The effective values of the guest CR0 and CR4 registers may differ from those included in the VMCS12. In particular, disabling EPT forces CR4.PAE=1 and disabling unrestricted guest mode forces CR0.PG=CR0.PE=1.

Therefore, checks on these bits cannot be delegated to the processor and must be performed by KVM.

Reported-by: Reima ISHII ishiir@g.ecc.u-tokyo.ac.jp Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com --- arch/x86/kvm/vmx/nested.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index d93c715cda6a..bceb5ad409c6 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -3021,7 +3021,7 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, enum vm_entry_failure_code *entry_failure_code) { - bool ia32e; + bool ia32e = !!(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE);

*entry_failure_code = ENTRY_FAIL_DEFAULT;

@@ -3047,6 +3047,13 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu, vmcs12->guest_ia32_perf_global_ctrl))) return -EINVAL;

+ if (CC((vmcs12->guest_cr0 & (X86_CR0_PG | X86_CR0_PE)) == X86_CR0_PG)) + return -EINVAL; + + if (CC(ia32e && !(vmcs12->guest_cr4 & X86_CR4_PAE)) || + CC(ia32e && !(vmcs12->guest_cr0 & X86_CR0_PG))) + return -EINVAL; + /* * If the load IA32_EFER VM-entry control is 1, the following checks * are performed on the field for the IA32_EFER MSR: @@ -3058,7 +3065,6 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu, */ if (to_vmx(vcpu)->nested.nested_run_pending && (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_EFER)) { - ia32e = (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) != 0; if (CC(!kvm_valid_efer(vcpu, vmcs12->guest_ia32_efer)) || CC(ia32e != !!(vmcs12->guest_ia32_efer & EFER_LMA)) || CC(((vmcs12->guest_cr0 & X86_CR0_PG) &&