Re: [Xen-devel] [PATCH][RESEND] xm reboot for vmx domain

[Ewan Mellor <ewan@xxxxxxxxxxxxx>]

On Thu, Nov 10, 2005 at 06:08:52PM +0800, Yu, Ke wrote:

> This patch fixes the bug that "xm reboot <domid>" can not reboot vmx
> domain.
> 
> In xm reboot process, control panel will wait until DomU notified it.
> Unlike DomU, vmx domain can not passively do that, since it runs
> unmodified OS. This patch adds the missing logic in control panel.
> Any comment? 
> 
> Signed-off-by: Xu Dan <dan.d.xu@xxxxxxxxx >
>              Yu Ke <ke.yu@xxxxxxxxx>

Content-Description: reboot1.patch
> [-- mutt.octet.filter file type: "'diff' output text" --]
> 
> [-- Statistics (lines words chars):  29 118 1176 /tmp/reboot1.patch --]
> 
> diff -r 0240a69e1f97 tools/python/xen/xend/XendDomainInfo.py
> --- a/tools/python/xen/xend/XendDomainInfo.py Wed Oct 26 13:59:29 2005
> +++ b/tools/python/xen/xend/XendDomainInfo.py Thu Oct 27 17:03:08 2005
> @@ -680,6 +680,14 @@
>          """Get this domain's target memory size, in KiB."""
>          return self.info['memory_KiB']
>  
> +    def vmx_get_xeninfo(self, xeninfo):
> +        """Get vmx xeninfo"""
> +        shutdown_reason = self.readDom('control/shutdown')
> +        if shutdown_reason:
> +            xeninfo['shutdown'] = 1
> +            for x in shutdown_reasons.keys():
> +                if shutdown_reasons[x] == shutdown_reason:
> +                    xeninfo['shutdown_reason'] = x
>  
>      def refreshShutdown(self, xeninfo = None):
>          # If set at the end of this method, a restart is required, with the
> @@ -701,6 +709,10 @@
>                      # machine.
>                      self.cleanupDomain()
>                      return
> +
> +            if self.image:
> +                if self.image.ostype == "vmx":
> +                    self.vmx_get_xeninfo(xeninfo)
>  
>              if xeninfo['dying']:
>                  # Dying means that a domain has been destroyed, but has not

Thanks for your resend, and sorry for not replying sooner.

The reason I did not apply this immediately is that I am concerned by the
arrangement here.  Up until now, all VMX-related code has been isolated in
image.py, but your patch brings VMX code directly into XendDomainInfo.py, and
I would like to avoid doing that if possible.

I am also concerned about race conditions.  The control/shutdown node is used
to tell the domain to shut down, but you are using it also as a flag to tell
Xend that the domain has actually shut down.  This means that if
refreshShutdown is called before the VMX guest has had time to see a new
control/shutdown entry, then Xend will think that the domain has shut down
even before it has started to do so.

I think that this patch needs some thought before it goes in.  Perhaps we
could discuss my concerns and move forward from there.

Thanks,

Ewan.

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