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qemu-e2k/dump/dump.c
Janosch Frank 113d8f4e95 s390x: pv: Add dump support 
Sometimes dumping a guest from the outside is the only way to get the
data that is needed. This can be the case if a dumping mechanism like
KDUMP hasn't been configured or data needs to be fetched at a specific
point. Dumping a protected guest from the outside without help from
fw/hw doesn't yield sufficient data to be useful. Hence we now
introduce PV dump support.

The PV dump support works by integrating the firmware into the dump
process. New Ultravisor calls are used to initiate the dump process,
dump cpu data, dump memory state and lastly complete the dump process.
The UV calls are exposed by KVM via the new KVM_PV_DUMP command and
its subcommands. The guest's data is fully encrypted and can only be
decrypted by the entity that owns the customer communication key for
the dumped guest. Also dumping needs to be allowed via a flag in the
SE header.

On the QEMU side of things we store the PV dump data in the newly
introduced architecture ELF sections (storage state and completion
data) and the cpu notes (for cpu dump data).

Users can use the zgetdump tool to convert the encrypted QEMU dump to an
unencrypted one.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Message-Id: <20221017083822.43118-11-frankja@linux.ibm.com>
2022-10-26 12:54:59 +04:00

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/*
* QEMU dump
*
* Copyright Fujitsu, Corp. 2011, 2012
*
* Authors:
* Wen Congyang <wency@cn.fujitsu.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 "qemu/cutils.h"
#include "elf.h"
#include "exec/hwaddr.h"
#include "monitor/monitor.h"
#include "sysemu/kvm.h"
#include "sysemu/dump.h"
#include "sysemu/memory_mapping.h"
#include "sysemu/runstate.h"
#include "sysemu/cpus.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-dump.h"
#include "qapi/qapi-events-dump.h"
#include "qapi/qmp/qerror.h"
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
#include "hw/misc/vmcoreinfo.h"
#include "migration/blocker.h"
#ifdef TARGET_X86_64
#include "win_dump.h"
#endif
#include <zlib.h>
#ifdef CONFIG_LZO
#include <lzo/lzo1x.h>
#endif
#ifdef CONFIG_SNAPPY
#include <snappy-c.h>
#endif
#ifndef ELF_MACHINE_UNAME
#define ELF_MACHINE_UNAME "Unknown"
#endif
#define MAX_GUEST_NOTE_SIZE (1 << 20) /* 1MB should be enough */
static Error *dump_migration_blocker;
#define ELF_NOTE_SIZE(hdr_size, name_size, desc_size) \
((DIV_ROUND_UP((hdr_size), 4) + \
DIV_ROUND_UP((name_size), 4) + \
DIV_ROUND_UP((desc_size), 4)) * 4)
static inline bool dump_is_64bit(DumpState *s)
{
return s->dump_info.d_class == ELFCLASS64;
}
static inline bool dump_has_filter(DumpState *s)
{
return s->filter_area_length > 0;
}
uint16_t cpu_to_dump16(DumpState *s, uint16_t val)
{
if (s->dump_info.d_endian == ELFDATA2LSB) {
val = cpu_to_le16(val);
} else {
val = cpu_to_be16(val);
}
return val;
}
uint32_t cpu_to_dump32(DumpState *s, uint32_t val)
{
if (s->dump_info.d_endian == ELFDATA2LSB) {
val = cpu_to_le32(val);
} else {
val = cpu_to_be32(val);
}
return val;
}
uint64_t cpu_to_dump64(DumpState *s, uint64_t val)
{
if (s->dump_info.d_endian == ELFDATA2LSB) {
val = cpu_to_le64(val);
} else {
val = cpu_to_be64(val);
}
return val;
}
static int dump_cleanup(DumpState *s)
{
guest_phys_blocks_free(&s->guest_phys_blocks);
memory_mapping_list_free(&s->list);
close(s->fd);
g_free(s->guest_note);
g_array_unref(s->string_table_buf);
s->guest_note = NULL;
if (s->resume) {
if (s->detached) {
qemu_mutex_lock_iothread();
}
vm_start();
if (s->detached) {
qemu_mutex_unlock_iothread();
}
}
migrate_del_blocker(dump_migration_blocker);
return 0;
}
static int fd_write_vmcore(const void *buf, size_t size, void *opaque)
{
DumpState *s = opaque;
size_t written_size;
written_size = qemu_write_full(s->fd, buf, size);
if (written_size != size) {
return -errno;
}
return 0;
}
static void prepare_elf64_header(DumpState *s, Elf64_Ehdr *elf_header)
{
/*
* phnum in the elf header is 16 bit, if we have more segments we
* set phnum to PN_XNUM and write the real number of segments to a
* special section.
*/
uint16_t phnum = MIN(s->phdr_num, PN_XNUM);
memset(elf_header, 0, sizeof(Elf64_Ehdr));
memcpy(elf_header, ELFMAG, SELFMAG);
elf_header->e_ident[EI_CLASS] = ELFCLASS64;
elf_header->e_ident[EI_DATA] = s->dump_info.d_endian;
elf_header->e_ident[EI_VERSION] = EV_CURRENT;
elf_header->e_type = cpu_to_dump16(s, ET_CORE);
elf_header->e_machine = cpu_to_dump16(s, s->dump_info.d_machine);
elf_header->e_version = cpu_to_dump32(s, EV_CURRENT);
elf_header->e_ehsize = cpu_to_dump16(s, sizeof(elf_header));
elf_header->e_phoff = cpu_to_dump64(s, s->phdr_offset);
elf_header->e_phentsize = cpu_to_dump16(s, sizeof(Elf64_Phdr));
elf_header->e_phnum = cpu_to_dump16(s, phnum);
elf_header->e_shoff = cpu_to_dump64(s, s->shdr_offset);
elf_header->e_shentsize = cpu_to_dump16(s, sizeof(Elf64_Shdr));
elf_header->e_shnum = cpu_to_dump16(s, s->shdr_num);
elf_header->e_shstrndx = cpu_to_dump16(s, s->shdr_num - 1);
}
static void prepare_elf32_header(DumpState *s, Elf32_Ehdr *elf_header)
{
/*
* phnum in the elf header is 16 bit, if we have more segments we
* set phnum to PN_XNUM and write the real number of segments to a
* special section.
