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author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2022-01-17 16:05:39 +0100 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-01-17 12:25:46 -0500 |
commit | ee3a5f9e3d9bf94159f3cc80da542fbe83502dd8 (patch) | |
tree | 984415f8a96b776099ee7acb4ef5596d8a603a49 /arch | |
parent | a21864486f7e220bd5938c6fb637613d9635739a (diff) | |
download | linux-stable-ee3a5f9e3d9bf94159f3cc80da542fbe83502dd8.tar.gz linux-stable-ee3a5f9e3d9bf94159f3cc80da542fbe83502dd8.tar.bz2 linux-stable-ee3a5f9e3d9bf94159f3cc80da542fbe83502dd8.zip |
KVM: x86: Do runtime CPUID update before updating vcpu->arch.cpuid_entries
kvm_update_cpuid_runtime() mangles CPUID data coming from userspace
VMM after updating 'vcpu->arch.cpuid_entries', this makes it
impossible to compare an update with what was previously
supplied. Introduce __kvm_update_cpuid_runtime() version which can be
used to tweak the input before it goes to 'vcpu->arch.cpuid_entries'
so the upcoming update check can compare tweaked data.
No functional change intended.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20220117150542.2176196-2-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/kvm/cpuid.c | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index c55e57b30e81..812190a707f6 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -145,14 +145,21 @@ static void kvm_update_kvm_cpuid_base(struct kvm_vcpu *vcpu) } } -static struct kvm_cpuid_entry2 *kvm_find_kvm_cpuid_features(struct kvm_vcpu *vcpu) +static struct kvm_cpuid_entry2 *__kvm_find_kvm_cpuid_features(struct kvm_vcpu *vcpu, + struct kvm_cpuid_entry2 *entries, int nent) { u32 base = vcpu->arch.kvm_cpuid_base; if (!base) return NULL; - return kvm_find_cpuid_entry(vcpu, base | KVM_CPUID_FEATURES, 0); + return cpuid_entry2_find(entries, nent, base | KVM_CPUID_FEATURES, 0); +} + +static struct kvm_cpuid_entry2 *kvm_find_kvm_cpuid_features(struct kvm_vcpu *vcpu) +{ + return __kvm_find_kvm_cpuid_features(vcpu, vcpu->arch.cpuid_entries, + vcpu->arch.cpuid_nent); } void kvm_update_pv_runtime(struct kvm_vcpu *vcpu) @@ -167,11 +174,12 @@ void kvm_update_pv_runtime(struct kvm_vcpu *vcpu) vcpu->arch.pv_cpuid.features = best->eax; } -void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu) +static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *entries, + int nent) { struct kvm_cpuid_entry2 *best; - best = kvm_find_cpuid_entry(vcpu, 1, 0); + best = cpuid_entry2_find(entries, nent, 1, 0); if (best) { /* Update OSXSAVE bit */ if (boot_cpu_has(X86_FEATURE_XSAVE)) @@ -182,33 +190,38 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu) vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE); } - best = kvm_find_cpuid_entry(vcpu, 7, 0); + best = cpuid_entry2_find(entries, nent, 7, 0); if (best && boot_cpu_has(X86_FEATURE_PKU) && best->function == 0x7) cpuid_entry_change(best, X86_FEATURE_OSPKE, kvm_read_cr4_bits(vcpu, X86_CR4_PKE)); - best = kvm_find_cpuid_entry(vcpu, 0xD, 0); + best = cpuid_entry2_find(entries, nent, 0xD, 0); if (best) best->ebx = xstate_required_size(vcpu->arch.xcr0, false); - best = kvm_find_cpuid_entry(vcpu, 0xD, 1); + best = cpuid_entry2_find(entries, nent, 0xD, 1); if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) || cpuid_entry_has(best, X86_FEATURE_XSAVEC))) best->ebx = xstate_required_size(vcpu->arch.xcr0, true); - best = kvm_find_kvm_cpuid_features(vcpu); + best = __kvm_find_kvm_cpuid_features(vcpu, entries, nent); if (kvm_hlt_in_guest(vcpu->kvm) && best && (best->eax & (1 << KVM_FEATURE_PV_UNHALT))) best->eax &= ~(1 << KVM_FEATURE_PV_UNHALT); if (!kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT)) { - best = kvm_find_cpuid_entry(vcpu, 0x1, 0); + best = cpuid_entry2_find(entries, nent, 0x1, 0); if (best) cpuid_entry_change(best, X86_FEATURE_MWAIT, vcpu->arch.ia32_misc_enable_msr & MSR_IA32_MISC_ENABLE_MWAIT); } } + +void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu) +{ + __kvm_update_cpuid_runtime(vcpu, vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent); +} EXPORT_SYMBOL_GPL(kvm_update_cpuid_runtime); static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) @@ -298,6 +311,8 @@ static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2, { int r; + __kvm_update_cpuid_runtime(vcpu, e2, nent); + r = kvm_check_cpuid(vcpu, e2, nent); if (r) return r; @@ -307,7 +322,6 @@ static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2, vcpu->arch.cpuid_nent = nent; kvm_update_kvm_cpuid_base(vcpu); - kvm_update_cpuid_runtime(vcpu); kvm_vcpu_after_set_cpuid(vcpu); return 0; |