1/*
2 * Copyright (c) 2014 Roger Pau Monn�� <roger.pau@citrix.com>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/param.h>
28#include <sys/systm.h>
29#include <sys/bus.h>
30#include <sys/kernel.h>
31#include <sys/module.h>
32#include <sys/pcpu.h>
33#include <sys/rman.h>
34#include <sys/smp.h>
35#include <sys/limits.h>
36#include <sys/vmmeter.h>
37
38#include <vm/vm.h>
39#include <vm/vm_page.h>
40#include <vm/vm_param.h>
41#include <vm/vm_phys.h>
42
43#include <xen/xen-os.h>
44#include <xen/gnttab.h>
45
46#include "xenmem_if.h"
47
48/*
49 * Allocate unused physical memory above 4GB in order to map memory
50 * from foreign domains. We use memory starting at 4GB in order to
51 * prevent clashes with MMIO/ACPI regions.
52 *
53 * Since this is not possible on i386 just use any available memory
54 * chunk above 1MB and hope we don't clash with anything else.
55 *
56 * Other architectures better document MMIO regions and drivers more
57 * reliably reserve them.  As such, allow using any unpopulated memory
58 * region.
59 */
60#ifdef __amd64__
61#define LOW_MEM_LIMIT	0x100000000ul
62#elif defined(__i386__)
63#define LOW_MEM_LIMIT	0x100000ul
64#else
65#define LOW_MEM_LIMIT	0
66#endif
67
68static void
69xenpv_identify(driver_t *driver, device_t parent)
70{
71	if (!xen_domain())
72		return;
73
74	/* Make sure there's only one xenpv device. */
75	if (devclass_get_device(devclass_find(driver->name), 0))
76		return;
77
78	/*
79	 * The xenpv bus should be the last to attach in order
80	 * to properly detect if an ISA bus has already been added.
81	 */
82	if (BUS_ADD_CHILD(parent, UINT_MAX, driver->name, 0) == NULL)
83		panic("Unable to attach xenpv bus.");
84}
85
86static int
87xenpv_probe(device_t dev)
88{
89
90	device_set_desc(dev, "Xen PV bus");
91	return (BUS_PROBE_NOWILDCARD);
92}
93
94static int
95xenpv_attach(device_t dev)
96{
97	int error;
98
99	/*
100	 * Let our child drivers identify any child devices that they
101	 * can find.  Once that is done attach any devices that we
102	 * found.
103	 */
104	error = bus_generic_probe(dev);
105	if (error)
106		return (error);
107
108	error = bus_generic_attach(dev);
109
110	return (error);
111}
112
113static struct resource *
114xenpv_alloc_physmem(device_t dev, device_t child, int *res_id, size_t size)
115{
116	struct resource *res;
117	vm_paddr_t phys_addr;
118	void *virt_addr;
119	int error;
120
121	res = bus_alloc_resource(child, SYS_RES_MEMORY, res_id, LOW_MEM_LIMIT,
122	    ~0, size, RF_ACTIVE | RF_UNMAPPED);
123	if (res == NULL)
124		return (NULL);
125
126	phys_addr = rman_get_start(res);
127	error = vm_phys_fictitious_reg_range(phys_addr, phys_addr + size,
128	    VM_MEMATTR_XEN);
129	if (error) {
130		bus_release_resource(child, SYS_RES_MEMORY, *res_id, res);
131		return (NULL);
132	}
133	virt_addr = pmap_mapdev_attr(phys_addr, size, VM_MEMATTR_XEN);
134	KASSERT(virt_addr != NULL, ("Failed to create linear mappings"));
135	rman_set_virtual(res, virt_addr);
136
137	return (res);
138}
139
140static int
141xenpv_free_physmem(device_t dev, device_t child, int res_id, struct resource *res)
142{
143	vm_paddr_t phys_addr;
144	void *virt_addr;
145	size_t size;
146
147	phys_addr = rman_get_start(res);
148	size = rman_get_size(res);
149	virt_addr = rman_get_virtual(res);
150
151	pmap_unmapdev(virt_addr, size);
152	vm_phys_fictitious_unreg_range(phys_addr, phys_addr + size);
153	return (bus_release_resource(child, SYS_RES_MEMORY, res_id, res));
154}
155
156static device_method_t xenpv_methods[] = {
157	/* Device interface */
158	DEVMETHOD(device_identify,		xenpv_identify),
159	DEVMETHOD(device_probe,			xenpv_probe),
160	DEVMETHOD(device_attach,		xenpv_attach),
161	DEVMETHOD(device_suspend,		bus_generic_suspend),
162	DEVMETHOD(device_resume,		bus_generic_resume),
163
164	/* Bus interface */
165	DEVMETHOD(bus_add_child,		bus_generic_add_child),
166	DEVMETHOD(bus_alloc_resource,		bus_generic_alloc_resource),
167	DEVMETHOD(bus_release_resource,		bus_generic_release_resource),
168	DEVMETHOD(bus_activate_resource,	bus_generic_activate_resource),
169	DEVMETHOD(bus_deactivate_resource,	bus_generic_deactivate_resource),
170
171	/* Interface to allocate memory for foreign mappings */
172	DEVMETHOD(xenmem_alloc,			xenpv_alloc_physmem),
173	DEVMETHOD(xenmem_free,			xenpv_free_physmem),
174
175	DEVMETHOD_END
176};
177
178static driver_t xenpv_driver = {
179	"xenpv",
180	xenpv_methods,
181	0,
182};
183
184DRIVER_MODULE(xenpv, nexus, xenpv_driver, 0, 0);
185
186struct resource *
187xenmem_alloc(device_t dev, int *res_id, size_t size)
188{
189	device_t parent;
190
191	parent = device_get_parent(dev);
192	if (parent == NULL)
193		return (NULL);
194	return (XENMEM_ALLOC(parent, dev, res_id, size));
195}
196
197int
198xenmem_free(device_t dev, int res_id, struct resource *res)
199{
200	device_t parent;
201
202	parent = device_get_parent(dev);
203	if (parent == NULL)
204		return (ENXIO);
205	return (XENMEM_FREE(parent, dev, res_id, res));
206}
207