Re: [PATCH v4 1/3] target/ppc: introduce ppc_maybe_interrupt

[Daniel Henrique Barboza]

On 10/21/22 11:21, Matheus Ferst wrote:
> This new method will check if any pending interrupt was unmasked and
> then call cpu_interrupt/cpu_reset_interrupt accordingly. Code that
> raises/lowers or masks/unmasks interrupts should call this method to
> keep CPU_INTERRUPT_HARD coherent with env->pending_interrupts.
>
> Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
> ---

Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>

> v4:
>    - Call gen_icount_io_start before helper_ppc_maybe_interrupt to avoid
>      the cpu_abort("Raised interrupt while not in I/O function")
>      in icount_handle_interrupt
> ---
>   hw/ppc/pnv_core.c        |  1 +
>   hw/ppc/ppc.c             |  7 +------
>   hw/ppc/spapr_hcall.c     |  6 ++++++
>   hw/ppc/spapr_rtas.c      |  2 +-
>   target/ppc/cpu.c         |  2 ++
>   target/ppc/cpu.h         |  1 +
>   target/ppc/excp_helper.c | 42 ++++++++++++++++++++++++++++++++++++++++
>   target/ppc/helper.h      |  1 +
>   target/ppc/helper_regs.c |  2 ++
>   target/ppc/translate.c   | 11 ++++++++++-
>   10 files changed, 67 insertions(+), 8 deletions(-)
>
> diff --git a/hw/ppc/pnv_core.c b/hw/ppc/pnv_core.c
> index 19e8eb885f..9ee79192dd 100644
> --- a/hw/ppc/pnv_core.c
> +++ b/hw/ppc/pnv_core.c
> @@ -58,6 +58,7 @@ static void pnv_core_cpu_reset(PnvCore *pc, PowerPCCPU *cpu)
>       env->msr |= MSR_HVB; /* Hypervisor mode */
>       env->spr[SPR_HRMOR] = pc->hrmor;
>       hreg_compute_hflags(env);
> +    ppc_maybe_interrupt(env);
>   
>       pcc->intc_reset(pc->chip, cpu);
>   }
> diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c
> index 77e611e81c..dc86c1c7db 100644
> --- a/hw/ppc/ppc.c
> +++ b/hw/ppc/ppc.c
> @@ -42,7 +42,6 @@ static void cpu_ppc_tb_start (CPUPPCState *env);
>   
>   void ppc_set_irq(PowerPCCPU *cpu, int irq, int level)
>   {
> -    CPUState *cs = CPU(cpu);
>       CPUPPCState *env = &cpu->env;
>       unsigned int old_pending;
>       bool locked = false;
> @@ -57,19 +56,15 @@ void ppc_set_irq(PowerPCCPU *cpu, int irq, int level)
>   
>       if (level) {
>           env->pending_interrupts |= irq;
> -        cpu_interrupt(cs, CPU_INTERRUPT_HARD);
>       } else {
>           env->pending_interrupts &= ~irq;
> -        if (env->pending_interrupts == 0) {
> -            cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
> -        }
>       }
>   
>       if (old_pending != env->pending_interrupts) {
> +        ppc_maybe_interrupt(env);
>           kvmppc_set_interrupt(cpu, irq, level);
>       }
>   
> -
>       trace_ppc_irq_set_exit(env, irq, level, env->pending_interrupts,
>                              CPU(cpu)->interrupt_request);
>   
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index 891206e893..925ff523cc 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -490,6 +490,7 @@ static target_ulong h_cede(PowerPCCPU *cpu, 
> SpaprMachineState *spapr,
>   
>       env->msr |= (1ULL << MSR_EE);
>       hreg_compute_hflags(env);
> +    ppc_maybe_interrupt(env);
>   
>       if (spapr_cpu->prod) {
>           spapr_cpu->prod = false;
> @@ -500,6 +501,7 @@ static target_ulong h_cede(PowerPCCPU *cpu, 
> SpaprMachineState *spapr,
>           cs->halted = 1;
>           cs->exception_index = EXCP_HLT;
>           cs->exit_request = 1;
> +        ppc_maybe_interrupt(env);
>       }
>   
>       return H_SUCCESS;
> @@ -521,6 +523,7 @@ static target_ulong h_confer_self(PowerPCCPU *cpu)
>       cs->halted = 1;
>       cs->exception_index = EXCP_HALTED;
>       cs->exit_request = 1;
> +    ppc_maybe_interrupt(&cpu->env);
>   
>       return H_SUCCESS;
>   }
> @@ -633,6 +636,7 @@ static target_ulong h_prod(PowerPCCPU *cpu, 
> SpaprMachineState *spapr,
>       spapr_cpu = spapr_cpu_state(tcpu);
>       spapr_cpu->prod = true;
>       cs->halted = 0;
> +    ppc_maybe_interrupt(&cpu->env);
>       qemu_cpu_kick(cs);
>   
>       return H_SUCCESS;
> @@ -1669,6 +1673,7 @@ static target_ulong h_enter_nested(PowerPCCPU *cpu,
>       spapr_cpu->in_nested = true;
>   
>       hreg_compute_hflags(env);
> +    ppc_maybe_interrupt(env);
>       tlb_flush(cs);
>       env->reserve_addr = -1; /* Reset the reservation */
>   
> @@ -1810,6 +1815,7 @@ out_restore_l1:
>       spapr_cpu->in_nested = false;
>   
>       hreg_compute_hflags(env);
> +    ppc_maybe_interrupt(env);
>       tlb_flush(cs);
>       env->reserve_addr = -1; /* Reset the reservation */
>   
> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> index d58b65e88f..3f664ea02c 100644
> --- a/hw/ppc/spapr_rtas.c
> +++ b/hw/ppc/spapr_rtas.c
> @@ -214,9 +214,9 @@ static void rtas_stop_self(PowerPCCPU *cpu, 
> SpaprMachineState *spapr,
>        * guest.
