[libvirt] [PATCH v2 2/2] qemu_process: detect updated video ram size values from QEMU

[Daniel P. Berrange]

On Fri, Jan 09, 2015 at 10:02:07AM +0100, Pavel Hrdina wrote:
> QEMU internally updates the size of video memory if the domain XML had
> provided too low memory size or there are some dependencies for a QXL
> devices 'vgamem' and 'ram' size. We need to know about the changes and
> store them into the status XML to not break migration or managedsave
> through different libvirt versions.
> 
> Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
> ---
>  src/qemu/qemu_monitor.c      | 38 ++++++++++++++++++++++++
>  src/qemu/qemu_monitor.h      |  4 +++
>  src/qemu/qemu_monitor_json.c | 69 ++++++++++++++++++++++++++++++++++++++++++
>  src/qemu/qemu_monitor_json.h |  3 ++
>  src/qemu/qemu_process.c      | 71 ++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 185 insertions(+)
> 
> diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
> index 55f07f3..45bb62f 100644
> --- a/src/qemu/qemu_monitor.c
> +++ b/src/qemu/qemu_monitor.c
> @@ -1154,6 +1154,44 @@ qemuMonitorFindBalloonObjectPath(qemuMonitorPtr mon,
>      return ret;
>  }
>  
> +
> +/**
> + * To update video memory size in status XML we need to load correct values from
> + * QEMU.  This is supported only with JSON monitor.
> + *
> + * Returns 0 on success, -1 on failure and sets proper error message.
> + */
> +int
> +qemuMonitorUpdateVideoMemorySize(qemuMonitorPtr mon,
> +                                 virDomainVideoDefPtr video,
> +                                 const char *videoName)
> +{
> +    int ret = -1;
> +    char *path = NULL;
> +
> +    if (mon->json) {
> +        if (qemuMonitorFindObjectPath(mon, "/", videoName, &path) < 0) {
> +            virReportError(VIR_ERR_INTERNAL_ERROR,
> +                           _("Failed to find QOM Object path for device '%s'"),
> +                           videoName);
> +            return -1;
> +        }
> +        if (qemuMonitorJSONUpdateVideoMemorySize(mon, video, path) < 0)
> +            goto cleanup;
> +    } else {
> +        virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
> +                       _("JSON monitor is required"));
> +        return -1;
> +    }

This fatal error is going to break all guest startup with non-json
monitor IIUC.

Regards,
Daniel
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