From: David Gibson <david@gibson.dropbear.id.au>
To: Laurent Vivier <lvivier@redhat.com>
Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org
Subject: Re: [PATCH] ppc/spapr: re-assert IRQs during event-scan if there are pending
Date: Fri, 16 Oct 2020 10:58:45 +1100 [thread overview]
Message-ID: <20201015235845.GA7078@yekko.fritz.box> (raw)
In-Reply-To: <20201015210318.117386-1-lvivier@redhat.com>
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On Thu, Oct 15, 2020 at 11:03:18PM +0200, Laurent Vivier wrote:
> If we hotplug a CPU during the first second of the kernel boot,
> the IRQ can be sent to the kernel while the RTAS event handler
> is not installed. The event is queued, but the kernel doesn't
> collect it and ignores the new CPU.
>
> As the code relies on edge-triggered IRQ, we can re-assert it
> during the event-scan RTAS call if there are still pending
> events (as it is already done in check-exception).
>
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Applied to ppc-for-5.2.
> ---
> hw/ppc/spapr_events.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
> index 1069d0197b4f..1add53547ec3 100644
> --- a/hw/ppc/spapr_events.c
> +++ b/hw/ppc/spapr_events.c
> @@ -1000,10 +1000,22 @@ static void event_scan(PowerPCCPU *cpu, SpaprMachineState *spapr,
> target_ulong args,
> uint32_t nret, target_ulong rets)
> {
> + int i;
> if (nargs != 4 || nret != 1) {
> rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
> return;
> }
> +
> + for (i = 0; i < EVENT_CLASS_MAX; i++) {
> + if (rtas_event_log_contains(EVENT_CLASS_MASK(i))) {
> + const SpaprEventSource *source =
> + spapr_event_sources_get_source(spapr->event_sources, i);
> +
> + g_assert(source->enabled);
> + qemu_irq_pulse(spapr_qirq(spapr, source->irq));
> + }
> + }
> +
> rtas_st(rets, 0, RTAS_OUT_NO_ERRORS_FOUND);
> }
>
--
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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prev parent reply other threads:[~2020-10-16 0:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-15 21:03 [PATCH] ppc/spapr: re-assert IRQs during event-scan if there are pending Laurent Vivier
2020-10-15 22:29 ` Greg Kurz
2020-10-15 23:58 ` David Gibson [this message]
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