The "vmxon_pa == vmcs12_pa == -1ull" test happens to work by accident: as
Enlightened VMCS is always supported, set_default_vmx_state() adds
'KVM_STATE_NESTED_EVMCS' to 'flags' and the following branch of
vmx_set_nested_state() is executed:
if ((kvm_state->flags & KVM_STATE_NESTED_EVMCS) &&
(!guest_can_use(vcpu, X86_FEATURE_VMX) ||
!vmx->nested.enlightened_vmcs_enabled))
return -EINVAL;
as 'enlightened_vmcs_enabled' is false. In fact, "vmxon_pa == vmcs12_pa ==
-1ull" is a valid state when not tainted by wrong flags so the test should
aim for this branch:
if (kvm_state->hdr.vmx.vmxon_pa == INVALID_GPA)
return 0;
Test all this properly:
- Without KVM_STATE_NESTED_EVMCS in the flags, the expected return value is
'0'.
- With KVM_STATE_NESTED_EVMCS flag (when supported) set, the expected
return value is '-EINVAL' prior to enabling eVMCS and '0' after.
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
.../kvm/x86_64/vmx_set_nested_state_test.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c b/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
index 41ea7028a1f8..67a62a5a8895 100644
--- a/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
+++ b/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
@@ -125,21 +125,25 @@ void test_vmx_nested_state(struct kvm_vcpu *vcpu)
/*
* Setting vmxon_pa == -1ull and vmcs_pa == -1ull exits early without
- * setting the nested state but flags other than eVMCS must be clear.
- * The eVMCS flag can be set if the enlightened VMCS capability has
- * been enabled.
+ * setting the nested state. When the eVMCS flag is not set, the
+ * expected return value is '0'.
*/
set_default_vmx_state(state, state_sz);
+ state->flags = 0;
state->hdr.vmx.vmxon_pa = -1ull;
state->hdr.vmx.vmcs12_pa = -1ull;
- test_nested_state_expect_einval(vcpu, state);
+ test_nested_state(vcpu, state);
- state->flags &= KVM_STATE_NESTED_EVMCS;
+ /*
+ * When eVMCS is supported, the eVMCS flag can only be set if the
+ * enlightened VMCS capability has been enabled.
+ */
if (have_evmcs) {
+ state->flags = KVM_STATE_NESTED_EVMCS;
test_nested_state_expect_einval(vcpu, state);
vcpu_enable_evmcs(vcpu);
+ test_nested_state(vcpu, state);
}
- test_nested_state(vcpu, state);
/* It is invalid to have vmxon_pa == -1ull and SMM flags non-zero. */
state->hdr.vmx.smm.flags = 1;
--
2.41.0
