A sample test module for the HVM hypercall interface.
Signed-off-by: Steve Ofsthun <sofsthun@xxxxxxxxxxxxxxx>
1) To use, put these files in a directory by themselves.
2) Edit the Makefile:
Set XEN_ROOT to a populated xen tree.
Set LINUX_ROOT to a linux build tree for your HVM domU kernel.
3) make
The output should be test.ko. You should be able to load this
module on an HVM guest using:
# insmod test.ko
Module output on the console should appear like:
hypercall_page @ ffffffffa020f000
xen_features[0].writable_page_tables = 1
xen_features[0].writable_descriptor_tables = 0
xen_features[0].auto_translated_physmap = 1
xen_features[0].supervisor_mode_kernel = 0
xen_features[0].pae_pgdir_above_4gb = 1
Enjoy,
Steve
--
Steve Ofsthun - Virtual Iron Software, Inc.
# Makefile for test driver
#EXTRA_CFLAGS += -DDEBUG
obj-m := test.o
test-objs := features.o hypercall.o
# Point XEN_ROOT at a valid xen tree
ifeq ($(XEN_ROOT),)
XEN_ROOT = ~/BK/xen-unstable-test64/
endif
# Point LINUX_ROOT at a valid linux tree
ifeq ($(LINUX_ROOT),)
LINUX_ROOT = $(XEN_ROOT)/linux-2.6.16-xen/
endif
LOCAL_DRIVER_LIST = .
LOCAL_DRIVER_DIRS := $(foreach dir,$(LOCAL_DRIVER_LIST),$(shell pwd)/$(dir))
default:
@if [ ! -d $(XEN_ROOT) ]; then \
echo XEN_ROOT must be set; exit 1; \
fi
@if [ ! -d $(LINUX_ROOT) ]; then \
echo LINUX_ROOT must be set; exit 1; \
fi
$(MAKE) -C $(LINUX_ROOT) SUBDIRS="$(LOCAL_DRIVER_DIRS)" modules
clean:
$(MAKE) -C $(LINUX_ROOT) SUBDIRS="$(LOCAL_DRIVER_DIRS)" $@
/******************************************************************************
* features.c
*
* Xen feature flags.
*
* Copyright (c) 2006, Ian Campbell, XenSource Inc.
*/
#include <linux/types.h>
#include <linux/cache.h>
#include <linux/module.h>
#include <asm/hypervisor.h>
#include <xen/features.h>
#ifndef __read_mostly
#define __read_mostly __cacheline_aligned
#endif
//#define DEBUG
u8 xen_features[XENFEAT_NR_SUBMAPS * 32] __read_mostly;
EXPORT_SYMBOL(xen_features);
#ifdef DEBUG
static const char *feature_names[XENFEAT_NR_SUBMAPS*32] = {
[XENFEAT_writable_page_tables] = "writable_page_tables",
[XENFEAT_writable_descriptor_tables] = "writable_descriptor_tables",
[XENFEAT_auto_translated_physmap] = "auto_translated_physmap",
[XENFEAT_supervisor_mode_kernel] = "supervisor_mode_kernel",
[XENFEAT_pae_pgdir_above_4gb] = "pae_pgdir_above_4gb"
};
#endif
void setup_xen_features(void)
{
xen_feature_info_t fi;
int i, j;
for (i = 0; i < XENFEAT_NR_SUBMAPS; i++) {
fi.submap_idx = i;
if (HYPERVISOR_xen_version(XENVER_get_features, &fi) < 0)
break;
for (j=0; j<32; j++)
xen_features[i*32+j] = !!(fi.submap & 1<<j);
}
#ifdef DEBUG
for (i = 0; i < XENFEAT_NR_SUBMAPS; i++) {
for (j=0; j<32; j++) {
if (feature_names[j])
printk("xen_features[%d].%s = %d\n", i,
feature_names[j], xen_features[i*32+j]);
}
}
#endif
}
EXPORT_SYMBOL(setup_xen_features);
/******************************************************************************
* hypercall.c
*
* Copyright (C) 2006, Virtual Iron Software, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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>
MODULE_LICENSE("GPL");
#include "hypercall.h"
char hypercall_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
static inline int
HYPERVISOR_arg_test(long a, long b, long c, long d, long e)
{
return _hypercall5(int, grant_table_op, a, b, c, d, e);
}
extern void setup_xen_features(void);
static int __init hypercall_page_setup(void)
{
hypercall_page_init(&hypercall_page);
printk(KERN_ERR "hypercall_page @ %p\n", &hypercall_page);
#if BITS_PER_LONG == 64
HYPERVISOR_arg_test(0x1111111111111111, 0x2222222222222222,
0x3333333333333333, 0x4444444444444444, 0x5555555555555555);
#else
HYPERVISOR_arg_test(0x11111111, 0x22222222,
0x33333333, 0x44444444, 0x55555555);
#endif
setup_xen_features();
return 0;
}
static void __exit hypercall_page_cleanup(void)
{
}
module_init(hypercall_page_setup);
module_exit(hypercall_page_cleanup);
/******************************************************************************
* hypercall.h
*
* Copyright (C) 2006, Virtual Iron Software, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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/version.h>
#include <asm/hypervisor.h>
#include <xen/interface/xen.h>
static inline int
check_amd(void)
{
char id[12];
__asm__ __volatile__(
"cpuid"
: "=b" (*(int *)(&id[0])),
"=c" (*(int *)(&id[8])),
"=d" (*(int *)(&id[4]))
: "a" (0)
);
return __builtin_memcmp(id, "AuthenticAMD", 12) == 0;
}
#define VMCALL_INSTR 0x0f,0x01,0xc1
#define VMMCALL_INSTR 0x0f,0x01,0xd6
#define NR_hypercalls (PAGE_SIZE/32)
static inline void hypercall_page_init(void *hypercall_page)
{
int i;
char *p;
char vmcall[3] = { VMCALL_INSTR };
char vmmcall[3] = { VMMCALL_INSTR };
int amd = check_amd();
for ( i = 0; i < NR_hypercalls; i++ )
{
p = (char *)(hypercall_page + (i * 32));
/*
* This call sequence works for 32-bit and 64-bit guests.
*/
memset(p, 0xcc, 32);
*(u8 *)(p+ 0) = 0xb8; /* mov $<i>,%eax */
*(u32 *)(p+ 1) = i;
if (amd) {
*(u8 *)(p+ 5) = vmmcall[0];
*(u8 *)(p+ 6) = vmmcall[1];
*(u8 *)(p+ 7) = vmmcall[2];
} else {
*(u8 *)(p+ 5) = vmcall[0];
*(u8 *)(p+ 6) = vmcall[1];
*(u8 *)(p+ 7) = vmcall[2];
}
*(u8 *)(p+ 8) = 0xc3; /* ret */
}
}
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