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usr.sbin/bhyve/snapshot.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2016 Flavius Anton
* Copyright (c) 2016 Mihai Tiganus
* Copyright (c) 2016-2019 Mihai Carabas
* Copyright (c) 2017-2019 Darius Mihai
* Copyright (c) 2017-2019 Elena Mihailescu
* Copyright (c) 2018-2019 Sergiu Weisz
* All rights reserved.
* The bhyve-snapshot feature was developed under sponsorships
* from Matthew Grooms.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#ifndef WITHOUT_CAPSICUM
#include <sys/capsicum.h>
#endif
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/un.h>
#include <machine/atomic.h>
#include <machine/segments.h>
#ifndef WITHOUT_CAPSICUM
#include <capsicum_helpers.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>
#include <pthread.h>
#include <pthread_np.h>
#include <sysexits.h>
#include <stdbool.h>
#include <machine/vmm.h>
#ifndef WITHOUT_CAPSICUM
#include <machine/vmm_dev.h>
#endif
#include <machine/vmm_snapshot.h>
#include <vmmapi.h>
#include "bhyverun.h"
#include "acpi.h"
#include "atkbdc.h"
#include "inout.h"
#include "dbgport.h"
#include "fwctl.h"
#include "ioapic.h"
#include "mem.h"
#include "mevent.h"
#include "mptbl.h"
#include "pci_emul.h"
#include "pci_irq.h"
#include "pci_lpc.h"
#include "smbiostbl.h"
#include "snapshot.h"
#include "xmsr.h"
#include "spinup_ap.h"
#include "rtc.h"
#include <libxo/xo.h>
#include <ucl.h>
extern int guest_ncpus;
#define MB (1024UL * 1024)
#define GB (1024UL * MB)
#define BHYVE_RUN_DIR "/var/run/bhyve"
#define CHECKPOINT_RUN_DIR BHYVE_RUN_DIR "/checkpoint"
#define MAX_VMNAME 100
#define MAX_MSG_SIZE 1024
#define SNAPSHOT_BUFFER_SIZE (20 * MB)
#define JSON_STRUCT_ARR_KEY "structs"
#define JSON_DEV_ARR_KEY "devices"
#define JSON_BASIC_METADATA_KEY "basic metadata"
#define JSON_SNAPSHOT_REQ_KEY "snapshot_req"
#define JSON_SIZE_KEY "size"
#define JSON_FILE_OFFSET_KEY "file_offset"
#define JSON_NCPUS_KEY "ncpus"
#define JSON_VMNAME_KEY "vmname"
#define JSON_MEMSIZE_KEY "memsize"
#define JSON_MEMFLAGS_KEY "memflags"
const struct vm_snapshot_dev_info snapshot_devs[] = {
{ "atkbdc", atkbdc_snapshot, NULL, NULL },
{ "virtio-net", pci_snapshot, pci_pause, pci_resume },
{ "virtio-blk", pci_snapshot, pci_pause, pci_resume },
{ "lpc", pci_snapshot, NULL, NULL },
{ "fbuf", pci_snapshot, NULL, NULL },
{ "xhci", pci_snapshot, NULL, NULL },
{ "e1000", pci_snapshot, NULL, NULL },
{ "ahci", pci_snapshot, pci_pause, pci_resume },
{ "ahci-hd", pci_snapshot, pci_pause, pci_resume },
{ "ahci-cd", pci_snapshot, NULL, NULL },
};
const struct vm_snapshot_kern_info snapshot_kern_structs[] = {
{ "vhpet", STRUCT_VHPET },
{ "vm", STRUCT_VM },
{ "vmx", STRUCT_VMX },
{ "vioapic", STRUCT_VIOAPIC },
{ "vlapic", STRUCT_VLAPIC },
{ "vmcx", STRUCT_VMCX },
{ "vatpit", STRUCT_VATPIT },
{ "vatpic", STRUCT_VATPIC },
{ "vpmtmr", STRUCT_VPMTMR },
{ "vrtc", STRUCT_VRTC },
};
static cpuset_t vcpus_active, vcpus_suspended;
static pthread_mutex_t vcpu_lock;
static pthread_cond_t vcpus_idle, vcpus_can_run;
static bool checkpoint_active;
/*
* TODO: Harden this function and all of its callers since 'base_str' is a user
* provided string.