*/
uint16_t phnum = MIN(s->phdr_num, PN_XNUM);
memset(elf_header, 0, sizeof(Elf32_Ehdr));
memcpy(elf_header, ELFMAG, SELFMAG);
elf_header->e_ident[EI_CLASS] = ELFCLASS32;
elf_header->e_ident[EI_DATA] = s->dump_info.d_endian;
elf_header->e_ident[EI_VERSION] = EV_CURRENT;
elf_header->e_type = cpu_to_dump16(s, ET_CORE);
elf_header->e_machine = cpu_to_dump16(s, s->dump_info.d_machine);
elf_header->e_version = cpu_to_dump32(s, EV_CURRENT);
elf_header->e_ehsize = cpu_to_dump16(s, sizeof(elf_header));
elf_header->e_phoff = cpu_to_dump32(s, s->phdr_offset);
elf_header->e_phentsize = cpu_to_dump16(s, sizeof(Elf32_Phdr));
elf_header->e_phnum = cpu_to_dump16(s, phnum);
elf_header->e_shoff = cpu_to_dump32(s, s->shdr_offset);
elf_header->e_shentsize = cpu_to_dump16(s, sizeof(Elf32_Shdr));
elf_header->e_shnum = cpu_to_dump16(s, s->shdr_num);
elf_header->e_shstrndx = cpu_to_dump16(s, s->shdr_num - 1);
}
static void write_elf_header(DumpState *s, Error **errp)
{
Elf32_Ehdr elf32_header;
Elf64_Ehdr elf64_header;
size_t header_size;
void *header_ptr;
int ret;
/* The NULL header and the shstrtab are always defined */
assert(s->shdr_num >= 2);
if (dump_is_64bit(s)) {
prepare_elf64_header(s, &elf64_header);
header_size = sizeof(elf64_header);
header_ptr = &elf64_header;
} else {
prepare_elf32_header(s, &elf32_header);
header_size = sizeof(elf32_header);
header_ptr = &elf32_header;
}
ret = fd_write_vmcore(header_ptr, header_size, s);
if (ret < 0) {
error_setg_errno(errp, -ret, "dump: failed to write elf header");
}
}
static void write_elf64_load(DumpState *s, MemoryMapping *memory_mapping,
int phdr_index, hwaddr offset,
hwaddr filesz, Error **errp)
{
Elf64_Phdr phdr;
int ret;
memset(&phdr, 0, sizeof(Elf64_Phdr));
phdr.p_type = cpu_to_dump32(s, PT_LOAD);
phdr.p_offset = cpu_to_dump64(s, offset);
phdr.p_paddr = cpu_to_dump64(s, memory_mapping->phys_addr);
phdr.p_filesz = cpu_to_dump64(s, filesz);
phdr.p_memsz = cpu_to_dump64(s, memory_mapping->length);
phdr.p_vaddr = cpu_to_dump64(s, memory_mapping->virt_addr) ?: phdr.p_paddr;
assert(memory_mapping->length >= filesz);
ret = fd_write_vmcore(&phdr, sizeof(Elf64_Phdr), s);
if (ret < 0) {
error_setg_errno(errp, -ret,
"dump: failed to write program header table");
}
}
static void write_elf32_load(DumpState *s, MemoryMapping *memory_mapping,
int phdr_index, hwaddr offset,
hwaddr filesz, Error **errp)
{
Elf32_Phdr phdr;
int ret;
memset(&phdr, 0, sizeof(Elf32_Phdr));
phdr.p_type = cpu_to_dump32(s, PT_LOAD);
phdr.p_offset = cpu_to_dump32(s, offset);
phdr.p_paddr = cpu_to_dump32(s, memory_mapping->phys_addr);
phdr.p_filesz = cpu_to_dump32(s, filesz);
phdr.p_memsz = cpu_to_dump32(s, memory_mapping->length);
phdr.p_vaddr =
cpu_to_dump32(s, memory_mapping->virt_addr) ?: phdr.p_paddr;
assert(memory_mapping->length >= filesz);
ret = fd_write_vmcore(&phdr, sizeof(Elf32_Phdr), s);
if (ret < 0) {
error_setg_errno(errp, -ret,
"dump: failed to write program header table");
}
}
static void prepare_elf64_phdr_note(DumpState *s, Elf64_Phdr *phdr)
{
memset(phdr, 0, sizeof(*phdr));
phdr->p_type = cpu_to_dump32(s, PT_NOTE);
phdr->p_offset = cpu_to_dump64(s, s->note_offset);
phdr->p_paddr = 0;
phdr->p_filesz = cpu_to_dump64(s, s->note_size);
phdr->p_memsz = cpu_to_dump64(s, s->note_size);
phdr->p_vaddr = 0;
}
static inline int cpu_index(CPUState *cpu)
{
return cpu->cpu_index + 1;
}
static void write_guest_note(WriteCoreDumpFunction f, DumpState *s,
Error **errp)
{
int ret;
if (s->guest_note) {
ret = f(s->guest_note, s->guest_note_size, s);
if (ret < 0) {
error_setg(errp, "dump: failed to write guest note");
}
}
}
static void write_elf64_notes(WriteCoreDumpFunction f, DumpState *s,
Error **errp)
{
CPUState *cpu;
int ret;
int id;
CPU_FOREACH(cpu) {
id = cpu_index(cpu);
ret = cpu_write_elf64_note(f, cpu, id, s);
if (ret < 0) {
error_setg(errp, "dump: failed to write elf notes");
return;
}
}
CPU_FOREACH(cpu) {
ret = cpu_write_elf64_qemunote(f, cpu, s);
if (ret < 0) {
error_setg(errp, "dump: failed to write CPU status");
return;
}
}
write_guest_note(f, s, errp);
}
static void prepare_elf32_phdr_note(DumpState *s, Elf32_Phdr *phdr)
{
memset(phdr, 0, sizeof(*phdr));
phdr->p_type = cpu_to_dump32(s, PT_NOTE);
phdr->p_offset = cpu_to_dump32(s, s->note_offset);
phdr->p_paddr = 0;
phdr->p_filesz = cpu_to_dump32(s, s->note_size);
phdr->p_memsz = cpu_to_dump32(s, s->note_size);
phdr->p_vaddr = 0;
}
static void write_elf32_notes(WriteCoreDumpFunction f, DumpState *s,
Error **errp)
{
CPUState *cpu;
int ret;
int id;
CPU_FOREACH(cpu) {
id = cpu_index(cpu);
ret = cpu_write_elf32_note(f, cpu, id, s);
if (ret < 0) {
error_setg(errp, "dump: failed to write elf notes");
return;
}
}
CPU_FOREACH(cpu) {
ret = cpu_write_elf32_qemunote(f, cpu, s);
if (ret < 0) {
error_setg(errp, "dump: failed to write CPU status");
return;
}
}
write_guest_note(f, s, errp);
}
static void write_elf_phdr_note(DumpState *s, Error **errp)
{
ERRP_GUARD();
Elf32_Phdr phdr32;
Elf64_Phdr phdr64;
void *phdr;
size_t size;
int ret;
if (dump_is_64bit(s)) {
prepare_elf64_phdr_note(s, &phdr64);
size = sizeof(phdr64);
phdr = &phdr64;
} else {
prepare_elf32_phdr_note(s, &phdr32);
size = sizeof(phdr32);
phdr = &phdr32;
}
ret = fd_write_vmcore(phdr, size, s);
if (ret < 0) {
error_setg_errno(errp, -ret,
"dump: failed to write program header table");
}
}
static void prepare_elf_section_hdr_zero(DumpState *s)
{
if (dump_is_64bit(s)) {
Elf64_Shdr *shdr64 = s->elf_section_hdrs;
shdr64->sh_info = cpu_to_dump32(s, s->phdr_num);
} else {
Elf32_Shdr *shdr32 = s->elf_section_hdrs;
shdr32->sh_info = cpu_to_dump32(s, s->phdr_num);
}
}
static void prepare_elf_section_hdr_string(DumpState *s, void *buff)
{
uint64_t index = s->string_table_buf->len;
const char strtab[] = ".shstrtab";
Elf32_Shdr shdr32 = {};
Elf64_Shdr shdr64 = {};
int shdr_size;
void *shdr;
g_array_append_vals(s->string_table_buf, strtab, sizeof(strtab));
if (dump_is_64bit(s)) {
shdr_size = sizeof(Elf64_Shdr);
shdr64.sh_type = SHT_STRTAB;
shdr64.sh_offset = s->section_offset + s->elf_section_data_size;
shdr64.sh_name = index;
shdr64.sh_size = s->string_table_buf->len;
shdr = &shdr64;
} else {
shdr_size = sizeof(Elf32_Shdr);
shdr32.sh_type = SHT_STRTAB;
shdr32.sh_offset = s->section_offset + s->elf_section_data_size;
shdr32.sh_name = index;
shdr32.sh_size = s->string_table_buf->len;
shdr = &shdr32;
}
memcpy(buff, shdr, shdr_size);
}
static bool prepare_elf_section_hdrs(DumpState *s, Error **errp)
{
size_t len, sizeof_shdr;
void *buff_hdr;
/*
* Section ordering:
* - HDR zero
* - Arch section hdrs
* - String table hdr
*/
sizeof_shdr = dump_is_64bit(s) ? sizeof(Elf64_Shdr) : sizeof(Elf32_Shdr);
len = sizeof_shdr * s->shdr_num;
s->elf_section_hdrs = g_malloc0(len);
buff_hdr = s->elf_section_hdrs;
/*
* The first section header is ALWAYS a special initial section
* header.
*
* The header should be 0 with one exception being that if
* phdr_num is PN_XNUM then the sh_info field contains the real
* number of segment entries.
*
* As we zero allocate the buffer we will only need to modify
* sh_info for the PN_XNUM case.
*/
if (s->phdr_num >= PN_XNUM) {
prepare_elf_section_hdr_zero(s);
}
buff_hdr += sizeof_shdr;
/* Add architecture defined section headers */
if (s->dump_info.arch_sections_write_hdr_fn
&& s->shdr_num > 2) {
buff_hdr += s->dump_info.arch_sections_write_hdr_fn(s, buff_hdr);
if (s->shdr_num >= SHN_LORESERVE) {
error_setg_errno(errp, EINVAL,
"dump: too many architecture defined sections");
return false;
}
}
/*
* String table is the last section since strings are added via
* arch_sections_write_hdr().
