Re: [PATCH 2/4] ppc/spapr: Add a nested state struct

["Nicholas Piggin" <npiggin@gmail.com>]

On Fri Jun 9, 2023 at 5:09 PM AEST, Harsh Prateek Bora wrote:
>
>
> On 6/8/23 14:43, Nicholas Piggin wrote:
> > Rather than use a copy of CPUPPCState to store the host state while
> > the environment has been switched to the L2, use a new struct for
> > this purpose.
> > 
> > Have helper functions to save and load this host state.
> > 
> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> > ---
> >   hw/ppc/spapr_hcall.c            | 150 ++++++++++++++++++++++++--------
> >   include/hw/ppc/spapr_cpu_core.h |   5 +-
> >   2 files changed, 115 insertions(+), 40 deletions(-)
> > 
> > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> > index 0582b524d1..d5b8d54692 100644
> > --- a/hw/ppc/spapr_hcall.c
> > +++ b/hw/ppc/spapr_hcall.c
> > @@ -1546,6 +1546,112 @@ static target_ulong h_copy_tofrom_guest(PowerPCCPU *cpu,
> >       return H_FUNCTION;
> >   }
> >   
> > +struct nested_ppc_state {
> > +    uint64_t gpr[32];
> > +    uint64_t lr;
> > +    uint64_t ctr;
> > +    uint64_t cfar;
> > +    uint64_t msr;
> > +    uint64_t nip;
> > +    uint32_t cr;
> > +
> > +    uint64_t xer;
> > +
> > +    uint64_t lpcr;
> > +    uint64_t lpidr;
> > +    uint64_t pidr;
> > +    uint64_t pcr;
> > +    uint64_t dpdes;
> > +    uint64_t hfscr;
> > +    uint64_t srr0;
> > +    uint64_t srr1;
> > +    uint64_t sprg0;
> > +    uint64_t sprg1;
> > +    uint64_t sprg2;
> > +    uint64_t sprg3;
> > +    uint64_t ppr;
> > +
> > +    int64_t tb_offset;
> > +};
> > +
>
> <snip>
>
> > +static void nested_load_state(PowerPCCPU *cpu, struct nested_ppc_state *load)
> > +{
> > +    CPUState *cs = CPU(cpu);
> > +    CPUPPCState *env = &cpu->env;
> > +
> > +    memcpy(env->gpr, load->gpr, sizeof(env->gpr));
> > +
> > +    env->lr = load->lr;
> > +    env->ctr = load->ctr;
> > +    env->cfar = load->cfar;
> > +    env->msr = load->msr;
> > +    env->nip = load->nip;
> > +
> > +    ppc_set_cr(env, load->cr);
> > +    cpu_write_xer(env, load->xer);
> > +
> > +    env->spr[SPR_LPCR] = load->lpcr;
> > +    env->spr[SPR_LPIDR] = load->lpidr;
> > +    env->spr[SPR_PCR] = load->pcr;
> > +    env->spr[SPR_DPDES] = load->dpdes;
> > +    env->spr[SPR_HFSCR] = load->hfscr;
> > +    env->spr[SPR_SRR0] = load->srr0;
> > +    env->spr[SPR_SRR1] = load->srr1;
> > +    env->spr[SPR_SPRG0] = load->sprg0;
> > +    env->spr[SPR_SPRG1] = load->sprg1;
> > +    env->spr[SPR_SPRG2] = load->sprg2;
> > +    env->spr[SPR_SPRG3] = load->sprg3;
> > +    env->spr[SPR_BOOKS_PID] = load->pidr;
> > +    env->spr[SPR_PPR] = load->ppr;
> > +
> > +    env->tb_env->tb_offset = load->tb_offset;
> > +
> > +    /*
> > +     * MSR updated, compute hflags and possible interrupts.
> > +     */
> > +    hreg_compute_hflags(env);
> > +    ppc_maybe_interrupt(env);
> > +
> > +    /*
> > +     * Nested HV does not tag TLB entries between L1 and L2, so must
> > +     * flush on transition.
> > +     */
> > +    tlb_flush(cs);
> > +    env->reserve_addr = -1; /* Reset the reservation */
> > +}
> > +
>
> <snip>
>
> > @@ -1766,34 +1872,8 @@ void spapr_exit_nested(PowerPCCPU *cpu, int excp)
> >       address_space_unmap(CPU(cpu)->as, regs, len, len, true);
> >   
> >   out_restore_l1:
> > -    memcpy(env->gpr, spapr_cpu->nested_host_state->gpr, sizeof(env->gpr));
> > -    env->lr = spapr_cpu->nested_host_state->lr;
> > -    env->ctr = spapr_cpu->nested_host_state->ctr;
> > -    memcpy(env->crf, spapr_cpu->nested_host_state->crf, sizeof(env->crf));
> > -    env->cfar = spapr_cpu->nested_host_state->cfar;
> > -    env->xer = spapr_cpu->nested_host_state->xer;
> > -    env->so = spapr_cpu->nested_host_state->so;
> > -    env->ca = spapr_cpu->nested_host_state->ca;
> > -    env->ov = spapr_cpu->nested_host_state->ov;
> > -    env->ov32 = spapr_cpu->nested_host_state->ov32;
> > -    env->ca32 = spapr_cpu->nested_host_state->ca32;
>
> Above fields so, ca, ov, ov32, ca32 are not taken care in 
> nested_load_state, ca being introduced in previous patch.

They should be, by cpu_write_xer.

Thanks,
Nick