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 #include "qemu/osdep.h"
  13 #include "qapi/error.h"
  14 #include "hw/nvram/fw_cfg.h"
  15 #include "hw/misc/vmcoreinfo.h"
  16
  17 static void fw_cfg_vmci_write(void *dev, off_t offset, size_t len)
  18 {
  19     VMCoreInfoState *s = VMCOREINFO(dev);
  20
  21     s->has_vmcoreinfo = offset == 0 && len == sizeof(s->vmcoreinfo)
  22         && s->vmcoreinfo.guest_format != FW_CFG_VMCOREINFO_FORMAT_NONE;
  23 }
  24
  25 static void vmcoreinfo_reset(void *dev)
  26 {
  27     VMCoreInfoState *s = VMCOREINFO(dev);
  28
  29     s->has_vmcoreinfo = false;
  30     memset(&s->vmcoreinfo, 0, sizeof(s->vmcoreinfo));
  31     s->vmcoreinfo.host_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF);
  32 }
  33
  34 static void vmcoreinfo_realize(DeviceState *dev, Error **errp)
  35 {
  36     VMCoreInfoState *s = VMCOREINFO(dev);
  37     FWCfgState *fw_cfg = fw_cfg_find();
  38     /* for gdb script dump-guest-memory.py */
  39     static VMCoreInfoState * volatile vmcoreinfo_state G_GNUC_UNUSED;
  40
  41     /* Given that this function is executing, there is at least one VMCOREINFO
  42      * device. Check if there are several.
  43      */
  44     if (!vmcoreinfo_find()) {
  45         error_setg(errp, "at most one %s device is permitted",
  46                    VMCOREINFO_DEVICE);
  47         return;
  48     }
  49
  50     if (!fw_cfg || !fw_cfg->dma_enabled) {
  51         error_setg(errp, "%s device requires fw_cfg with DMA",
  52                    VMCOREINFO_DEVICE);
  53         return;
  54     }
  55
  56     fw_cfg_add_file_callback(fw_cfg, FW_CFG_VMCOREINFO_FILENAME,
  57                              NULL, fw_cfg_vmci_write, s,
  58                              &s->vmcoreinfo, sizeof(s->vmcoreinfo), false);
  59
  60     qemu_register_reset(vmcoreinfo_reset, dev);
  61     vmcoreinfo_state = s;
  62 }
  63
  64 static const VMStateDescription vmstate_vmcoreinfo = {
  65     .name = "vmcoreinfo",
  66     .version_id = 1,
  67     .minimum_version_id = 1,
  68     .fields = (VMStateField[]) {
  69         VMSTATE_BOOL(has_vmcoreinfo, VMCoreInfoState),
  70         VMSTATE_UINT16(vmcoreinfo.host_format, VMCoreInfoState),
  71         VMSTATE_UINT16(vmcoreinfo.guest_format, VMCoreInfoState),
  72         VMSTATE_UINT32(vmcoreinfo.size, VMCoreInfoState),
  73         VMSTATE_UINT64(vmcoreinfo.paddr, VMCoreInfoState),
  74         VMSTATE_END_OF_LIST()
  75     },
  76 };
  77
  78 static void vmcoreinfo_device_class_init(ObjectClass *klass, void *data)
  79 {
  80     DeviceClass *dc = DEVICE_CLASS(klass);
  81
  82     dc->vmsd = &vmstate_vmcoreinfo;
  83     dc->realize = vmcoreinfo_realize;
  84     dc->hotpluggable = false;
  85     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
  86 }
  87
  88 static const TypeInfo vmcoreinfo_device_info = {
  89     .name          = VMCOREINFO_DEVICE,
  90     .parent        = TYPE_DEVICE,
  91     .instance_size = sizeof(VMCoreInfoState),
  92     .class_init    = vmcoreinfo_device_class_init,
  93 };
  94
  95 static void vmcoreinfo_register_types(void)
  96 {
  97     type_register_static(&vmcoreinfo_device_info);
  98 }
  99
 100 type_init(vmcoreinfo_register_types)