*/
prepare_elf_section_hdr_string(s, buff_hdr);
return true;
}
static void write_elf_section_headers(DumpState *s, Error **errp)
{
size_t sizeof_shdr = dump_is_64bit(s) ? sizeof(Elf64_Shdr) : sizeof(Elf32_Shdr);
int ret;
if (!prepare_elf_section_hdrs(s, errp)) {
return;
}
ret = fd_write_vmcore(s->elf_section_hdrs, s->shdr_num * sizeof_shdr, s);
if (ret < 0) {
error_setg_errno(errp, -ret, "dump: failed to write section headers");
}
g_free(s->elf_section_hdrs);
}
static void write_elf_sections(DumpState *s, Error **errp)
{
int ret;
if (s->elf_section_data_size) {
/* Write architecture section data */
ret = fd_write_vmcore(s->elf_section_data,
s->elf_section_data_size, s);
if (ret < 0) {
error_setg_errno(errp, -ret,
"dump: failed to write architecture section data");
return;
}
}
/* Write string table */
ret = fd_write_vmcore(s->string_table_buf->data,
s->string_table_buf->len, s);
if (ret < 0) {
error_setg_errno(errp, -ret, "dump: failed to write string table data");
}
}
static void write_data(DumpState *s, void *buf, int length, Error **errp)
{
int ret;
ret = fd_write_vmcore(buf, length, s);
if (ret < 0) {
error_setg_errno(errp, -ret, "dump: failed to save memory");
} else {
s->written_size += length;
}
}
/* write the memory to vmcore. 1 page per I/O. */
static void write_memory(DumpState *s, GuestPhysBlock *block, ram_addr_t start,
int64_t size, Error **errp)
{
ERRP_GUARD();
int64_t i;
for (i = 0; i < size / s->dump_info.page_size; i++) {
write_data(s, block->host_addr + start + i * s->dump_info.page_size,
s->dump_info.page_size, errp);
if (*errp) {
return;
}
}
if ((size % s->dump_info.page_size) != 0) {
write_data(s, block->host_addr + start + i * s->dump_info.page_size,
size % s->dump_info.page_size, errp);
if (*errp) {
return;
}
}
}
/* get the memory's offset and size in the vmcore */
static void get_offset_range(hwaddr phys_addr,
ram_addr_t mapping_length,
DumpState *s,
hwaddr *p_offset,
hwaddr *p_filesz)
{
GuestPhysBlock *block;
hwaddr offset = s->memory_offset;
int64_t size_in_block, start;
/* When the memory is not stored into vmcore, offset will be -1 */
*p_offset = -1;
*p_filesz = 0;
if (dump_has_filter(s)) {
if (phys_addr < s->filter_area_begin ||
phys_addr >= s->filter_area_begin + s->filter_area_length) {
return;
}
}
QTAILQ_FOREACH(block, &s->guest_phys_blocks.head, next) {
if (dump_has_filter(s)) {
if (block->target_start >= s->filter_area_begin + s->filter_area_length ||
block->target_end <= s->filter_area_begin) {
/* This block is out of the range */
continue;
}
if (s->filter_area_begin <= block->target_start) {
start = block->target_start;
} else {
start = s->filter_area_begin;
}
size_in_block = block->target_end - start;
if (s->filter_area_begin + s->filter_area_length < block->target_end) {
size_in_block -= block->target_end - (s->filter_area_begin + s->filter_area_length);
}
} else {
start = block->target_start;
size_in_block = block->target_end - block->target_start;
}
if (phys_addr >= start && phys_addr < start + size_in_block) {
*p_offset = phys_addr - start + offset;
/* The offset range mapped from the vmcore file must not spill over
* the GuestPhysBlock, clamp it. The rest of the mapping will be
* zero-filled in memory at load time; see
* <http://refspecs.linuxbase.org/elf/gabi4+/ch5.pheader.html>.
*/
*p_filesz = phys_addr + mapping_length <= start + size_in_block ?
mapping_length :
size_in_block - (phys_addr - start);
return;
}
offset += size_in_block;
}
}
static void write_elf_phdr_loads(DumpState *s, Error **errp)
{
ERRP_GUARD();
hwaddr offset, filesz;
MemoryMapping *memory_mapping;
uint32_t phdr_index = 1;
QTAILQ_FOREACH(memory_mapping, &s->list.head, next) {
get_offset_range(memory_mapping->phys_addr,
memory_mapping->length,
s, &offset, &filesz);
if (dump_is_64bit(s)) {
write_elf64_load(s, memory_mapping, phdr_index++, offset,
filesz, errp);
} else {
write_elf32_load(s, memory_mapping, phdr_index++, offset,
filesz, errp);
}
if (*errp) {
return;
}
if (phdr_index >= s->phdr_num) {
break;
}
}
}
static void write_elf_notes(DumpState *s, Error **errp)
{
if (dump_is_64bit(s)) {
write_elf64_notes(fd_write_vmcore, s, errp);
} else {
write_elf32_notes(fd_write_vmcore, s, errp);
}
}
/* write elf header, PT_NOTE and elf note to vmcore. */
static void dump_begin(DumpState *s, Error **errp)
{
ERRP_GUARD();
/*
* the vmcore's format is:
* --------------
* | elf header |
* --------------
* | sctn_hdr |
* --------------
* | PT_NOTE |
* --------------
* | PT_LOAD |
* --------------
* | ...... |
* --------------
* | PT_LOAD |
* --------------
* | elf note |
* --------------
* | memory |
* --------------
*
* we only know where the memory is saved after we write elf note into
* vmcore.
*/
/* write elf header to vmcore */
write_elf_header(s, errp);
if (*errp) {
return;
}
/* write section headers to vmcore */
write_elf_section_headers(s, errp);
if (*errp) {
return;
}
/* write PT_NOTE to vmcore */
write_elf_phdr_note(s, errp);
if (*errp) {
return;
}
/* write all PT_LOADs to vmcore */
write_elf_phdr_loads(s, errp);
if (*errp) {
return;
}
/* write notes to vmcore */
write_elf_notes(s, errp);
}
int64_t dump_filtered_memblock_size(GuestPhysBlock *block,
int64_t filter_area_start,
int64_t filter_area_length)
{
int64_t size, left, right;
/* No filter, return full size */
if (!filter_area_length) {
return block->target_end - block->target_start;
}
/* calculate the overlapped region. */
left = MAX(filter_area_start, block->target_start);
right = MIN(filter_area_start + filter_area_length, block->target_end);
size = right - left;
size = size > 0 ? size : 0;
return size;
}
int64_t dump_filtered_memblock_start(GuestPhysBlock *block,
int64_t filter_area_start,
int64_t filter_area_length)
{
if (filter_area_length) {
/* return -1 if the block is not within filter area */
if (block->target_start >= filter_area_start + filter_area_length ||
block->target_end <= filter_area_start) {
return -1;
}
if (filter_area_start > block->target_start) {
return filter_area_start - block->target_start;
}
}
return 0;
}
/* write all memory to vmcore */
static void dump_iterate(DumpState *s, Error **errp)
{
ERRP_GUARD();
GuestPhysBlock *block;
int64_t memblock_size, memblock_start;
QTAILQ_FOREACH(block, &s->guest_phys_blocks.head, next) {
memblock_start = dump_filtered_memblock_start(block, s->filter_area_begin, s->filter_area_length);
if (memblock_start == -1) {
continue;
}
memblock_size = dump_filtered_memblock_size(block, s->filter_area_begin, s->filter_area_length);
/* Write the memory to file */
write_memory(s, block, memblock_start, memblock_size, errp);
if (*errp) {
return;
}
}
}
static void dump_end(DumpState *s, Error **errp)
{
int rc;
ERRP_GUARD();
if (s->elf_section_data_size) {
s->elf_section_data = g_malloc0(s->elf_section_data_size);
}
/* Adds the architecture defined section data to s->elf_section_data */
if (s->dump_info.arch_sections_write_fn &&
s->elf_section_data_size) {
rc = s->dump_info.arch_sections_write_fn(s, s->elf_section_data);
if (rc) {
error_setg_errno(errp, rc,
"dump: failed to get arch section data");
g_free(s->elf_section_data);
return;
}
}
/* write sections to vmcore */
write_elf_sections(s, errp);
}
static void create_vmcore(DumpState *s, Error **errp)
{
ERRP_GUARD();
dump_begin(s, errp);
if (*errp) {
return;
}
/* Iterate over memory and dump it to file */
dump_iterate(s, errp);
if (*errp) {
return;
}
/* Write the section data */
dump_end(s, errp);
}
static int write_start_flat_header(int fd)
{
MakedumpfileHeader *mh;
int ret = 0;
QEMU_BUILD_BUG_ON(sizeof *mh > MAX_SIZE_MDF_HEADER);
mh = g_malloc0(MAX_SIZE_MDF_HEADER);
memcpy(mh->signature, MAKEDUMPFILE_SIGNATURE,
MIN(sizeof mh->signature, sizeof MAKEDUMPFILE_SIGNATURE));
mh->type = cpu_to_be64(TYPE_FLAT_HEADER);
mh->version = cpu_to_be64(VERSION_FLAT_HEADER);
size_t written_size;
written_size = qemu_write_full(fd, mh, MAX_SIZE_MDF_HEADER);
if (written_size != MAX_SIZE_MDF_HEADER) {
ret = -1;
}
g_free(mh);
return ret;
}
static int write_end_flat_header(int fd)
{
MakedumpfileDataHeader mdh;
mdh.offset = END_FLAG_FLAT_HEADER;
mdh.buf_size = END_FLAG_FLAT_HEADER;
size_t written_size;
written_size = qemu_write_full(fd, &mdh, sizeof(mdh));
if (written_size != sizeof(mdh)) {
return -1;
}
return 0;
}
static int write_buffer(int fd, off_t offset, const void *buf, size_t size)
{
size_t written_size;
MakedumpfileDataHeader mdh;
mdh.offset = cpu_to_be64(offset);
mdh.buf_size = cpu_to_be64(size);
written_size = qemu_write_full(fd, &mdh, sizeof(mdh));
if (written_size != sizeof(mdh)) {
return -1;
}
written_size = qemu_write_full(fd, buf, size);
if (written_size != size) {
return -1;
}
return 0;
}
static int buf_write_note(const void *buf, size_t size, void *opaque)
{
DumpState *s = opaque;
/* note_buf is not enough */
if (s->note_buf_offset + size > s->note_size) {
return -1;
}
memcpy(s->note_buf + s->note_buf_offset, buf, size);
s->note_buf_offset += size;
return 0;
}
/*
* This function retrieves various sizes from an elf header.
