Re: [Xen-devel] [PATCH] xen/pvhvm: add soft reset on kexec/kdump support

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 09/25/2015 03:35 PM, Konrad Rzeszutek Wilk wrote:
> On Fri, Sep 25, 2015 at 03:19:57PM -0400, Boris Ostrovsky wrote:
> > On 09/25/2015 03:01 PM, Konrad Rzeszutek Wilk wrote:
> > > On Fri, Sep 25, 2015 at 01:17:40PM -0400, Boris Ostrovsky wrote:
> > > > On 09/25/2015 12:07 PM, Vitaly Kuznetsov wrote:
> > > > > > Also, I am not sure I see how this new op will be used in the
> > > > > > hypervisor --- currently AFAICS it is only processed under
> > > > > > is_hardware_domain(). Are there other patches that will support HVM
> > > > > > guests?
> > > > > Please see my Xen series:
> > > > > http://lists.xenproject.org/archives/html/xen-devel/2015-09/msg00547.html
> > > > > (last 'full' submission).
> > > > >
> > > > > All patches from my 'toolstack-assisted approach to PVHVM guest kexec'
> > > > > are already merged to xen.git (first 10 are already in 'master' and the
> > > > > last one is in 'staging').
> > > > OK, so I was looking at the right tree. Then I don't understand how
> > > > SHUTDOWN_soft_reset would be reached for a non-privileged domain. The only
> > > > path that I see is
> > > >
> > > >      domain_shutdown()
> > > >      {
> > > >          ...
> > > >          if ( is_hardware_domain(d) )
> > > >              hwdom_shutdown(reason);
> > > >          ...
> > > >      }
> > > >
> > > > Is there another path to handle this op?
> > > Yes:
> > >   e1bd9812966de9a16f30a58e7162b80bd6af361b libxc: support XEN_DOMCTL_soft_reset 
> > > operation
> > > and
> > >   c57e6ebd8c3e490e353e68d96abec1dad01e72f5 (lib)xl: soft reset support
> > That's toolstack issuing hypercalls from dom0.
> >
> > I am asking about (non-privileged) guest itself calling SCHEDOP_shutdown.
> The hypervisor ends up calling:
> __domain_finalise_shutdown which sends an VIRQ_DOM_EXC to dom0 which
> makes the toolstack do all of those operations.
OK. But the I don't see anyone checking that 'reason' (or 
'shutdown_code') is SHUTDOWN_soft_reset. In other words, the guest can 
do 'xen_reboot(23)' or 'xen_reboot(154)'. Or, it seems, even 
'xen_reboot(SHUTDOWN_reboot)'? The only value it shouldn't be is 
SHUTDOWN_suspend.
-boris


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