Guest xstate permissions should be set by userspace VMM before vcpu creation. Extend KVM_SET_CPUID2 to verify that every feature reported in CPUID[0xD] has proper permission set.
Signed-off-by: Jing Liu jing2.liu@intel.com --- arch/x86/kvm/cpuid.c | 36 ++++++++++++++++++++++++------------ 1 file changed, 24 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 4855344091b8..a068373a7fbd 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -81,7 +81,9 @@ static inline struct kvm_cpuid_entry2 *cpuid_entry2_find( return NULL; }
-static int kvm_check_cpuid(struct kvm_cpuid_entry2 *entries, int nent) +static int kvm_check_cpuid(struct kvm_vcpu *vcpu, + struct kvm_cpuid_entry2 *entries, + int nent) { struct kvm_cpuid_entry2 *best;
@@ -97,6 +99,16 @@ static int kvm_check_cpuid(struct kvm_cpuid_entry2 *entries, int nent) return -EINVAL; }
+ /* Check guest permissions for dynamically-enabled xfeatures */ + best = cpuid_entry2_find(entries, nent, 0xd, 0); + if (best) { + u64 xfeatures; + + xfeatures = best->eax | ((u64)best->edx << 32); + if (xfeatures & ~vcpu->arch.guest_fpu.perm) + return -ENXIO; + } + return 0; }
@@ -277,21 +289,21 @@ u64 kvm_vcpu_reserved_gpa_bits_raw(struct kvm_vcpu *vcpu) static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2, int nent) { - int r; + int r;
- r = kvm_check_cpuid(e2, nent); - if (r) - return r; + r = kvm_check_cpuid(vcpu, e2, nent); + if (r) + return r;
- kvfree(vcpu->arch.cpuid_entries); - vcpu->arch.cpuid_entries = e2; - vcpu->arch.cpuid_nent = nent; + kvfree(vcpu->arch.cpuid_entries); + vcpu->arch.cpuid_entries = e2; + vcpu->arch.cpuid_nent = nent;
- kvm_update_kvm_cpuid_base(vcpu); - kvm_update_cpuid_runtime(vcpu); - kvm_vcpu_after_set_cpuid(vcpu); + kvm_update_kvm_cpuid_base(vcpu); + kvm_update_cpuid_runtime(vcpu); + kvm_vcpu_after_set_cpuid(vcpu);
- return 0; + return 0; }
/* when an old userspace process fills a new kernel module */