*
* @note has to be a valid ELF note. The return sizes are unmodified
* (not padded or rounded up to be multiple of 4).
*/
static void get_note_sizes(DumpState *s, const void *note,
uint64_t *note_head_size,
uint64_t *name_size,
uint64_t *desc_size)
{
uint64_t note_head_sz;
uint64_t name_sz;
uint64_t desc_sz;
if (dump_is_64bit(s)) {
const Elf64_Nhdr *hdr = note;
note_head_sz = sizeof(Elf64_Nhdr);
name_sz = tswap64(hdr->n_namesz);
desc_sz = tswap64(hdr->n_descsz);
} else {
const Elf32_Nhdr *hdr = note;
note_head_sz = sizeof(Elf32_Nhdr);
name_sz = tswap32(hdr->n_namesz);
desc_sz = tswap32(hdr->n_descsz);
}
if (note_head_size) {
*note_head_size = note_head_sz;
}
if (name_size) {
*name_size = name_sz;
}
if (desc_size) {
*desc_size = desc_sz;
}
}
static bool note_name_equal(DumpState *s,
const uint8_t *note, const char *name)
{
int len = strlen(name) + 1;
uint64_t head_size, name_size;
get_note_sizes(s, note, &head_size, &name_size, NULL);
head_size = ROUND_UP(head_size, 4);
return name_size == len && memcmp(note + head_size, name, len) == 0;
}
/* write common header, sub header and elf note to vmcore */
static void create_header32(DumpState *s, Error **errp)
{
ERRP_GUARD();
DiskDumpHeader32 *dh = NULL;
KdumpSubHeader32 *kh = NULL;
size_t size;
uint32_t block_size;
uint32_t sub_hdr_size;
uint32_t bitmap_blocks;
uint32_t status = 0;
uint64_t offset_note;
/* write common header, the version of kdump-compressed format is 6th */
size = sizeof(DiskDumpHeader32);
dh = g_malloc0(size);
memcpy(dh->signature, KDUMP_SIGNATURE, SIG_LEN);
dh->header_version = cpu_to_dump32(s, 6);
block_size = s->dump_info.page_size;
dh->block_size = cpu_to_dump32(s, block_size);
sub_hdr_size = sizeof(struct KdumpSubHeader32) + s->note_size;
sub_hdr_size = DIV_ROUND_UP(sub_hdr_size, block_size);
dh->sub_hdr_size = cpu_to_dump32(s, sub_hdr_size);
/* dh->max_mapnr may be truncated, full 64bit is in kh.max_mapnr_64 */
dh->max_mapnr = cpu_to_dump32(s, MIN(s->max_mapnr, UINT_MAX));
dh->nr_cpus = cpu_to_dump32(s, s->nr_cpus);
bitmap_blocks = DIV_ROUND_UP(s->len_dump_bitmap, block_size) * 2;
dh->bitmap_blocks = cpu_to_dump32(s, bitmap_blocks);
strncpy(dh->utsname.machine, ELF_MACHINE_UNAME, sizeof(dh->utsname.machine));
if (s->flag_compress & DUMP_DH_COMPRESSED_ZLIB) {
status |= DUMP_DH_COMPRESSED_ZLIB;
}
#ifdef CONFIG_LZO
if (s->flag_compress & DUMP_DH_COMPRESSED_LZO) {
status |= DUMP_DH_COMPRESSED_LZO;
}
#endif
#ifdef CONFIG_SNAPPY
if (s->flag_compress & DUMP_DH_COMPRESSED_SNAPPY) {
status |= DUMP_DH_COMPRESSED_SNAPPY;
}
#endif
dh->status = cpu_to_dump32(s, status);
if (write_buffer(s->fd, 0, dh, size) < 0) {
error_setg(errp, "dump: failed to write disk dump header");
goto out;
}
/* write sub header */
size = sizeof(KdumpSubHeader32);
kh = g_malloc0(size);
/* 64bit max_mapnr_64 */
kh->max_mapnr_64 = cpu_to_dump64(s, s->max_mapnr);
kh->phys_base = cpu_to_dump32(s, s->dump_info.phys_base);
kh->dump_level = cpu_to_dump32(s, DUMP_LEVEL);
offset_note = DISKDUMP_HEADER_BLOCKS * block_size + size;
if (s->guest_note &&
note_name_equal(s, s->guest_note, "VMCOREINFO")) {
uint64_t hsize, name_size, size_vmcoreinfo_desc, offset_vmcoreinfo;
get_note_sizes(s, s->guest_note,
&hsize, &name_size, &size_vmcoreinfo_desc);
offset_vmcoreinfo = offset_note + s->note_size - s->guest_note_size +
(DIV_ROUND_UP(hsize, 4) + DIV_ROUND_UP(name_size, 4)) * 4;
kh->offset_vmcoreinfo = cpu_to_dump64(s, offset_vmcoreinfo);
kh->size_vmcoreinfo = cpu_to_dump32(s, size_vmcoreinfo_desc);
}
kh->offset_note = cpu_to_dump64(s, offset_note);
kh->note_size = cpu_to_dump32(s, s->note_size);
if (write_buffer(s->fd, DISKDUMP_HEADER_BLOCKS *
block_size, kh, size) < 0) {
error_setg(errp, "dump: failed to write kdump sub header");
goto out;
}
/* write note */
s->note_buf = g_malloc0(s->note_size);
s->note_buf_offset = 0;
/* use s->note_buf to store notes temporarily */
write_elf32_notes(buf_write_note, s, errp);
if (*errp) {
goto out;
}
if (write_buffer(s->fd, offset_note, s->note_buf,
s->note_size) < 0) {
error_setg(errp, "dump: failed to write notes");
goto out;
}
/* get offset of dump_bitmap */
s->offset_dump_bitmap = (DISKDUMP_HEADER_BLOCKS + sub_hdr_size) *
block_size;
/* get offset of page */
s->offset_page = (DISKDUMP_HEADER_BLOCKS + sub_hdr_size + bitmap_blocks) *
block_size;
out:
g_free(dh);
g_free(kh);
g_free(s->note_buf);
}
/* write common header, sub header and elf note to vmcore */
static void create_header64(DumpState *s, Error **errp)
{
ERRP_GUARD();
DiskDumpHeader64 *dh = NULL;
KdumpSubHeader64 *kh = NULL;
size_t size;
uint32_t block_size;
uint32_t sub_hdr_size;
uint32_t bitmap_blocks;
uint32_t status = 0;
uint64_t offset_note;
/* write common header, the version of kdump-compressed format is 6th */
size = sizeof(DiskDumpHeader64);
dh = g_malloc0(size);
memcpy(dh->signature, KDUMP_SIGNATURE, SIG_LEN);
dh->header_version = cpu_to_dump32(s, 6);
block_size = s->dump_info.page_size;
dh->block_size = cpu_to_dump32(s, block_size);
sub_hdr_size = sizeof(struct KdumpSubHeader64) + s->note_size;
sub_hdr_size = DIV_ROUND_UP(sub_hdr_size, block_size);
dh->sub_hdr_size = cpu_to_dump32(s, sub_hdr_size);
/* dh->max_mapnr may be truncated, full 64bit is in kh.max_mapnr_64 */
dh->max_mapnr = cpu_to_dump32(s, MIN(s->max_mapnr, UINT_MAX));
dh->nr_cpus = cpu_to_dump32(s, s->nr_cpus);
bitmap_blocks = DIV_ROUND_UP(s->len_dump_bitmap, block_size) * 2;
dh->bitmap_blocks = cpu_to_dump32(s, bitmap_blocks);
strncpy(dh->utsname.machine, ELF_MACHINE_UNAME, sizeof(dh->utsname.machine));
if (s->flag_compress & DUMP_DH_COMPRESSED_ZLIB) {
status |= DUMP_DH_COMPRESSED_ZLIB;
}
#ifdef CONFIG_LZO
if (s->flag_compress & DUMP_DH_COMPRESSED_LZO) {
status |= DUMP_DH_COMPRESSED_LZO;
}
#endif
#ifdef CONFIG_SNAPPY
if (s->flag_compress & DUMP_DH_COMPRESSED_SNAPPY) {
status |= DUMP_DH_COMPRESSED_SNAPPY;
}
#endif
dh->status = cpu_to_dump32(s, status);
if (write_buffer(s->fd, 0, dh, size) < 0) {
error_setg(errp, "dump: failed to write disk dump header");
goto out;
}
/* write sub header */
size = sizeof(KdumpSubHeader64);
kh = g_malloc0(size);
/* 64bit max_mapnr_64 */
kh->max_mapnr_64 = cpu_to_dump64(s, s->max_mapnr);
kh->phys_base = cpu_to_dump64(s, s->dump_info.phys_base);
kh->dump_level = cpu_to_dump32(s, DUMP_LEVEL);
offset_note = DISKDUMP_HEADER_BLOCKS * block_size + size;
if (s->guest_note &&
