Add new ports: i386-xen and x86_64-xen. This allows running GRUB in

XEN PV environment and load kernels.

grub-core/kern/x86_64/xen/hypercall.S

@@ -0,0 +1,53 @@
+/* hypercall.S - wrappers for Xen hypercalls */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2011  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/symbol.h>
+#include <grub/xen.h>
+
+FUNCTION(grub_xen_sched_op)
+	movq $__HYPERVISOR_sched_op, %rax
+	syscall
+	ret
+
+FUNCTION(grub_xen_event_channel_op)
+	movq $__HYPERVISOR_event_channel_op, %rax
+	syscall
+	ret
+
+FUNCTION(grub_xen_update_va_mapping)
+	movq $__HYPERVISOR_update_va_mapping, %rax
+	syscall
+	ret
+
+FUNCTION(grub_xen_mmuext_op)
+	movq %rcx, %r10
+	movq $__HYPERVISOR_mmuext_op, %rax
+	syscall
+	ret
+
+FUNCTION(grub_xen_grant_table_op)
+	movq $__HYPERVISOR_grant_table_op, %rax
+	syscall
+	ret
+
+FUNCTION(grub_xen_mmu_update)
+	movq %rcx, %r10
+	movq $__HYPERVISOR_mmu_update, %rax
+	syscall
+	ret