*/
static char *
strcat_extension(const char *base_str, const char *ext)
{
char *res;
size_t base_len, ext_len;
base_len = strnlen(base_str, MAX_VMNAME);
ext_len = strnlen(ext, MAX_VMNAME);
if (base_len + ext_len > MAX_VMNAME) {
fprintf(stderr, "Filename exceeds maximum length.\n");
return (NULL);
}
res = malloc(base_len + ext_len + 1);
if (res == NULL) {
perror("Failed to allocate memory.");
return (NULL);
}
memcpy(res, base_str, base_len);
memcpy(res + base_len, ext, ext_len);
res[base_len + ext_len] = 0;
return (res);
}
void
destroy_restore_state(struct restore_state *rstate)
{
if (rstate == NULL) {
fprintf(stderr, "Attempting to destroy NULL restore struct.\n");
return;
}
if (rstate->kdata_map != MAP_FAILED)
munmap(rstate->kdata_map, rstate->kdata_len);
if (rstate->kdata_fd > 0)
close(rstate->kdata_fd);
if (rstate->vmmem_fd > 0)
close(rstate->vmmem_fd);
if (rstate->meta_root_obj != NULL)
ucl_object_unref(rstate->meta_root_obj);
if (rstate->meta_parser != NULL)
ucl_parser_free(rstate->meta_parser);
}
static int
load_vmmem_file(const char *filename, struct restore_state *rstate)
{
struct stat sb;
int err;
rstate->vmmem_fd = open(filename, O_RDONLY);
if (rstate->vmmem_fd < 0) {
perror("Failed to open restore file");
return (-1);
}
err = fstat(rstate->vmmem_fd, &sb);
if (err < 0) {
perror("Failed to stat restore file");
goto err_load_vmmem;
}
if (sb.st_size == 0) {
fprintf(stderr, "Restore file is empty.\n");
goto err_load_vmmem;
}
rstate->vmmem_len = sb.st_size;
return (0);
err_load_vmmem:
if (rstate->vmmem_fd > 0)
close(rstate->vmmem_fd);
return (-1);
}
static int
load_kdata_file(const char *filename, struct restore_state *rstate)
{
struct stat sb;
int err;
rstate->kdata_fd = open(filename, O_RDONLY);
if (rstate->kdata_fd < 0) {
perror("Failed to open kernel data file");
return (-1);
}
err = fstat(rstate->kdata_fd, &sb);
if (err < 0) {
perror("Failed to stat kernel data file");
goto err_load_kdata;
}
if (sb.st_size == 0) {
fprintf(stderr, "Kernel data file is empty.\n");
goto err_load_kdata;
}
rstate->kdata_len = sb.st_size;
rstate->kdata_map = mmap(NULL, rstate->kdata_len, PROT_READ,
MAP_SHARED, rstate->kdata_fd, 0);
if (rstate->kdata_map == MAP_FAILED) {
perror("Failed to map restore file");
goto err_load_kdata;
}
return (0);
err_load_kdata:
if (rstate->kdata_fd > 0)
close(rstate->kdata_fd);
return (-1);
}
static int
load_metadata_file(const char *filename, struct restore_state *rstate)
{
const ucl_object_t *obj;
struct ucl_parser *parser;
int err;
parser = ucl_parser_new(UCL_PARSER_DEFAULT);
if (parser == NULL) {
fprintf(stderr, "Failed to initialize UCL parser.\n");
goto err_load_metadata;
}
err = ucl_parser_add_file(parser, filename);
if (err == 0) {
fprintf(stderr, "Failed to parse metadata file: '%s'\n",
filename);
err = -1;
goto err_load_metadata;
}
obj = ucl_parser_get_object(parser);
if (obj == NULL) {
fprintf(stderr, "Failed to parse object.\n");
err = -1;
goto err_load_metadata;
}
rstate->meta_parser = parser;
rstate->meta_root_obj = (ucl_object_t *)obj;
return (0);
err_load_metadata:
if (parser != NULL)
ucl_parser_free(parser);
return (err);
}
int
load_restore_file(const char *filename, struct restore_state *rstate)
{
int err = 0;
char *kdata_filename = NULL, *meta_filename = NULL;
assert(filename != NULL);
assert(rstate != NULL);
memset(rstate, 0, sizeof(*rstate));
rstate->kdata_map = MAP_FAILED;
err = load_vmmem_file(filename, rstate);
if (err != 0) {
fprintf(stderr, "Failed to load guest RAM file.\n");
goto err_restore;
}
kdata_filename = strcat_extension(filename, ".kern");
if (kdata_filename == NULL) {
fprintf(stderr, "Failed to construct kernel data filename.\n");
goto err_restore;
}
err = load_kdata_file(kdata_filename, rstate);
if (err != 0) {
fprintf(stderr, "Failed to load guest kernel data file.\n");
goto err_restore;
}
meta_filename = strcat_extension(filename, ".meta");
if (meta_filename == NULL) {
fprintf(stderr, "Failed to construct kernel metadata filename.\n");
goto err_restore;
}
err = load_metadata_file(meta_filename, rstate);