note_name_equal(s, s->guest_note, "VMCOREINFO")) {
uint64_t hsize, name_size, size_vmcoreinfo_desc, offset_vmcoreinfo;
get_note_sizes(s, s->guest_note,
&hsize, &name_size, &size_vmcoreinfo_desc);
offset_vmcoreinfo = offset_note + s->note_size - s->guest_note_size +
(DIV_ROUND_UP(hsize, 4) + DIV_ROUND_UP(name_size, 4)) * 4;
kh->offset_vmcoreinfo = cpu_to_dump64(s, offset_vmcoreinfo);
kh->size_vmcoreinfo = cpu_to_dump64(s, size_vmcoreinfo_desc);
}
kh->offset_note = cpu_to_dump64(s, offset_note);
kh->note_size = cpu_to_dump64(s, s->note_size);
if (write_buffer(s->fd, DISKDUMP_HEADER_BLOCKS *
block_size, kh, size) < 0) {
error_setg(errp, "dump: failed to write kdump sub header");
goto out;
}
/* write note */
s->note_buf = g_malloc0(s->note_size);
s->note_buf_offset = 0;
/* use s->note_buf to store notes temporarily */
write_elf64_notes(buf_write_note, s, errp);
if (*errp) {
goto out;
}
if (write_buffer(s->fd, offset_note, s->note_buf,
s->note_size) < 0) {
error_setg(errp, "dump: failed to write notes");
goto out;
}
/* get offset of dump_bitmap */
s->offset_dump_bitmap = (DISKDUMP_HEADER_BLOCKS + sub_hdr_size) *
block_size;
/* get offset of page */
s->offset_page = (DISKDUMP_HEADER_BLOCKS + sub_hdr_size + bitmap_blocks) *
block_size;
out:
g_free(dh);
g_free(kh);
g_free(s->note_buf);
}
static void write_dump_header(DumpState *s, Error **errp)
{
if (dump_is_64bit(s)) {
create_header64(s, errp);
} else {
create_header32(s, errp);
}
}
static size_t dump_bitmap_get_bufsize(DumpState *s)
{
return s->dump_info.page_size;
}
/*
* set dump_bitmap sequencely. the bit before last_pfn is not allowed to be
* rewritten, so if need to set the first bit, set last_pfn and pfn to 0.
* set_dump_bitmap will always leave the recently set bit un-sync. And setting
* (last bit + sizeof(buf) * 8) to 0 will do flushing the content in buf into
* vmcore, ie. synchronizing un-sync bit into vmcore.
*/
static int set_dump_bitmap(uint64_t last_pfn, uint64_t pfn, bool value,
uint8_t *buf, DumpState *s)
{
off_t old_offset, new_offset;
off_t offset_bitmap1, offset_bitmap2;
uint32_t byte, bit;
size_t bitmap_bufsize = dump_bitmap_get_bufsize(s);
size_t bits_per_buf = bitmap_bufsize * CHAR_BIT;
/* should not set the previous place */
assert(last_pfn <= pfn);
/*
* if the bit needed to be set is not cached in buf, flush the data in buf
* to vmcore firstly.
* making new_offset be bigger than old_offset can also sync remained data
* into vmcore.
*/
old_offset = bitmap_bufsize * (last_pfn / bits_per_buf);
new_offset = bitmap_bufsize * (pfn / bits_per_buf);
while (old_offset < new_offset) {
/* calculate the offset and write dump_bitmap */
offset_bitmap1 = s->offset_dump_bitmap + old_offset;
if (write_buffer(s->fd, offset_bitmap1, buf,
bitmap_bufsize) < 0) {
return -1;
}
/* dump level 1 is chosen, so 1st and 2nd bitmap are same */
offset_bitmap2 = s->offset_dump_bitmap + s->len_dump_bitmap +
old_offset;
if (write_buffer(s->fd, offset_bitmap2, buf,
bitmap_bufsize) < 0) {
return -1;
}
memset(buf, 0, bitmap_bufsize);
old_offset += bitmap_bufsize;
}
/* get the exact place of the bit in the buf, and set it */
byte = (pfn % bits_per_buf) / CHAR_BIT;
bit = (pfn % bits_per_buf) % CHAR_BIT;
if (value) {
buf[byte] |= 1u << bit;
} else {
buf[byte] &= ~(1u << bit);
}
return 0;
}
static uint64_t dump_paddr_to_pfn(DumpState *s, uint64_t addr)
{
int target_page_shift = ctz32(s->dump_info.page_size);
return (addr >> target_page_shift) - ARCH_PFN_OFFSET;
}
static uint64_t dump_pfn_to_paddr(DumpState *s, uint64_t pfn)
{
int target_page_shift = ctz32(s->dump_info.page_size);
return (pfn + ARCH_PFN_OFFSET) << target_page_shift;
}
/*
* Return the page frame number and the page content in *bufptr. bufptr can be
* NULL. If not NULL, *bufptr must contains a target page size of pre-allocated
* memory. This is not necessarily the memory returned.
*/
static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr,
uint8_t **bufptr, DumpState *s)
{
GuestPhysBlock *block = *blockptr;
uint32_t page_size = s->dump_info.page_size;
uint8_t *buf = NULL, *hbuf;
hwaddr addr;
/* block == NULL means the start of the iteration */
if (!block) {
block = QTAILQ_FIRST(&s->guest_phys_blocks.head);
*blockptr = block;
addr = block->target_start;
*pfnptr = dump_paddr_to_pfn(s, addr);
} else {
*pfnptr += 1;
addr = dump_pfn_to_paddr(s, *pfnptr);
}
assert(block != NULL);
while (1) {
if (addr >= block->target_start && addr < block->target_end) {
size_t n = MIN(block->target_end - addr, page_size - addr % page_size);
hbuf = block->host_addr + (addr - block->target_start);
if (!buf) {
if (n == page_size) {
/* this is a whole target page, go for it */
assert(addr % page_size == 0);
buf = hbuf;
break;
} else if (bufptr) {
assert(*bufptr);
buf = *bufptr;
memset(buf, 0, page_size);
} else {
return true;
}
}
memcpy(buf + addr % page_size, hbuf, n);
addr += n;
if (addr % page_size == 0) {
/* we filled up the page */
break;
}
} else {
/* the next page is in the next block */
*blockptr = block = QTAILQ_NEXT(block, next);
if (!block) {
break;
}
addr = block->target_start;
/* are we still in the same page? */
if (dump_paddr_to_pfn(s, addr) != *pfnptr) {
if (buf) {
/* no, but we already filled something earlier, return it */
break;
} else {
/* else continue from there */
*pfnptr = dump_paddr_to_pfn(s, addr);
}
}
}
}
if (bufptr) {
*bufptr = buf;
}
return buf != NULL;
}
static void write_dump_bitmap(DumpState *s, Error **errp)
{
int ret = 0;
uint64_t last_pfn, pfn;
void *dump_bitmap_buf;
size_t num_dumpable;
GuestPhysBlock *block_iter = NULL;
size_t bitmap_bufsize = dump_bitmap_get_bufsize(s);
size_t bits_per_buf = bitmap_bufsize * CHAR_BIT;
/* dump_bitmap_buf is used to store dump_bitmap temporarily */
dump_bitmap_buf = g_malloc0(bitmap_bufsize);
num_dumpable = 0;
last_pfn = 0;
/*
* exam memory page by page, and set the bit in dump_bitmap corresponded
* to the existing page.
*/
while (get_next_page(&block_iter, &pfn, NULL, s)) {
ret = set_dump_bitmap(last_pfn, pfn, true, dump_bitmap_buf, s);
if (ret < 0) {
error_setg(errp, "dump: failed to set dump_bitmap");
goto out;
}
last_pfn = pfn;
num_dumpable++;
}
/*
* set_dump_bitmap will always leave the recently set bit un-sync. Here we
* set the remaining bits from last_pfn to the end of the bitmap buffer to
* 0. With those set, the un-sync bit will be synchronized into the vmcore.
