Re: [PATCH] spapr: propagate LPCR to hot-plugged CPUs

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, May 24, 2021 at 01:41:32PM +0200, Cédric Le Goater wrote:
> Distros have started using the 'scv' instructions (glibc 2.33) which
> relies on the LPCR AIL bits. Unfortunately, the LPCR of hot-plugged
> CPUs is not synchronized with the rest of machine and it breaks the
> guest OS.
> 
> Fix that by using the first CPU to set the LPCR value of all hot-plugged
> CPUs.
> 
> Signed-off-by: Cédric Le Goater <clg@kaod.org>

I'm assuming this is obsoleted by Nick Piggin's rework of LPCR
initialization.  This patch does fix a real bug, but it leaves LPCR
initialization a bit of a mess.

> ---
>  hw/ppc/spapr.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index c23bcc449071..e463c2570c7a 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -3890,6 +3890,8 @@ static void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev)
>          for (i = 0; i < cc->nr_threads; i++) {
>              ppc_set_compat(core->threads[i], POWERPC_CPU(first_cpu)->compat_pvr,
>                             &error_abort);
> +            ppc_store_lpcr(core->threads[i],
> +                           POWERPC_CPU(first_cpu)->env.spr[SPR_LPCR]);
>          }
>      }
>  

-- 
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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