if (err != 0) {
fprintf(stderr, "Failed to load guest metadata file.\n");
goto err_restore;
}
return (0);
err_restore:
destroy_restore_state(rstate);
if (kdata_filename != NULL)
free(kdata_filename);
if (meta_filename != NULL)
free(meta_filename);
return (-1);
}
#define JSON_GET_INT_OR_RETURN(key, obj, result_ptr, ret) \
do { \
const ucl_object_t *obj__; \
obj__ = ucl_object_lookup(obj, key); \
if (obj__ == NULL) { \
fprintf(stderr, "Missing key: '%s'", key); \
return (ret); \
} \
if (!ucl_object_toint_safe(obj__, result_ptr)) { \
fprintf(stderr, "Cannot convert '%s' value to int.", key); \
return (ret); \
} \
} while(0)
#define JSON_GET_STRING_OR_RETURN(key, obj, result_ptr, ret) \
do { \
const ucl_object_t *obj__; \
obj__ = ucl_object_lookup(obj, key); \
if (obj__ == NULL) { \
fprintf(stderr, "Missing key: '%s'", key); \
return (ret); \
} \
if (!ucl_object_tostring_safe(obj__, result_ptr)) { \
fprintf(stderr, "Cannot convert '%s' value to string.", key); \
return (ret); \
} \
} while(0)
static void *
lookup_struct(enum snapshot_req struct_id, struct restore_state *rstate,
size_t *struct_size)
{
const ucl_object_t *structs = NULL, *obj = NULL;
ucl_object_iter_t it = NULL;
int64_t snapshot_req, size, file_offset;
structs = ucl_object_lookup(rstate->meta_root_obj, JSON_STRUCT_ARR_KEY);
if (structs == NULL) {
fprintf(stderr, "Failed to find '%s' object.\n",
JSON_STRUCT_ARR_KEY);
return (NULL);
}
if (ucl_object_type((ucl_object_t *)structs) != UCL_ARRAY) {
fprintf(stderr, "Object '%s' is not an array.\n",
JSON_STRUCT_ARR_KEY);
return (NULL);
}
while ((obj = ucl_object_iterate(structs, &it, true)) != NULL) {
snapshot_req = -1;
JSON_GET_INT_OR_RETURN(JSON_SNAPSHOT_REQ_KEY, obj,
&snapshot_req, NULL);
assert(snapshot_req >= 0);
if ((enum snapshot_req) snapshot_req == struct_id) {
JSON_GET_INT_OR_RETURN(JSON_SIZE_KEY, obj,
&size, NULL);
assert(size >= 0);
JSON_GET_INT_OR_RETURN(JSON_FILE_OFFSET_KEY, obj,
&file_offset, NULL);
assert(file_offset >= 0);
assert(file_offset + size <= rstate->kdata_len);
*struct_size = (size_t)size;
return (rstate->kdata_map + file_offset);
}
}
return (NULL);
}
static void *
lookup_check_dev(const char *dev_name, struct restore_state *rstate,
const ucl_object_t *obj, size_t *data_size)
{
const char *snapshot_req;
int64_t size, file_offset;
snapshot_req = NULL;
JSON_GET_STRING_OR_RETURN(JSON_SNAPSHOT_REQ_KEY, obj,
&snapshot_req, NULL);
assert(snapshot_req != NULL);
if (!strcmp(snapshot_req, dev_name)) {
JSON_GET_INT_OR_RETURN(JSON_SIZE_KEY, obj,
&size, NULL);
assert(size >= 0);
JSON_GET_INT_OR_RETURN(JSON_FILE_OFFSET_KEY, obj,
&file_offset, NULL);
assert(file_offset >= 0);
assert(file_offset + size <= rstate->kdata_len);
*data_size = (size_t)size;
return (rstate->kdata_map + file_offset);
}
return (NULL);
}
static void*
lookup_dev(const char *dev_name, struct restore_state *rstate,
size_t *data_size)
{
const ucl_object_t *devs = NULL, *obj = NULL;
ucl_object_iter_t it = NULL;
void *ret;
devs = ucl_object_lookup(rstate->meta_root_obj, JSON_DEV_ARR_KEY);
if (devs == NULL) {
fprintf(stderr, "Failed to find '%s' object.\n",
JSON_DEV_ARR_KEY);
return (NULL);
}
if (ucl_object_type((ucl_object_t *)devs) != UCL_ARRAY) {
fprintf(stderr, "Object '%s' is not an array.\n",
JSON_DEV_ARR_KEY);
return (NULL);
}
while ((obj = ucl_object_iterate(devs, &it, true)) != NULL) {
ret = lookup_check_dev(dev_name, rstate, obj, data_size);
if (ret != NULL)
return (ret);
}
return (NULL);
}
static const ucl_object_t *
lookup_basic_metadata_object(struct restore_state *rstate)
{
const ucl_object_t *basic_meta_obj = NULL;
basic_meta_obj = ucl_object_lookup(rstate->meta_root_obj,
JSON_BASIC_METADATA_KEY);
if (basic_meta_obj == NULL) {
fprintf(stderr, "Failed to find '%s' object.\n",
JSON_BASIC_METADATA_KEY);
return (NULL);
}
if (ucl_object_type((ucl_object_t *)basic_meta_obj) != UCL_OBJECT) {
fprintf(stderr, "Object '%s' is not a JSON object.\n",
JSON_BASIC_METADATA_KEY);
return (NULL);
}
return (basic_meta_obj);
}
const char *
lookup_vmname(struct restore_state *rstate)
{
