[PATCH 44/60] kvm: x86: Move cpu_caps to struct kvm_vcpu_arch_common
From: Jörg Rödel <joro@8bytes.org>
Date: 2026-06-08 14:43:25
Also in:
kvm, kvm-riscv, kvmarm, linux-mips, lkml, loongarch
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Joerg Roedel <redacted> Now that CPUID state is shared across all planes, cpu_caps can be shared as well. Signed-off-by: Joerg Roedel <redacted> --- arch/x86/include/asm/kvm_host.h | 33 +++++++++++++++++---------------- arch/x86/kvm/cpuid.c | 18 +++++++++--------- arch/x86/kvm/cpuid.h | 17 +++++++++-------- arch/x86/kvm/svm/svm.c | 4 ++-- arch/x86/kvm/vmx/vmx.c | 2 +- 5 files changed, 38 insertions(+), 36 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3a64bdae6e23..b0d040528f9d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h@@ -800,6 +800,23 @@ struct kvm_vcpu_arch_common { struct kvm_cpuid_entry2 *cpuid_entries; bool cpuid_dynamic_bits_dirty; bool is_amd_compatible; + + /* + * cpu_caps holds the effective guest capabilities, i.e. the features + * the vCPU is allowed to use. Typically, but not always, features can + * be used by the guest if and only if both KVM and userspace want to + * expose the feature to the guest. + * + * A common exception is for virtualization holes, i.e. when KVM can't + * prevent the guest from using a feature, in which case the vCPU "has" + * the feature regardless of what KVM or userspace desires. + * + * Note, features that don't require KVM involvement in any way are + * NOT enforced/sanitized by KVM, i.e. are taken verbatim from the + * guest CPUID provided by userspace. + */ + u32 cpu_caps[NR_KVM_CPU_CAPS]; + }; int kvm_arch_vcpu_common_init(struct kvm_vcpu_common *common);
@@ -925,22 +942,6 @@ struct kvm_vcpu_arch { int halt_request; /* real mode on Intel only */ - /* - * cpu_caps holds the effective guest capabilities, i.e. the features - * the vCPU is allowed to use. Typically, but not always, features can - * be used by the guest if and only if both KVM and userspace want to - * expose the feature to the guest. - * - * A common exception is for virtualization holes, i.e. when KVM can't - * prevent the guest from using a feature, in which case the vCPU "has" - * the feature regardless of what KVM or userspace desires. - * - * Note, features that don't require KVM involvement in any way are - * NOT enforced/sanitized by KVM, i.e. are taken verbatim from the - * guest CPUID provided by userspace. - */ - u32 cpu_caps[NR_KVM_CPU_CAPS]; - u64 reserved_gpa_bits; int maxphyaddr;
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 6d948d63306c..27e2f7e25038 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c@@ -284,7 +284,7 @@ static __always_inline void kvm_update_feature_runtime(struct kvm_vcpu *vcpu, bool has_feature) { cpuid_entry_change(entry, x86_feature, has_feature); - guest_cpu_cap_change(vcpu, x86_feature, has_feature); + guest_cpu_cap_change(vcpu->common, x86_feature, has_feature); } static void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
@@ -382,7 +382,7 @@ void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) bool allow_gbpages; int i; - memset(vcpu->arch.cpu_caps, 0, sizeof(vcpu->arch.cpu_caps)); + memset(common->arch.cpu_caps, 0, sizeof(common->arch.cpu_caps)); BUILD_BUG_ON(ARRAY_SIZE(reverse_cpuid) != NR_KVM_CPU_CAPS); /*
@@ -408,9 +408,9 @@ void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) * in guest CPUID. Note, this includes features that are * supported by KVM but aren't advertised to userspace! */ - vcpu->arch.cpu_caps[i] = kvm_cpu_caps[i] | - cpuid_get_reg_unsafe(&emulated, cpuid.reg); - vcpu->arch.cpu_caps[i] &= cpuid_get_reg_unsafe(entry, cpuid.reg); + common->arch.cpu_caps[i] = kvm_cpu_caps[i] | + cpuid_get_reg_unsafe(&emulated, cpuid.reg); + common->arch.cpu_caps[i] &= cpuid_get_reg_unsafe(entry, cpuid.reg); } kvm_update_cpuid_runtime(vcpu);
@@ -428,7 +428,7 @@ void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) */ allow_gbpages = tdp_enabled ? boot_cpu_has(X86_FEATURE_GBPAGES) : guest_cpu_cap_has(vcpu, X86_FEATURE_GBPAGES); - guest_cpu_cap_change(vcpu, X86_FEATURE_GBPAGES, allow_gbpages); + guest_cpu_cap_change(common, X86_FEATURE_GBPAGES, allow_gbpages); best = kvm_find_cpuid_entry(vcpu, 1); if (best && apic) {
