Re: [Qemu-devel] [RFC PATCH 05/17] target/ppc/POWER9: Adapt LPCR handling for POWER9

[Suraj Jitindar Singh <sjitindarsingh@gmail.com>]

On Tue, 2017-01-17 at 15:37 +1100, David Gibson wrote:
> On Tue, Jan 17, 2017 at 11:48:31AM +1100, Suraj Jitindar Singh wrote:
> > 
> > On Tue, 2017-01-17 at 08:40 +1100, David Gibson wrote:
> > > 
> > > On Fri, Jan 13, 2017 at 05:28:11PM +1100, Suraj Jitindar Singh
> > > wrote:
> > > > 
> > > > 
> > > > The logical partitioning control register controls a threads
> > > > operation
> > > > based on the partition it is currently executing. Add new
> > > > definitions and
> > > > update the mask used when writing to the LPCR based on the
> > > > POWER9
> > > > spec.
> > > > 
> > > > Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
> > > > ---
> > > >  target/ppc/cpu.h            | 20 +++++++++++++++++++-
> > > >  target/ppc/mmu-hash64.c     |  8 ++++++++
> > > >  target/ppc/translate_init.c | 24 ++++++++++++++++++------
> > > >  3 files changed, 45 insertions(+), 7 deletions(-)
> > > > 
> > > > diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> > > > index afb7ddb..0ab49b3 100644
> > > > --- a/target/ppc/cpu.h
> > > > +++ b/target/ppc/cpu.h
> > > > @@ -379,15 +379,22 @@ struct ppc_slb_t {
> > > >  #define LPCR_ISL          (1ull << (63 - 2))
> > > >  #define LPCR_KBV          (1ull << (63 - 3))
> > > >  #define LPCR_DPFD_SHIFT   (63 - 11)
> > > > -#define LPCR_DPFD         (0x3ull << LPCR_DPFD_SHIFT)
> > > > +#define LPCR_DPFD         (0x7ull << LPCR_DPFD_SHIFT)
> > > Changing this define effectively changes the valid LPCR mask for
> > > existing POWER8 and POWER7 models, which is not what you want, I
> > > think.
> > I should have explained this better in the commit message, this has
> > always been a 3 bit field (at least in POWER7-9) so the mask has
> > just
> > always been wrong. Afaik fixing this up won't really change
> > anything -
> > it relates to data stream prefetch depth.
> > 
> > I realise this should probably be a separate patch though, or
> > atleast
> > mentioned in the commit message.
> Right, yes.  Please make the bugfix a separate patch with the
> explanation in the commit message.
> 
> > 
> > > 
> > > 
> > > > 
> > > > 
> > > >  #define LPCR_VRMASD_SHIFT (63 - 16)
> > > >  #define LPCR_VRMASD       (0x1full << LPCR_VRMASD_SHIFT)
> > > > +/* P9: Power-saving mode Exit Cause Enable (Upper Section)
> > > > Mask */
> > > > +#define LPCR_PECE_U_SHIFT (63 - 19)
> > > > +#define LPCR_PECE_U_MASK  (0x7ull << LPCR_PECE_U_SHIFT)
> > > > +#define LPCR_HVEE         (1ull << (63 - 17)) /* Hypervisor
> > > > Virt
> > > > Exit Enable */
> > > >  #define LPCR_RMLS_SHIFT   (63 - 37)
> > > >  #define LPCR_RMLS         (0xfull << LPCR_RMLS_SHIFT)
> > > >  #define LPCR_ILE          (1ull << (63 - 38))
> > > >  #define LPCR_AIL_SHIFT    (63 - 40)      /* Alternate
> > > > interrupt
> > > > location */
> > > >  #define LPCR_AIL          (3ull << LPCR_AIL_SHIFT)
> > > > +#define LPCR_UPRT         (1ull << (63 - 41)) /* Use Process
> > > > Table
> > > > */
> > > > +#define LPCR_EVIRT        (1ull << (63 - 42)) /* Enhanced
> > > > Virtualisation */
> > > >  #define LPCR_ONL          (1ull << (63 - 45))
> > > > +#define LPCR_LD           (1ull << (63 - 46)) /* Large
> > > > Decrementer
> > > > */
> > > >  #define LPCR_P7_PECE0     (1ull << (63 - 49))
> > > >  #define LPCR_P7_PECE1     (1ull << (63 - 50))
> > > >  #define LPCR_P7_PECE2     (1ull << (63 - 51))
> > > > @@ -396,11 +403,22 @@ struct ppc_slb_t {
> > > >  #define LPCR_P8_PECE2     (1ull << (63 - 49))
> > > >  #define LPCR_P8_PECE3     (1ull << (63 - 50))
> > > >  #define LPCR_P8_PECE4     (1ull << (63 - 51))
> > > > +/* P9: Power-saving mode Exit Cause Enable (Lower Section)
> > > > Mask */
> > > > +#define LPCR_PECE_L_SHIFT (63 - 51)
> > > > +#define LPCR_PECE_L_MASK  (0x1full << LPCR_PECE_L_SHIFT)
