diff options
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 54 |
1 files changed, 32 insertions, 22 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 40e46098af48..6b56ed325ec4 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -142,10 +142,10 @@ static inline struct kvm_cpuid_entry2 *cpuid_entry2_find( return NULL; } -static int kvm_check_cpuid(struct kvm_vcpu *vcpu, - struct kvm_cpuid_entry2 *entries, - int nent) +static int kvm_check_cpuid(struct kvm_vcpu *vcpu) { + struct kvm_cpuid_entry2 *entries = vcpu->arch.cpuid_entries; + int nent = vcpu->arch.cpuid_nent; struct kvm_cpuid_entry2 *best; u64 xfeatures; @@ -178,9 +178,6 @@ static int kvm_check_cpuid(struct kvm_vcpu *vcpu, return fpu_enable_guest_xfd_features(&vcpu->arch.guest_fpu, xfeatures); } -static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *entries, - int nent); - /* Check whether the supplied CPUID data is equal to what is already set for the vCPU. */ static int kvm_cpuid_check_equal(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2, int nent) @@ -196,8 +193,10 @@ static int kvm_cpuid_check_equal(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 * CPUID processing is functionally correct only because any change in * CPUID is disallowed, i.e. using stale data is ok because the below * checks will reject the change. + * + * Note! @e2 and @nent track the _old_ CPUID entries! */ - __kvm_update_cpuid_runtime(vcpu, e2, nent); + kvm_update_cpuid_runtime(vcpu); if (nent != vcpu->arch.cpuid_nent) return -EINVAL; @@ -350,9 +349,11 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu) } EXPORT_SYMBOL_GPL(kvm_update_cpuid_runtime); -static bool kvm_cpuid_has_hyperv(struct kvm_cpuid_entry2 *entries, int nent) +static bool kvm_cpuid_has_hyperv(struct kvm_vcpu *vcpu) { #ifdef CONFIG_KVM_HYPERV + struct kvm_cpuid_entry2 *entries = vcpu->arch.cpuid_entries; + int nent = vcpu->arch.cpuid_nent; struct kvm_cpuid_entry2 *entry; entry = cpuid_entry2_find(entries, nent, HYPERV_CPUID_INTERFACE, @@ -429,8 +430,7 @@ void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) __cr4_reserved_bits(guest_cpuid_has, vcpu); #undef __kvm_cpu_cap_has - kvm_hv_set_cpuid(vcpu, kvm_cpuid_has_hyperv(vcpu->arch.cpuid_entries, - vcpu->arch.cpuid_nent)); + kvm_hv_set_cpuid(vcpu, kvm_cpuid_has_hyperv(vcpu)); /* Invoke the vendor callback only after the above state is updated. */ kvm_x86_call(vcpu_after_set_cpuid)(vcpu); @@ -472,6 +472,15 @@ static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2, int r; /* + * Swap the existing (old) entries with the incoming (new) entries in + * order to massage the new entries, e.g. to account for dynamic bits + * that KVM controls, without clobbering the current guest CPUID, which + * KVM needs to preserve in order to unwind on failure. + */ + swap(vcpu->arch.cpuid_entries, e2); + swap(vcpu->arch.cpuid_nent, nent); + + /* * KVM does not correctly handle changing guest CPUID after KVM_RUN, as * MAXPHYADDR, GBPAGES support, AMD reserved bit behavior, etc.. aren't * tracked in kvm_mmu_page_role. As a result, KVM may miss guest page @@ -485,27 +494,21 @@ static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2, if (kvm_vcpu_has_run(vcpu)) { r = kvm_cpuid_check_equal(vcpu, e2, nent); if (r) - return r; - - kvfree(e2); - return 0; + goto err; + goto success; } #ifdef CONFIG_KVM_HYPERV - if (kvm_cpuid_has_hyperv(e2, nent)) { + if (kvm_cpuid_has_hyperv(vcpu)) { r = kvm_hv_vcpu_init(vcpu); if (r) - return r; + goto err; } #endif - r = kvm_check_cpuid(vcpu, e2, nent); + r = kvm_check_cpuid(vcpu); if (r) - return r; - - kvfree(vcpu->arch.cpuid_entries); - vcpu->arch.cpuid_entries = e2; - vcpu->arch.cpuid_nent = nent; + goto err; vcpu->arch.kvm_cpuid = kvm_get_hypervisor_cpuid(vcpu, KVM_SIGNATURE); #ifdef CONFIG_KVM_XEN @@ -513,7 +516,14 @@ static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2, #endif kvm_vcpu_after_set_cpuid(vcpu); +success: + kvfree(e2); return 0; + +err: + swap(vcpu->arch.cpuid_entries, e2); + swap(vcpu->arch.cpuid_nent, nent); + return r; } /* when an old userspace process fills a new kernel module */ |