hw/misc/vmcoreinfo.c

   1 /*
   2  * Virtual Machine coreinfo device
   3  *
   4  * Copyright (C) 2017 Red Hat, Inc.
   5  *
   6  * Authors: Marc-André Lureau <marcandre.lureau@redhat.com>
   7  *
   8  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   9  * See the COPYING file in the top-level directory.
  10  *
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "qapi/error.h"
  15 #include "qemu/module.h"
  16 #include "sysemu/reset.h"
  17 #include "hw/nvram/fw_cfg.h"
  18 #include "migration/vmstate.h"
  19 #include "hw/misc/vmcoreinfo.h"
  20
  21 static void fw_cfg_vmci_write(void *dev, off_t offset, size_t len)
  22 {
  23     VMCoreInfoState *s = VMCOREINFO(dev);
  24
  25     s->has_vmcoreinfo = offset == 0 && len == sizeof(s->vmcoreinfo)
  26         && s->vmcoreinfo.guest_format != FW_CFG_VMCOREINFO_FORMAT_NONE;
  27 }
  28
  29 static void vmcoreinfo_reset(void *dev)
  30 {
  31     VMCoreInfoState *s = VMCOREINFO(dev);
  32
  33     s->has_vmcoreinfo = false;
  34     memset(&s->vmcoreinfo, 0, sizeof(s->vmcoreinfo));
  35     s->vmcoreinfo.host_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF);
  36 }
  37
  38 static void vmcoreinfo_realize(DeviceState *dev, Error **errp)
  39 {
  40     VMCoreInfoState *s = VMCOREINFO(dev);
  41     FWCfgState *fw_cfg = fw_cfg_find();
  42     /* for gdb script dump-guest-memory.py */
  43     static VMCoreInfoState * volatile vmcoreinfo_state G_GNUC_UNUSED;
  44
  45     /* Given that this function is executing, there is at least one VMCOREINFO
  46      * device. Check if there are several.
  47      */
  48     if (!vmcoreinfo_find()) {
  49         error_setg(errp, "at most one %s device is permitted",
  50                    VMCOREINFO_DEVICE);
  51         return;
  52     }
  53
  54     if (!fw_cfg || !fw_cfg->dma_enabled) {
  55         error_setg(errp, "%s device requires fw_cfg with DMA",
  56                    VMCOREINFO_DEVICE);
  57         return;
  58     }
  59
  60     fw_cfg_add_file_callback(fw_cfg, FW_CFG_VMCOREINFO_FILENAME,
  61                              NULL, fw_cfg_vmci_write, s,
  62                              &s->vmcoreinfo, sizeof(s->vmcoreinfo), false);
  63
  64     /*
  65      * This device requires to register a global reset because it is
  66      * not plugged to a bus (which, as its QOM parent, would reset it).
  67      */
  68     qemu_register_reset(vmcoreinfo_reset, dev);
  69     vmcoreinfo_state = s;
  70 }
  71
  72 static const VMStateDescription vmstate_vmcoreinfo = {
  73     .name = "vmcoreinfo",
  74     .version_id = 1,
  75     .minimum_version_id = 1,
  76     .fields = (VMStateField[]) {
  77         VMSTATE_BOOL(has_vmcoreinfo, VMCoreInfoState),
  78         VMSTATE_UINT16(vmcoreinfo.host_format, VMCoreInfoState),
  79         VMSTATE_UINT16(vmcoreinfo.guest_format, VMCoreInfoState),
  80         VMSTATE_UINT32(vmcoreinfo.size, VMCoreInfoState),
  81         VMSTATE_UINT64(vmcoreinfo.paddr, VMCoreInfoState),
  82         VMSTATE_END_OF_LIST()
  83     },
  84 };
  85
  86 static void vmcoreinfo_device_class_init(ObjectClass *klass, void *data)
  87 {
  88     DeviceClass *dc = DEVICE_CLASS(klass);
  89
  90     dc->vmsd = &vmstate_vmcoreinfo;
  91     dc->realize = vmcoreinfo_realize;
  92     dc->hotpluggable = false;
  93     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
  94 }
  95
  96 static const TypeInfo vmcoreinfo_device_info = {
  97     .name          = VMCOREINFO_DEVICE,
  98     .parent        = TYPE_DEVICE,
  99     .instance_size = sizeof(VMCoreInfoState),
 100     .class_init    = vmcoreinfo_device_class_init,
 101 };
 102
 103 static void vmcoreinfo_register_types(void)
 104 {
 105     type_register_static(&vmcoreinfo_device_info);
 106 }
 107
 108 type_init(vmcoreinfo_register_types)