> > > > +#define LPCR_PDEE         (1ull << (63 - 47)) /* Privileged
> > > > Doorbell Exit EN */
> > > > +#define LPCR_HDEE         (1ull << (63 - 48)) /* Hyperv
> > > > Doorbell
> > > > Exit Enable */
> > > > +#define LPCR_EEE          (1ull << (63 - 49)) /* External Exit
> > > > Enable        */
> > > > +#define LPCR_DEE          (1ull << (63 - 50)) /* Decrementer
> > > > Exit
> > > > Enable     */
> > > > +#define LPCR_OEE          (1ull << (63 - 51)) /* Other Exit
> > > > Enable           */
> > > >  #define LPCR_MER          (1ull << (63 - 52))
> > > > +#define LPCR_GTSE         (1ull << (63 - 53)) /* Guest
> > > > Translation
> > > > Shootdown */
> > > >  #define LPCR_TC           (1ull << (63 - 54))
> > > > +#define LPCR_HEIC         (1ull << (63 - 59)) /* HV Extern
> > > > Interrupt Control */
> > > >  #define LPCR_LPES0        (1ull << (63 - 60))
> > > >  #define LPCR_LPES1        (1ull << (63 - 61))
> > > >  #define LPCR_RMI          (1ull << (63 - 62))
> > > > +#define LPCR_HVICE        (1ull << (63 - 62)) /* HV
> > > > Virtualisation
> > > > Int Enable */
> > > >  #define LPCR_HDICE        (1ull << (63 - 63))
> > > >  
> > > >  #define msr_sf   ((env->msr >> MSR_SF)   & 1)
> > > > diff --git a/target/ppc/mmu-hash64.c b/target/ppc/mmu-hash64.c
> > > > index fdb7a78..3a2acb8 100644
> > > > --- a/target/ppc/mmu-hash64.c
> > > > +++ b/target/ppc/mmu-hash64.c
> > > > @@ -1050,6 +1050,14 @@ void helper_store_lpcr(CPUPPCState *env,
> > > > target_ulong val)
> > > >                        LPCR_P8_PECE2 | LPCR_P8_PECE3 |
> > > > LPCR_P8_PECE4 |
> > > >                        LPCR_MER | LPCR_TC | LPCR_LPES0 |
> > > > LPCR_HDICE);
> > > >          break;
> > > > +    case POWERPC_MMU_3_00: /* P9 */
> > > > +        lpcr = val & (LPCR_VPM1 | LPCR_ISL | LPCR_KBV |
> > > > LPCR_DPFD
> > > > > 
> > > > > 
> > > > +                      (LPCR_PECE_U_MASK & LPCR_HVEE) |
> > > > LPCR_ILE |
> > > > LPCR_AIL |
> > > > +                      LPCR_UPRT | LPCR_EVIRT | LPCR_ONL |
> > > > +                      (LPCR_PECE_L_MASK & (LPCR_PDEE |
> > > > LPCR_HDEE |
> > > > LPCR_EEE |
> > > > +                      LPCR_DEE | LPCR_OEE)) | LPCR_MER |
> > > > LPCR_GTSE
> > > > > 
> > > > > LPCR_TC |
> > > > +                      LPCR_HEIC | LPCR_LPES0 | LPCR_HVICE |
> > > > LPCR_HDICE);
> > > > +        break;
> > > >      default:
> > > >          ;
> > > >      }
> > > > diff --git a/target/ppc/translate_init.c
> > > > b/target/ppc/translate_init.c
> > > > index 2402eef..a1994d3 100644
> > > > --- a/target/ppc/translate_init.c
> > > > +++ b/target/ppc/translate_init.c
> > > > @@ -8887,12 +8887,24 @@ void cpu_ppc_set_papr(PowerPCCPU *cpu)
> > > >      lpcr->default_value &= ~LPCR_RMLS;
> > > >      lpcr->default_value |= 1ull << LPCR_RMLS_SHIFT;
> > > >  
> > > > -    /* P7 and P8 has slightly different PECE bits, mostly
> > > > because
> > > > P8 adds
> > > > -     * bit 47 and 48 which are reserved on P7. Here we set
> > > > them
> > > > all, which
> > > > -     * will work as expected for both implementations
> > > > -     */
> > > > -    lpcr->default_value |= LPCR_P8_PECE0 | LPCR_P8_PECE1 |
> > > > LPCR_P8_PECE2 |
> > > > -                           LPCR_P8_PECE3 | LPCR_P8_PECE4;
> > > > +    switch (env->mmu_model) {
> > > I'm not sure of mmu_model is conceptually the right thing to
> > > switch
> > > on, although I guess it will work in practice.
> > Well we need something to indicate our default value, which is
> > dictated
> > by the cpu model, and given that a cpu model correlates to a mmu
> > model
> > I can't think of a better option.
> Yeah, I guess it's probably reasonable.  We can always change it
> later
> if we need to.
I mean I can add another mmu flag to indicate that the mmu supports ISA
v3.00 features, POWERPC_MMU_V3 or something. This could be useful in
the likely event that future mmus also support the new features and
want to display support for them.

