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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [Qemu-devel] [PATCH v6 2/5] shutdown: Prepare for use of an enum in reset/shutdown_request
Eric Blake <eblake@xxxxxxxxxx> writes:
> We want to track why a guest was shutdown; in particular, being able
> to tell the difference between a guest request (such as ACPI request)
> and host request (such as SIGINT) will prove useful to libvirt.
> Since all requests eventually end up changing shutdown_requested in
> vl.c, the logical change is to make that value track the reason,
> rather than its current 0/1 contents.
>
> Since command-line options control whether a reset request is turned
> into a shutdown request instead, the same treatment is given to
> reset_requested.
>
> This patch adds an internal enum ShutdownCause that describes reasons
> that a shutdown can be requested, and changes qemu_system_reset() to
> pass the reason through, although for now it is not reported. The
> enum could be exported via QAPI at a later date, if deemed necessary,
> but for now, there has not been a request to expose that much detail
> to end clients.
>
> For now, we only populate the reason with HOST_ERROR, along with FIXME
> comments that describe our plans for how to pass an actual correct
> reason.
In other words, replacing 0 by SHUTDOWN_CAUSE_NONE, and 1 by
SHUTDOWN_CAUSE_HOST_ERROR. Makes sense.
> The next patches will then actually wire things up to modify
> events to report data based on the reason, and to pass the correct enum
> value in from various call-sites that can trigger a reset/shutdown (big
> enough that it was worth splitting from this patch).
>
> Signed-off-by: Eric Blake <eblake@xxxxxxxxxx>
>
> ---
> v6: make ShutdownCause internal-only, add SHUTDOWN_CAUSE_NONE so that
> comparison to 0 still works, tweak initial FIXME values
> v5: no change
> v4: s/ShutdownType/ShutdownCause/, no thanks to mingw header pollution
> v3: new patch
> ---
> include/sysemu/sysemu.h | 22 ++++++++++++++++++---
> vl.c | 51
> +++++++++++++++++++++++++++++++------------------
> hw/i386/xen/xen-hvm.c | 7 +++++--
> migration/colo.c | 2 +-
> migration/savevm.c | 2 +-
> 5 files changed, 58 insertions(+), 26 deletions(-)
>
> diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> index 16175f7..e4da9d4 100644
> --- a/include/sysemu/sysemu.h
> +++ b/include/sysemu/sysemu.h
> @@ -36,6 +36,22 @@ void vm_state_notify(int running, RunState state);
> #define VMRESET_SILENT false
> #define VMRESET_REPORT true
>
> +/* Enumeration of various causes for shutdown. */
> +typedef enum ShutdownCause ShutdownCause;
> +enum ShutdownCause {
Why define the typedef separately here? What's wrong with
typedef enum ShutdownCause {
...
} ShutdownCause;
?
> + SHUTDOWN_CAUSE_NONE, /* No shutdown requested yet */
Comment is fine. Possible alternative: /* No shutdown request pending */
> + SHUTDOWN_CAUSE_HOST_QMP, /* Reaction to a QMP command, like 'quit'
> */
> + SHUTDOWN_CAUSE_HOST_SIGNAL, /* Reaction to a signal, such as SIGINT */
> + SHUTDOWN_CAUSE_HOST_UI, /* Reaction to UI event, like window close
> */
> + SHUTDOWN_CAUSE_HOST_ERROR, /* An error prevents further use of guest
> */
> + SHUTDOWN_CAUSE_GUEST_SHUTDOWN,/* Guest requested shutdown, such as via
> + ACPI or other hardware-specific means */
> + SHUTDOWN_CAUSE_GUEST_RESET, /* Guest requested reset, and command line
> + turns that into a shutdown */
> + SHUTDOWN_CAUSE_GUEST_PANIC, /* Guest panicked, and command line turns
> + that into a shutdown */
> +};
> +
> void vm_start(void);
> int vm_prepare_start(void);
> int vm_stop(RunState state);
> @@ -62,10 +78,10 @@ void qemu_system_debug_request(void);
> void qemu_system_vmstop_request(RunState reason);
