[PATCH v2 2/2] KVM: TDX: WARN if a SEAMCALL VM-Exit makes its way out to KVM

[Sean Christopherson <seanjc@google.com>]

WARN if KVM observes a SEAMCALL VM-Exit while running a TD guest, as the
TDX-Module is supposed to inject a #UD, per the "Unconditionally Blocked
Instructions" section of the TDX-Module base specification.

Reported-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/vmx/tdx.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 097304bf1e1d..ffcfe95f224f 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -2148,6 +2148,9 @@ int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)
 		 * - If it's not an MSMI, no need to do anything here.
 		 */
 		return 1;
+	case EXIT_REASON_SEAMCALL:
+		WARN_ON_ONCE(1);
+		break;
 	default:
 		break;
 	}
-- 
2.51.0.858.gf9c4a03a3a-goog