It will need special handling for TDX VMs all around the QEMU.
Introduce is_tdx_vm() helper to query if it's a TDX VM.

Cache tdx_guest object thus no need to cast from ms->cgs every time.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
changes in v3:
- replace object_dynamic_cast with TDX_GUEST();
---
 target/i386/kvm/tdx.c | 15 ++++++++++++++-
 target/i386/kvm/tdx.h | 10 ++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index ad76abd58373..3c59b3b45419 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -21,8 +21,16 @@
 #include "kvm_i386.h"
 #include "tdx.h"
 
+static TdxGuest *tdx_guest;
+
 static struct kvm_tdx_capabilities *tdx_caps;
 
+/* It's valid after kvm_confidential_guest_init()->kvm_tdx_init() */
+bool is_tdx_vm(void)
+{
+    return !!tdx_guest;
+}
+
 enum tdx_ioctl_level{
     TDX_VM_IOCTL,
     TDX_VCPU_IOCTL,
@@ -103,15 +111,20 @@ static int get_tdx_capabilities(Error **errp)
 
 int tdx_kvm_init(MachineState *ms, Error **errp)
 {
+    TdxGuest *tdx = TDX_GUEST(OBJECT(ms->cgs));
     int r = 0;
 
     ms->require_guest_memfd = true;
 
     if (!tdx_caps) {
         r = get_tdx_capabilities(errp);
+        if (r) {
+            return r;
+        }
     }
 
-    return r;
+    tdx_guest = tdx;
+    return 0;
 }
 
 /* tdx guest */
diff --git a/target/i386/kvm/tdx.h b/target/i386/kvm/tdx.h
index c8a23d95258d..4036ca2f3f99 100644
--- a/target/i386/kvm/tdx.h
+++ b/target/i386/kvm/tdx.h
@@ -1,6 +1,10 @@
 #ifndef QEMU_I386_TDX_H
 #define QEMU_I386_TDX_H
 
+#ifndef CONFIG_USER_ONLY
+#include CONFIG_DEVICES /* CONFIG_TDX */
+#endif
+
 #include "exec/confidential-guest-support.h"
 
 #define TYPE_TDX_GUEST "tdx-guest"
@@ -16,6 +20,12 @@ typedef struct TdxGuest {
     uint64_t attributes;    /* TD attributes */
 } TdxGuest;
 
+#ifdef CONFIG_TDX
+bool is_tdx_vm(void);
+#else
+#define is_tdx_vm() 0
+#endif /* CONFIG_TDX */
+
 int tdx_kvm_init(MachineState *ms, Error **errp);
 
 #endif /* QEMU_I386_TDX_H */
-- 
2.34.1