xen: Use newly added dmops for mapping VGA memory

Xen unstable (to be in 4.11) has two new dmops, relocate_memory and
pin_memory_cacheattr. Use these to set up the VGA memory, replacing the
previous calls to libxc. This allows the VGA console to work properly
when QEMU is running restricted (-xen-domid-restrict).

Wrapper functions are provided to allow QEMU to work with older versions
of Xen.

Tweak the error handling while making this change:
* Report pin_memory_cacheattr errors.
* Report errors even when DEBUG_HVM is not set. This is useful for
trying to understand why VGA is not working, since otherwise it just
fails silently.
* Fix the return values when an error occurs. The functions now
consistently return -1 and set errno.

CC: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/configure b/configure
index 5cf9dde235..aa35aef14b 100755
--- a/configure
+++ b/configure
@@ -2221,6 +2221,25 @@ EOF
     # Xen unstable
     elif
         cat > $TMPC <<EOF &&
+#undef XC_WANT_COMPAT_DEVICEMODEL_API
+#define __XEN_TOOLS__
+#include <xendevicemodel.h>
+int main(void) {
+  xendevicemodel_handle *xd;
+
+  xd = xendevicemodel_open(0, 0);
+  xendevicemodel_pin_memory_cacheattr(xd, 0, 0, 0, 0);
+
+  return 0;
+}
+EOF
+        compile_prog "" "$xen_libs -lxendevicemodel $xen_stable_libs -lxentoolcore"
+      then
+      xen_stable_libs="-lxendevicemodel $xen_stable_libs -lxentoolcore"
+      xen_ctrl_version=41100
+      xen=yes
+    elif
+        cat > $TMPC <<EOF &&
 #undef XC_WANT_COMPAT_MAP_FOREIGN_API
 #include <xenforeignmemory.h>
 #include <xentoolcore.h>