TD guest can use TDG.VP.VMCALL<REPORT_FATAL_ERROR> to request termination
with error message encoded in GPRs.

Parse and print the error message, and terminate the TD guest in the
handler.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
 target/i386/kvm/tdx.c | 39 +++++++++++++++++++++++++++++++++++++++
 target/i386/kvm/tdx.h |  1 +
 2 files changed, 40 insertions(+)

diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index f1c60274c448..1c79032ca262 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -1078,6 +1078,43 @@ static int tdx_handle_get_quote(X86CPU *cpu, struct kvm_tdx_vmcall *vmcall)
     return 0;
 }
 
+static int tdx_handle_report_fatal_error(X86CPU *cpu,
+                                         struct kvm_tdx_vmcall *vmcall)
+{
+    uint64_t error_code = vmcall->in_r12;
+    char *message = NULL;
+
+    if (error_code & 0xffff) {
+        error_report("TDX: REPORT_FATAL_ERROR: invalid error code: "
+                     "0x%lx\n", error_code);
+        return -1;
+    }
+
+    /* it has optional message */
+    if (vmcall->in_r14) {
+        uint64_t * tmp;
+
+#define GUEST_PANIC_INFO_TDX_MESSAGE_MAX        64
+        message = g_malloc0(GUEST_PANIC_INFO_TDX_MESSAGE_MAX + 1);
+
+        tmp = (uint64_t *)message;
+        /* The order is defined in TDX GHCI spec */
+        *(tmp++) = cpu_to_le64(vmcall->in_r14);
+        *(tmp++) = cpu_to_le64(vmcall->in_r15);
+        *(tmp++) = cpu_to_le64(vmcall->in_rbx);
+        *(tmp++) = cpu_to_le64(vmcall->in_rdi);
+        *(tmp++) = cpu_to_le64(vmcall->in_rsi);
+        *(tmp++) = cpu_to_le64(vmcall->in_r8);
+        *(tmp++) = cpu_to_le64(vmcall->in_r9);
+        *(tmp++) = cpu_to_le64(vmcall->in_rdx);
+        message[GUEST_PANIC_INFO_TDX_MESSAGE_MAX] = '\0';
+        assert((char *)tmp == message + GUEST_PANIC_INFO_TDX_MESSAGE_MAX);
+    }
+
+    error_report("TD guest reports fatal error. %s\n", message ? : "");
+    return -1;
+}
+
 static int tdx_handle_setup_event_notify_interrupt(X86CPU *cpu,
                                                    struct kvm_tdx_vmcall *vmcall)
 {
@@ -1112,6 +1149,8 @@ static int tdx_handle_vmcall(X86CPU *cpu, struct kvm_tdx_vmcall *vmcall)
         return tdx_handle_map_gpa(cpu, vmcall);
     case TDG_VP_VMCALL_GET_QUOTE:
         return tdx_handle_get_quote(cpu, vmcall);
+    case TDG_VP_VMCALL_REPORT_FATAL_ERROR:
+        return  tdx_handle_report_fatal_error(cpu, vmcall);
     case TDG_VP_VMCALL_SETUP_EVENT_NOTIFY_INTERRUPT:
         return tdx_handle_setup_event_notify_interrupt(cpu, vmcall);
     default:
diff --git a/target/i386/kvm/tdx.h b/target/i386/kvm/tdx.h
index cedc7d7e226f..37fdd845f462 100644
--- a/target/i386/kvm/tdx.h
+++ b/target/i386/kvm/tdx.h
@@ -20,6 +20,7 @@ typedef struct TdxGuestClass {
 
 #define TDG_VP_VMCALL_MAP_GPA                           0x10001ULL
 #define TDG_VP_VMCALL_GET_QUOTE                         0x10002ULL
+#define TDG_VP_VMCALL_REPORT_FATAL_ERROR                0x10003ULL
 #define TDG_VP_VMCALL_SETUP_EVENT_NOTIFY_INTERRUPT      0x10004ULL
 
 #define TDG_VP_VMCALL_SUCCESS           0x0000000000000000ULL
-- 
2.34.1