Re: [Qemu-devel] [PATCH 07/12] target/ppc: Add basic support for "new format" HPTE as found on POWER9

[David Gibson]

On Tue, Feb 19, 2019 at 03:05:29PM +1100, David Gibson wrote:
> On Fri, Feb 15, 2019 at 06:00:24PM +0100, Cédric Le Goater wrote:
> > From: Benjamin Herrenschmidt <address@hidden>
> > 
> > POWER9 (arch v3) slightly changes the HPTE format. The B bits move
> > from the first to the second half of the HPTE, and the AVPN/ARPN
> > are slightly shorter.
> > 
> > However, under SPAPR, the hypercalls still take the old format
> > (and probably will for the foreseable future).
> > 
> > The simplest way to support this is thus to convert the HPTEs from
> > new to old format when reading them if the MMU model is v3 and there
> > is no virtual hypervisor, leaving the rest of the code unchanged.
> > 
> > Signed-off-by: Benjamin Herrenschmidt <address@hidden>
> > Signed-off-by: Cédric Le Goater <address@hidden>
> 
> Kinda hacky, but definitely the easiest way in the short to medium
> term.

So, this doesn't compile as-is without the include rearrangement I
objected to earlier in the series.

But.. I'm not actually seeing any reason (here or later in the series)
that ppc64_v3_new_to_old_hpte() really needs to be in the header.  So
I'm applying this with it moved into mmu-hash64.c.

> 
> > ---
> >  target/ppc/mmu-book3s-v3.h | 12 ++++++++++++
> >  target/ppc/mmu-hash64.h    |  5 +++++
> >  target/ppc/mmu-hash64.c    |  5 +++++
> >  3 files changed, 22 insertions(+)
> > 
> > diff --git a/target/ppc/mmu-book3s-v3.h b/target/ppc/mmu-book3s-v3.h
> > index 4e59742d7eac..216ff296c088 100644
> > --- a/target/ppc/mmu-book3s-v3.h
> > +++ b/target/ppc/mmu-book3s-v3.h
> > @@ -56,6 +56,18 @@ static inline bool ppc64_v3_radix(PowerPCCPU *cpu)
> >      return !!(cpu->env.spr[SPR_LPCR] & LPCR_HR);
> >  }
> >  
> > +static inline void ppc64_v3_new_to_old_hpte(target_ulong *pte0,
> > +                                            target_ulong *pte1)
> > +{
> > +    /* Insert B into pte0 */
> > +    *pte0 = (*pte0 & HPTE64_V_COMMON_BITS) |
> > +            ((*pte1 & HPTE64_R_3_0_SSIZE_MASK) <<
> > +             (HPTE64_V_SSIZE_SHIFT - HPTE64_R_3_0_SSIZE_SHIFT));
> > +
> > +    /* Remove B from pte1 */
> > +    *pte1 = *pte1 & ~HPTE64_R_3_0_SSIZE_MASK;
> > +}
> > +
> >  hwaddr ppc64_v3_get_phys_page_debug(PowerPCCPU *cpu, vaddr eaddr);
> >  
> >  int ppc64_v3_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr, int rwx,
> > diff --git a/target/ppc/mmu-hash64.h b/target/ppc/mmu-hash64.h
> > index f11efc9cbc1f..016d6b44ee75 100644
> > --- a/target/ppc/mmu-hash64.h
> > +++ b/target/ppc/mmu-hash64.h
> > @@ -102,6 +102,11 @@ void ppc_hash64_filter_pagesizes(PowerPCCPU *cpu,
> >  #define HPTE64_V_1TB_SEG        0x4000000000000000ULL
> >  #define HPTE64_V_VRMA_MASK      0x4001ffffff000000ULL
> >  
> > +/* Format changes for ARCH v3 */
> > +#define HPTE64_V_COMMON_BITS    0x000fffffffffffffULL
> > +#define HPTE64_R_3_0_SSIZE_SHIFT 58
> > +#define HPTE64_R_3_0_SSIZE_MASK (3ULL << HPTE64_R_3_0_SSIZE_SHIFT)
> > +
> >  static inline hwaddr ppc_hash64_hpt_base(PowerPCCPU *cpu)
> >  {
> >      if (cpu->vhyp) {
> > diff --git a/target/ppc/mmu-hash64.c b/target/ppc/mmu-hash64.c
> > index b3c4d33faa55..9afaab8a177c 100644
> > --- a/target/ppc/mmu-hash64.c
> > +++ b/target/ppc/mmu-hash64.c
> > @@ -514,6 +514,11 @@ static hwaddr ppc_hash64_pteg_search(PowerPCCPU *cpu, 
> > hwaddr hash,
> >          smp_rmb();
> >          pte1 = ppc_hash64_hpte1(cpu, pteg, i);
> >  
> > +        /* Convert format if necessary */
> > +        if (cpu->env.mmu_model == POWERPC_MMU_3_00 && !cpu->vhyp) {
> > +            ppc64_v3_new_to_old_hpte(&pte0, &pte1);
> > +        }
> > +
> >          /* This compares V, B, H (secondary) and the AVPN */
> >          if (HPTE64_V_COMPARE(pte0, ptem)) {
> >              *pshift = hpte_page_shift(sps, pte0, pte1);
> 



-- 
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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