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

[Boris Ostrovsky]

On 09/29/2015 07:39 AM, Vitaly Kuznetsov wrote:
> Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> writes:
>
> > 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.
> Xen hypervisor doesn't analyzie the reason, it is being analyzed by the
> toolstack (XEN_DOMCTL_getdomaininfo returns this info encoded in flags
> with XEN_DOMINF_shutdownshift shift).

Thanks.

My problem was that I didn't realize that toolstack generates macros for 
shutdown reasons from libxl_types.idl and I couldn't see who looks for 
SHUTDOWN_soft_reset.

-boris

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