x86: re-introduce map_domain_page() et al

This is being done mostly in the form previously used on x86-32,
utilizing the second L3 page table slot within the per-domain mapping
area for those mappings. It remains to be determined whether that
concept is really suitable, or whether instead re-implementing at least
the non-global variant from scratch would be better.

Also add the helpers {clear,copy}_domain_page() as well as initial uses
of them.

One question is whether, to exercise the non-trivial code paths, we
shouldn't make the trivial shortcuts conditional upon NDEBUG being
defined. See the debugging patch at the end of the series.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 9d5a254eea..0fe547b313 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -19,6 +19,7 @@ obj-bin-y += dmi_scan.init.o
 obj-y += domctl.o
 obj-y += domain.o
 obj-bin-y += domain_build.init.o
+obj-y += domain_page.o
 obj-y += e820.o
 obj-y += extable.o
 obj-y += flushtlb.o