Re: [Qemu-devel] [Qemu-ppc] [PATCH] pseries: Correct panic behaviour for pseries machine type

[David Gibson]

On Wed, Jun 07, 2017 at 07:10:55PM +0200, Thomas Huth wrote:
> On 07.06.2017 16:34, Paolo Bonzini wrote:
> > 
> > 
> > On 07/06/2017 09:33, Thomas Huth wrote:
> >> On 07.06.2017 09:07, David Gibson wrote:
> >>> The pseries machine type doesn't usually use the 'pvpanic' device as such,
> >>> because it has a firmware/hypervisor facility with roughly the same
> >>> purpose.  The 'ibm,os-term' RTAS call notifies the hypervisor that the
> >>> guest has crashed.
> >>>
> >>> Our implementation of this call was sending a GUEST_PANICKED qmp event;
> >>> however, it was not doing the other usual panic actions, making its
> >>> behaviour different from pvpanic for no good reason.
> >>>
> >>> To correct this, we should call qemu_system_guest_panicked() rather than
> >>> directly sending the panic event.
> >>>
> >>> Signed-off-by: David Gibson <address@hidden>
> >>> ---
> >>>  hw/ppc/spapr_rtas.c | 7 ++-----
> >>>  1 file changed, 2 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> >>> index 707c4d4..94a2799 100644
> >>> --- a/hw/ppc/spapr_rtas.c
> >>> +++ b/hw/ppc/spapr_rtas.c
> >>> @@ -293,12 +293,9 @@ static void rtas_ibm_os_term(PowerPCCPU *cpu,
> >>>                              target_ulong args,
> >>>                              uint32_t nret, target_ulong rets)
> >>>  {
> >>> -    target_ulong ret = 0;
> >>> +    qemu_system_guest_panicked(NULL);
> >>>  
> >>> -    qapi_event_send_guest_panicked(GUEST_PANIC_ACTION_PAUSE, false, NULL,
> >>> -                                   &error_abort);
> >>> -
> >>> -    rtas_st(rets, 0, ret);
> >>> +    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
> >>>  }
> >>>  
> >>>  static void rtas_set_power_level(PowerPCCPU *cpu, sPAPRMachineState 
> >>> *spapr,
> >>>
> >>
> >> If I get that qemu_system_guest_panicked() function right, it will stop
> >> the VM, won't it? That contradicts the LoPAPR spec that says that the
> >> RTAS call returns if the "ibm,extended-os-term" property is available in
> >> the device tree.
> > 
> > It does return... but only after the user starts the guest again with
> > "cont".
> 
> OK, I guess that's enough to say that the "ibm,extended-os-term"
> property can stay ... so I think the patch is fine as it is right now.

So.. can I have an R-b?

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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