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KVM: nVMX: add missing consistency checks for CR0 and CR4

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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>
This commit is contained in:
Paolo Bonzini 2023-03-10 11:10:56 -05:00
parent bceeedb2f0
commit 112e66017b
1 changed files with 8 additions and 2 deletions
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10
arch/x86/kvm/vmx/nested.c
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@ -3022,7 +3022,7 @@ 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;
@ -3048,6 +3048,13 @@ 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:
@ -3059,7 +3066,6 @@ 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) &&