> void qemu_system_vmstop_request_prepare(void);
> bool qemu_vmstop_requested(RunState *r);
> -int qemu_shutdown_requested_get(void);
> -int qemu_reset_requested_get(void);
> +ShutdownCause qemu_shutdown_requested_get(void);
> +ShutdownCause qemu_reset_requested_get(void);
> void qemu_system_killed(int signal, pid_t pid);
> -void qemu_system_reset(bool report);
> +void qemu_system_reset(bool report, ShutdownCause reason);
> void qemu_system_guest_panicked(GuestPanicInformation *info);
> size_t qemu_target_page_size(void);
>
> diff --git a/vl.c b/vl.c
> index f22a3ac..6069fb2 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1597,8 +1597,9 @@ void vm_state_notify(int running, RunState state)
> }
> }
>
> -static int reset_requested;
> -static int shutdown_requested, shutdown_signal;
> +static ShutdownCause reset_requested;
> +static ShutdownCause shutdown_requested;
> +static int shutdown_signal;
> static pid_t shutdown_pid;
> static int powerdown_requested;
> static int debug_requested;
> @@ -1612,19 +1613,19 @@ static NotifierList wakeup_notifiers =
> NOTIFIER_LIST_INITIALIZER(wakeup_notifiers);
> static uint32_t wakeup_reason_mask = ~(1 << QEMU_WAKEUP_REASON_NONE);
>
> -int qemu_shutdown_requested_get(void)
> +ShutdownCause qemu_shutdown_requested_get(void)
> {
> return shutdown_requested;
> }
>
> -int qemu_reset_requested_get(void)
> +ShutdownCause qemu_reset_requested_get(void)
> {
> return reset_requested;
> }
>
> static int qemu_shutdown_requested(void)
> {
> - return atomic_xchg(&shutdown_requested, 0);
> + return atomic_xchg(&shutdown_requested, SHUTDOWN_CAUSE_NONE);
> }
>
> static void qemu_kill_report(void)
> @@ -1647,14 +1648,14 @@ static void qemu_kill_report(void)
> }
> }
>
> -static int qemu_reset_requested(void)
> +static ShutdownCause qemu_reset_requested(void)
> {
> - int r = reset_requested;
> + ShutdownCause r = reset_requested;
Good opportunity to insert a blank line here.
> if (r && replay_checkpoint(CHECKPOINT_RESET_REQUESTED)) {
> - reset_requested = 0;
> + reset_requested = SHUTDOWN_CAUSE_NONE;
> return r;
> }
> - return false;
> + return SHUTDOWN_CAUSE_NONE;
> }
>
> static int qemu_suspend_requested(void)
> @@ -1686,7 +1687,12 @@ static int qemu_debug_requested(void)
> return r;
> }
>
> -void qemu_system_reset(bool report)
> +/*
> + * Reset the VM. If @report is VMRESET_REPORT, issue an event, using
> + * the @reason interpreted as ShutdownCause for details. Otherwise,
> + * @report is VMRESET_SILENT and @reason is ignored.
> + */
"interpreted as ShutdownCause"? It *is* a ShutdownCause. Leftover?
> +void qemu_system_reset(bool report, ShutdownCause reason)
> {
> MachineClass *mc;
>
> @@ -1700,6 +1706,7 @@ void qemu_system_reset(bool report)
> qemu_devices_reset();
> }
> if (report) {
> + assert(reason);
> qapi_event_send_reset(&error_abort);
> }
> cpu_synchronize_all_post_reset();
Looks like we're not using @reason "for details" just yet.
> @@ -1738,9 +1745,10 @@ void qemu_system_guest_panicked(GuestPanicInformation
> *info)
> void qemu_system_reset_request(void)
> {
> if (no_reboot) {
> - shutdown_requested = 1;
> + /* FIXME - add a parameter to allow callers to specify reason */
> + shutdown_requested = SHUTDOWN_CAUSE_HOST_ERROR;
> } else {
> - reset_requested = 1;
> + reset_requested = SHUTDOWN_CAUSE_HOST_ERROR;
> }
> cpu_stop_current();
> qemu_notify_event();
> @@ -1807,7 +1815,7 @@ void qemu_system_killed(int signal, pid_t pid)
> /* Cannot call qemu_system_shutdown_request directly because
> * we are in a signal handler.
> */
> - shutdown_requested = 1;
> + shutdown_requested = SHUTDOWN_CAUSE_HOST_SIGNAL;
Should this be SHUTDOWN_CAUSE_HOST_ERROR, to be updated in the next
patch? Alternatively, tweak this patch's commit message?