>        * For the same reason, set PSSCR_EC.
>        */
> -    ppc_store_lpcr(cpu, env->spr[SPR_LPCR] & ~pcc->lpcr_pm);
>       env->spr[SPR_PSSCR] |= PSSCR_EC;
>       cs->halted = 1;
> +    ppc_store_lpcr(cpu, env->spr[SPR_LPCR] & ~pcc->lpcr_pm);
>       kvmppc_set_reg_ppc_online(cpu, 0);
>       qemu_cpu_kick(cs);
>   }
> diff --git a/target/ppc/cpu.c b/target/ppc/cpu.c
> index e95b4c5ee1..1a97b41c6b 100644
> --- a/target/ppc/cpu.c
> +++ b/target/ppc/cpu.c
> @@ -82,6 +82,8 @@ void ppc_store_lpcr(PowerPCCPU *cpu, target_ulong val)
>       env->spr[SPR_LPCR] = val & pcc->lpcr_mask;
>       /* The gtse bit affects hflags */
>       hreg_compute_hflags(env);
> +
> +    ppc_maybe_interrupt(env);
>   }
>   #endif
>   
> diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> index ad758b00e5..cc2d0305ff 100644
> --- a/target/ppc/cpu.h
> +++ b/target/ppc/cpu.h
> @@ -1358,6 +1358,7 @@ int ppc64_cpu_write_elf64_note(WriteCoreDumpFunction f, 
> CPUState *cs,
>   int ppc32_cpu_write_elf32_note(WriteCoreDumpFunction f, CPUState *cs,
>                                  int cpuid, DumpState *s);
>   #ifndef CONFIG_USER_ONLY
> +void ppc_maybe_interrupt(CPUPPCState *env);
>   void ppc_cpu_do_interrupt(CPUState *cpu);
>   bool ppc_cpu_exec_interrupt(CPUState *cpu, int int_req);
>   void ppc_cpu_do_system_reset(CPUState *cs);
> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
> index e9beb002e3..8b67053728 100644
> --- a/target/ppc/excp_helper.c
> +++ b/target/ppc/excp_helper.c
> @@ -390,6 +390,7 @@ static void powerpc_set_excp_state(PowerPCCPU *cpu, 
> target_ulong vector,
>       env->nip = vector;
>       env->msr = msr;
>       hreg_compute_hflags(env);
> +    ppc_maybe_interrupt(env);
>   
>       powerpc_reset_excp_state(cpu);
>   
> @@ -2050,6 +2051,40 @@ static int ppc_next_unmasked_interrupt(CPUPPCState *env)
>       }
>   }
>   
> +/*
> + * Sets CPU_INTERRUPT_HARD if there is at least one unmasked interrupt to be
> + * delivered and clears CPU_INTERRUPT_HARD otherwise.
