ia64/xen: implement arch specific part of xen grant table.

Xen implements grant tables which is for sharing pages with
guest domains.
This patch implements arch specific part of grant table initialization.
and xen_alloc_vm_area()/xen_free_vm_area() which are helper functions
for xen grant table.
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/include/asm/xen/grant_table.h

+/******************************************************************************
+ * arch/ia64/include/asm/xen/grant_table.h
+ *
+ * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan K.K.
+ *
+ * This program 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#ifndef _ASM_IA64_XEN_GRANT_TABLE_H
+#define _ASM_IA64_XEN_GRANT_TABLE_H
+
+struct vm_struct *xen_alloc_vm_area(unsigned long size);
+void xen_free_vm_area(struct vm_struct *area);
+
+#endif /* _ASM_IA64_XEN_GRANT_TABLE_H */

arch/ia64/xen/Makefile

@@ -2,4 +2,4 @@
 # Makefile for Xen components
 #
 
-obj-y := hypercall.o xencomm.o xcom_hcall.o
+obj-y := hypercall.o xencomm.o xcom_hcall.o grant-table.o

arch/ia64/xen/grant-table.c

+/******************************************************************************
+ * arch/ia64/xen/grant-table.c
+ *
+ * Copyright (c) 2006 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan K.K.
+ *
+ * This program 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+
+#include <xen/interface/xen.h>
+#include <xen/interface/memory.h>
+#include <xen/grant_table.h>
+
+#include <asm/xen/hypervisor.h>
+
+struct vm_struct *xen_alloc_vm_area(unsigned long size)
+{
+	int order;
+	unsigned long virt;
+	unsigned long nr_pages;
+	struct vm_struct *area;
+
+	order = get_order(size);
+	virt = __get_free_pages(GFP_KERNEL, order);
+	if (virt == 0)
+		goto err0;
+	nr_pages = 1 << order;
+	scrub_pages(virt, nr_pages);
+
+	area = kmalloc(sizeof(*area), GFP_KERNEL);
+	if (area == NULL)
+		goto err1;
+
+	area->flags = VM_IOREMAP;
+	area->addr = (void *)virt;
+	area->size = size;
+	area->pages = NULL;
+	area->nr_pages = nr_pages;
+	area->phys_addr = 0;	/* xenbus_map_ring_valloc uses this field!  */
+
+	return area;
+
+err1:
+	free_pages(virt, order);
+err0:
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(xen_alloc_vm_area);
+
+void xen_free_vm_area(struct vm_struct *area)
+{
+	unsigned int order = get_order(area->size);
+	unsigned long i;
+	unsigned long phys_addr = __pa(area->addr);
+
+	/* This area is used for foreign page mappping.
+	 * So underlying machine page may not be assigned. */
+	for (i = 0; i < (1 << order); i++) {
+		unsigned long ret;
+		unsigned long gpfn = (phys_addr >> PAGE_SHIFT) + i;
+		struct xen_memory_reservation reservation = {
+			.nr_extents   = 1,
+			.address_bits = 0,
+			.extent_order = 0,
+			.domid        = DOMID_SELF
+		};
+		set_xen_guest_handle(reservation.extent_start, &gpfn);
+		ret = HYPERVISOR_memory_op(XENMEM_populate_physmap,
+					   &reservation);
+		BUG_ON(ret != 1);
+	}
+	free_pages((unsigned long)area->addr, order);
+	kfree(area);
+}
+EXPORT_SYMBOL_GPL(xen_free_vm_area);
+
+
+/****************************************************************************
+ * grant table hack
+ * cmd: GNTTABOP_xxx
+ */
+
+int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
+			   unsigned long max_nr_gframes,
+			   struct grant_entry **__shared)
+{
+	*__shared = __va(frames[0] << PAGE_SHIFT);
+	return 0;
+}
+
+void arch_gnttab_unmap_shared(struct grant_entry *shared,
+			      unsigned long nr_gframes)
+{
+	/* nothing */
+}
+
+static void
+gnttab_map_grant_ref_pre(struct gnttab_map_grant_ref *uop)
+{
+	uint32_t flags;
+
+	flags = uop->flags;
+
+	if (flags & GNTMAP_host_map) {
+		if (flags & GNTMAP_application_map) {
+			printk(KERN_DEBUG
+			       "GNTMAP_application_map is not supported yet: "
+			       "flags 0x%x\n", flags);
+			BUG();
+		}
+		if (flags & GNTMAP_contains_pte) {
+			printk(KERN_DEBUG
+			       "GNTMAP_contains_pte is not supported yet: "
+			       "flags 0x%x\n", flags);
+			BUG();
+		}
+	} else if (flags & GNTMAP_device_map) {
+		printk("GNTMAP_device_map is not supported yet 0x%x\n", flags);
+		BUG();	/* not yet. actually this flag is not used. */
+	} else {
+		BUG();
+	}
+}
+
+int
+HYPERVISOR_grant_table_op(unsigned int cmd, void *uop, unsigned int count)
+{
+	if (cmd == GNTTABOP_map_grant_ref) {
+		unsigned int i;
+		for (i = 0; i < count; i++) {
+			gnttab_map_grant_ref_pre(
+				(struct gnttab_map_grant_ref *)uop + i);
+		}
+	}
+	return xencomm_hypercall_grant_table_op(cmd, uop, count);
+}
+
+EXPORT_SYMBOL(HYPERVISOR_grant_table_op);