diff options
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/include/asm/kvm_host.h | 19 | ||||
-rw-r--r-- | arch/x86/kvm/cpuid.c | 4 | ||||
-rw-r--r-- | arch/x86/kvm/cpuid.h | 46 | ||||
-rw-r--r-- | arch/x86/kvm/governed_features.h | 9 |
4 files changed, 78 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index dad9331c5270..007fa8bfd634 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -831,6 +831,25 @@ struct kvm_vcpu_arch { struct kvm_cpuid_entry2 *cpuid_entries; struct kvm_hypervisor_cpuid kvm_cpuid; + /* + * FIXME: Drop this macro and use KVM_NR_GOVERNED_FEATURES directly + * when "struct kvm_vcpu_arch" is no longer defined in an + * arch/x86/include/asm header. The max is mostly arbitrary, i.e. + * can be increased as necessary. + */ +#define KVM_MAX_NR_GOVERNED_FEATURES BITS_PER_LONG + + /* + * Track whether or not the guest is allowed to use features that are + * governed by KVM, where "governed" means KVM needs to manage state + * and/or explicitly enable the feature in hardware. Typically, but + * not always, governed features can be used by the guest if and only + * if both KVM and userspace want to expose the feature to the guest. + */ + struct { + DECLARE_BITMAP(enabled, KVM_MAX_NR_GOVERNED_FEATURES); + } governed_features; + u64 reserved_gpa_bits; int maxphyaddr; diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 5a88affb2e1a..4ba43ae008cb 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -313,6 +313,10 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) struct kvm_lapic *apic = vcpu->arch.apic; struct kvm_cpuid_entry2 *best; + BUILD_BUG_ON(KVM_NR_GOVERNED_FEATURES > KVM_MAX_NR_GOVERNED_FEATURES); + bitmap_zero(vcpu->arch.governed_features.enabled, + KVM_MAX_NR_GOVERNED_FEATURES); + best = kvm_find_cpuid_entry(vcpu, 1); if (best && apic) { if (cpuid_entry_has(best, X86_FEATURE_TSC_DEADLINE_TIMER)) diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h index b1658c0de847..284fa4704553 100644 --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -232,4 +232,50 @@ static __always_inline bool guest_pv_has(struct kvm_vcpu *vcpu, return vcpu->arch.pv_cpuid.features & (1u << kvm_feature); } +enum kvm_governed_features { +#define KVM_GOVERNED_FEATURE(x) KVM_GOVERNED_##x, +#include "governed_features.h" + KVM_NR_GOVERNED_FEATURES +}; + +static __always_inline int kvm_governed_feature_index(unsigned int x86_feature) +{ + switch (x86_feature) { +#define KVM_GOVERNED_FEATURE(x) case x: return KVM_GOVERNED_##x; +#include "governed_features.h" + default: + return -1; + } +} + +static __always_inline bool kvm_is_governed_feature(unsigned int x86_feature) +{ + return kvm_governed_feature_index(x86_feature) >= 0; +} + +static __always_inline void kvm_governed_feature_set(struct kvm_vcpu *vcpu, + unsigned int x86_feature) +{ + BUILD_BUG_ON(!kvm_is_governed_feature(x86_feature)); + + __set_bit(kvm_governed_feature_index(x86_feature), + vcpu->arch.governed_features.enabled); +} + +static __always_inline void kvm_governed_feature_check_and_set(struct kvm_vcpu *vcpu, + unsigned int x86_feature) +{ + if (kvm_cpu_cap_has(x86_feature) && guest_cpuid_has(vcpu, x86_feature)) + kvm_governed_feature_set(vcpu, x86_feature); +} + +static __always_inline bool guest_can_use(struct kvm_vcpu *vcpu, + unsigned int x86_feature) +{ + BUILD_BUG_ON(!kvm_is_governed_feature(x86_feature)); + + return test_bit(kvm_governed_feature_index(x86_feature), + vcpu->arch.governed_features.enabled); +} + #endif diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_features.h new file mode 100644 index 000000000000..40ce8e6608cd --- /dev/null +++ b/arch/x86/kvm/governed_features.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#if !defined(KVM_GOVERNED_FEATURE) || defined(KVM_GOVERNED_X86_FEATURE) +BUILD_BUG() +#endif + +#define KVM_GOVERNED_X86_FEATURE(x) KVM_GOVERNED_FEATURE(X86_FEATURE_##x) + +#undef KVM_GOVERNED_X86_FEATURE +#undef KVM_GOVERNED_FEATURE |