[libvirt] [PATCH 2/3] setting QEMU_CAPS_WAKEUP_SUSPEND_SUPPORT qemu capability

[Peter Krempa]

On Mon, Apr 01, 2019 at 18:18:25 -0300, Daniel Henrique Barboza wrote:
> QEMU_CAPS_WAKEUP_SUSPEND_SUPPORT is a bool that represents the value
> of the wakeup-suspend-support flag of the new query-current-machine
> QMP API, available in QEMU 4.0.
> 
> The flag is set in qemuProcessLaunch, using a new function called
> qemuProcessSetupWakeupSuspendSupport. This function checks first
> if the QEMU process has support for the new API, which is reflected
> by the QEMU_CAPS_QUERY_CURRENT_MACHINE cap. If positive, query it
> and set QEMU_CAPS_WAKEUP_SUSPEND_SUPPORT with the current value
> of wakeup-suspend-support.
> ---
>  src/qemu/qemu_monitor.c      |  8 ++++++++
>  src/qemu/qemu_monitor.h      |  3 +++
>  src/qemu/qemu_monitor_json.c | 35 +++++++++++++++++++++++++++++++++
>  src/qemu/qemu_monitor_json.h |  4 ++++
>  src/qemu/qemu_process.c      | 38 ++++++++++++++++++++++++++++++++++++
>  5 files changed, 88 insertions(+)
> 
> diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
> index babcbde878..fc6dc2197a 100644
> --- a/src/qemu/qemu_monitor.c
> +++ b/src/qemu/qemu_monitor.c
> @@ -4472,3 +4472,11 @@ qemuMonitorGetPRManagerInfo(qemuMonitorPtr mon,
>      virHashFree(info);
>      return ret;
>  }
> +
> +int
> +qemuMonitorGetWakeupSuspendSupport(qemuMonitorPtr mon, bool *enabled)
> +{
> +    QEMU_CHECK_MONITOR(mon);
> +
> +    return qemuMonitorJSONGetWakeupSuspendSupport(mon, enabled);
> +}
> diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
> index 086195ff98..62074c1acb 100644
> --- a/src/qemu/qemu_monitor.h
> +++ b/src/qemu/qemu_monitor.h
> @@ -1220,4 +1220,7 @@ struct _qemuMonitorPRManagerInfo {
>  int qemuMonitorGetPRManagerInfo(qemuMonitorPtr mon,
>                                  virHashTablePtr *retinfo);
>  
> +int qemuMonitorGetWakeupSuspendSupport(qemuMonitorPtr mon,
> +                                       bool *enabled);
> +
>  #endif /* LIBVIRT_QEMU_MONITOR_H */
> diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
> index 743a88b914..16d34fb217 100644
> --- a/src/qemu/qemu_monitor_json.c
> +++ b/src/qemu/qemu_monitor_json.c
> @@ -8452,3 +8452,38 @@ qemuMonitorJSONGetPRManagerInfo(qemuMonitorPtr mon,
>      return ret;
>  
>  }
> +
> +int
> +qemuMonitorJSONGetWakeupSuspendSupport(qemuMonitorPtr mon, bool *enabled)

This should be a generic function which returns all responses from
query-current-machine. Having a single-use one will make us refactor
this later.

The code in qemu_caps.c should then decide which ones to consider to use
as caps. You can inspire yourself in the way we detect e.g. command.s

> +{
> +    int ret = -1;
> +    virJSONValuePtr cmd, data;
> +    virJSONValuePtr reply = NULL;
> +
> +    if (!(cmd = qemuMonitorJSONMakeCommand("query-current-machine",
> +                                           NULL)))
> +        return -1;
> +
> +    if (qemuMonitorJSONCommand(mon, cmd, &reply) < 0)
> +        goto cleanup;
> +
> +    if (qemuMonitorJSONCheckReply(cmd, reply, VIR_JSON_TYPE_OBJECT) < 0)
> +        goto cleanup;
> +
> +    data = virJSONValueObjectGetObject(reply, "return");
> +
> +    if (virJSONValueObjectGetBoolean(data, "wakeup-suspend-support",
> +                                     enabled)) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> +                       _("missing wakeup-suspend-support in "
> +                         "query-current-machine response"));
> +        goto cleanup;
> +    }
> +
> +    ret = 0;
> +
> + cleanup:
> +    virJSONValueFree(cmd);
> +    virJSONValueFree(reply);
> +    return ret;
> +}
> diff --git a/src/qemu/qemu_monitor_json.h b/src/qemu/qemu_monitor_json.h
> index c10513da15..ede828d622 100644
> --- a/src/qemu/qemu_monitor_json.h
> +++ b/src/qemu/qemu_monitor_json.h
> @@ -576,4 +576,8 @@ int qemuMonitorJSONGetPRManagerInfo(qemuMonitorPtr mon,
>                                      virHashTablePtr info)
>      ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
>  
> +int qemuMonitorJSONGetWakeupSuspendSupport(qemuMonitorPtr mon,
> +                                           bool *enabled)
> +    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
> +
>  #endif /* LIBVIRT_QEMU_MONITOR_JSON_H */
> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
> index dc7317b723..71984714de 100644
> --- a/src/qemu/qemu_process.c
> +++ b/src/qemu/qemu_process.c
> @@ -6449,6 +6449,41 @@ qemuProcessSetupDiskThrottlingBlockdev(virQEMUDriverPtr driver,
>      return ret;
>  }
>  
> +/**
> + * qemuProcessSetupWakeupSuspendSupport:
> + *
> + * Sets up QEMU_CAPS_WAKEUP_SUSPEND_SUPPORT in case QEMU has support
> + * for the query-current-machine QMP API. This can be verified by
> + * checking for the QEMU_CAPS_QUERY_CURRENT_MACHINE cap.
> + */
> +static int
> +qemuProcessSetupWakeupSuspendSupport(virQEMUDriverPtr driver,
> +                                       virDomainObjPtr vm,
> +                                       qemuDomainAsyncJob asyncJob)

Again please make this more generic so that the next person does not
have to refactor it.

> +{
> +    qemuDomainObjPrivatePtr priv = vm->privateData;
> +    bool enabled;
> +    int ret = -1;
> +
> +    if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_QUERY_CURRENT_MACHINE))
> +        return 0;
> +
> +    if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
> +        return -1;
> +
> +    if (qemuMonitorGetWakeupSuspendSupport(qemuDomainGetMonitor(vm), &enabled) < 0)
> +        goto cleanup;
> +
> +    if (enabled)
> +        virQEMUCapsSet(priv->qemuCaps, QEMU_CAPS_WAKEUP_SUSPEND_SUPPORT);

You don't have the lock on @vm until you exit the monitor so @priv
should not be modified.

> +
> +    ret = 0;
> +
> + cleanup:
> +    if (qemuDomainObjExitMonitor(driver, vm) < 0)
> +        ret = -1;
> +    return ret;
> +}
>  
>  /**
>   * qemuProcessLaunch:
> @@ -6777,6 +6812,9 @@ qemuProcessLaunch(virConnectPtr conn,
>          qemuProcessAutoDestroyAdd(driver, vm, conn) < 0)
>          goto cleanup;
>  
> +    if (qemuProcessSetupWakeupSuspendSupport(driver, vm, asyncJob) < 0)
> +        goto cleanup;
> +
>      ret = 0;
>  
>   cleanup:
> -- 
> 2.20.1
> 
> --
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> libvir-list at redhat.com
> https://www.redhat.com/mailman/listinfo/libvir-list
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