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 != 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(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
  39     /* Given that this function is executing, there is at least one VMCOREINFO
  40      * device. Check if there are several.
  41      */
  42     if (!vmcoreinfo_find()) {
  43         error_setg(errp, "at most one %s device is permitted",
  44                    VMCOREINFO_DEVICE);
  45         return;
  46     }
  47
  48     if (!fw_cfg || !fw_cfg->dma_enabled) {
  49         error_setg(errp, "%s device requires fw_cfg with DMA",
  50                    VMCOREINFO_DEVICE);
  51         return;
  52     }
  53
  54     fw_cfg_add_file_callback(fw_cfg, "etc/vmcoreinfo",
  55                              NULL, fw_cfg_vmci_write, s,
  56                              &s->vmcoreinfo, sizeof(s->vmcoreinfo), false);
  57
  58     qemu_register_reset(vmcoreinfo_reset, dev);
  59 }
  60
  61 static const VMStateDescription vmstate_vmcoreinfo = {
  62     .name = "vmcoreinfo",
  63     .version_id = 1,
  64     .minimum_version_id = 1,
  65     .fields = (VMStateField[]) {
  66         VMSTATE_BOOL(has_vmcoreinfo, VMCoreInfoState),
  67         VMSTATE_UINT16(vmcoreinfo.host_format, VMCoreInfoState),
  68         VMSTATE_UINT16(vmcoreinfo.guest_format, VMCoreInfoState),
  69         VMSTATE_UINT32(vmcoreinfo.size, VMCoreInfoState),
  70         VMSTATE_UINT64(vmcoreinfo.paddr, VMCoreInfoState),
  71         VMSTATE_END_OF_LIST()
  72     },
  73 };
  74
  75 static void vmcoreinfo_device_class_init(ObjectClass *klass, void *data)
  76 {
  77     DeviceClass *dc = DEVICE_CLASS(klass);
  78
  79     dc->vmsd = &vmstate_vmcoreinfo;
  80     dc->realize = vmcoreinfo_realize;
  81     dc->hotpluggable = false;
  82 }
  83
  84 static const TypeInfo vmcoreinfo_device_info = {
  85     .name          = VMCOREINFO_DEVICE,
  86     .parent        = TYPE_DEVICE,
  87     .instance_size = sizeof(VMCoreInfoState),
  88     .class_init    = vmcoreinfo_device_class_init,
  89 };
  90
  91 static void vmcoreinfo_register_types(void)
  92 {
  93     type_register_static(&vmcoreinfo_device_info);
  94 }
  95
  96 type_init(vmcoreinfo_register_types)