> qemu_notify_event();
> }
>
> @@ -1815,7 +1823,8 @@ void qemu_system_shutdown_request(void)
> {
> trace_qemu_system_shutdown_request();
> replay_shutdown_request();
> - shutdown_requested = 1;
> + /* FIXME - add a parameter to allow callers to specify reason */
> + shutdown_requested = SHUTDOWN_CAUSE_HOST_ERROR;
> qemu_notify_event();
> }
>
> @@ -1846,13 +1855,16 @@ void qemu_system_debug_request(void)
> static bool main_loop_should_exit(void)
> {
> RunState r;
> + ShutdownCause request;
> +
> if (qemu_debug_requested()) {
> vm_stop(RUN_STATE_DEBUG);
> }
> if (qemu_suspend_requested()) {
> qemu_system_suspend();
> }
> - if (qemu_shutdown_requested()) {
> + request = qemu_shutdown_requested();
> + if (request) {
> qemu_kill_report();
> qapi_event_send_shutdown(&error_abort);
> if (no_shutdown) {
The detour through @request appears isn't necessary here. Perhaps you
do it for consistency with the next hunk. Do you? Just asking to make
sure I get what you're doing.
Hmm, there's another one in xen-hvm.c, but consistency hardly applies
there. If later patches add more uses, you might want delay the change
until then.
> @@ -1861,9 +1873,10 @@ static bool main_loop_should_exit(void)
> return true;
> }
> }
> - if (qemu_reset_requested()) {
> + request = qemu_reset_requested();
> + if (request) {
> pause_all_vcpus();
> - qemu_system_reset(VMRESET_REPORT);
> + qemu_system_reset(VMRESET_REPORT, request);
> resume_all_vcpus();
> if (!runstate_check(RUN_STATE_RUNNING) &&
> !runstate_check(RUN_STATE_INMIGRATE)) {
> @@ -1872,7 +1885,7 @@ static bool main_loop_should_exit(void)
> }
> if (qemu_wakeup_requested()) {
> pause_all_vcpus();
> - qemu_system_reset(VMRESET_SILENT);
> + qemu_system_reset(VMRESET_SILENT, SHUTDOWN_CAUSE_NONE);
> notifier_list_notify(&wakeup_notifiers, &wakeup_reason);
> wakeup_reason = QEMU_WAKEUP_REASON_NONE;
> resume_all_vcpus();
> @@ -4686,7 +4699,7 @@ int main(int argc, char **argv, char **envp)
> reading from the other reads, because timer polling functions query
> clock values from the log. */
> replay_checkpoint(CHECKPOINT_RESET);
> - qemu_system_reset(VMRESET_SILENT);
> + qemu_system_reset(VMRESET_SILENT, SHUTDOWN_CAUSE_NONE);
> register_global_state();
> if (replay_mode != REPLAY_MODE_NONE) {
> replay_vmstate_init();
> diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
> index b1c05ff..b1001c1 100644
> --- a/hw/i386/xen/xen-hvm.c
> +++ b/hw/i386/xen/xen-hvm.c
> @@ -1089,11 +1089,14 @@ static void cpu_handle_ioreq(void *opaque)
> * causes Xen to powerdown the domain.
> */
> if (runstate_is_running()) {
> + ShutdownCause request;
> +
> if (qemu_shutdown_requested_get()) {
> destroy_hvm_domain(false);
> }
> - if (qemu_reset_requested_get()) {
> - qemu_system_reset(VMRESET_REPORT);
> + request = qemu_reset_requested_get();
> + if (request) {
> + qemu_system_reset(VMRESET_REPORT, request);
> destroy_hvm_domain(true);
> }
> }
> diff --git a/migration/colo.c b/migration/colo.c
> index 963c802..bf5b7e9 100644
> --- a/migration/colo.c
> +++ b/migration/colo.c
> @@ -623,7 +623,7 @@ void *colo_process_incoming_thread(void *opaque)
> }
>
> qemu_mutex_lock_iothread();
> - qemu_system_reset(VMRESET_SILENT);
> + qemu_system_reset(VMRESET_SILENT, SHUTDOWN_CAUSE_NONE);
> vmstate_loading = true;
> if (qemu_loadvm_state(fb) < 0) {
> error_report("COLO: loadvm failed");
> diff --git a/migration/savevm.c b/migration/savevm.c
> index a00c1ab..9ac2d22 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -2300,7 +2300,7 @@ int load_vmstate(const char *name)
> return -EINVAL;
> }
>
> - qemu_system_reset(VMRESET_SILENT);
> + qemu_system_reset(VMRESET_SILENT, SHUTDOWN_CAUSE_NONE);
> mis->from_src_file = f;
>
> aio_context_acquire(aio_context);
You seem to be passing SHUTDOWN_CAUSE_NONE exactly with VMRESET_SILENT.
Would it be possible to have SHUTDOWN_CAUSE_NONE imply !report, any
other case imply report, and get rid of the first parameter?
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