On Wed, Dec 21, 2022 at 10:15:28PM +0000, Peter Maydell wrote: > On Wed, 21 Dec 2022 at 16:03, Cédric Le Goater <c...@kaod.org> wrote: > > > > On 12/21/22 13:33, Peter Maydell wrote: > > > On Wed, 21 Dec 2022 at 01:35, David Gibson <da...@gibson.dropbear.id.au> > > > wrote: > > >> On Mon, Dec 19, 2022 at 10:39:40AM +0000, Peter Maydell wrote: > > >>> OK. I still think we should consistently change all the places that are > > >>> accessing this data structure, though, not just half of them. > > >> > > >> Yes, that makes sense. Although what exactly constitutes "this data > > >> structure" is a bit complex here. If we mean just the spapr specific > > >> "external HPT", then there are only a few more references to it. If > > >> we mean all instances of a powerpc hashed page table, then there are a > > >> bunch more in the cpu target code. > > > > > > I had in mind "places where we write this specific array of bytes > > > spapr->htab".
Seems a reasonable amount to tackle for now.
> > spapr_store_hpte() seems to be the most annoying part. It is used
> > by hcalls h_enter, h_remove, h_protect. Reworking the interface
> > to present pte0/pte1 as BE variables means reworking the whole
> > hw/ppc/spapr_softmmu.c file. That's feasible but not a small task
> > since the changes will root down in the target hash mmu code which
> > is shared by all platforms ... :/
>
> Don't you just need to change spapr_store_hpte() to use stq_be_p()
> instead of stq_p() ?
I think Peter is right. The values passed to the function are "host
endian" (really, they don't have an endianness since they'll be in
registers).
> > spapr_hpte_set_c() are spapr_hpte_set_r() are of a different kind.
>
> That code seems to suggest we already implicitly assume that
> spapr->htab fields have a given endianness...
Yes, we absolutely do. We rely on the HPTE always being big-endian.
--
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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