3 files changed, 54 insertions, 0 deletions
diff --git a/OvmfPkg/Include/Library/XenHypercallLib.h b/OvmfPkg/Include/Library/XenHypercallLib.h
index 1a468ea..509855d 100644
--- a/OvmfPkg/Include/Library/XenHypercallLib.h
+++ b/OvmfPkg/Include/Library/XenHypercallLib.h
@@ -17,6 +17,22 @@
 #define __XEN_HYPERCALL_LIB_H__
 
 /**
+  Check if the Xen Hypercall library is able to make calls to the Xen
+  hypervisor.
+
+  Client code should call further functions in this library only if, and after,
+  this function returns TRUE.
+
+  @retval TRUE   Hypercalls are available.
+  @retval FALSE  Hypercalls are not available.
+**/
+BOOLEAN
+EFIAPI
+XenHypercallIsAvailable (
+  VOID
+  );
+
+/**
   This function will put the two arguments in the right place (registers) and
   invoke the hypercall identified by HypercallID.
 
diff --git a/OvmfPkg/Library/XenHypercallLib/ArmXenHypercall.c b/OvmfPkg/Library/XenHypercallLib/ArmXenHypercall.c
index 1f213d6..58cd3ec 100644
--- a/OvmfPkg/Library/XenHypercallLib/ArmXenHypercall.c
+++ b/OvmfPkg/Library/XenHypercallLib/ArmXenHypercall.c
@@ -15,6 +15,25 @@
 
 #include <Base.h>
 
+/**
+  Check if the Xen Hypercall library is able to make calls to the Xen
+  hypervisor.
+
+  Client code should call further functions in this library only if, and after,
+  this function returns TRUE.
+
+  @retval TRUE   Hypercalls are available.
+  @retval FALSE  Hypercalls are not available.
+**/
+BOOLEAN
+EFIAPI
+XenHypercallIsAvailable (
+  VOID
+  )
+{
+  return TRUE;
+}
+
 RETURN_STATUS
 EFIAPI
 XenHypercallLibInit (
diff --git a/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c b/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
index 7ee1f2f..67892bc 100644
--- a/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
+++ b/OvmfPkg/Library/XenHypercallLib/X86XenHypercall.c
@@ -19,6 +19,25 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
 STATIC VOID    *HyperPage;
 
+/**
+  Check if the Xen Hypercall library is able to make calls to the Xen
+  hypervisor.
+
+  Client code should call further functions in this library only if, and after,
+  this function returns TRUE.
+
+  @retval TRUE   Hypercalls are available.
+  @retval FALSE  Hypercalls are not available.
+**/
+BOOLEAN
+EFIAPI
+XenHypercallIsAvailable (
+  VOID
+  )
+{
+  return HyperPage != NULL;
+}
+
 //
 // Interface exposed by the ASM implementation of the core hypercall
 //