*/
if (num_dumpable > 0) {
ret = set_dump_bitmap(last_pfn, last_pfn + bits_per_buf, false,
dump_bitmap_buf, s);
if (ret < 0) {
error_setg(errp, "dump: failed to sync dump_bitmap");
goto out;
}
}
/* number of dumpable pages that will be dumped later */
s->num_dumpable = num_dumpable;
out:
g_free(dump_bitmap_buf);
}
static void prepare_data_cache(DataCache *data_cache, DumpState *s,
off_t offset)
{
data_cache->fd = s->fd;
data_cache->data_size = 0;
data_cache->buf_size = 4 * dump_bitmap_get_bufsize(s);
data_cache->buf = g_malloc0(data_cache->buf_size);
data_cache->offset = offset;
}
static int write_cache(DataCache *dc, const void *buf, size_t size,
bool flag_sync)
{
/*
* dc->buf_size should not be less than size, otherwise dc will never be
* enough
*/
assert(size <= dc->buf_size);
/*
* if flag_sync is set, synchronize data in dc->buf into vmcore.
* otherwise check if the space is enough for caching data in buf, if not,
* write the data in dc->buf to dc->fd and reset dc->buf
*/
if ((!flag_sync && dc->data_size + size > dc->buf_size) ||
(flag_sync && dc->data_size > 0)) {
if (write_buffer(dc->fd, dc->offset, dc->buf, dc->data_size) < 0) {
return -1;
}
dc->offset += dc->data_size;
dc->data_size = 0;
}
if (!flag_sync) {
memcpy(dc->buf + dc->data_size, buf, size);
dc->data_size += size;
}
return 0;
}
static void free_data_cache(DataCache *data_cache)
{
g_free(data_cache->buf);
}
static size_t get_len_buf_out(size_t page_size, uint32_t flag_compress)
{
switch (flag_compress) {
case DUMP_DH_COMPRESSED_ZLIB:
return compressBound(page_size);
case DUMP_DH_COMPRESSED_LZO:
/*
* LZO will expand incompressible data by a little amount. Please check
* the following URL to see the expansion calculation:
* http://www.oberhumer.com/opensource/lzo/lzofaq.php
*/
return page_size + page_size / 16 + 64 + 3;
#ifdef CONFIG_SNAPPY
case DUMP_DH_COMPRESSED_SNAPPY:
return snappy_max_compressed_length(page_size);
#endif
}
return 0;
}
static void write_dump_pages(DumpState *s, Error **errp)
{
int ret = 0;
DataCache page_desc, page_data;
size_t len_buf_out, size_out;
#ifdef CONFIG_LZO
lzo_bytep wrkmem = NULL;
#endif
uint8_t *buf_out = NULL;
off_t offset_desc, offset_data;
PageDescriptor pd, pd_zero;
uint8_t *buf;
GuestPhysBlock *block_iter = NULL;
uint64_t pfn_iter;
g_autofree uint8_t *page = NULL;
/* get offset of page_desc and page_data in dump file */
offset_desc = s->offset_page;
offset_data = offset_desc + sizeof(PageDescriptor) * s->num_dumpable;
prepare_data_cache(&page_desc, s, offset_desc);
prepare_data_cache(&page_data, s, offset_data);
/* prepare buffer to store compressed data */
len_buf_out = get_len_buf_out(s->dump_info.page_size, s->flag_compress);
assert(len_buf_out != 0);
#ifdef CONFIG_LZO
wrkmem = g_malloc(LZO1X_1_MEM_COMPRESS);
#endif
buf_out = g_malloc(len_buf_out);
/*
* init zero page's page_desc and page_data, because every zero page
* uses the same page_data
*/
pd_zero.size = cpu_to_dump32(s, s->dump_info.page_size);
pd_zero.flags = cpu_to_dump32(s, 0);
pd_zero.offset = cpu_to_dump64(s, offset_data);
pd_zero.page_flags = cpu_to_dump64(s, 0);
buf = g_malloc0(s->dump_info.page_size);
ret = write_cache(&page_data, buf, s->dump_info.page_size, false);
g_free(buf);
if (ret < 0) {
error_setg(errp, "dump: failed to write page data (zero page)");
goto out;
}
offset_data += s->dump_info.page_size;
page = g_malloc(s->dump_info.page_size);
/*
* dump memory to vmcore page by page. zero page will all be resided in the
* first page of page section
*/
for (buf = page; get_next_page(&block_iter, &pfn_iter, &buf, s); buf = page) {
/* check zero page */
if (buffer_is_zero(buf, s->dump_info.page_size)) {
ret = write_cache(&page_desc, &pd_zero, sizeof(PageDescriptor),
false);
if (ret < 0) {
error_setg(errp, "dump: failed to write page desc");
goto out;
}
} else {
/*
* not zero page, then:
* 1. compress the page
* 2. write the compressed page into the cache of page_data
* 3. get page desc of the compressed page and write it into the
* cache of page_desc
*
* only one compression format will be used here, for
* s->flag_compress is set. But when compression fails to work,
* we fall back to save in plaintext.
*/
size_out = len_buf_out;
if ((s->flag_compress & DUMP_DH_COMPRESSED_ZLIB) &&
(compress2(buf_out, (uLongf *)&size_out, buf,
s->dump_info.page_size, Z_BEST_SPEED) == Z_OK) &&
(size_out < s->dump_info.page_size)) {
pd.flags = cpu_to_dump32(s, DUMP_DH_COMPRESSED_ZLIB);
pd.size = cpu_to_dump32(s, size_out);
ret = write_cache(&page_data, buf_out, size_out, false);
if (ret < 0) {
error_setg(errp, "dump: failed to write page data");
goto out;
}
#ifdef CONFIG_LZO
} else if ((s->flag_compress & DUMP_DH_COMPRESSED_LZO) &&
(lzo1x_1_compress(buf, s->dump_info.page_size, buf_out,
(lzo_uint *)&size_out, wrkmem) == LZO_E_OK) &&
(size_out < s->dump_info.page_size)) {
pd.flags = cpu_to_dump32(s, DUMP_DH_COMPRESSED_LZO);
pd.size = cpu_to_dump32(s, size_out);
ret = write_cache(&page_data, buf_out, size_out, false);
if (ret < 0) {
error_setg(errp, "dump: failed to write page data");
goto out;
}
#endif
#ifdef CONFIG_SNAPPY
} else if ((s->flag_compress & DUMP_DH_COMPRESSED_SNAPPY) &&
(snappy_compress((char *)buf, s->dump_info.page_size,
(char *)buf_out, &size_out) == SNAPPY_OK) &&
(size_out < s->dump_info.page_size)) {
pd.flags = cpu_to_dump32(s, DUMP_DH_COMPRESSED_SNAPPY);
pd.size = cpu_to_dump32(s, size_out);
ret = write_cache(&page_data, buf_out, size_out, false);
if (ret < 0) {
error_setg(errp, "dump: failed to write page data");
goto out;
}
#endif
} else {
/*
* fall back to save in plaintext, size_out should be
* assigned the target's page size
*/
pd.flags = cpu_to_dump32(s, 0);
size_out = s->dump_info.page_size;
pd.size = cpu_to_dump32(s, size_out);
ret = write_cache(&page_data, buf,
s->dump_info.page_size, false);
if (ret < 0) {
error_setg(errp, "dump: failed to write page data");
goto out;
}
}
/* get and write page desc here */
pd.page_flags = cpu_to_dump64(s, 0);
pd.offset = cpu_to_dump64(s, offset_data);
offset_data += size_out;
ret = write_cache(&page_desc, &pd, sizeof(PageDescriptor), false);
if (ret < 0) {
error_setg(errp, "dump: failed to write page desc");
goto out;
}
}
s->written_size += s->dump_info.page_size;
}
ret = write_cache(&page_desc, NULL, 0, true);
if (ret < 0) {
error_setg(errp, "dump: failed to sync cache for page_desc");
goto out;
}
ret = write_cache(&page_data, NULL, 0, true);
if (ret < 0) {
error_setg(errp, "dump: failed to sync cache for page_data");
goto out;
}
out:
free_data_cache(&page_desc);
free_data_cache(&page_data);
#ifdef CONFIG_LZO
g_free(wrkmem);
#endif
g_free(buf_out);
}
static void create_kdump_vmcore(DumpState *s, Error **errp)
{
ERRP_GUARD();
int ret;
/*
* the kdump-compressed format is:
* File offset
* +------------------------------------------+ 0x0
* | main header (struct disk_dump_header) |
* |------------------------------------------+ block 1
* | sub header (struct kdump_sub_header) |
* |------------------------------------------+ block 2
* | 1st-dump_bitmap |
* |------------------------------------------+ block 2 + X blocks
* | 2nd-dump_bitmap | (aligned by block)
* |------------------------------------------+ block 2 + 2 * X blocks
* | page desc for pfn 0 (struct page_desc) | (aligned by block)
* | page desc for pfn 1 (struct page_desc) |
* | : |
* |------------------------------------------| (not aligned by block)
* | page data (pfn 0) |
* | page data (pfn 1) |
* | : |
* +------------------------------------------+
*/
ret = write_start_flat_header(s->fd);
if (ret < 0) {
error_setg(errp, "dump: failed to write start flat header");
return;
}
write_dump_header(s, errp);
if (*errp) {
return;
}
write_dump_bitmap(s, errp);
if (*errp) {
return;
}
write_dump_pages(s, errp);
if (*errp) {
return;
}
ret = write_end_flat_header(s->fd);
if (ret < 0) {
error_setg(errp, "dump: failed to write end flat header");
return;
}
}
static int validate_start_block(DumpState *s)
{
GuestPhysBlock *block;
if (!dump_has_filter(s)) {
return 0;
}
QTAILQ_FOREACH(block, &s->guest_phys_blocks.head, next) {
/* This block is out of the range */
if (block->target_start >= s->filter_area_begin + s->filter_area_length ||
block->target_end <= s->filter_area_begin) {
continue;
}
return 0;
}
return -1;
}
static void get_max_mapnr(DumpState *s)
{
GuestPhysBlock *last_block;
last_block = QTAILQ_LAST(&s->guest_phys_blocks.head);
s->max_mapnr = dump_paddr_to_pfn(s, last_block->target_end);
}
static DumpState dump_state_global = { .status = DUMP_STATUS_NONE };
static void dump_state_prepare(DumpState *s)
{
/* zero the struct, setting status to active */
*s = (DumpState) { .status = DUMP_STATUS_ACTIVE };
}
bool qemu_system_dump_in_progress(void)
{
DumpState *state = &dump_state_global;
return (qatomic_read(&state->status) == DUMP_STATUS_ACTIVE);
}
/*
* calculate total size of memory to be dumped (taking filter into
* account.)
