[PATCH v5 14/65] i386/tdx: Implement tdx_kvm_init() to initialize TDX VM context

[Xiaoyao Li <xiaoyao.li@xxxxxxxxx>]

Implement TDX specific ConfidentialGuestSupportClass::kvm_init()
callback, tdx_kvm_init().

Set ms->require_guest_memfd to true to require private guest memfd
allocation for any memory backend.

More TDX specific initialization will be added later.

Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
---
Changes in v5:
 - remove Acked-by from Gerd since the patch changed due to use
   ConfidentialGuestSupportClass::kvm_init();
---
 target/i386/kvm/kvm.c | 11 +----------
 target/i386/kvm/tdx.c | 13 +++++++++++++
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 898f8fb30c61..52d99d30bdc8 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -2550,16 +2550,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
     Error *local_err = NULL;
 
     /*
-     * Initialize SEV context, if required
-     *
-     * If no memory encryption is requested (ms->cgs == NULL) this is
-     * a no-op.
-     *
-     * It's also a no-op if a non-SEV confidential guest support
-     * mechanism is selected.  SEV is the only mechanism available to
-     * select on x86 at present, so this doesn't arise, but if new
-     * mechanisms are supported in future (e.g. TDX), they'll need
-     * their own initialization either here or elsewhere.
+     * Initialize confidential guest (SEV/TDX) context, if required
      */
     if (ms->cgs) {
         ret = confidential_guest_kvm_init(ms->cgs, &local_err);
diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index d3792d4a3d56..d9a1dd46dc69 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -14,8 +14,18 @@
 #include "qemu/osdep.h"
 #include "qom/object_interfaces.h"
 
+#include "hw/i386/x86.h"
 #include "tdx.h"
 
+static int tdx_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
+{
+    MachineState *ms = MACHINE(qdev_get_machine());
+
+    ms->require_guest_memfd = true;
+
+    return 0;
+}
+
 /* tdx guest */
 OBJECT_DEFINE_TYPE_WITH_INTERFACES(TdxGuest,
                                    tdx_guest,
@@ -37,4 +47,7 @@ static void tdx_guest_finalize(Object *obj)
 
 static void tdx_guest_class_init(ObjectClass *oc, void *data)
 {
+    ConfidentialGuestSupportClass *klass = CONFIDENTIAL_GUEST_SUPPORT_CLASS(oc);
+
+    klass->kvm_init = tdx_kvm_init;
 }
-- 
2.34.1