target/ppc: introduce ppc_maybe_interrupt

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>
Message-Id: <20221021142156.4134411-2-matheus.ferst@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>

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);
 }

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);
 

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 */
 

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);
 }

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
 

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);

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);
 
@@ -2044,6 +2045,40 @@ 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)
 {
@@ -2479,6 +2514,11 @@ 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)
 {
@@ -2499,6 +2539,8 @@ 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) */
 

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)

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;

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 {