e.g.

#define POWERPC_MMU_V3 0x00100000

POWERPC_MMU_3_00       = ... | POWERPC_MMU_V3;

if (env->mmu_model & POWERPC_MMU_V3) {
    // ISA v3.00 specific stuffs
}

Not sure if this makes more sense than just checking the mmu_model
directly as I currently am, I guess it'll be necessary eventually for
the next mmu model for us to be able to claim v3.00 support.

Thoughts?
> 
> > 
> > > 
> > > 
> > > > 
> > > > 
> > > > +    case POWERPC_MMU_3_00:
> > > > +        /* By default we choose legacy mode and switch to new
> > > > hash
> > > > or radix
> > > > +         * when a register process table hcall is made. So
> > > > disable
> > > > process
> > > > +         * tables and guest translation shootdown by default
> > > > +         */
> > > > +        lpcr->default_value &= ~(LPCR_UPRT | LPCR_GTSE);
> > > > +        lpcr->default_value |= LPCR_PDEE | LPCR_HDEE |
> > > > LPCR_EEE |
> > > > LPCR_DEE |
> > > > +                               LPCR_OEE;
> > > > +        break;
> > > > +    default:
> > > > +        /* P7 and P8 has slightly different PECE bits, mostly
> > > > because P8 adds
> > > > +         * bit 47 and 48 which are reserved on P7. Here we set
> > > > them all, which
> > > > +         * will work as expected for both implementations
> > > > +         */
> > > > +        lpcr->default_value |= LPCR_P8_PECE0 | LPCR_P8_PECE1 |
> > > > LPCR_P8_PECE2 |
> > > > +                               LPCR_P8_PECE3 | LPCR_P8_PECE4;
> > > > +    }
> > > >  
> > > >      /* We should be followed by a CPU reset but update the
> > > > active
> > > > value
> > > >       * just in case...