xref: /openbmc/qemu/hw/core/guest-loader.c (revision 835fde4a) 
1 /*
2  * Guest Loader
3  *
4  * Copyright (C) 2020 Linaro
5  * Written by Alex Bennée <alex.bennee@linaro.org>
6  * (based on the generic-loader by Li Guang <lig.fnst@cn.fujitsu.com>)
7  *
8  * SPDX-License-Identifier: GPL-2.0-or-later
9  *
10  * This work is licensed under the terms of the GNU GPL, version 2 or later.
11  * See the COPYING file in the top-level directory.
12  */
13 
14 /*
15  * Much like the generic-loader this is treated as a special device
16  * inside QEMU. However unlike the generic-loader this device is used
17  * to load guest images for hypervisors. As part of that process the
18  * hypervisor needs to have platform information passed to it by the
19  * lower levels of the stack (e.g. firmware/bootloader). If you boot
20  * the hypervisor directly you use the guest-loader to load the Dom0
21  * or equivalent guest images in the right place in the same way a
22  * boot loader would.
23  *
24  * This is only relevant for full system emulation.
25  */
26 
27 #include "qemu/osdep.h"
28 #include "hw/core/cpu.h"
29 #include "hw/sysbus.h"
30 #include "sysemu/dma.h"
31 #include "hw/loader.h"
32 #include "hw/qdev-properties.h"
33 #include "qapi/error.h"
34 #include "qemu/module.h"
35 #include "guest-loader.h"
36 #include "sysemu/device_tree.h"
37 #include "hw/boards.h"
38 
39 /*
40  * Insert some FDT nodes for the loaded blob.
41  */
42 static void loader_insert_platform_data(GuestLoaderState *s, int size,
43                                         Error **errp)
44 {
45     MachineState *machine = MACHINE(qdev_get_machine());
46     void *fdt = machine->fdt;
47     g_autofree char *node = g_strdup_printf("/chosen/module@0x%08" PRIx64,
48                                             s->addr);
49     uint64_t reg_attr[2] = {cpu_to_be64(s->addr), cpu_to_be64(size)};
50 
51     if (!fdt) {
52         error_setg(errp, "Cannot modify FDT fields if the machine has none");
53         return;
54     }
55 
56     qemu_fdt_add_subnode(fdt, node);
57     qemu_fdt_setprop(fdt, node, "reg", &reg_attr, sizeof(reg_attr));
58 
59     if (s->kernel) {
60         const char *compat[2] = { "multiboot,module", "multiboot,kernel" };
61         if (qemu_fdt_setprop_string_array(fdt, node, "compatible",
62                                           (char **) &compat,
63                                           ARRAY_SIZE(compat)) < 0) {
64             error_setg(errp, "couldn't set %s/compatible", node);
65             return;
66         }
67         if (s->args) {
68             if (qemu_fdt_setprop_string(fdt, node, "bootargs", s->args) < 0) {
69                 error_setg(errp, "couldn't set %s/bootargs", node);
70             }
71         }
72     } else if (s->initrd) {
73         const char *compat[2] = { "multiboot,module", "multiboot,ramdisk" };
74         if (qemu_fdt_setprop_string_array(fdt, node, "compatible",
75                                           (char **) &compat,
76                                           ARRAY_SIZE(compat)) < 0) {
77             error_setg(errp, "couldn't set %s/compatible", node);
78             return;
79         }
80     }
81 }
82 
83 static void guest_loader_realize(DeviceState *dev, Error **errp)
84 {
85     GuestLoaderState *s = GUEST_LOADER(dev);
86     char *file = s->kernel ? s->kernel : s->initrd;
87     int size = 0;
88 
89     /* Perform some error checking on the user's options */
90     if (s->kernel && s->initrd) {
91         error_setg(errp, "Cannot specify a kernel and initrd in same stanza");
92         return;
93     } else if (!s->kernel && !s->initrd)  {
94         error_setg(errp, "Need to specify a kernel or initrd image");
95         return;
96     } else if (!s->addr) {
97         error_setg(errp, "Need to specify the address of guest blob");
98         return;
99     } else if (s->args && !s->kernel) {
100         error_setg(errp, "Boot args only relevant to kernel blobs");
101     }
102 
103     /* Default to the maximum size being the machine's ram size */
104     size = load_image_targphys_as(file, s->addr, current_machine->ram_size,
105                                   NULL);
106     if (size < 0) {
107         error_setg(errp, "Cannot load specified image %s", file);
108         return;
109     }
110 
111     /* Now the image is loaded we need to update the platform data */
112     loader_insert_platform_data(s, size, errp);
113 }
114 
115 static Property guest_loader_props[] = {
116     DEFINE_PROP_UINT64("addr", GuestLoaderState, addr, 0),
117     DEFINE_PROP_STRING("kernel", GuestLoaderState, kernel),
118     DEFINE_PROP_STRING("bootargs", GuestLoaderState, args),
119     DEFINE_PROP_STRING("initrd", GuestLoaderState, initrd),
120     DEFINE_PROP_END_OF_LIST(),
121 };
122 
123 static void guest_loader_class_init(ObjectClass *klass, void *data)
124 {
125     DeviceClass *dc = DEVICE_CLASS(klass);
126 
127     dc->realize = guest_loader_realize;
128     device_class_set_props(dc, guest_loader_props);
129     dc->desc = "Guest Loader";
130     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
131 }
132 
133 static TypeInfo guest_loader_info = {
134     .name = TYPE_GUEST_LOADER,
135     .parent = TYPE_DEVICE,
136     .instance_size = sizeof(GuestLoaderState),
137     .class_init = guest_loader_class_init,
138 };
139 
140 static void guest_loader_register_type(void)
141 {
142     type_register_static(&guest_loader_info);
143 }
144 
145 type_init(guest_loader_register_type)
146