xref: /openbmc/qemu/hw/core/guest-loader.c (revision d0bf492f) 
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 "sysemu/dma.h"
30 #include "hw/loader.h"
31 #include "hw/qdev-properties.h"
32 #include "qapi/error.h"
33 #include "qemu/module.h"
34 #include "guest-loader.h"
35 #include "sysemu/device_tree.h"
36 #include "hw/boards.h"
37 
38 /*
39  * Insert some FDT nodes for the loaded blob.
40  */
41 static void loader_insert_platform_data(GuestLoaderState *s, int size,
42                                         Error **errp)
43 {
44     MachineState *machine = MACHINE(qdev_get_machine());
45     void *fdt = machine->fdt;
46     g_autofree char *node = g_strdup_printf("/chosen/module@0x%08" PRIx64,
47                                             s->addr);
48     uint64_t reg_attr[2] = {cpu_to_be64(s->addr), cpu_to_be64(size)};
49 
50     if (!fdt) {
51         error_setg(errp, "Cannot modify FDT fields if the machine has none");
52         return;
53     }
54 
55     qemu_fdt_add_subnode(fdt, node);
56     qemu_fdt_setprop(fdt, node, "reg", &reg_attr, sizeof(reg_attr));
57 
58     if (s->kernel) {
59         const char *compat[2] = { "multiboot,module", "multiboot,kernel" };
60         if (qemu_fdt_setprop_string_array(fdt, node, "compatible",
61                                           (char **) &compat,
62                                           ARRAY_SIZE(compat)) < 0) {
63             error_setg(errp, "couldn't set %s/compatible", node);
64             return;
65         }
66         if (s->args) {
67             if (qemu_fdt_setprop_string(fdt, node, "bootargs", s->args) < 0) {
68                 error_setg(errp, "couldn't set %s/bootargs", node);
69             }
70         }
71     } else if (s->initrd) {
72         const char *compat[2] = { "multiboot,module", "multiboot,ramdisk" };
73         if (qemu_fdt_setprop_string_array(fdt, node, "compatible",
74                                           (char **) &compat,
75                                           ARRAY_SIZE(compat)) < 0) {
76             error_setg(errp, "couldn't set %s/compatible", node);
77             return;
78         }
79     }
80 }
81 
82 static void guest_loader_realize(DeviceState *dev, Error **errp)
83 {
84     GuestLoaderState *s = GUEST_LOADER(dev);
85     char *file = s->kernel ? s->kernel : s->initrd;
86     int size = 0;
87 
88     /* Perform some error checking on the user's options */
89     if (s->kernel && s->initrd) {
90         error_setg(errp, "Cannot specify a kernel and initrd in same stanza");
91         return;
92     } else if (!s->kernel && !s->initrd)  {
93         error_setg(errp, "Need to specify a kernel or initrd image");
94         return;
95     } else if (!s->addr) {
96         error_setg(errp, "Need to specify the address of guest blob");
97         return;
98     } else if (s->args && !s->kernel) {
99         error_setg(errp, "Boot args only relevant to kernel blobs");
100     }
101 
102     /* Default to the maximum size being the machine's ram size */
103     size = load_image_targphys_as(file, s->addr, current_machine->ram_size,
104                                   NULL);
105     if (size < 0) {
106         error_setg(errp, "Cannot load specified image %s", file);
107         return;
108     }
109 
110     /* Now the image is loaded we need to update the platform data */
111     loader_insert_platform_data(s, size, errp);
112 }
113 
114 static Property guest_loader_props[] = {
115     DEFINE_PROP_UINT64("addr", GuestLoaderState, addr, 0),
116     DEFINE_PROP_STRING("kernel", GuestLoaderState, kernel),
117     DEFINE_PROP_STRING("bootargs", GuestLoaderState, args),
118     DEFINE_PROP_STRING("initrd", GuestLoaderState, initrd),
119     DEFINE_PROP_END_OF_LIST(),
120 };
121 
122 static void guest_loader_class_init(ObjectClass *klass, void *data)
123 {
124     DeviceClass *dc = DEVICE_CLASS(klass);
125 
126     dc->realize = guest_loader_realize;
127     device_class_set_props(dc, guest_loader_props);
128     dc->desc = "Guest Loader";
129     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
130 }
131 
132 static const TypeInfo guest_loader_info = {
133     .name = TYPE_GUEST_LOADER,
134     .parent = TYPE_DEVICE,
135     .instance_size = sizeof(GuestLoaderState),
136     .class_init = guest_loader_class_init,
137 };
138 
139 static void guest_loader_register_type(void)
140 {
141     type_register_static(&guest_loader_info);
142 }
143 
144 type_init(guest_loader_register_type)
145