Re: [PATCH for-5.0 v5 15/23] ppc/xive: Use the XiveFabric and XivePresenter interfaces

[Greg Kurz <groug@kaod.org>]

On Thu, 21 Nov 2019 08:01:44 +0100
Cédric Le Goater <clg@kaod.org> wrote:

> On 20/11/2019 19:30, Greg Kurz wrote:
> > On Fri, 15 Nov 2019 17:24:28 +0100
> > Cédric Le Goater <clg@kaod.org> wrote:
> > 
> >> Now that the machines have handlers implementing the XiveFabric and
> >> XivePresenter interfaces, remove xive_presenter_match() and make use
> >> of the 'match_nvt' handler of the machine.
> >>
> >> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> >> ---
> >>  hw/intc/xive.c | 48 +++++++++++++++++-------------------------------
> >>  1 file changed, 17 insertions(+), 31 deletions(-)
> >>
> > 
> > Nice diffstat :)
> > 
> >> diff --git a/hw/intc/xive.c b/hw/intc/xive.c
> >> index 1c9e58f8deac..ab62bda85788 100644
> >> --- a/hw/intc/xive.c
> >> +++ b/hw/intc/xive.c
> >> @@ -1423,30 +1423,6 @@ int xive_presenter_tctx_match(XivePresenter *xptr, XiveTCTX *tctx,
> >>      return -1;
> >>  }
> >>  
> >> -static bool xive_presenter_match(XiveRouter *xrtr, uint8_t format,
> >> -                                 uint8_t nvt_blk, uint32_t nvt_idx,
> >> -                                 bool cam_ignore, uint8_t priority,
> >> -                                 uint32_t logic_serv, XiveTCTXMatch *match)
> >> -{
> >> -    XivePresenter *xptr = XIVE_PRESENTER(xrtr);
> >> -    XivePresenterClass *xpc = XIVE_PRESENTER_GET_CLASS(xptr);
> >> -    int count;
> >> -
> >> -    count = xpc->match_nvt(xptr, format, nvt_blk, nvt_idx, cam_ignore,
> >> -                           priority, logic_serv, match);
> >> -    if (count < 0) {
> >> -        return false;
> >> -    }
> >> -
> >> -    if (!match->tctx) {
> >> -        qemu_log_mask(LOG_UNIMP, "XIVE: NVT %x/%x is not dispatched\n",
> >> -                      nvt_blk, nvt_idx);
> > 
> > Maybe keep this trace...
> 
> It's in spapr_xive_match_nvt() now.
> 

Not really... spapr_xive_match_nvt() has a trace for the opposite case of duplicate
matches:

            if (match->tctx) {
                qemu_log_mask(LOG_GUEST_ERROR, "XIVE: already found a thread "
                              "context NVT %x/%x\n", nvt_blk, nvt_idx);
                return -1;
            }

> > 
> >> -        return false;
> >> -    }
> >> -
> >> -    return true;
> >> -}
> >> -
> >>  /*
> >>   * This is our simple Xive Presenter Engine model. It is merged in the
> >>   * Router as it does not require an extra object.
> >> @@ -1462,22 +1438,32 @@ static bool xive_presenter_match(XiveRouter *xrtr, uint8_t format,
> >>   *
> >>   * The parameters represent what is sent on the PowerBus
> >>   */
> >> -static bool xive_presenter_notify(XiveRouter *xrtr, uint8_t format,
> >> +static bool xive_presenter_notify(uint8_t format,
> >>                                    uint8_t nvt_blk, uint32_t nvt_idx,
> >>                                    bool cam_ignore, uint8_t priority,
> >>                                    uint32_t logic_serv)
> >>  {
> >> +    XiveFabric *xfb = XIVE_FABRIC(qdev_get_machine());
> >> +    XiveFabricClass *xfc = XIVE_FABRIC_GET_CLASS(xfb);
> >>      XiveTCTXMatch match = { .tctx = NULL, .ring = 0 };
> >> -    bool found;
> >> +    int count;
> >>  
> >> -    found = xive_presenter_match(xrtr, format, nvt_blk, nvt_idx, cam_ignore,
> >> -                                 priority, logic_serv, &match);
> >> -    if (found) {
> >> +    /*
> >> +     * Ask the machine to scan the interrupt controllers for a match
> >> +     */
> >> +    count = xfc->match_nvt(xfb, format, nvt_blk, nvt_idx, cam_ignore,
> >> +                           priority, logic_serv, &match);
> >> +    if (count < 0) {
> >> +        return false;
> >> +    }
> >> +
> >> +    /* handle CPU exception delivery */
> >> +    if (count) {
> >>          ipb_update(&match.tctx->regs[match.ring], priority);
> >>          xive_tctx_notify(match.tctx, match.ring);
> >>      }
> > 
> > ... in an else block here ^^ ?
> > 
> >>  
> >> -    return found;
> >> +    return count;
> > 
> > Implicit cast is ok I guess, but !!count would ensure no paranoid
> > compiler ever complains.
> 
> yes. 
> 
> Thanks,
> 
> C.
> 
> 
> > 
> >>  }
> >>  
> >>  /*
> >> @@ -1590,7 +1576,7 @@ static void xive_router_end_notify(XiveRouter *xrtr, uint8_t end_blk,
> >>          return;
> >>      }
> >>  
> >> -    found = xive_presenter_notify(xrtr, format, nvt_blk, nvt_idx,
> >> +    found = xive_presenter_notify(format, nvt_blk, nvt_idx,
> >>                            xive_get_field32(END_W7_F0_IGNORE, end.w7),
> >>                            priority,
> >>                            xive_get_field32(END_W7_F1_LOG_SERVER_ID, end.w7));
> > 
>