From: Greg Kurz <groug@kaod.org>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: "Alexey Kardashevskiy" <aik@ozlabs.ru>,
"Daniel Henrique Barboza" <danielhb413@gmail.com>,
qemu-ppc@nongnu.org, qemu-devel@nongnu.org,
"Cédric Le Goater" <clg@kaod.org>
Subject: Re: [PATCH qemu] spapr: Force 32bit when resetting a core
Date: Fri, 7 Jan 2022 14:39:10 +0100 [thread overview]
Message-ID: <20220107143910.4443af02@bahia> (raw)
In-Reply-To: <Ydgvt0VwFUP0MD5h@yekko>
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On Fri, 7 Jan 2022 23:19:03 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:
> On Fri, Jan 07, 2022 at 12:57:47PM +0100, Greg Kurz wrote:
> > On Fri, 7 Jan 2022 18:24:23 +1100
> > Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
> >
> > > "PowerPC Processor binding to IEEE 1275" says in
> > > "8.2.1. Initial Register Values" that the initial state is defined as
> > > 32bit so do it for both SLOF and VOF.
> > >
> > > This should not cause behavioral change as SLOF switches to 64bit very
> > > early anyway.
> >
> > Only one CPU goes through SLOF. What about the other ones, including
> > hot plugged CPUs ?
>
> Those will be started by the start-cpu RTAS call which has its own
> semantics.
>
Ah indeed, there's code in linux/arch/powerpc/kernel/head_64.S to switch
secondaries to 64bit... but then, as noted by Cedric, ppc_cpu_reset(),
which is called earlier sets MSR_SF but the changelog of commit 8b9f2118ca40
doesn't provide much details on the motivation. Any idea ?
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next prev parent reply other threads:[~2022-01-07 13:42 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-07 7:24 [PATCH qemu] spapr: Force 32bit when resetting a core Alexey Kardashevskiy
2022-01-07 7:45 ` Cédric Le Goater
2022-01-07 11:57 ` Greg Kurz
2022-01-07 12:19 ` David Gibson
2022-01-07 13:39 ` Greg Kurz [this message]
2022-01-10 2:52 ` Alexey Kardashevskiy
2022-01-10 3:10 ` David Gibson
2022-01-14 14:12 ` Cédric Le Goater
2022-01-15 14:21 ` Mark Cave-Ayland
2022-01-17 14:52 ` Cédric Le Goater
2022-01-18 8:30 ` Mark Cave-Ayland
2022-01-18 9:12 ` Cédric Le Goater
2022-01-19 15:10 ` Frédéric Bonnard
2022-01-15 21:48 ` BALATON Zoltan
2022-01-14 13:51 ` Cédric Le Goater
2022-01-16 16:45 ` Peter Maydell
2022-01-19 4:03 ` Alexey Kardashevskiy
2022-01-19 10:16 ` Peter Maydell
2022-01-19 11:05 ` Cédric Le Goater
2022-01-25 10:38 ` Cédric Le Goater
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