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 "hw/nvram/fw_cfg.h"
  17 #include "hw/misc/vmcoreinfo.h"
  18
  19 static void fw_cfg_vmci_write(void *dev, off_t offset, size_t len)
  20 {
  21     VMCoreInfoState *s = VMCOREINFO(dev);
  22
  23     s->has_vmcoreinfo = offset == 0 && len == sizeof(s->vmcoreinfo)
  24         && s->vmcoreinfo.guest_format != FW_CFG_VMCOREINFO_FORMAT_NONE;
  25 }
  26
  27 static void vmcoreinfo_reset(void *dev)
  28 {
  29     VMCoreInfoState *s = VMCOREINFO(dev);
  30
  31     s->has_vmcoreinfo = false;
  32     memset(&s->vmcoreinfo, 0, sizeof(s->vmcoreinfo));
  33     s->vmcoreinfo.host_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF);
  34 }
  35
  36 static void vmcoreinfo_realize(DeviceState *dev, Error **errp)
  37 {
  38     VMCoreInfoState *s = VMCOREINFO(dev);
  39     FWCfgState *fw_cfg = fw_cfg_find();
  40     /* for gdb script dump-guest-memory.py */
  41     static VMCoreInfoState * volatile vmcoreinfo_state G_GNUC_UNUSED;
  42
  43     /* Given that this function is executing, there is at least one VMCOREINFO
  44      * device. Check if there are several.
  45      */
  46     if (!vmcoreinfo_find()) {
  47         error_setg(errp, "at most one %s device is permitted",
  48                    VMCOREINFO_DEVICE);
  49         return;
  50     }
  51
  52     if (!fw_cfg || !fw_cfg->dma_enabled) {
  53         error_setg(errp, "%s device requires fw_cfg with DMA",
  54                    VMCOREINFO_DEVICE);
  55         return;
  56     }
  57
  58     fw_cfg_add_file_callback(fw_cfg, FW_CFG_VMCOREINFO_FILENAME,
  59                              NULL, fw_cfg_vmci_write, s,
  60                              &s->vmcoreinfo, sizeof(s->vmcoreinfo), false);
  61
  62     qemu_register_reset(vmcoreinfo_reset, dev);
  63     vmcoreinfo_state = s;
  64 }
  65
  66 static const VMStateDescription vmstate_vmcoreinfo = {
  67     .name = "vmcoreinfo",
  68     .version_id = 1,
  69     .minimum_version_id = 1,
  70     .fields = (VMStateField[]) {
  71         VMSTATE_BOOL(has_vmcoreinfo, VMCoreInfoState),
  72         VMSTATE_UINT16(vmcoreinfo.host_format, VMCoreInfoState),
  73         VMSTATE_UINT16(vmcoreinfo.guest_format, VMCoreInfoState),
  74         VMSTATE_UINT32(vmcoreinfo.size, VMCoreInfoState),
  75         VMSTATE_UINT64(vmcoreinfo.paddr, VMCoreInfoState),
  76         VMSTATE_END_OF_LIST()
  77     },
  78 };
  79
  80 static void vmcoreinfo_device_class_init(ObjectClass *klass, void *data)
  81 {
  82     DeviceClass *dc = DEVICE_CLASS(klass);
  83
  84     dc->vmsd = &vmstate_vmcoreinfo;
  85     dc->realize = vmcoreinfo_realize;
  86     dc->hotpluggable = false;
  87     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
  88 }
  89
  90 static const TypeInfo vmcoreinfo_device_info = {
  91     .name          = VMCOREINFO_DEVICE,
  92     .parent        = TYPE_DEVICE,
  93     .instance_size = sizeof(VMCoreInfoState),
  94     .class_init    = vmcoreinfo_device_class_init,
  95 };
  96
  97 static void vmcoreinfo_register_types(void)
  98 {
  99     type_register_static(&vmcoreinfo_device_info);
 100 }
 101
 102 type_init(vmcoreinfo_register_types)