> + *
> + * This method is called by ppc_set_interrupt when an interrupt is raised or
> + * lowered, and should also be called whenever an interrupt masking condition
> + * is changed, e.g.:
> + *  - When relevant bits of MSR are altered, like EE, HV, PR, etc.;
> + *  - When relevant bits of LPCR are altered, like PECE, HDICE, HVICE, etc.;
> + *  - When PSSCR[EC] or env->resume_as_sreset are changed;
> + *  - When cs->halted is changed and the CPU has a different interrupt masking
> + *    logic in power-saving mode (e.g., POWER7/8/9/10);
> + */
> +void ppc_maybe_interrupt(CPUPPCState *env)
> +{
> +    CPUState *cs = env_cpu(env);
> +    bool locked = false;
> +
> +    if (!qemu_mutex_iothread_locked()) {
> +        locked = true;
> +        qemu_mutex_lock_iothread();
> +    }
> +
> +    if (ppc_next_unmasked_interrupt(env)) {
> +        cpu_interrupt(cs, CPU_INTERRUPT_HARD);
> +    } else {
> +        cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
> +    }
> +
> +    if (locked) {
> +        qemu_mutex_unlock_iothread();
> +    }
> +}
> +
>   #if defined(TARGET_PPC64)
>   static void p7_deliver_interrupt(CPUPPCState *env, int interrupt)
>   {
> @@ -2497,6 +2532,11 @@ void helper_store_msr(CPUPPCState *env, target_ulong val)
>       }
>   }
>   
> +void helper_ppc_maybe_interrupt(CPUPPCState *env)
> +{
> +    ppc_maybe_interrupt(env);
> +}
> +
>   #if defined(TARGET_PPC64)
>   void helper_scv(CPUPPCState *env, uint32_t lev)
>   {
> @@ -2517,6 +2557,8 @@ void helper_pminsn(CPUPPCState *env, powerpc_pm_insn_t 
> insn)
>       /* Condition for waking up at 0x100 */
>       env->resume_as_sreset = (insn != PPC_PM_STOP) ||
>           (env->spr[SPR_PSSCR] & PSSCR_EC);
> +
> +    ppc_maybe_interrupt(env);
>   }
>   #endif /* defined(TARGET_PPC64) */
>   
> diff --git a/target/ppc/helper.h b/target/ppc/helper.h
> index 8344fe39c6..25533b8f33 100644
> --- a/target/ppc/helper.h
> +++ b/target/ppc/helper.h
> @@ -10,6 +10,7 @@ DEF_HELPER_4(HASHSTP, void, env, tl, tl, tl)
>   DEF_HELPER_4(HASHCHKP, void, env, tl, tl, tl)
>   #if !defined(CONFIG_USER_ONLY)
>   DEF_HELPER_2(store_msr, void, env, tl)
> +DEF_HELPER_1(ppc_maybe_interrupt, void, env)
>   DEF_HELPER_1(rfi, void, env)
>   DEF_HELPER_1(40x_rfci, void, env)
>   DEF_HELPER_1(rfci, void, env)
> diff --git a/target/ppc/helper_regs.c b/target/ppc/helper_regs.c
> index 12235ea2e9..2e85e124ab 100644
> --- a/target/ppc/helper_regs.c
> +++ b/target/ppc/helper_regs.c
> @@ -260,6 +260,8 @@ int hreg_store_msr(CPUPPCState *env, target_ulong value, 
> int alter_hv)
>       env->msr = value;
>       hreg_compute_hflags(env);
>   #if !defined(CONFIG_USER_ONLY)
> +    ppc_maybe_interrupt(env);
> +
>       if (unlikely(FIELD_EX64(env->msr, MSR, POW))) {
>           if (!env->pending_interrupts && (*env->check_pow)(env)) {
>               cs->halted = 1;
> diff --git a/target/ppc/translate.c b/target/ppc/translate.c
> index 64893e3670..aa9f47d7d1 100644
> --- a/target/ppc/translate.c
> +++ b/target/ppc/translate.c
> @@ -305,6 +305,14 @@ static void gen_icount_io_start(DisasContext *ctx)
>       }
>   }
>   
> +#if !defined(CONFIG_USER_ONLY)
> +static void gen_ppc_maybe_interrupt(DisasContext *ctx)
> +{
> +    gen_icount_io_start(ctx);
> +    gen_helper_ppc_maybe_interrupt(cpu_env);
> +}
> +#endif
> +
>   /*
>    * Tells the caller what is the appropriate exception to generate and prepares
>    * SPR registers for this exception.
> @@ -6161,7 +6169,6 @@ static void gen_tlbilx_booke206(DisasContext *ctx)
>   #endif /* defined(CONFIG_USER_ONLY) */
>   }
>   
> -
>   /* wrtee */
>   static void gen_wrtee(DisasContext *ctx)
>   {
> @@ -6175,6 +6182,7 @@ static void gen_wrtee(DisasContext *ctx)
>       tcg_gen_andi_tl(t0, cpu_gpr[rD(ctx->opcode)], (1 << MSR_EE));
>       tcg_gen_andi_tl(cpu_msr, cpu_msr, ~(1 << MSR_EE));
>       tcg_gen_or_tl(cpu_msr, cpu_msr, t0);
> +    gen_ppc_maybe_interrupt(ctx);
>       tcg_temp_free(t0);
>       /*
>        * Stop translation to have a chance to raise an exception if we
> @@ -6193,6 +6201,7 @@ static void gen_wrteei(DisasContext *ctx)
>       CHK_SV(ctx);
>       if (ctx->opcode & 0x00008000) {
>           tcg_gen_ori_tl(cpu_msr, cpu_msr, (1 << MSR_EE));
> +        gen_ppc_maybe_interrupt(ctx);
>           /* Stop translation to have a chance to raise an exception */
>           ctx->base.is_jmp = DISAS_EXIT_UPDATE;
>       } else {