const char *vmname;
const ucl_object_t *obj;
obj = lookup_basic_metadata_object(rstate);
if (obj == NULL)
return (NULL);
JSON_GET_STRING_OR_RETURN(JSON_VMNAME_KEY, obj, &vmname, NULL);
return (vmname);
}
int
lookup_memflags(struct restore_state *rstate)
{
int64_t memflags;
const ucl_object_t *obj;
obj = lookup_basic_metadata_object(rstate);
if (obj == NULL)
return (0);
JSON_GET_INT_OR_RETURN(JSON_MEMFLAGS_KEY, obj, &memflags, 0);
return ((int)memflags);
}
size_t
lookup_memsize(struct restore_state *rstate)
{
int64_t memsize;
const ucl_object_t *obj;
obj = lookup_basic_metadata_object(rstate);
if (obj == NULL)
return (0);
JSON_GET_INT_OR_RETURN(JSON_MEMSIZE_KEY, obj, &memsize, 0);
if (memsize < 0)
memsize = 0;
return ((size_t)memsize);
}
int
lookup_guest_ncpus(struct restore_state *rstate)
{
int64_t ncpus;
const ucl_object_t *obj;
obj = lookup_basic_metadata_object(rstate);
if (obj == NULL)
return (0);
JSON_GET_INT_OR_RETURN(JSON_NCPUS_KEY, obj, &ncpus, 0);
return ((int)ncpus);
}
int
restore_vm_mem(struct vmctx *ctx, struct restore_state *rstate)
{
return vm_restore_mem(ctx, rstate->vmmem_fd, rstate->vmmem_len);
}
static int
vm_restore_kern_struct(struct vmctx *ctx, struct restore_state *rstate,
const struct vm_snapshot_kern_info *info)
{
void *struct_ptr;
size_t struct_size;
int ret;
struct vm_snapshot_meta *meta;
struct_ptr = lookup_struct(info->req, rstate, &struct_size);
if (struct_ptr == NULL) {
fprintf(stderr, "%s: Failed to lookup struct %s\r\n",
__func__, info->struct_name);
ret = -1;
goto done;
}
if (struct_size == 0) {
fprintf(stderr, "%s: Kernel struct size was 0 for: %s\r\n",
__func__, info->struct_name);
ret = -1;
goto done;
}
meta = &(struct vm_snapshot_meta) {
.ctx = ctx,
.dev_name = info->struct_name,
.dev_req = info->req,
.buffer.buf_start = struct_ptr,
.buffer.buf_size = struct_size,
.buffer.buf = struct_ptr,
.buffer.buf_rem = struct_size,
.op = VM_SNAPSHOT_RESTORE,
};
ret = vm_snapshot_req(meta);
if (ret != 0) {
fprintf(stderr, "%s: Failed to restore struct: %s\r\n",
__func__, info->struct_name);
goto done;
}
done:
return (ret);
}
int
vm_restore_kern_structs(struct vmctx *ctx, struct restore_state *rstate)
{
int ret;
int i;
for (i = 0; i < nitems(snapshot_kern_structs); i++) {
ret = vm_restore_kern_struct(ctx, rstate,
&snapshot_kern_structs[i]);
if (ret != 0)
return (ret);
}
return (0);
}
int
vm_restore_user_dev(struct vmctx *ctx, struct restore_state *rstate,
const struct vm_snapshot_dev_info *info)
{
void *dev_ptr;
size_t dev_size;
int ret;
struct vm_snapshot_meta *meta;
dev_ptr = lookup_dev(info->dev_name, rstate, &dev_size);
if (dev_ptr == NULL) {
fprintf(stderr, "Failed to lookup dev: %s\r\n", info->dev_name);
fprintf(stderr, "Continuing the restore/migration process\r\n");
return (0);
}
if (dev_size == 0) {
fprintf(stderr, "%s: Device size is 0. "
"Assuming %s is not used\r\n",
__func__, info->dev_name);
return (0);
}
meta = &(struct vm_snapshot_meta) {
.ctx = ctx,
.dev_name = info->dev_name,
.buffer.buf_start = dev_ptr,
.buffer.buf_size = dev_size,
.buffer.buf = dev_ptr,
.buffer.buf_rem = dev_size,
.op = VM_SNAPSHOT_RESTORE,
};
ret = (*info->snapshot_cb)(meta);
if (ret != 0) {
fprintf(stderr, "Failed to restore dev: %s\r\n",
info->dev_name);
return (-1);
}
return (0);
}
int
vm_restore_user_devs(struct vmctx *ctx, struct restore_state *rstate)
{
int ret;
int i;
for (i = 0; i < nitems(snapshot_devs); i++) {
ret = vm_restore_user_dev(ctx, rstate, &snapshot_devs[i]);
if (ret != 0)
return (ret);
}
return 0;
}
int
vm_pause_user_devs(struct vmctx *ctx)
{
const struct vm_snapshot_dev_info *info;
int ret;
int i;
for (i = 0; i < nitems(snapshot_devs); i++) {
info = &snapshot_devs[i];
if (info->pause_cb == NULL)
continue;
ret = info->pause_cb(ctx, info->dev_name);
if (ret != 0)
return (ret);
}
return (0);
}
int
vm_resume_user_devs(struct vmctx *ctx)
{
const struct vm_snapshot_dev_info *info;
int ret;
int i;
for (i = 0; i < nitems(snapshot_devs); i++) {
info = &snapshot_devs[i];
if (info->resume_cb == NULL)
continue;
ret = info->resume_cb(ctx, info->dev_name);
