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Re: [Qemu-devel] [PATCH v14 1/4] add a new runstate: RUN_STATE_GUEST_PAN
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH v14 1/4] add a new runstate: RUN_STATE_GUEST_PANICKED |
Date: |
Wed, 20 Mar 2013 09:58:04 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) |
Hu Tao <address@hidden> writes:
> The guest will be in this state when it is panicked.
>
> Signed-off-by: Wen Congyang <address@hidden>
> Signed-off-by: Hu Tao <address@hidden>
> ---
> include/sysemu/sysemu.h | 1 +
> qapi-schema.json | 5 ++++-
> qmp.c | 3 +--
> vl.c | 13 +++++++++++--
> 4 files changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> index b19ec95..0412a8a 100644
> --- a/include/sysemu/sysemu.h
> +++ b/include/sysemu/sysemu.h
> @@ -22,6 +22,7 @@ int qemu_uuid_parse(const char *str, uint8_t *uuid);
> bool runstate_check(RunState state);
> void runstate_set(RunState new_state);
> int runstate_is_running(void);
> +bool runstate_needs_reset(void);
> typedef struct vm_change_state_entry VMChangeStateEntry;
> typedef void VMChangeStateHandler(void *opaque, int running, RunState state);
>
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 28b070f..003cbf2 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -174,11 +174,14 @@
> # @suspended: guest is suspended (ACPI S3)
> #
> # @watchdog: the watchdog action is configured to pause and has been
> triggered
> +#
> +# @guest-panicked: guest has been panicked as a result of guest OS panic
> ##
> { 'enum': 'RunState',
> 'data': [ 'debug', 'inmigrate', 'internal-error', 'io-error', 'paused',
> 'postmigrate', 'prelaunch', 'finish-migrate', 'restore-vm',
> - 'running', 'save-vm', 'shutdown', 'suspended', 'watchdog' ] }
> + 'running', 'save-vm', 'shutdown', 'suspended', 'watchdog',
> + 'guest-panicked' ] }
>
> ##
> # @SnapshotInfo
RUN_STATE_GUEST_PANICKED is similar to RUN_STATE_INTERNAL_ERROR and
RUN_STATE_SHUTDOWN: the only way for the guest to continue is reset.
Correct?
> diff --git a/qmp.c b/qmp.c
> index 55b056b..a1ebb5d 100644
> --- a/qmp.c
> +++ b/qmp.c
> @@ -149,8 +149,7 @@ void qmp_cont(Error **errp)
> {
> Error *local_err = NULL;
>
> - if (runstate_check(RUN_STATE_INTERNAL_ERROR) ||
> - runstate_check(RUN_STATE_SHUTDOWN)) {
> + if (runstate_needs_reset()) {
> error_set(errp, QERR_RESET_REQUIRED);
> return;
> } else if (runstate_check(RUN_STATE_SUSPENDED)) {
> diff --git a/vl.c b/vl.c
> index c03edf1..926822b 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -566,6 +566,7 @@ static const RunStateTransition
> runstate_transitions_def[] = {
> { RUN_STATE_RUNNING, RUN_STATE_SAVE_VM },
> { RUN_STATE_RUNNING, RUN_STATE_SHUTDOWN },
> { RUN_STATE_RUNNING, RUN_STATE_WATCHDOG },
> + { RUN_STATE_RUNNING, RUN_STATE_GUEST_PANICKED },
>
> { RUN_STATE_SAVE_VM, RUN_STATE_RUNNING },
>
This permits runstate_set(RUN_STATE_GUEST_PANICKED) in
RUN_STATE_RUNNING. Used in PATCH 3/4. Good.
> @@ -580,6 +581,8 @@ static const RunStateTransition
> runstate_transitions_def[] = {
> { RUN_STATE_WATCHDOG, RUN_STATE_RUNNING },
> { RUN_STATE_WATCHDOG, RUN_STATE_FINISH_MIGRATE },
>
> + { RUN_STATE_GUEST_PANICKED, RUN_STATE_PAUSED },
> +
> { RUN_STATE_MAX, RUN_STATE_MAX },
> };
This permits runstate_set(RUN_STATE_PAUSED) in RUN_STATE_GUEST_PANICKED.
An example for such a transition is in the last patch hunk: main loop
resetting the guest.
Let's examine the other transitions to RUN_STATE_PAUSED, and whether
they can now come from RUN_STATE_GUEST_PANICKED:
* gdb_read_byte()
No, because vm_stop() is protected by runstate_is_running() here.
* gdb_chr_event() case CHR_EVENT_OPENED
Can this happen in RUN_STATE_GUEST_PANICKED? Jan?
What about RUN_STATE_INTERNAL_ERROR and RUN_STATE_SHUTDOWN?
* gdb_sigterm_handler()
No, because vm_stop() is protected by runstate_is_running() here.
Aside: despite its name, this function handles SIGINT. Ugh.
* process_incoming_migration_co()
No, because we're in RUN_STATE_INMIGRATE here, aren't we? Juan?
* qmp_stop()
No, because vm_stop() calls do_vm_stop() to do the actual state
transition, which protects it by runstate_is_running().
We can ignore the conditional, it merely punts the vm_stop() to the
main loop.
Next question: RUN_STATE_INTERNAL_ERROR and RUN_STATE_SHUTDOWN may go to
RUN_STATE_FINISH_MIGRATE, but RUN_STATE_GUEST_PANICKED may not. Why?
>
> @@ -621,6 +624,13 @@ int runstate_is_running(void)
> return runstate_check(RUN_STATE_RUNNING);
> }
>
> +bool runstate_needs_reset(void)
> +{
> + return runstate_check(RUN_STATE_INTERNAL_ERROR) ||
> + runstate_check(RUN_STATE_SHUTDOWN) ||
> + runstate_check(RUN_STATE_GUEST_PANICKED);
> +}
> +
> StatusInfo *qmp_query_status(Error **errp)
> {
> StatusInfo *info = g_malloc0(sizeof(*info));
> @@ -1966,8 +1976,7 @@ static bool main_loop_should_exit(void)
> cpu_synchronize_all_states();
> qemu_system_reset(VMRESET_REPORT);
> resume_all_vcpus();
> - if (runstate_check(RUN_STATE_INTERNAL_ERROR) ||
> - runstate_check(RUN_STATE_SHUTDOWN)) {
> + if (runstate_needs_reset()) {
> runstate_set(RUN_STATE_PAUSED);
> }
> }