This patch implements initial vmstate creation or loading at the start of record/replay. It is needed for rewinding the execution in the replay mode.
v3 changes: - added rrsnapshot option Signed-off-by: Pavel Dovgalyuk <pavel.dovga...@ispras.ru> --- docs/replay.txt | 12 ++++++++++++ include/sysemu/replay.h | 6 ++++++ qemu-options.hx | 8 +++++--- replay/Makefile.objs | 1 + replay/replay-internal.h | 3 +++ replay/replay-snapshot.c | 31 +++++++++++++++++++++++++++++++ replay/replay.c | 7 +++++++ vl.c | 8 +++++++- 8 files changed, 72 insertions(+), 4 deletions(-) create mode 100644 replay/replay-snapshot.c diff --git a/docs/replay.txt b/docs/replay.txt index 5be8f25..ce3c6b8 100644 --- a/docs/replay.txt +++ b/docs/replay.txt @@ -204,6 +204,18 @@ Overlay file may be specified as follows: -drive driver=blkreplay,if=none,image=img-direct, overlay=overlay.qcow2,id=img-blkreplay +Snapshotting +------------ + +New VM snapshots may be created in replay mode. They can be used later +to recover the desired VM state. All VM states created in replay mode +are associated with the moment of time in the replay scenario. +After recovering the VM state replay will start from that position. + +Default starting snapshot name may be overridden with icount field +rrsnapshot as follows: + -icount shift=7,rr=record,rrfile=replay.bin,rrsnapshot=non_default_snapshot + Network devices --------------- diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h index a408633..aa378ce 100644 --- a/include/sysemu/replay.h +++ b/include/sysemu/replay.h @@ -145,4 +145,10 @@ void replay_unregister_net(ReplayNetState *rns); void replay_net_packet_event(ReplayNetState *rns, unsigned flags, const struct iovec *iov, int iovcnt); +/* VM state operations */ + +/*! Called at the start of execution. + Loads or saves initial vmstate depending on execution mode. */ +void replay_vmstate_init(void); + #endif diff --git a/qemu-options.hx b/qemu-options.hx index 0b621bb..1483ad8 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -3367,12 +3367,12 @@ re-inject them. ETEXI DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ - "-icount [shift=N|auto][,align=on|off][,sleep=on|off,rr=record|replay,rrfile=<filename>]\n" \ + "-icount [shift=N|auto][,align=on|off][,sleep=on|off,rr=record|replay,rrfile=<filename>,rrsnapshot=<snapshot>]\n" \ " enable virtual instruction counter with 2^N clock ticks per\n" \ " instruction, enable aligning the host and virtual clocks\n" \ " or disable real time cpu sleeping\n", QEMU_ARCH_ALL) STEXI -@item -icount [shift=@var{N}|auto][,rr=record|replay,rrfile=@var{filename}] +@item -icount [shift=@var{N}|auto][,rr=record|replay,rrfile=@var{filename},rrsnapshot=@var{snapshot}] @findex -icount Enable virtual instruction counter. The virtual cpu will execute one instruction every 2^@var{N} ns of virtual time. If @code{auto} is specified @@ -3404,7 +3404,9 @@ when the shift value is high (how high depends on the host machine). When @option{rr} option is specified deterministic record/replay is enabled. Replay log is written into @var{filename} file in record mode and -read from this file in replay mode. +read from this file in replay mode. At the start of record new snapshot +is created. It get 'replay_init' name or the one specified with @{snapshot} +option. In replay mode this option is used to load the initial VM state. ETEXI DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ diff --git a/replay/Makefile.objs b/replay/Makefile.objs index f55a6b5..4600d74 100644 --- a/replay/Makefile.objs +++ b/replay/Makefile.objs @@ -5,3 +5,4 @@ common-obj-y += replay-time.o common-obj-y += replay-input.o common-obj-y += replay-char.o common-obj-y += replay-net.o +common-obj-y += replay-snapshot.o diff --git a/replay/replay-internal.h b/replay/replay-internal.h index d28cfb7..6f2f6e2 100644 --- a/replay/replay-internal.h +++ b/replay/replay-internal.h @@ -71,6 +71,9 @@ extern unsigned int replay_data_kind; /* File for replay writing */ extern FILE *replay_file; +/* Default name of the initial VM snapshot */ +extern char *replay_snapshot; + void replay_put_byte(uint8_t byte); void replay_put_event(uint8_t event); void replay_put_word(uint16_t word); diff --git a/replay/replay-snapshot.c b/replay/replay-snapshot.c new file mode 100644 index 0000000..6079b29 --- /dev/null +++ b/replay/replay-snapshot.c @@ -0,0 +1,31 @@ +/* + * replay-snapshot.c + * + * Copyright (c) 2010-2016 Institute for System Programming + * of the Russian Academy of Sciences. + * + * 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 "qemu-common.h" +#include "sysemu/replay.h" +#include "replay-internal.h" +#include "sysemu/sysemu.h" +#include "monitor/monitor.h" +#include "qapi/qmp/qstring.h" + +void replay_vmstate_init(void) +{ + if (replay_mode == REPLAY_MODE_RECORD) { + QDict *opts = qdict_new(); + qdict_put(opts, "name", qstring_from_str(replay_snapshot)); + hmp_savevm(cur_mon, opts); + QDECREF(opts); + } else if (replay_mode == REPLAY_MODE_PLAY) { + load_vmstate(replay_snapshot); + } +} diff --git a/replay/replay.c b/replay/replay.c index e040f6f..ef1e5e9 100644 --- a/replay/replay.c +++ b/replay/replay.c @@ -26,6 +26,7 @@ #define HEADER_SIZE (sizeof(uint32_t) + sizeof(uint64_t)) ReplayMode replay_mode = REPLAY_MODE_NONE; +char *replay_snapshot; /* Name of replay file */ static char *replay_filename; @@ -291,6 +292,8 @@ void replay_configure(QemuOpts *opts) exit(1); } + replay_snapshot = g_strdup(qemu_opt_get(opts, "rrsnapshot")); + replay_enable(fname, mode); out: @@ -343,6 +346,10 @@ void replay_finish(void) g_free(replay_filename); replay_filename = NULL; } + if (replay_snapshot) { + g_free(replay_snapshot); + replay_snapshot = NULL; + } replay_finish_events(); replay_mutex_destroy(); diff --git a/vl.c b/vl.c index 9adca19..c0d43f0 100644 --- a/vl.c +++ b/vl.c @@ -460,6 +460,10 @@ static QemuOptsList qemu_icount_opts = { }, { .name = "rrfile", .type = QEMU_OPT_STRING, + }, { + .name = "rrsnapshot", + .type = QEMU_OPT_STRING, + .def_value_str = "replay_init" }, { /* end of list */ } }, @@ -4590,7 +4594,9 @@ int main(int argc, char **argv, char **envp) replay_checkpoint(CHECKPOINT_RESET); qemu_system_reset(VMRESET_SILENT); register_global_state(); - if (loadvm) { + if (replay_mode != REPLAY_MODE_NONE) { + replay_vmstate_init(); + } else if (loadvm) { if (load_vmstate(loadvm) < 0) { autostart = 0; }