if (ret != 0)
return (ret);
}
return (0);
}
static int
vm_snapshot_kern_struct(int data_fd, xo_handle_t *xop, const char *array_key,
struct vm_snapshot_meta *meta, off_t *offset)
{
int ret;
size_t data_size;
ssize_t write_cnt;
ret = vm_snapshot_req(meta);
if (ret != 0) {
fprintf(stderr, "%s: Failed to snapshot struct %s\r\n",
__func__, meta->dev_name);
ret = -1;
goto done;
}
data_size = vm_get_snapshot_size(meta);
write_cnt = write(data_fd, meta->buffer.buf_start, data_size);
if (write_cnt != data_size) {
perror("Failed to write all snapshotted data.");
ret = -1;
goto done;
}
/* Write metadata. */
xo_open_instance_h(xop, array_key);
xo_emit_h(xop, "{:debug_name/%s}\n", meta->dev_name);
xo_emit_h(xop, "{:" JSON_SNAPSHOT_REQ_KEY "/%d}\n",
meta->dev_req);
xo_emit_h(xop, "{:" JSON_SIZE_KEY "/%lu}\n", data_size);
xo_emit_h(xop, "{:" JSON_FILE_OFFSET_KEY "/%lu}\n", *offset);
xo_close_instance_h(xop, JSON_STRUCT_ARR_KEY);
*offset += data_size;
done:
return (ret);
}
static int
vm_snapshot_kern_structs(struct vmctx *ctx, int data_fd, xo_handle_t *xop)
{
int ret, i, error;
size_t offset, buf_size;
char *buffer;
struct vm_snapshot_meta *meta;
error = 0;
offset = 0;
buf_size = SNAPSHOT_BUFFER_SIZE;
buffer = malloc(SNAPSHOT_BUFFER_SIZE * sizeof(char));
if (buffer == NULL) {
error = ENOMEM;
perror("Failed to allocate memory for snapshot buffer");
goto err_vm_snapshot_kern_data;
}
meta = &(struct vm_snapshot_meta) {
.ctx = ctx,
.buffer.buf_start = buffer,
.buffer.buf_size = buf_size,
.op = VM_SNAPSHOT_SAVE,
};
xo_open_list_h(xop, JSON_STRUCT_ARR_KEY);
for (i = 0; i < nitems(snapshot_kern_structs); i++) {
meta->dev_name = snapshot_kern_structs[i].struct_name;
meta->dev_req = snapshot_kern_structs[i].req;
memset(meta->buffer.buf_start, 0, meta->buffer.buf_size);
meta->buffer.buf = meta->buffer.buf_start;
meta->buffer.buf_rem = meta->buffer.buf_size;
ret = vm_snapshot_kern_struct(data_fd, xop, JSON_DEV_ARR_KEY,
meta, &offset);
if (ret != 0) {
error = -1;
goto err_vm_snapshot_kern_data;
}
}
xo_close_list_h(xop, JSON_STRUCT_ARR_KEY);
err_vm_snapshot_kern_data:
if (buffer != NULL)
free(buffer);
return (error);
}
static int
vm_snapshot_basic_metadata(struct vmctx *ctx, xo_handle_t *xop)
{
int error;
size_t memsize;
int memflags;
char vmname_buf[MAX_VMNAME];
memset(vmname_buf, 0, MAX_VMNAME);
error = vm_get_name(ctx, vmname_buf, MAX_VMNAME - 1);
if (error != 0) {
perror("Failed to get VM name");
goto err;
}
memsize = vm_get_lowmem_size(ctx) + vm_get_highmem_size(ctx);
memflags = vm_get_memflags(ctx);
xo_open_container_h(xop, JSON_BASIC_METADATA_KEY);
xo_emit_h(xop, "{:" JSON_NCPUS_KEY "/%ld}\n", guest_ncpus);
xo_emit_h(xop, "{:" JSON_VMNAME_KEY "/%s}\n", vmname_buf);
xo_emit_h(xop, "{:" JSON_MEMSIZE_KEY "/%lu}\n", memsize);
xo_emit_h(xop, "{:" JSON_MEMFLAGS_KEY "/%d}\n", memflags);
xo_close_container_h(xop, JSON_BASIC_METADATA_KEY);
err:
return (error);
}
static int
vm_snapshot_dev_write_data(int data_fd, xo_handle_t *xop, const char *array_key,
struct vm_snapshot_meta *meta, off_t *offset)
{
int ret;
size_t data_size;
data_size = vm_get_snapshot_size(meta);
ret = write(data_fd, meta->buffer.buf_start, data_size);
if (ret != data_size) {
perror("Failed to write all snapshotted data.");
return (-1);
}
/* Write metadata. */
xo_open_instance_h(xop, array_key);
xo_emit_h(xop, "{:" JSON_SNAPSHOT_REQ_KEY "/%s}\n", meta->dev_name);
xo_emit_h(xop, "{:" JSON_SIZE_KEY "/%lu}\n", data_size);
xo_emit_h(xop, "{:" JSON_FILE_OFFSET_KEY "/%lu}\n", *offset);
xo_close_instance_h(xop, array_key);
*offset += data_size;
return (0);
}
static int
vm_snapshot_user_dev(const struct vm_snapshot_dev_info *info,
int data_fd, xo_handle_t *xop,
struct vm_snapshot_meta *meta, off_t *offset)
{
int ret;
ret = (*info->snapshot_cb)(meta);
if (ret != 0) {
fprintf(stderr, "Failed to snapshot %s; ret=%d\r\n",
meta->dev_name, ret);
return (ret);
}
ret = vm_snapshot_dev_write_data(data_fd, xop, JSON_DEV_ARR_KEY, meta,
offset);
if (ret != 0)
return (ret);
return (0);
}
static int
vm_snapshot_user_devs(struct vmctx *ctx, int data_fd, xo_handle_t *xop)
