diff options
| -rw-r--r-- | docs/specs/vmcoreinfo.txt | 41 | ||||
| -rw-r--r-- | hw/misc/Makefile.objs | 1 | ||||
| -rw-r--r-- | hw/misc/vmcoreinfo.c | 96 | ||||
| -rw-r--r-- | include/hw/misc/vmcoreinfo.h | 46 |
4 files changed, 184 insertions, 0 deletions
diff --git a/docs/specs/vmcoreinfo.txt b/docs/specs/vmcoreinfo.txt new file mode 100644 index 0000000000..2868a77142 --- /dev/null +++ b/docs/specs/vmcoreinfo.txt @@ -0,0 +1,41 @@ +================= +VMCoreInfo device +================= + +The `-device vmcoreinfo` will create a fw_cfg entry for a guest to +store dump details. + +etc/vmcoreinfo +************** + +A guest may use this fw_cfg entry to add information details to qemu +dumps. + +The entry of 16 bytes has the following layout, in little-endian:: + +#define VMCOREINFO_FORMAT_NONE 0x0 +#define VMCOREINFO_FORMAT_ELF 0x1 + + struct FWCfgVMCoreInfo { + uint16_t host_format; /* formats host supports */ + uint16_t guest_format; /* format guest supplies */ + uint32_t size; /* size of vmcoreinfo region */ + uint64_t paddr; /* physical address of vmcoreinfo region */ + }; + +Only full write (of 16 bytes) are considered valid for further +processing of entry values. + +A write of 0 in guest_format will disable further processing of +vmcoreinfo entry values & content. + +Format & content +**************** + +As of qemu 2.11, only VMCOREINFO_FORMAT_ELF is supported. + +The entry gives location and size of an ELF note that is appended in +qemu dumps. + +The note format/class must be of the target bitness and the size must +be less than 1Mb. diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs index e8f0a02f35..19202d90cf 100644 --- a/hw/misc/Makefile.objs +++ b/hw/misc/Makefile.objs @@ -9,6 +9,7 @@ common-obj-$(CONFIG_PCI_TESTDEV) += pci-testdev.o common-obj-$(CONFIG_EDU) += edu.o common-obj-y += unimp.o +common-obj-y += vmcoreinfo.o obj-$(CONFIG_VMPORT) += vmport.o diff --git a/hw/misc/vmcoreinfo.c b/hw/misc/vmcoreinfo.c new file mode 100644 index 0000000000..a618e12677 --- /dev/null +++ b/hw/misc/vmcoreinfo.c @@ -0,0 +1,96 @@ +/* + * Virtual Machine coreinfo device + * + * Copyright (C) 2017 Red Hat, Inc. + * + * Authors: Marc-André Lureau <marcandre.lureau@redhat.com> + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + * + */ +#include "qemu/osdep.h" +#include "qapi/error.h" +#include "hw/nvram/fw_cfg.h" +#include "hw/misc/vmcoreinfo.h" + +static void fw_cfg_vmci_write(void *dev, off_t offset, size_t len) +{ + VMCoreInfoState *s = VMCOREINFO(dev); + + s->has_vmcoreinfo = offset == 0 && len == sizeof(s->vmcoreinfo) + && s->vmcoreinfo.guest_format != VMCOREINFO_FORMAT_NONE; +} + +static void vmcoreinfo_reset(void *dev) +{ + VMCoreInfoState *s = VMCOREINFO(dev); + + s->has_vmcoreinfo = false; + memset(&s->vmcoreinfo, 0, sizeof(s->vmcoreinfo)); + s->vmcoreinfo.host_format = cpu_to_le16(VMCOREINFO_FORMAT_ELF); +} + +static void vmcoreinfo_realize(DeviceState *dev, Error **errp) +{ + VMCoreInfoState *s = VMCOREINFO(dev); + FWCfgState *fw_cfg = fw_cfg_find(); + + /* Given that this function is executing, there is at least one VMCOREINFO + * device. Check if there are several. + */ + if (!vmcoreinfo_find()) { + error_setg(errp, "at most one %s device is permitted", + VMCOREINFO_DEVICE); + return; + } + + if (!fw_cfg || !fw_cfg->dma_enabled) { + error_setg(errp, "%s device requires fw_cfg with DMA", + VMCOREINFO_DEVICE); + return; + } + + fw_cfg_add_file_callback(fw_cfg, "etc/vmcoreinfo", + NULL, fw_cfg_vmci_write, s, + &s->vmcoreinfo, sizeof(s->vmcoreinfo), false); + + qemu_register_reset(vmcoreinfo_reset, dev); +} + +static const VMStateDescription vmstate_vmcoreinfo = { + .name = "vmcoreinfo", + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_BOOL(has_vmcoreinfo, VMCoreInfoState), + VMSTATE_UINT16(vmcoreinfo.host_format, VMCoreInfoState), + VMSTATE_UINT16(vmcoreinfo.guest_format, VMCoreInfoState), + VMSTATE_UINT32(vmcoreinfo.size, VMCoreInfoState), + VMSTATE_UINT64(vmcoreinfo.paddr, VMCoreInfoState), + VMSTATE_END_OF_LIST() + }, +}; + +static void vmcoreinfo_device_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->vmsd = &vmstate_vmcoreinfo; + dc->realize = vmcoreinfo_realize; + dc->hotpluggable = false; +} + +static const TypeInfo vmcoreinfo_device_info = { + .name = VMCOREINFO_DEVICE, + .parent = TYPE_DEVICE, + .instance_size = sizeof(VMCoreInfoState), + .class_init = vmcoreinfo_device_class_init, +}; + +static void vmcoreinfo_register_types(void) +{ + type_register_static(&vmcoreinfo_device_info); +} + +type_init(vmcoreinfo_register_types) diff --git a/include/hw/misc/vmcoreinfo.h b/include/hw/misc/vmcoreinfo.h new file mode 100644 index 0000000000..c3aa856545 --- /dev/null +++ b/include/hw/misc/vmcoreinfo.h @@ -0,0 +1,46 @@ +/* + * Virtual Machine coreinfo device + * + * Copyright (C) 2017 Red Hat, Inc. + * + * Authors: Marc-André Lureau <marcandre.lureau@redhat.com> + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + * + */ +#ifndef VMCOREINFO_H +#define VMCOREINFO_H + +#include "hw/qdev.h" + +#define VMCOREINFO_DEVICE "vmcoreinfo" +#define VMCOREINFO(obj) OBJECT_CHECK(VMCoreInfoState, (obj), VMCOREINFO_DEVICE) + +#define VMCOREINFO_FORMAT_NONE 0x0 +#define VMCOREINFO_FORMAT_ELF 0x1 + +/* all fields are little-endian */ +typedef struct FWCfgVMCoreInfo { + uint16_t host_format; /* set on reset */ + uint16_t guest_format; + uint32_t size; + uint64_t paddr; +} QEMU_PACKED FWCfgVMCoreInfo; + +typedef struct VMCoreInfoState { + DeviceClass parent_obj; + + bool has_vmcoreinfo; + FWCfgVMCoreInfo vmcoreinfo; +} VMCoreInfoState; + +/* returns NULL unless there is exactly one device */ +static inline VMCoreInfoState *vmcoreinfo_find(void) +{ + Object *o = object_resolve_path_type("", VMCOREINFO_DEVICE, NULL); + + return o ? VMCOREINFO(o) : NULL; +} + +#endif |