xref: /openbmc/qemu/hw/pci-host/remote.c (revision 278f064e)
1 /*
2  * Remote PCI host device
3  *
4  * Unlike PCI host devices that model physical hardware, the purpose
5  * of this PCI host is to host multi-process QEMU devices.
6  *
7  * Multi-process QEMU extends the PCI host of a QEMU machine into a
8  * remote process. Any PCI device attached to the remote process is
9  * visible in the QEMU guest. This allows existing QEMU device models
10  * to be reused in the remote process.
11  *
12  * This PCI host is purely a container for PCI devices. It's fake in the
13  * sense that the guest never sees this PCI host and has no way of
14  * accessing it. Its job is just to provide the environment that QEMU
15  * PCI device models need when running in a remote process.
16  *
17  * Copyright © 2018, 2021 Oracle and/or its affiliates.
18  *
19  * This work is licensed under the terms of the GNU GPL, version 2 or later.
20  * See the COPYING file in the top-level directory.
21  *
22  */
23 
24 #include "qemu/osdep.h"
25 #include "qemu-common.h"
26 
27 #include "hw/pci/pci.h"
28 #include "hw/pci/pci_host.h"
29 #include "hw/pci/pcie_host.h"
30 #include "hw/qdev-properties.h"
31 #include "hw/pci-host/remote.h"
32 #include "exec/memory.h"
33 
34 static const char *remote_pcihost_root_bus_path(PCIHostState *host_bridge,
35                                                 PCIBus *rootbus)
36 {
37     return "0000:00";
38 }
39 
40 static void remote_pcihost_realize(DeviceState *dev, Error **errp)
41 {
42     PCIHostState *pci = PCI_HOST_BRIDGE(dev);
43     RemotePCIHost *s = REMOTE_PCIHOST(dev);
44 
45     pci->bus = pci_root_bus_new(DEVICE(s), "remote-pci",
46                                 s->mr_pci_mem, s->mr_sys_io,
47                                 0, TYPE_PCIE_BUS);
48 }
49 
50 static void remote_pcihost_class_init(ObjectClass *klass, void *data)
51 {
52     DeviceClass *dc = DEVICE_CLASS(klass);
53     PCIHostBridgeClass *hc = PCI_HOST_BRIDGE_CLASS(klass);
54 
55     hc->root_bus_path = remote_pcihost_root_bus_path;
56     dc->realize = remote_pcihost_realize;
57 
58     dc->user_creatable = false;
59     set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
60     dc->fw_name = "pci";
61 }
62 
63 static const TypeInfo remote_pcihost_info = {
64     .name = TYPE_REMOTE_PCIHOST,
65     .parent = TYPE_PCIE_HOST_BRIDGE,
66     .instance_size = sizeof(RemotePCIHost),
67     .class_init = remote_pcihost_class_init,
68 };
69 
70 static void remote_pcihost_register(void)
71 {
72     type_register_static(&remote_pcihost_info);
73 }
74 
75 type_init(remote_pcihost_register)
76