Re: [PATCH v1 22/28] target/riscv: Allow specifying MMU stage

[Alistair Francis <alistair23@gmail.com>]

On Thu, Oct 3, 2019 at 8:53 AM Palmer Dabbelt <palmer@sifive.com> wrote:
>
> On Fri, 23 Aug 2019 16:38:47 PDT (-0700), Alistair Francis wrote:
> > Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
> > ---
> >  target/riscv/cpu_helper.c | 39 ++++++++++++++++++++++++++++++---------
> >  1 file changed, 30 insertions(+), 9 deletions(-)
> >
> > diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> > index 098873c83e..9aa6906acd 100644
> > --- a/target/riscv/cpu_helper.c
> > +++ b/target/riscv/cpu_helper.c
> > @@ -318,10 +318,19 @@ void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv)
> >   *
> >   * Adapted from Spike's mmu_t::translate and mmu_t::walk
> >   *
> > + * @env: CPURISCVState
> > + * @physical: This will be set to the calculated physical address
> > + * @prot: The returned protection attributes
> > + * @addr: The virtual address to be translated
> > + * @access_type: The type of MMU access
> > + * @mmu_idx: Indicates current privilege level
> > + * @first_stage: Are we in first stage translation?
> > + *               Second stage is used for hypervisor guest translation
> >   */
> >  static int get_physical_address(CPURISCVState *env, hwaddr *physical,
> >                                  int *prot, target_ulong addr,
> > -                                int access_type, int mmu_idx)
> > +                                int access_type, int mmu_idx,
> > +                                bool first_stage)
> >  {
> >      /* NOTE: the env->pc value visible here will not be
> >       * correct, but the value visible to the exception handler
> > @@ -518,13 +527,23 @@ restart:
> >  }
> >
> >  static void raise_mmu_exception(CPURISCVState *env, target_ulong address,
> > -                                MMUAccessType access_type, bool pmp_violation)
> > +                                MMUAccessType access_type, bool pmp_violation,
> > +                                bool first_stage)
> >  {
> >      CPUState *cs = env_cpu(env);
> > -    int page_fault_exceptions =
> > -        (env->priv_ver >= PRIV_VERSION_1_10_0) &&
> > -        get_field(env->satp, SATP_MODE) != VM_1_10_MBARE &&
> > -        !pmp_violation;
> > +    int page_fault_exceptions;
> > +    if (first_stage) {
> > +        page_fault_exceptions =
> > +            (env->priv_ver >= PRIV_VERSION_1_10_0) &&
> > +            get_field(env->satp, SATP_MODE) != VM_1_10_MBARE &&
> > +            !pmp_violation;
> > +            riscv_cpu_set_force_hs_excep(env, CLEAR_HS_EXCEP);
>
> It might just be email, but the indentation looks wrong here.

Yep, fixed.

>
> > +    } else {
> > +        page_fault_exceptions =
> > +            get_field(env->hgatp, HGATP_MODE) != VM_1_10_MBARE &&
> > +            !pmp_violation;
> > +            riscv_cpu_set_force_hs_excep(env, FORCE_HS_EXCEP);
> > +    }
> >      switch (access_type) {
> >      case MMU_INST_FETCH:
> >          cs->exception_index = page_fault_exceptions ?
> > @@ -551,7 +570,8 @@ hwaddr riscv_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
> >      int prot;
> >      int mmu_idx = cpu_mmu_index(&cpu->env, false);
> >
> > -    if (get_physical_address(&cpu->env, &phys_addr, &prot, addr, 0, mmu_idx)) {
> > +    if (get_physical_address(&cpu->env, &phys_addr, &prot, addr, 0, mmu_idx,
> > +                             true)) {
> >          return -1;
> >      }
> >      return phys_addr;
> > @@ -613,7 +633,8 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
> >      qemu_log_mask(CPU_LOG_MMU, "%s ad %" VADDR_PRIx " rw %d mmu_idx %d\n",
> >                    __func__, address, access_type, mmu_idx);
> >
> > -    ret = get_physical_address(env, &pa, &prot, address, access_type, mmu_idx);
> > +    ret = get_physical_address(env, &pa, &prot, address, access_type, mmu_idx,
> > +                               true);
> >
> >      if (mode == PRV_M && access_type != MMU_INST_FETCH) {
> >          if (get_field(*env->mstatus, MSTATUS_MPRV)) {
> > @@ -640,7 +661,7 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
> >      } else if (probe) {
> >          return false;
> >      } else {
> > -        raise_mmu_exception(env, address, access_type, pmp_violation);
> > +        raise_mmu_exception(env, address, access_type, pmp_violation, true);
> >          riscv_raise_exception(env, cs->exception_index, retaddr);
> >      }
> >  #else
>
> I don't think it makes sense to split off these two (23 and 24, that add the
> argument) out from the implementation.

The goal was just to make it easier to review. If you want them
combined I can easily combine them.

Alistair