KVM: x86: nVMX: don't fail nested VM entry on invalid guest state if !from_vmentry
It is possible that when non root mode is entered via special entry
(!from_vmentry), that is from SMM or from loading the nested state,
the L2 state could be invalid in regard to non unrestricted guest mode,
but later it can become valid.
(for example when RSM emulation restores segment registers from SMRAM)
Thus delay the check to VM entry, where we will check this and fail.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210913140954.165665-7-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index bc9c9cc..b89c78e 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2583,8 +2583,13 @@
* Guest state is invalid and unrestricted guest is disabled,
* which means L1 attempted VMEntry to L2 with invalid state.
* Fail the VMEntry.
+ *
+ * However when force loading the guest state (SMM exit or
+ * loading nested state after migration, it is possible to
+ * have invalid guest state now, which will be later fixed by
+ * restoring L2 register state
*/
- if (CC(!vmx_guest_state_valid(vcpu))) {
+ if (CC(from_vmentry && !vmx_guest_state_valid(vcpu))) {
*entry_failure_code = ENTRY_FAIL_DEFAULT;
return -EINVAL;
}
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 1c2296f..7df6f4b 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6628,7 +6628,10 @@
* consistency check VM-Exit due to invalid guest state and bail.
*/
if (unlikely(vmx->emulation_required)) {
- vmx->fail = 0;
+
+ /* We don't emulate invalid state of a nested guest */
+ vmx->fail = is_guest_mode(vcpu);
+
vmx->exit_reason.full = EXIT_REASON_INVALID_STATE;
vmx->exit_reason.failed_vmentry = 1;
kvm_register_mark_available(vcpu, VCPU_EXREG_EXIT_INFO_1);
