Re: [PATCH 09/11] include/exec: added functions to the stubs in exec-all.h

[Lucas Mateus Martins Araujo e Castro]

On 17/05/2021 00:58, David Gibson wrote:

> On Thu, May 13, 2021 at 06:44:01PM -0500, Richard Henderson wrote:
> 65;6401;1c> On 5/13/21 9:03 AM, Lucas Mateus Martins Araujo e Castro wrote:
> > > tlb_set_page is called by many ppc_hash64_handle_mmu_fault,
> > > ppc_radix64_handle_mmu_fault and ppc_hash32_handle_mmu_fault, all of
> > > which from what I've seen are only used inside #if
> > > defined(CONFIG_SOFTMMU).
> > >         
> > tlb_set_page should only be called from one place: ppc_cpu_tlb_fill.  The
> > other functions should fill in data, much like get_physical_address.
> >
> >
> > > So what is the best way to deal with these tlb_set_page calls? Should
> > > these part of the _handle_mmu_fault functions never be reached or should
> > > these functions never be called?
> > >         
> > There is some duplication between get_physical_address* and
> > *handle_mmu_fault that should be fixed.
> >
> > What should be happening is that you have one function (per mmu type) that
> > takes a virtual address and resolves a physical address. This bit of code
> > should be written so that it is usable by both
> > CPUClass.get_phys_page_attrs_debug and TCGCPUOps.tlb_fill.  It appears as if
> > ppc_radix64_xlate is the right interface for this.
> >
> > It appears that real mode handling is duplicated between hash64 and radix64,
> > which could be unified.
> >       
> Any common handling between the hash and radix MMUs should go in
> mmu-book3s-v3.*  That covers common things across the v3 (POWER9 and
> later) MMUs which includes both hash and radix mode.
>

I'm not completely sure how this should be handled, there's a get_physical_address in mmu_helper.c but it's a static function and divided by processor families instead of MMU types, so get_physical_address_* should be a new function?

The new get_physical_address_* function would be a mmu-hash(32|64) that do something like ppc_radix64_xlate and add a function to mmu-book3s-v3 that call either the radix64 or the hash64 function and also handle real mode access.

Also should the tlb_set_page calls in *_handle_mmu_fault be changed to ppc_cpu_tlb_fill or the function should themselves fill it?

> > You should only call tlb_set_page from TCGCPUOps.tlb_fill, aka
> > ppc_cpu_tlb_fill.  TCGCPUOps.tlb_fill is obviously TCG only.
> >
> > The version you are looking at here is system emulation specific (sysemu,
> > !defined(CONFIG_USER_ONLY)).  There is a second version of this function,
> > with the same signature, that is used for user emulation in the helpfully
> > named user_only_helper.c.
> >
> >
> > r~
> >
> >       
>

--
Lucas Mateus M. Araujo e Castro
Instituto de Pesquisas ELDORADO
Departamento Computação Embarcada
Estagiario
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