{
int ret, i;
off_t offset;
void *buffer;
size_t buf_size;
struct vm_snapshot_meta *meta;
buf_size = SNAPSHOT_BUFFER_SIZE;
offset = lseek(data_fd, 0, SEEK_CUR);
if (offset < 0) {
perror("Failed to get data file current offset.");
return (-1);
}
buffer = malloc(buf_size);
if (buffer == NULL) {
perror("Failed to allocate memory for snapshot buffer");
ret = ENOSPC;
goto snapshot_err;
}
meta = &(struct vm_snapshot_meta) {
.ctx = ctx,
.buffer.buf_start = buffer,
.buffer.buf_size = buf_size,
.op = VM_SNAPSHOT_SAVE,
};
xo_open_list_h(xop, JSON_DEV_ARR_KEY);
/* Restore other devices that support this feature */
for (i = 0; i < nitems(snapshot_devs); i++) {
meta->dev_name = snapshot_devs[i].dev_name;
memset(meta->buffer.buf_start, 0, meta->buffer.buf_size);
meta->buffer.buf = meta->buffer.buf_start;
meta->buffer.buf_rem = meta->buffer.buf_size;
ret = vm_snapshot_user_dev(&snapshot_devs[i], data_fd, xop,
meta, &offset);
if (ret != 0)
goto snapshot_err;
}
xo_close_list_h(xop, JSON_DEV_ARR_KEY);
snapshot_err:
if (buffer != NULL)
free(buffer);
return (ret);
}
static int
vm_mem_write_to_file(int fd, const void *src, size_t dst_offset, size_t len)
{
size_t write_total;
ssize_t cnt_write;
size_t to_write;
write_total = 0;
to_write = len;
if (lseek(fd, dst_offset, SEEK_SET) < 0 ) {
perror("Failed to changed file offset");
return (-1);
}
while (write_total < len) {
cnt_write = write(fd, src + write_total, to_write);
if (cnt_write < 0) {
perror("Failed to write in file");
return (-1);
}
to_write -= cnt_write;
write_total += cnt_write;
}
return (0);
}
void
checkpoint_cpu_add(int vcpu)
{
pthread_mutex_lock(&vcpu_lock);
CPU_SET(vcpu, &vcpus_active);
if (checkpoint_active) {
CPU_SET(vcpu, &vcpus_suspended);
while (checkpoint_active)
pthread_cond_wait(&vcpus_can_run, &vcpu_lock);
CPU_CLR(vcpu, &vcpus_suspended);
}
pthread_mutex_unlock(&vcpu_lock);
}
/*
* When a vCPU is suspended for any reason, it calls
* checkpoint_cpu_suspend(). This records that the vCPU is idle.
* Before returning from suspension, checkpoint_cpu_resume() is
* called. In suspend we note that the vCPU is idle. In resume we
* pause the vCPU thread until the checkpoint is complete. The reason
* for the two-step process is that vCPUs might already be stopped in
* the debug server when a checkpoint is requested. This approach
* allows us to account for and handle those vCPUs.
*/
void
checkpoint_cpu_suspend(int vcpu)
{
pthread_mutex_lock(&vcpu_lock);
CPU_SET(vcpu, &vcpus_suspended);
if (checkpoint_active && CPU_CMP(&vcpus_active, &vcpus_suspended) == 0)
pthread_cond_signal(&vcpus_idle);
pthread_mutex_unlock(&vcpu_lock);
}
void
checkpoint_cpu_resume(int vcpu)
{
pthread_mutex_lock(&vcpu_lock);
while (checkpoint_active)
pthread_cond_wait(&vcpus_can_run, &vcpu_lock);
CPU_CLR(vcpu, &vcpus_suspended);
pthread_mutex_unlock(&vcpu_lock);
}
static void
vm_vcpu_pause(struct vmctx *ctx)
{
pthread_mutex_lock(&vcpu_lock);
checkpoint_active = true;
vm_suspend_cpu(ctx, -1);
while (CPU_CMP(&vcpus_active, &vcpus_suspended) != 0)
pthread_cond_wait(&vcpus_idle, &vcpu_lock);
pthread_mutex_unlock(&vcpu_lock);
}
static void
vm_vcpu_resume(struct vmctx *ctx)
{
pthread_mutex_lock(&vcpu_lock);
checkpoint_active = false;
pthread_mutex_unlock(&vcpu_lock);
vm_resume_cpu(ctx, -1);
pthread_cond_broadcast(&vcpus_can_run);
}
static int
vm_checkpoint(struct vmctx *ctx, char *checkpoint_file, bool stop_vm)
{
int fd_checkpoint = 0, kdata_fd = 0;
int ret = 0;
int error = 0;
size_t guest_lowmem, guest_highmem, guest_memsize;
char *guest_baseaddr;
char *guest_lowmem_addr, *guest_highmem_addr;
xo_handle_t *xop = NULL;
char *meta_filename = NULL;
char *kdata_filename = NULL;
FILE *meta_file = NULL;
kdata_filename = strcat_extension(checkpoint_file, ".kern");
if (kdata_filename == NULL) {
fprintf(stderr, "Failed to construct kernel data filename.\n");
return (-1);
}
kdata_fd = open(kdata_filename, O_WRONLY | O_CREAT | O_TRUNC, 0700);
if (kdata_fd < 0) {
perror("Failed to open kernel data snapshot file.");
error = -1;
goto done;
}
