xen,configure: detect Xen 4.2

Xen 4.2 is the first to support xc_hvm_inject_msi: use it to determine
if we are running on it.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>

diff --git a/configure b/configure
index 1d94acd..38f45f3 100755 (executable)
--- a/configure
+++ b/configure
@@ -1398,6 +1398,31 @@ int main(void) {
   xc_hvm_set_mem_type(0, 0, HVMMEM_ram_ro, 0, 0);
   xc_gnttab_open(NULL, 0);
   xc_domain_add_to_physmap(0, 0, XENMAPSPACE_gmfn, 0, 0);
+  xc_hvm_inject_msi(xc, 0, 0xf0000000, 0x00000000);
+  return 0;
+}
+EOF
+      compile_prog "" "$xen_libs"
+    ) ; then
+    xen_ctrl_version=420
+    xen=yes
+
+  elif (
+      cat > $TMPC <<EOF
+#include <xenctrl.h>
+#include <xs.h>
+#include <stdint.h>
+#include <xen/hvm/hvm_info_table.h>
+#if !defined(HVM_MAX_VCPUS)
+# error HVM_MAX_VCPUS not defined
+#endif
+int main(void) {
+  xc_interface *xc;
+  xs_daemon_open();
+  xc = xc_interface_open(0, 0, 0);
+  xc_hvm_set_mem_type(0, 0, HVMMEM_ram_ro, 0, 0);
+  xc_gnttab_open(NULL, 0);
+  xc_domain_add_to_physmap(0, 0, XENMAPSPACE_gmfn, 0, 0);
   return 0;
 }
 EOF