Re: [Qemu-devel] [Qemu-ppc] [for-2.11 PATCH 16/26] spapr: enable PHB hotplug for pseries-2.11

[Michael Roth]

Quoting Greg Kurz (2017-07-26 09:32:27)
> On Wed, 26 Jul 2017 14:42:23 +1000
> Alexey Kardashevskiy <address@hidden> wrote:
> 
> > On 26/07/17 04:01, Greg Kurz wrote:
> > > From: Michael Roth <address@hidden>
> > > 
> > > The 'dr_phb_enabled' field of that class can be set as
> > > part of machine-specific init code, and is then propagated
> > > to sPAPREnvironment to conditionally enable creation of DRC
> > > objects and device-tree description to facilitate hotplug
> > > of PHBs.
> > > 
> > > Since we can't migrate this state to older machine types,
> > > default the option to true and disable it for older machine
> > > types.
> > > 
> > > Signed-off-by: Michael Roth <address@hidden>
> > > Signed-off-by: Greg Kurz <address@hidden>
> > > ---
> > > Changes since RFC:
> > > - rebased against ppc-for-2.10
> > > - updated changelog and title
> > > - set default to true and disable for 2.10 and older
> > > ---
> > >  hw/ppc/spapr.c         |    6 ++++++
> > >  include/hw/ppc/spapr.h |    3 +++
> > >  2 files changed, 9 insertions(+)
> > > 
> > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > > index 277daa4f9645..8dc505343c0f 100644
> > > --- a/hw/ppc/spapr.c
> > > +++ b/hw/ppc/spapr.c
> > > @@ -2382,6 +2382,8 @@ static void ppc_spapr_init(MachineState *machine)
> > >      /* We always have at least the nvram device on VIO */
> > >      spapr_create_nvram(spapr);
> > >  
> > > +    spapr->dr_phb_enabled = smc->dr_phb_enabled;
> > > +
> > >      /* Set up PCI */
> > >      spapr_pci_rtas_init();
> > >  
> > > @@ -3482,6 +3484,7 @@ static void spapr_machine_class_init(ObjectClass 
> > > *oc, void *data)
> > >       * in which LMBs are represented and hot-added
> > >       */
> > >      mc->numa_mem_align_shift = 28;
> > > +    smc->dr_phb_enabled = true;
> > >  }
> > >  
> > >  static const TypeInfo spapr_machine_info = {
> > > @@ -3558,8 +3561,11 @@ static void 
> > > spapr_machine_2_10_instance_options(MachineState *machine)
> > >  
> > >  static void spapr_machine_2_10_class_options(MachineClass *mc)
> > >  {
> > > +    sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
> > > +
> > >      spapr_machine_2_11_class_options(mc);
> > >      SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_10);
> > > +    smc->dr_phb_enabled = false;
> > >  }
> > >  
> > >  DEFINE_SPAPR_MACHINE(2_10, "2.10", false);
> > > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> > > index 2a303a705c17..8004d9c2ab2c 100644
> > > --- a/include/hw/ppc/spapr.h
> > > +++ b/include/hw/ppc/spapr.h
> > > @@ -59,6 +59,7 @@ struct sPAPRMachineClass {
> > >  
> > >      /*< public >*/
> > >      bool dr_lmb_enabled;       /* enable dynamic-reconfig/hotplug of 
> > > LMBs */
> > > +    bool dr_phb_enabled;       /* enable dynamic-reconfig/hotplug of 
> > > PHBs */
> > >      bool use_ohci_by_default;  /* use USB-OHCI instead of XHCI */
> > >      const char *tcg_default_cpu; /* which (TCG) CPU to simulate by 
> > > default */
> > >      bool pre_2_10_has_unused_icps;
> > > @@ -122,6 +123,8 @@ struct sPAPRMachineState {
> > >       * occurs during the unplug process. */
> > >      QTAILQ_HEAD(, sPAPRDIMMState) pending_dimm_unplugs;
> > >  
> > > +    bool dr_phb_enabled; /* hotplug / dynamic-reconfiguration of PHBs */ 
> > >  
> > 
> > The one in the class seems sufficient unless we are going to allow
> > disabling this via the command line.
> > 
> 
> I kept the original patch but you're right indeed. I don't see why
> someone would want to disable this from the cmdline, so I guess I
> should just drop the per-instance flag.
> 
> Mike, any thoughts ?

Not sure why I did it like that originally, and can't think of a good reason
we'd want to disable it specifically either, so I agree we should probably
just drop it.

> 
> > 
> > 
> > > +
> > >      /*< public >*/
> > >      char *kvm_type;
> > >      MemoryHotplugState hotplug_memory;
> > > 
> > >   
> > 
> > 
>