@@ -536,8 +536,8 @@ static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2, swap(common->arch.cpuid_entries, e2); swap(common->arch.cpuid_nent, nent); - memcpy(vcpu_caps, vcpu->arch.cpu_caps, sizeof(vcpu_caps)); - BUILD_BUG_ON(sizeof(vcpu_caps) != sizeof(vcpu->arch.cpu_caps)); + memcpy(vcpu_caps, common->arch.cpu_caps, sizeof(vcpu_caps)); + BUILD_BUG_ON(sizeof(vcpu_caps) != sizeof(common->arch.cpu_caps)); /* * KVM does not correctly handle changing guest CPUID after KVM_RUN or
@@ -582,7 +582,7 @@ static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2, return 0; err: - memcpy(vcpu->arch.cpu_caps, vcpu_caps, sizeof(vcpu_caps)); + memcpy(common->arch.cpu_caps, vcpu_caps, sizeof(vcpu_caps)); swap(common->arch.cpuid_entries, e2); swap(common->arch.cpuid_nent, nent); return r;
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 143ea8531611..75abf447eabf 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h@@ -239,36 +239,37 @@ static __always_inline bool guest_pv_has(struct kvm_vcpu *vcpu, return vcpu->arch.pv_cpuid.features & (1u << kvm_feature); } -static __always_inline void guest_cpu_cap_set(struct kvm_vcpu *vcpu, +static __always_inline void guest_cpu_cap_set(struct kvm_vcpu_common *common, unsigned int x86_feature) { unsigned int x86_leaf = __feature_leaf(x86_feature); - vcpu->arch.cpu_caps[x86_leaf] |= __feature_bit(x86_feature); + common->arch.cpu_caps[x86_leaf] |= __feature_bit(x86_feature); } -static __always_inline void guest_cpu_cap_clear(struct kvm_vcpu *vcpu, +static __always_inline void guest_cpu_cap_clear(struct kvm_vcpu_common *common, unsigned int x86_feature) { unsigned int x86_leaf = __feature_leaf(x86_feature); - vcpu->arch.cpu_caps[x86_leaf] &= ~__feature_bit(x86_feature); + common->arch.cpu_caps[x86_leaf] &= ~__feature_bit(x86_feature); } -static __always_inline void guest_cpu_cap_change(struct kvm_vcpu *vcpu, +static __always_inline void guest_cpu_cap_change(struct kvm_vcpu_common *common, unsigned int x86_feature, bool guest_has_cap) { if (guest_has_cap) - guest_cpu_cap_set(vcpu, x86_feature); + guest_cpu_cap_set(common, x86_feature); else - guest_cpu_cap_clear(vcpu, x86_feature); + guest_cpu_cap_clear(common, x86_feature); } static __always_inline bool guest_cpu_cap_has(struct kvm_vcpu *vcpu, unsigned int x86_feature) { unsigned int x86_leaf = __feature_leaf(x86_feature); + struct kvm_vcpu_common *common = vcpu->common; /* * Except for MWAIT, querying dynamic feature bits is disallowed, so
@@ -278,7 +279,7 @@ static __always_inline bool guest_cpu_cap_has(struct kvm_vcpu *vcpu, x86_feature == X86_FEATURE_OSXSAVE || x86_feature == X86_FEATURE_OSPKE); - return vcpu->arch.cpu_caps[x86_leaf] & __feature_bit(x86_feature); + return common->arch.cpu_caps[x86_leaf] & __feature_bit(x86_feature); } static inline bool kvm_vcpu_is_legal_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 612db7ad8b2a..0b57dde29e40 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c@@ -4706,7 +4706,7 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) * XSS on VM-Enter/VM-Exit. Failure to do so would effectively give * the guest read/write access to the host's XSS. */ - guest_cpu_cap_change(vcpu, X86_FEATURE_XSAVES, + guest_cpu_cap_change(vcpu->common, X86_FEATURE_XSAVES, boot_cpu_has(X86_FEATURE_XSAVES) && guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVE));
@@ -4716,7 +4716,7 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) * SVM on Intel is bonkers and extremely unlikely to work). */ if (guest_cpuid_is_intel_compatible(vcpu)) - guest_cpu_cap_clear(vcpu, X86_FEATURE_V_VMSAVE_VMLOAD); + guest_cpu_cap_clear(vcpu->common, X86_FEATURE_V_VMSAVE_VMLOAD); if (is_sev_guest(vcpu)) sev_vcpu_after_set_cpuid(svm);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 62e180651143..d10aa5f60cad 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c@@ -7994,7 +7994,7 @@ void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) * set if and only if XSAVE is supported. */ if (!guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVE)) - guest_cpu_cap_clear(vcpu, X86_FEATURE_XSAVES); + guest_cpu_cap_clear(vcpu->common, X86_FEATURE_XSAVES); vmx_setup_uret_msrs(vmx);
--
2.53.0