[v1,31/40] i386/tdx: Disable SMM for TDX VMs

Commit Message

Xiaoyao Li Aug. 2, 2022, 7:47 a.m. UTC

TDX doesn't support SMM and VMM cannot emulate SMM for TDX VMs because
VMM cannot manipulate TDX VM's memory.

Disable SMM for TDX VMs and error out if user requests to enable SMM.

Signed-off-by: Xiaoyao Li <[e-mail]>
Acked-by: Gerd Hoffmann <[e-mail]>
---
 target/i386/kvm/tdx.c | 8 ++++++++
 1 file changed, 8 insertions(+)

Patch

diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index 1de767a990ba..70c56b7ba32c 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -657,9 +657,17 @@  static Notifier tdx_machine_done_notify = {
 
 int tdx_kvm_init(MachineState *ms, Error **errp)
 {
+    X86MachineState *x86ms = X86_MACHINE(ms);
     TdxGuest *tdx = (TdxGuest *)object_dynamic_cast(OBJECT(ms->cgs),
                                                     TYPE_TDX_GUEST);
 
+    if (x86ms->smm == ON_OFF_AUTO_AUTO) {
+        x86ms->smm = ON_OFF_AUTO_OFF;
+    } else if (x86ms->smm == ON_OFF_AUTO_ON) {
+        error_setg(errp, "TDX VM doesn't support SMM");
+        return -EINVAL;
+    }
+
     if (!tdx_caps) {
         get_tdx_capabilities();
     }