*/
static int64_t dump_calculate_size(DumpState *s)
{
GuestPhysBlock *block;
int64_t total = 0;
QTAILQ_FOREACH(block, &s->guest_phys_blocks.head, next) {
total += dump_filtered_memblock_size(block,
s->filter_area_begin,
s->filter_area_length);
}
return total;
}
static void vmcoreinfo_update_phys_base(DumpState *s)
{
uint64_t size, note_head_size, name_size, phys_base;
char **lines;
uint8_t *vmci;
size_t i;
if (!note_name_equal(s, s->guest_note, "VMCOREINFO")) {
return;
}
get_note_sizes(s, s->guest_note, &note_head_size, &name_size, &size);
note_head_size = ROUND_UP(note_head_size, 4);
vmci = s->guest_note + note_head_size + ROUND_UP(name_size, 4);
*(vmci + size) = '\0';
lines = g_strsplit((char *)vmci, "\n", -1);
for (i = 0; lines[i]; i++) {
const char *prefix = NULL;
if (s->dump_info.d_machine == EM_X86_64) {
prefix = "NUMBER(phys_base)=";
} else if (s->dump_info.d_machine == EM_AARCH64) {
prefix = "NUMBER(PHYS_OFFSET)=";
}
if (prefix && g_str_has_prefix(lines[i], prefix)) {
if (qemu_strtou64(lines[i] + strlen(prefix), NULL, 16,
&phys_base) < 0) {
warn_report("Failed to read %s", prefix);
} else {
s->dump_info.phys_base = phys_base;
}
break;
}
}
g_strfreev(lines);
}
static void dump_init(DumpState *s, int fd, bool has_format,
DumpGuestMemoryFormat format, bool paging, bool has_filter,
int64_t begin, int64_t length, Error **errp)
{
ERRP_GUARD();
VMCoreInfoState *vmci = vmcoreinfo_find();
CPUState *cpu;
int nr_cpus;
int ret;
s->has_format = has_format;
s->format = format;
s->written_size = 0;
/* kdump-compressed is conflict with paging and filter */
if (has_format && format != DUMP_GUEST_MEMORY_FORMAT_ELF) {
assert(!paging && !has_filter);
}
if (runstate_is_running()) {
vm_stop(RUN_STATE_SAVE_VM);
s->resume = true;
} else {
s->resume = false;
}
/* If we use KVM, we should synchronize the registers before we get dump
* info or physmap info.
*/
cpu_synchronize_all_states();
nr_cpus = 0;
CPU_FOREACH(cpu) {
nr_cpus++;
}
s->fd = fd;
if (has_filter && !length) {
error_setg(errp, QERR_INVALID_PARAMETER, "length");
goto cleanup;
}
s->filter_area_begin = begin;
s->filter_area_length = length;
/* First index is 0, it's the special null name */
s->string_table_buf = g_array_new(FALSE, TRUE, 1);
/*
* Allocate the null name, due to the clearing option set to true
* it will be 0.
*/
g_array_set_size(s->string_table_buf, 1);
memory_mapping_list_init(&s->list);
guest_phys_blocks_init(&s->guest_phys_blocks);
guest_phys_blocks_append(&s->guest_phys_blocks);
s->total_size = dump_calculate_size(s);
#ifdef DEBUG_DUMP_GUEST_MEMORY
fprintf(stderr, "DUMP: total memory to dump: %lu\n", s->total_size);
#endif
/* it does not make sense to dump non-existent memory */
if (!s->total_size) {
error_setg(errp, "dump: no guest memory to dump");
goto cleanup;
}
/* Is the filter filtering everything? */
if (validate_start_block(s) == -1) {
error_setg(errp, QERR_INVALID_PARAMETER, "begin");
goto cleanup;
}
/* get dump info: endian, class and architecture.
* If the target architecture is not supported, cpu_get_dump_info() will
* return -1.
*/
ret = cpu_get_dump_info(&s->dump_info, &s->guest_phys_blocks);
if (ret < 0) {
error_setg(errp, QERR_UNSUPPORTED);
goto cleanup;
}
if (!s->dump_info.page_size) {
s->dump_info.page_size = TARGET_PAGE_SIZE;
}
s->note_size = cpu_get_note_size(s->dump_info.d_class,
s->dump_info.d_machine, nr_cpus);
if (s->note_size < 0) {
error_setg(errp, QERR_UNSUPPORTED);
goto cleanup;
}
/*
* The goal of this block is to (a) update the previously guessed
* phys_base, (b) copy the guest note out of the guest.
* Failure to do so is not fatal for dumping.
*/
if (vmci) {
uint64_t addr, note_head_size, name_size, desc_size;
uint32_t size;
uint16_t format;
note_head_size = dump_is_64bit(s) ?
sizeof(Elf64_Nhdr) : sizeof(Elf32_Nhdr);
format = le16_to_cpu(vmci->vmcoreinfo.guest_format);
size = le32_to_cpu(vmci->vmcoreinfo.size);
addr = le64_to_cpu(vmci->vmcoreinfo.paddr);
if (!vmci->has_vmcoreinfo) {
warn_report("guest note is not present");
} else if (size < note_head_size || size > MAX_GUEST_NOTE_SIZE) {
warn_report("guest note size is invalid: %" PRIu32, size);
} else if (format != FW_CFG_VMCOREINFO_FORMAT_ELF) {
warn_report("guest note format is unsupported: %" PRIu16, format);
} else {
s->guest_note = g_malloc(size + 1); /* +1 for adding \0 */
cpu_physical_memory_read(addr, s->guest_note, size);
get_note_sizes(s, s->guest_note, NULL, &name_size, &desc_size);
s->guest_note_size = ELF_NOTE_SIZE(note_head_size, name_size,
desc_size);
if (name_size > MAX_GUEST_NOTE_SIZE ||
desc_size > MAX_GUEST_NOTE_SIZE ||
s->guest_note_size > size) {
warn_report("Invalid guest note header");
g_free(s->guest_note);
s->guest_note = NULL;
} else {
vmcoreinfo_update_phys_base(s);
s->note_size += s->guest_note_size;
}
}
}
/* get memory mapping */
if (paging) {
qemu_get_guest_memory_mapping(&s->list, &s->guest_phys_blocks, errp);
if (*errp) {
goto cleanup;
}
} else {
qemu_get_guest_simple_memory_mapping(&s->list, &s->guest_phys_blocks);
}
s->nr_cpus = nr_cpus;
get_max_mapnr(s);
uint64_t tmp;
tmp = DIV_ROUND_UP(DIV_ROUND_UP(s->max_mapnr, CHAR_BIT),
s->dump_info.page_size);
s->len_dump_bitmap = tmp * s->dump_info.page_size;
/* init for kdump-compressed format */
if (has_format && format != DUMP_GUEST_MEMORY_FORMAT_ELF) {
switch (format) {
case DUMP_GUEST_MEMORY_FORMAT_KDUMP_ZLIB:
s->flag_compress = DUMP_DH_COMPRESSED_ZLIB;
break;
case DUMP_GUEST_MEMORY_FORMAT_KDUMP_LZO:
#ifdef CONFIG_LZO
if (lzo_init() != LZO_E_OK) {
error_setg(errp, "failed to initialize the LZO library");
goto cleanup;
}
#endif
s->flag_compress = DUMP_DH_COMPRESSED_LZO;
break;
case DUMP_GUEST_MEMORY_FORMAT_KDUMP_SNAPPY:
s->flag_compress = DUMP_DH_COMPRESSED_SNAPPY;
break;
default:
s->flag_compress = 0;
}
return;
}
if (dump_has_filter(s)) {
memory_mapping_filter(&s->list, s->filter_area_begin, s->filter_area_length);
}
/*
* The first section header is always a special one in which most
* fields are 0. The section header string table is also always
* set.
