On Thu, Feb 14, 2013 at 10:44:34AM -0200, Erlon Cruz wrote:
> On Sun, Feb 10, 2013 at 10:10 PM, David Gibson
> <da...@gibson.dropbear.id.au> wrote:
> >
> > On Thu, Feb 07, 2013 at 09:28:20AM -0200, Erlon Cruz wrote:
> > > From: Erlon Cruz <erlon.c...@br.flextronics.com>
> > >
> > > This h_call is useful for DLPAR in future amongst other things. Given an
> > > index
> > > it fetches the corresponding PTE stored in the htab.
> >
> > Nice. It would be good to add in this little bit of PAPR compliance.
> >
> > Couple of small nits in the implementation:
> >
> > >
> > > Signed-off-by: Erlon Cruz <erlon.c...@br.flextronics.com>
> > > ---
> > > hw/spapr_hcall.c | 58
> > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > > 1 file changed, 58 insertions(+)
> > >
> > > diff --git a/hw/spapr_hcall.c b/hw/spapr_hcall.c
> > > index 2889742..5ba07e5 100644
> > > --- a/hw/spapr_hcall.c
> > > +++ b/hw/spapr_hcall.c
> > > @@ -323,6 +323,63 @@ static target_ulong h_protect(PowerPCCPU *cpu,
> > > sPAPREnvironment *spapr,
> > > return H_SUCCESS;
> > > }
> > >
> > > +static target_ulong h_read(PowerPCCPU *cpu, sPAPREnvironment *spapr,
> > > + target_ulong opcode, target_ulong *args)
> > > +{
> > > + CPUPPCState *env = &cpu->env;
> > > + target_ulong flags = args[0];
> > > + target_ulong pte_index = args[1];
> > > + uint8_t *hpte;
> > > +
> > > + if ((pte_index * HASH_PTE_SIZE_64) & ~env->htab_mask) {
> > > + return H_PARAMETER;
> > > + }
> > > +
> > > + if (!(flags & H_READ_4)) {
> >
> > It would be nice to combine the H_READ_4 and !H_READ_4 paths together,
> > since except for the masking and stopping sooner the !H_READ_4 path is
> > just like the H_READ_4 path.
>
> Ok.
>
> >
> >
> > > + target_ulong v, r;
> > > + target_ulong *pteh = &args[0];
> > > + target_ulong *ptel = &args[1];
> > > +
> > > + hpte = env->external_htab + (pte_index * HASH_PTE_SIZE_64);
> > > +
> > > + v = ldq_p(hpte);
> > > + r = ldq_p(hpte + (HASH_PTE_SIZE_64/2));
> > > +
> > > + if (flags & H_R_XLATE) {
> > > + /* FIXME: include a valid logical page num in the pte */
> >
> > This comment is misleading. Since you do copy out both words of the
> > hpte, and qemu stores the external_htab in terms of guest physical (==
> > logical) addresses, in fact you're *always* supplying a valid logical
> > page num. So you've already correctly implemented the flag as a
> > no-op.
> >
> > I believe that flag is included for the benefit of a true hypervisor,
> > where the native htab would be stored as true physical addresses, and
> > it might be expensive for the hypervisor to recompute the logical
> > address.
>
> Ok, then I think we can just skip this checking.
Yes.
> > That said, I actually wrote such helpers about 15 minutes ago as part
> > of my MMU cleanup series.
>
> Should I wait for the helpers to send It again?
Probably not, my series will be a little while because it will
probably need to wait for the big cpu qomification series.
--
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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