Re: [PATCH 5/6] spapr: Don't use CPU_FOREACH() in 'info pic'

[Greg Kurz <groug@kaod.org>]

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On Thu, 24 Oct 2019 14:02:31 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> On Wed, Oct 23, 2019 at 04:52:21PM +0200, Greg Kurz wrote:
> > Now that presenter objects are parented to the interrupt controller, stop
> > relying on CPU_FOREACH() which can race with CPU hotplug and crash QEMU.
> > 
> > Signed-off-by: Greg Kurz <groug@kaod.org>
> 
> So.. we might be able to go further than this.  Having the
> TYPE_INTERRUPT_STATS_PROVIDER interrupt on the machine is actually an
> spapr and pnv oddity.  In most cases that interface is on the various
> components of the interrupt controller directly.  hmp_info_irq() scans
> the whole QOM tree looking for everything with the interface to
> produce the info pic output.
> 
> It would be nice if we can do the same for xics and xive.  The tricky
> bit is that we do have the possibility of both, in which case the
> individual components would need to know if they're currently "active"
> and minimize their output if so.
> 

Yes but this looks like 4.3 material. If we want to fix this for 4.2,
I'm now thinking it might be safer to keep CPU_FOREACH() and check the
state.

> > ---
> >  hw/intc/spapr_xive.c  |    8 +-------
> >  hw/intc/xics.c        |   12 ++++++++++++
> >  hw/intc/xics_spapr.c  |    8 +-------
> >  hw/intc/xive.c        |   12 ++++++++++++
> >  include/hw/ppc/xics.h |    1 +
> >  include/hw/ppc/xive.h |    2 ++
> >  6 files changed, 29 insertions(+), 14 deletions(-)
> > 
> > diff --git a/hw/intc/spapr_xive.c b/hw/intc/spapr_xive.c
> > index d74ee71e76b4..05763a58cf5d 100644
> > --- a/hw/intc/spapr_xive.c
> > +++ b/hw/intc/spapr_xive.c
> > @@ -579,14 +579,8 @@ static void spapr_xive_set_irq(SpaprInterruptController *intc, int irq, int val)
> >  static void spapr_xive_print_info(SpaprInterruptController *intc, Monitor *mon)
> >  {
> >      SpaprXive *xive = SPAPR_XIVE(intc);
> > -    CPUState *cs;
> > -
> > -    CPU_FOREACH(cs) {
> > -        PowerPCCPU *cpu = POWERPC_CPU(cs);
> > -
> > -        xive_tctx_pic_print_info(spapr_cpu_state(cpu)->tctx, mon);
> > -    }
> >  
> > +    xive_presenter_print_info(XIVE_ROUTER(intc), mon);
> >      spapr_xive_pic_print_info(xive, mon);
> >  }
> >  
> > diff --git a/hw/intc/xics.c b/hw/intc/xics.c
> > index d5e4db668a4b..6e820c4851f3 100644
> > --- a/hw/intc/xics.c
> > +++ b/hw/intc/xics.c
> > @@ -88,6 +88,18 @@ void ics_pic_print_info(ICSState *ics, Monitor *mon)
> >      }
> >  }
> >  
> > +static int do_ics_pic_print_icp_infos(Object *child, void *opaque)
> > +{
> > +    icp_pic_print_info(ICP(child), opaque);
> > +    return 0;
> > +}
> > +
> > +void ics_pic_print_icp_infos(ICSState *ics, const char *type, Monitor *mon)
> > +{
> > +    object_child_foreach_type(OBJECT(ics), type, do_ics_pic_print_icp_infos,
> > +                              mon);
> > +}
> > +
> >  /*
> >   * ICP: Presentation layer
> >   */
> > diff --git a/hw/intc/xics_spapr.c b/hw/intc/xics_spapr.c
> > index 080ed73aad64..7624d693c8da 100644
> > --- a/hw/intc/xics_spapr.c
> > +++ b/hw/intc/xics_spapr.c
> > @@ -400,14 +400,8 @@ static void xics_spapr_set_irq(SpaprInterruptController *intc, int irq, int val)
> >  static void xics_spapr_print_info(SpaprInterruptController *intc, Monitor *mon)
> >  {
> >      ICSState *ics = ICS_SPAPR(intc);
> > -    CPUState *cs;
> > -
> > -    CPU_FOREACH(cs) {
> > -        PowerPCCPU *cpu = POWERPC_CPU(cs);
> > -
> > -        icp_pic_print_info(spapr_cpu_state(cpu)->icp, mon);
> > -    }
> >  
> > +    ics_pic_print_icp_infos(ics, TYPE_ICP, mon);
> >      ics_pic_print_info(ics, mon);
> >  }
> >  
> > diff --git a/hw/intc/xive.c b/hw/intc/xive.c
> > index 8d2da4a11163..40ce43152456 100644
> > --- a/hw/intc/xive.c
> > +++ b/hw/intc/xive.c
> > @@ -547,6 +547,18 @@ void xive_tctx_pic_print_info(XiveTCTX *tctx, Monitor *mon)
> >      }
> >  }
> >  
> > +static int do_xive_presenter_print_info(Object *child, void *opaque)
> > +{
> > +    xive_tctx_pic_print_info(XIVE_TCTX(child), opaque);
> > +    return 0;
> > +}
> > +
> > +void xive_presenter_print_info(XiveRouter *xrtr, Monitor *mon)
> > +{
> > +    object_child_foreach_type(OBJECT(xrtr), TYPE_XIVE_TCTX,
> > +                              do_xive_presenter_print_info, mon);
> > +}
> > +
> >  void xive_tctx_reset(XiveTCTX *tctx)
> >  {
> >      memset(tctx->regs, 0, sizeof(tctx->regs));
> > diff --git a/include/hw/ppc/xics.h b/include/hw/ppc/xics.h
> > index f4827e748fd8..4de1f421c997 100644
> > --- a/include/hw/ppc/xics.h
> > +++ b/include/hw/ppc/xics.h
> > @@ -175,6 +175,7 @@ static inline bool ics_irq_free(ICSState *ics, uint32_t srcno)
> >  void ics_set_irq_type(ICSState *ics, int srcno, bool lsi);
> >  void icp_pic_print_info(ICPState *icp, Monitor *mon);
> >  void ics_pic_print_info(ICSState *ics, Monitor *mon);
> > +void ics_pic_print_icp_infos(ICSState *ics, const char *type, Monitor *mon);
> >  
> >  void ics_resend(ICSState *ics);
> >  void icp_resend(ICPState *ss);
> > diff --git a/include/hw/ppc/xive.h b/include/hw/ppc/xive.h
> > index 8fd439ec9bba..14690428a0aa 100644
> > --- a/include/hw/ppc/xive.h
> > +++ b/include/hw/ppc/xive.h
> > @@ -367,6 +367,8 @@ int xive_router_write_nvt(XiveRouter *xrtr, uint8_t nvt_blk, uint32_t nvt_idx,
> >  XiveTCTX *xive_router_get_tctx(XiveRouter *xrtr, CPUState *cs);
> >  void xive_router_notify(XiveNotifier *xn, uint32_t lisn);
> >  
> > +void xive_presenter_print_info(XiveRouter *xrtr, Monitor *mon);
> > +
> >  /*
> >   * XIVE END ESBs
> >   */
> > 
> 


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