fd_checkpoint = open(checkpoint_file, O_RDWR | O_CREAT | O_TRUNC, 0700);
if (fd_checkpoint < 0) {
perror("Failed to create checkpoint file");
error = -1;
goto done;
}
ret = vm_get_guestmem_from_ctx(ctx, &guest_baseaddr, &guest_lowmem, &guest_highmem);
guest_memsize = guest_lowmem + guest_highmem;
if (ret < 0) {
fprintf(stderr, "Failed to get guest mem information (base, low, high)\n");
error = -1;
goto done;
}
/* make space for VMs address space */
ret = ftruncate(fd_checkpoint, guest_memsize);
if (ret < 0) {
perror("Failed to truncate checkpoint file\n");
goto done;
}
meta_filename = strcat_extension(checkpoint_file, ".meta");
if (meta_filename == NULL) {
fprintf(stderr, "Failed to construct vm metadata filename.\n");
goto done;
}
meta_file = fopen(meta_filename, "w");
if (meta_file == NULL) {
perror("Failed to open vm metadata snapshot file.");
goto done;
}
xop = xo_create_to_file(meta_file, XO_STYLE_JSON, XOF_PRETTY);
if (xop == NULL) {
perror("Failed to get libxo handle on metadata file.");
goto done;
}
ret = vm_snapshot_basic_metadata(ctx, xop);
if (ret != 0) {
fprintf(stderr, "Failed to snapshot vm basic metadata.\n");
error = -1;
goto done;
}
guest_lowmem_addr = guest_baseaddr;
if (guest_highmem > 0)
guest_highmem_addr = guest_baseaddr + 4*GB;
vm_vcpu_pause(ctx);
ret = vm_pause_user_devs(ctx);
if (ret != 0) {
fprintf(stderr, "Could not pause devices\r\n");
error = ret;
goto done;
}
ret = vm_snapshot_kern_structs(ctx, kdata_fd, xop);
if (ret != 0) {
fprintf(stderr, "Failed to snapshot vm kernel data.\n");
error = -1;
goto done;
}
ret = vm_snapshot_user_devs(ctx, kdata_fd, xop);
if (ret != 0) {
fprintf(stderr, "Failed to snapshot device state.\n");
error = -1;
goto done;
}
if (vm_mem_write_to_file(fd_checkpoint, guest_lowmem_addr,
0, guest_lowmem) != 0) {
perror("Could not write lowmem");
error = -1;
goto done;
}
if (guest_highmem > 0) {
if (vm_mem_write_to_file(fd_checkpoint, guest_highmem_addr,
guest_lowmem, guest_highmem) != 0) {
perror("Could not write highmem");
error = -1;
goto done;
}
}
xo_finish_h(xop);
if (stop_vm) {
vm_destroy(ctx);
exit(0);
}
done:
ret = vm_resume_user_devs(ctx);
if (ret != 0)
fprintf(stderr, "Could not resume devices\r\n");
vm_vcpu_resume(ctx);
if (fd_checkpoint > 0)
close(fd_checkpoint);
if (meta_filename != NULL)
free(meta_filename);
if (kdata_filename != NULL)
free(kdata_filename);
if (xop != NULL)
xo_destroy(xop);
if (meta_file != NULL)
fclose(meta_file);
if (kdata_fd > 0)
close(kdata_fd);
return (error);
}
int
get_checkpoint_msg(int conn_fd, struct vmctx *ctx)
{
unsigned char buf[MAX_MSG_SIZE];
struct checkpoint_op *checkpoint_op;
int len, recv_len, total_recv = 0;
int err = 0;
len = sizeof(struct checkpoint_op); /* expected length */
while ((recv_len = recv(conn_fd, buf + total_recv, len - total_recv, 0)) > 0) {
total_recv += recv_len;
}
if (recv_len < 0) {
perror("Error while receiving data from bhyvectl");
err = -1;
goto done;
}
checkpoint_op = (struct checkpoint_op *)buf;
switch (checkpoint_op->op) {
case START_CHECKPOINT:
err = vm_checkpoint(ctx, checkpoint_op->snapshot_filename, false);
break;
case START_SUSPEND:
err = vm_checkpoint(ctx, checkpoint_op->snapshot_filename, true);
break;
default:
fprintf(stderr, "Unrecognized checkpoint operation.\n");
err = -1;
}
done:
close(conn_fd);
return (err);
}
/*
* Listen for commands from bhyvectl
*/
void *
checkpoint_thread(void *param)
{
struct checkpoint_thread_info *thread_info;
socklen_t addr_len;
int conn_fd, ret;
thread_info = (struct checkpoint_thread_info *)param;
addr_len = sizeof(thread_info->addr);
while ((conn_fd = accept(thread_info->socket_fd,
(struct sockaddr *) thread_info->addr,
&addr_len)) > -1) {
ret = get_checkpoint_msg(conn_fd, thread_info->ctx);
if (ret != 0) {
fprintf(stderr, "Failed to read message on checkpoint "
"socket. Retrying.\n");
}
addr_len = sizeof(struct sockaddr_un);
}
if (conn_fd < -1) {
perror("Failed to accept connection");
}
return (NULL);
}
/*
* Create directory tree to store runtime specific information:
* i.e. UNIX sockets for IPC with bhyvectl.
