On Fri, Jan 14, 2022 at 08:07:21AM +0100, Cédric le Goater wrote: > On 1/14/22 00:41, David Gibson wrote: > > On Thu, Jan 13, 2022 at 06:51:56PM +0000, Dr. David Alan Gilbert wrote: > > > Hi, > > > Is there any easy way of getting a machine where the pbr403 vmstate > > > would be generated? > > > > The condition in pbr403_needed is... > > > > return (pvr & 0xffff0000) == 0x00200000; > > > > .. which looks to be the PVR for ppc403 models. That makes sense with > > the section name... but not so much with the fact that it's under > > cpu/tlb6xx. The 6xx MMU is basically unrelated to the 40x MMU. But > > it looks like the vmstate_tlbemb might be shared between then, because > > of bad ideas of the past. > > > > But in any case, we already dropped what little 403 support we ever > > had - there's nothing with that PVR even listed in > > target/ppc/cpu-models.h. > > > > So I think we should just drop it. > > yes. But we can not remove env.pb since this would break migration > compatibility, correct ?
Only if it appears in a migration section that's actually emitted by a
supported machine type. As far as I can tell the only section that
does that is vmstate_pbr403, which we're also dropping so we should be
fine.
It is also touched in the *super* old cpu_load_old. I suspect we
could probably just drop that completely, since I don't think we
realistically support migration from a version that old anyway. But
even if we don't want to do that right now, we can just replace the
reads into env->pb with discarding reads and we'll be fine. We don't
implement any cpus that actually used those fields, so we can ignore
them in the migration stream.
--
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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