KVM translates TDG.VP.VMCALL<MapGPA> to KVM_HC_MAP_GPA_RANGE, and QEMU
needs to enable user exit on KVM_HC_MAP_GPA_RANGE in order to handle the
memory conversion requested by TD guest.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
changes in v6:
 - new patch;
---
 target/i386/kvm/tdx.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index 33d7ed039051..b34707e93f4d 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -20,6 +20,8 @@
 #include "sysemu/sysemu.h"
 #include "exec/ramblock.h"
 
+#include <linux/kvm_para.h>
+
 #include "hw/i386/e820_memory_layout.h"
 #include "hw/i386/x86.h"
 #include "hw/i386/tdvf.h"
@@ -362,6 +364,11 @@ static int tdx_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
         }
     }
 
+    /* TDX relies on KVM_HC_MAP_GPA_RANGE to handle TDG.VP.VMCALL<MapGPA> */
+    if (!kvm_enable_hypercall(BIT_ULL(KVM_HC_MAP_GPA_RANGE))) {
+        return -EOPNOTSUPP;
+    }
+
     qemu_add_machine_init_done_notifier(&tdx_machine_done_notify);
 
     tdx_guest = tdx;
-- 
2.34.1