From: David Gibson <david@gibson.dropbear.id.au>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
qemu-ppc@nongnu.org, qemu-devel@nongnu.org,
Peter Maydell <peter.maydell@linaro.org>
Subject: Re: [PATCH qemu v6 1/6] ppc: Start CPU in the default mode which is big-endian 32bit
Date: Thu, 13 Feb 2020 14:34:51 +1100 [thread overview]
Message-ID: <20200213033451.GE124369@umbus.fritz.box> (raw)
In-Reply-To: <5b900904-ccb6-58c7-5e11-c8de1154cc52@ozlabs.ru>
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On Thu, Feb 13, 2020 at 02:09:17PM +1100, Alexey Kardashevskiy wrote:
>
>
> On 12/02/2020 16:43, David Gibson wrote:
> > On Mon, Feb 03, 2020 at 02:29:38PM +1100, Alexey Kardashevskiy wrote:
> >> At the moment we enforce 64bit mode on a CPU when reset. This does not
> >> make difference as SLOF or Linux set the desired mode straight away.
> >> However if we ever boot something other than these two,
> >> this might not work as, for example, GRUB expects the default MSR state
> >> and does not work properly.
> >>
> >> This removes setting MSR_SF from the PPC CPU reset.
> >
> > Hrm. This is in the core cpu model so it doesn't just affect pseries,
> > but powernv (and theoretically others) as well. Generally the cpu
> > model should have the bare metal behaviour, and we can override it in
> > the pseries machine if necessary.
> >
> > So for a bare metal POWER system, what mode do we start in? I'm
> > guessing it probably doesn't matter in practice, since the skiboot
> > firmware also probably does a mode set on entry, but it'd be nice to
> > get this right in theory.
>
>
> Huh. "Figure 65. MSR setting due to interrupt" of PowerISA 3.0 says
> "The SF bit is set to 1" so after all the existing behavior is correct
> and my patch is just wrong. Cool.
Well, I guess SF after interrupt isn't *necessarily* the same as SF at
reset, but it's a good place to start.
--
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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next prev parent reply other threads:[~2020-02-13 4:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-03 3:29 [PATCH qemu v6 0/6] spapr: Kill SLOF Alexey Kardashevskiy
2020-02-03 3:29 ` [PATCH qemu v6 1/6] ppc: Start CPU in the default mode which is big-endian 32bit Alexey Kardashevskiy
2020-02-12 5:43 ` David Gibson
2020-02-13 3:09 ` Alexey Kardashevskiy
2020-02-13 3:34 ` David Gibson [this message]
2020-02-03 3:29 ` [PATCH qemu v6 2/6] ppc/spapr: Move GPRs setup to one place Alexey Kardashevskiy
2020-02-12 18:44 ` Fabiano Rosas
2020-02-13 8:41 ` Greg Kurz
2020-02-03 3:29 ` [PATCH qemu v6 3/6] spapr/spapr: Make vty_getchars public Alexey Kardashevskiy
2020-02-03 3:29 ` [PATCH qemu v6 4/6] spapr/cas: Separate CAS handling from rebuilding the FDT Alexey Kardashevskiy
2020-02-03 3:29 ` [PATCH qemu v6 5/6] spapr: Allow changing offset for -kernel image Alexey Kardashevskiy
2020-02-12 18:54 ` Fabiano Rosas
2020-02-13 2:58 ` David Gibson
2020-02-03 3:29 ` [PATCH qemu v6 6/6] spapr: Implement Open Firmware client interface Alexey Kardashevskiy
2020-02-03 13:03 ` BALATON Zoltan
2020-02-05 4:18 ` Alexey Kardashevskiy
2020-02-05 4:59 ` [PATCH qemu v6] spapr: OF CI networking Alexey Kardashevskiy
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