned int x86_feature)
{
const struct cpuid_reg cpuid = x86_feature_cpuid(x86_feature);
struct kvm_cpuid_entry2 *entry;
entry = kvm_find_cpuid_entry(vcpu, cpuid.function, cpuid.index);
if (!entry)
return NULL;
return __cpuid_entry_get_reg(entry, cpuid.reg);
}
static __always_inline bool guest_cpuid_has(struct kvm_vcpu *vcpu,
unsigned int 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 int 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_or_hygon(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
best = kvm_find_cpuid_entry(vcpu, 0, 0);
return best &&
(is_guest_vendor_amd(best->ebx, best->ecx, best->edx) ||
is_guest_vendor_hygon(best->ebx, best->ecx, best->edx));
}
static inline bool guest_cpuid_is_intel(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
best = kvm_find_cpuid_entry(vcpu, 0, 0);
return best && is_guest_vendor_intel(best->ebx, best->ecx, best->edx);
}
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 guest_has_spec_ctrl_msr(struct kvm_vcpu *vcpu)
{
return (guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL) ||
guest_cpuid_has(vcpu, X86_FEATURE_AMD_STIBP) ||
guest_cpuid_has(vcpu, X86_FEATURE_AMD_IBRS) ||
guest_cpuid_has(vcpu, X86_FEATURE_AMD_SSBD));
}
static inline bool guest_has_pred_cmd_msr(struct kvm_vcpu *vcpu)
{
return (guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL) ||
guest_cpuid_has(vcpu, X86_FEATURE_AMD_IBPB));
}
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;
}
static __always_inline void kvm_cpu_cap_clear(unsigned int x86_feature)
{
unsigned int x86_leaf = __feature_leaf(x86_feature);
reverse_cpuid_check(x86_leaf);
kvm_cpu_caps[x86_leaf] &= ~__feature_bit(x86_feature);
}
static __always_inline void kvm_cpu_cap_set(unsigned int x86_feature)
{
unsigned int x86_leaf = __feature_leaf(x86_feature);
reverse_cpuid_check(x86_leaf);
kvm_cpu_caps[x86_leaf] |= __feature_bit(x86_feature);
}
static __always_inline u32 kvm_cpu_cap_get(unsigned int x86_feature)
{
unsigned int x86_leaf = __feature_leaf(x86_feature);
reverse_cpuid_check(x86_leaf);
return kvm_cpu_caps[x86_leaf] & __feature_bit(x86_feature);
}
static __always_inline bool kvm_cpu_cap_has(unsigned int x86_feature)
{
return !!kvm_cpu_cap_get(x86_feature);
}
static __always_inline void kvm_cpu_cap_check_and_set(unsigned int x86_feature)
{
if (boot_cpu_has(x86_feature))
kvm_cpu_cap_set(x86_feature);
}
static __always_inline bool guest_pv_has(struct kvm_vcpu *vcpu,
unsigned int kvm_feature)
{
if (!vcpu->arch.pv_cpuid.enforce)
return true;
return vcpu->arch.pv_cpuid.features & (1u << kvm_feature);
}
#endif
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