*/
s->shdr_num = 2;
/*
* Adds the number of architecture sections to shdr_num and sets
* elf_section_data_size so we know the offsets and sizes of all
* parts.
*/
if (s->dump_info.arch_sections_add_fn) {
s->dump_info.arch_sections_add_fn(s);
}
/*
* calculate shdr_num so we know the offsets and sizes of all
* parts.
* Calculate phdr_num
*
* The absolute maximum amount of phdrs is UINT32_MAX - 1 as
* sh_info is 32 bit. There's special handling once we go over
* UINT16_MAX - 1 but that is handled in the ehdr and section
* code.
*/
s->phdr_num = 1; /* Reserve PT_NOTE */
if (s->list.num <= UINT32_MAX - 1) {
s->phdr_num += s->list.num;
} else {
s->phdr_num = UINT32_MAX;
}
/*
* Now that the number of section and program headers is known we
* can calculate the offsets of the headers and data.
*/
if (dump_is_64bit(s)) {
s->shdr_offset = sizeof(Elf64_Ehdr);
s->phdr_offset = s->shdr_offset + sizeof(Elf64_Shdr) * s->shdr_num;
s->note_offset = s->phdr_offset + sizeof(Elf64_Phdr) * s->phdr_num;
} else {
s->shdr_offset = sizeof(Elf32_Ehdr);
s->phdr_offset = s->shdr_offset + sizeof(Elf32_Shdr) * s->shdr_num;
s->note_offset = s->phdr_offset + sizeof(Elf32_Phdr) * s->phdr_num;
}
s->memory_offset = s->note_offset + s->note_size;
s->section_offset = s->memory_offset + s->total_size;
return;
cleanup:
dump_cleanup(s);
}
/* this operation might be time consuming. */
static void dump_process(DumpState *s, Error **errp)
{
ERRP_GUARD();
DumpQueryResult *result = NULL;
if (s->has_format && s->format == DUMP_GUEST_MEMORY_FORMAT_WIN_DMP) {
#ifdef TARGET_X86_64
create_win_dump(s, errp);
#endif
} else if (s->has_format && s->format != DUMP_GUEST_MEMORY_FORMAT_ELF) {
create_kdump_vmcore(s, errp);
} else {
create_vmcore(s, errp);
}
/* make sure status is written after written_size updates */
smp_wmb();
qatomic_set(&s->status,
(*errp ? DUMP_STATUS_FAILED : DUMP_STATUS_COMPLETED));
/* send DUMP_COMPLETED message (unconditionally) */
result = qmp_query_dump(NULL);
/* should never fail */
assert(result);
qapi_event_send_dump_completed(result, !!*errp, (*errp ?
error_get_pretty(*errp) : NULL));
qapi_free_DumpQueryResult(result);
dump_cleanup(s);
}
static void *dump_thread(void *data)
{
DumpState *s = (DumpState *)data;
dump_process(s, NULL);
return NULL;
}
DumpQueryResult *qmp_query_dump(Error **errp)
{
DumpQueryResult *result = g_new(DumpQueryResult, 1);
DumpState *state = &dump_state_global;
result->status = qatomic_read(&state->status);
/* make sure we are reading status and written_size in order */
smp_rmb();
result->completed = state->written_size;
result->total = state->total_size;
return result;
}
void qmp_dump_guest_memory(bool paging, const char *file,
bool has_detach, bool detach,
bool has_begin, int64_t begin, bool has_length,
int64_t length, bool has_format,
DumpGuestMemoryFormat format, Error **errp)
{
ERRP_GUARD();
const char *p;
int fd = -1;
DumpState *s;
bool detach_p = false;
if (runstate_check(RUN_STATE_INMIGRATE)) {
error_setg(errp, "Dump not allowed during incoming migration.");
return;
}
/* if there is a dump in background, we should wait until the dump
* finished */
if (qemu_system_dump_in_progress()) {
error_setg(errp, "There is a dump in process, please wait.");
return;
}
/*
* kdump-compressed format need the whole memory dumped, so paging or
* filter is not supported here.
*/
if ((has_format && format != DUMP_GUEST_MEMORY_FORMAT_ELF) &&
(paging || has_begin || has_length)) {
error_setg(errp, "kdump-compressed format doesn't support paging or "
"filter");
return;
}
if (has_begin && !has_length) {
error_setg(errp, QERR_MISSING_PARAMETER, "length");
return;
}
if (!has_begin && has_length) {
error_setg(errp, QERR_MISSING_PARAMETER, "begin");
return;
}
if (has_detach) {
detach_p = detach;
}
/* check whether lzo/snappy is supported */
#ifndef CONFIG_LZO
if (has_format && format == DUMP_GUEST_MEMORY_FORMAT_KDUMP_LZO) {
error_setg(errp, "kdump-lzo is not available now");
return;
}
#endif
#ifndef CONFIG_SNAPPY
if (has_format && format == DUMP_GUEST_MEMORY_FORMAT_KDUMP_SNAPPY) {
error_setg(errp, "kdump-snappy is not available now");
return;
}
#endif
#ifndef TARGET_X86_64
if (has_format && format == DUMP_GUEST_MEMORY_FORMAT_WIN_DMP) {
error_setg(errp, "Windows dump is only available for x86-64");
return;
}
#endif
#if !defined(WIN32)
if (strstart(file, "fd:", &p)) {
fd = monitor_get_fd(monitor_cur(), p, errp);
if (fd == -1) {
return;
}
}
#endif
if (strstart(file, "file:", &p)) {
fd = qemu_open_old(p, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, S_IRUSR);
if (fd < 0) {
error_setg_file_open(errp, errno, p);
return;
}
}
if (fd == -1) {
error_setg(errp, QERR_INVALID_PARAMETER, "protocol");
return;
}
if (!dump_migration_blocker) {
error_setg(&dump_migration_blocker,
"Live migration disabled: dump-guest-memory in progress");
}
/*
* Allows even for -only-migratable, but forbid migration during the
* process of dump guest memory.
*/
if (migrate_add_blocker_internal(dump_migration_blocker, errp)) {
/* Remember to release the fd before passing it over to dump state */
close(fd);
return;
}
s = &dump_state_global;
dump_state_prepare(s);
dump_init(s, fd, has_format, format, paging, has_begin,
begin, length, errp);
if (*errp) {
qatomic_set(&s->status, DUMP_STATUS_FAILED);
return;
}
if (detach_p) {
/* detached dump */
s->detached = true;
qemu_thread_create(&s->dump_thread, "dump_thread", dump_thread,
s, QEMU_THREAD_DETACHED);
} else {
/* sync dump */
dump_process(s, errp);
}
}
DumpGuestMemoryCapability *qmp_query_dump_guest_memory_capability(Error **errp)
{
DumpGuestMemoryCapability *cap =
g_new0(DumpGuestMemoryCapability, 1);
DumpGuestMemoryFormatList **tail = &cap->formats;
/* elf is always available */
QAPI_LIST_APPEND(tail, DUMP_GUEST_MEMORY_FORMAT_ELF);
/* kdump-zlib is always available */
QAPI_LIST_APPEND(tail, DUMP_GUEST_MEMORY_FORMAT_KDUMP_ZLIB);
/* add new item if kdump-lzo is available */
#ifdef CONFIG_LZO
QAPI_LIST_APPEND(tail, DUMP_GUEST_MEMORY_FORMAT_KDUMP_LZO);
#endif
/* add new item if kdump-snappy is available */
#ifdef CONFIG_SNAPPY
QAPI_LIST_APPEND(tail, DUMP_GUEST_MEMORY_FORMAT_KDUMP_SNAPPY);
#endif
/* Windows dump is available only if target is x86_64 */
#ifdef TARGET_X86_64
QAPI_LIST_APPEND(tail, DUMP_GUEST_MEMORY_FORMAT_WIN_DMP);
#endif
return cap;
}
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