1 files changed, 22 insertions, 0 deletions
diff --git a/OvmfPkg/XenBusDxe/Ia32/hypercall.S b/OvmfPkg/XenBusDxe/Ia32/hypercall.S
new file mode 100644
index 0000000000..77d3478475
--- /dev/null
+++ b/OvmfPkg/XenBusDxe/Ia32/hypercall.S
@@ -0,0 +1,22 @@
+# INTN
+# EFIAPI
+# XenHypercall2 (
+#   IN     VOID *HypercallAddr,
+#   IN OUT INTN Arg1,
+#   IN OUT INTN Arg2
+#   );
+ASM_GLOBAL ASM_PFX(XenHypercall2)
+ASM_PFX(XenHypercall2):
+  # Save only ebx, ecx is supposed to be a scratch register and needs to be
+  # saved by the caller
+  push %ebx
+  # Copy HypercallAddr to eax
+  mov 8(%esp), %eax
+  # Copy Arg1 to the register expected by Xen
+  mov 12(%esp), %ebx
+  # Copy Arg2 to the register expected by Xen
+  mov 16(%esp), %ecx
+  # Call HypercallAddr
+  call *%eax
+  pop %ebx
+  ret