*/
static int
make_checkpoint_dir(void)
{
int err;
err = mkdir(BHYVE_RUN_DIR, 0755);
if (err < 0 && errno != EEXIST)
return (err);
err = mkdir(CHECKPOINT_RUN_DIR, 0755);
if (err < 0 && errno != EEXIST)
return (err);
return 0;
}
/*
* Create the listening socket for IPC with bhyvectl
*/
int
init_checkpoint_thread(struct vmctx *ctx)
{
struct sockaddr_un addr;
int socket_fd;
pthread_t checkpoint_pthread;
char vmname_buf[MAX_VMNAME];
int ret, err = 0;
err = pthread_mutex_init(&vcpu_lock, NULL);
if (err != 0)
errc(1, err, "checkpoint mutex init");
err = pthread_cond_init(&vcpus_idle, NULL);
if (err == 0)
err = pthread_cond_init(&vcpus_can_run, NULL);
if (err != 0)
errc(1, err, "checkpoint cv init");
socket_fd = socket(PF_UNIX, SOCK_STREAM, 0);
if (socket_fd < 0) {
perror("Socket creation failed (IPC with bhyvectl");
err = -1;
goto fail;
}
err = make_checkpoint_dir();
if (err < 0) {
perror("Failed to create checkpoint runtime directory");
goto fail;
}
memset(&addr, 0, sizeof(struct sockaddr_un));
addr.sun_family = AF_UNIX;
err = vm_get_name(ctx, vmname_buf, MAX_VMNAME - 1);
if (err != 0) {
perror("Failed to get VM name");
goto fail;
}
snprintf(addr.sun_path, sizeof(addr.sun_path), "%s/%s",
CHECKPOINT_RUN_DIR, vmname_buf);
unlink(addr.sun_path);
if (bind(socket_fd, (struct sockaddr *)&addr,
sizeof(struct sockaddr_un)) != 0) {
perror("Failed to bind socket (IPC with bhyvectl)");
err = -1;
goto fail;
}
if (listen(socket_fd, 10) < 0) {
perror("Failed to listen on socket (IPC with bhyvectl)");
err = -1;
goto fail;
}
memset(&checkpoint_info, 0, sizeof(struct checkpoint_thread_info));
checkpoint_info.ctx = ctx;
checkpoint_info.socket_fd = socket_fd;
checkpoint_info.addr = &addr;
/* TODO: start thread for listening connections */
pthread_set_name_np(checkpoint_pthread, "checkpoint thread");
ret = pthread_create(&checkpoint_pthread, NULL, checkpoint_thread,
&checkpoint_info);
if (ret < 0) {
err = ret;
goto fail;
}
return (0);
fail:
if (socket_fd > 0)
close(socket_fd);
unlink(addr.sun_path);
return (err);
}
void
vm_snapshot_buf_err(const char *bufname, const enum vm_snapshot_op op)
{
const char *__op;
if (op == VM_SNAPSHOT_SAVE)
__op = "save";
else if (op == VM_SNAPSHOT_RESTORE)
__op = "restore";
else
__op = "unknown";
fprintf(stderr, "%s: snapshot-%s failed for %s\r\n",
__func__, __op, bufname);
}
int
vm_snapshot_buf(volatile void *data, size_t data_size,
struct vm_snapshot_meta *meta)
{
struct vm_snapshot_buffer *buffer;
int op;
buffer = &meta->buffer;
op = meta->op;
if (buffer->buf_rem < data_size) {
fprintf(stderr, "%s: buffer too small\r\n", __func__);
return (E2BIG);
}
if (op == VM_SNAPSHOT_SAVE)
memcpy(buffer->buf, (uint8_t *) data, data_size);
else if (op == VM_SNAPSHOT_RESTORE)
memcpy((uint8_t *) data, buffer->buf, data_size);
else
return (EINVAL);
buffer->buf += data_size;
buffer->buf_rem -= data_size;
return (0);
}
size_t
vm_get_snapshot_size(struct vm_snapshot_meta *meta)
{
size_t length;
struct vm_snapshot_buffer *buffer;
buffer = &meta->buffer;
if (buffer->buf_size < buffer->buf_rem) {
fprintf(stderr, "%s: Invalid buffer: size = %zu, rem = %zu\r\n",
__func__, buffer->buf_size, buffer->buf_rem);
length = 0;
} else {
length = buffer->buf_size - buffer->buf_rem;
}
return (length);
}
int
vm_snapshot_guest2host_addr(void **addrp, size_t len, bool restore_null,
struct vm_snapshot_meta *meta)
{
int ret;
vm_paddr_t gaddr;
if (meta->op == VM_SNAPSHOT_SAVE) {
gaddr = paddr_host2guest(meta->ctx, *addrp);
if (gaddr == (vm_paddr_t) -1) {
if (!restore_null ||
(restore_null && (*addrp != NULL))) {
ret = EFAULT;
goto done;
}
}
SNAPSHOT_VAR_OR_LEAVE(gaddr, meta, ret, done);
} else if (meta->op == VM_SNAPSHOT_RESTORE) {
SNAPSHOT_VAR_OR_LEAVE(gaddr, meta, ret, done);
if (gaddr == (vm_paddr_t) -1) {
if (!restore_null) {
ret = EFAULT;
goto done;
}
}
*addrp = paddr_guest2host(meta->ctx, gaddr, len);
} else {
ret = EINVAL;
}
done:
return (ret);
}
int
vm_snapshot_buf_cmp(volatile void *data, size_t data_size,
struct vm_snapshot_meta *meta)
{
struct vm_snapshot_buffer *buffer;
int op;
int ret;
buffer = &meta->buffer;
op = meta->op;
if (buffer->buf_rem < data_size) {
fprintf(stderr, "%s: buffer too small\r\n", __func__);
ret = E2BIG;
goto done;
}
if (op == VM_SNAPSHOT_SAVE) {
ret = 0;
memcpy(buffer->buf, (uint8_t *) data, data_size);
} else if (op == VM_SNAPSHOT_RESTORE) {
ret = memcmp((uint8_t *) data, buffer->buf, data_size);
} else {
ret = EINVAL;
goto done;
}
buffer->buf += data_size;
buffer->buf_rem -= data_size;
done:
return (ret);
}