target/ppc: Add msgsnd/p and DPDES SMT support

Doorbells in SMT need to coordinate msgsnd/msgclr and DPDES access from
multiple threads that affect the same state.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

3 files changed, 71 insertions, 11 deletions

diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index 8e2fec3551..2158390e27 100644
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -3186,22 +3186,42 @@ void helper_book3s_msgclrp(CPUPPCState *env, target_ulong rb)
 }
 
 /*
- * sends a message to other threads that are on the same
+ * sends a message to another thread  on the same
  * multi-threaded processor
  */
 void helper_book3s_msgsndp(CPUPPCState *env, target_ulong rb)
 {
-    int pir = env->spr_cb[SPR_PIR].default_value;
+    CPUState *cs = env_cpu(env);
+    PowerPCCPU *cpu = POWERPC_CPU(cs);
+    CPUState *ccs;
+    uint32_t nr_threads = cs->nr_threads;
+    int ttir = rb & PPC_BITMASK(57, 63);
 
     helper_hfscr_facility_check(env, HFSCR_MSGP, "msgsndp", HFSCR_IC_MSGP);
 
-    if (!dbell_type_server(rb)) {
+    if (!dbell_type_server(rb) || ttir >= nr_threads) {
+        return;
+    }
+
+    if (nr_threads == 1) {
+        ppc_set_irq(cpu, PPC_INTERRUPT_DOORBELL, 1);
         return;
     }
 
-    /* TODO: TCG supports only one thread */
+    /* Does iothread need to be locked for walking CPU list? */
+    qemu_mutex_lock_iothread();
+    THREAD_SIBLING_FOREACH(cs, ccs) {
+        PowerPCCPU *ccpu = POWERPC_CPU(ccs);
+        uint32_t thread_id = ppc_cpu_tir(ccpu);
+
+        if (ttir == thread_id) {
+            ppc_set_irq(ccpu, PPC_INTERRUPT_DOORBELL, 1);
+            qemu_mutex_unlock_iothread();
+            return;
+        }
+    }
 
-    book3s_msgsnd_common(pir, PPC_INTERRUPT_DOORBELL);
+    g_assert_not_reached();
 }
 #endif /* TARGET_PPC64 */
 
diff --git a/target/ppc/misc_helper.c b/target/ppc/misc_helper.c
index a058eb24cd..1f1af21f33 100644
--- a/target/ppc/misc_helper.c
+++ b/target/ppc/misc_helper.c
@@ -184,14 +184,31 @@ void helper_store_pcr(CPUPPCState *env, target_ulong value)
  */
 target_ulong helper_load_dpdes(CPUPPCState *env)
 {
+    CPUState *cs = env_cpu(env);
+    CPUState *ccs;
+    uint32_t nr_threads = cs->nr_threads;
     target_ulong dpdes = 0;
 
     helper_hfscr_facility_check(env, HFSCR_MSGP, "load DPDES", HFSCR_IC_MSGP);
 
-    /* TODO: TCG supports only one thread */
-    if (env->pending_interrupts & PPC_INTERRUPT_DOORBELL) {
-        dpdes = 1;
+    if (nr_threads == 1) {
+        if (env->pending_interrupts & PPC_INTERRUPT_DOORBELL) {
+            dpdes = 1;
+        }
+        return dpdes;
+    }
+
+    qemu_mutex_lock_iothread();
+    THREAD_SIBLING_FOREACH(cs, ccs) {
+        PowerPCCPU *ccpu = POWERPC_CPU(ccs);
+        CPUPPCState *cenv = &ccpu->env;
+        uint32_t thread_id = ppc_cpu_tir(ccpu);
+
+        if (cenv->pending_interrupts & PPC_INTERRUPT_DOORBELL) {
+            dpdes |= (0x1 << thread_id);
+        }
     }
+    qemu_mutex_unlock_iothread();
 
     return dpdes;
 }
@@ -199,17 +216,32 @@ target_ulong helper_load_dpdes(CPUPPCState *env)
 void helper_store_dpdes(CPUPPCState *env, target_ulong val)
 {
     PowerPCCPU *cpu = env_archcpu(env);
+    CPUState *cs = env_cpu(env);
+    CPUState *ccs;
+    uint32_t nr_threads = cs->nr_threads;
 
     helper_hfscr_facility_check(env, HFSCR_MSGP, "store DPDES", HFSCR_IC_MSGP);
 
-    /* TODO: TCG supports only one thread */
-    if (val & ~0x1) {
+    if (val & ~(nr_threads - 1)) {
         qemu_log_mask(LOG_GUEST_ERROR, "Invalid DPDES register value "
                       TARGET_FMT_lx"\n", val);
+        val &= (nr_threads - 1); /* Ignore the invalid bits */
+    }
+
+    if (nr_threads == 1) {
+        ppc_set_irq(cpu, PPC_INTERRUPT_DOORBELL, val & 0x1);
         return;
     }
 
-    ppc_set_irq(cpu, PPC_INTERRUPT_DOORBELL, val & 0x1);
+    /* Does iothread need to be locked for walking CPU list? */
+    qemu_mutex_lock_iothread();
+    THREAD_SIBLING_FOREACH(cs, ccs) {
+        PowerPCCPU *ccpu = POWERPC_CPU(ccs);
+        uint32_t thread_id = ppc_cpu_tir(ccpu);
+
+        ppc_set_irq(cpu, PPC_INTERRUPT_DOORBELL, val & (0x1 << thread_id));
+    }
+    qemu_mutex_unlock_iothread();
 }
 #endif /* defined(TARGET_PPC64) */
 
diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index c321a39027..372ee600b2 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -815,11 +815,19 @@ void spr_write_pcr(DisasContext *ctx, int sprn, int gprn)
 /* DPDES */
 void spr_read_dpdes(DisasContext *ctx, int gprn, int sprn)
 {
+    if (!gen_serialize_core(ctx)) {
+        return;
+    }
+
     gen_helper_load_dpdes(cpu_gpr[gprn], cpu_env);
 }
 
 void spr_write_dpdes(DisasContext *ctx, int sprn, int gprn)
 {
+    if (!gen_serialize_core(ctx)) {
+        return;
+    }
+
     gen_helper_store_dpdes(cpu_env, cpu_gpr[gprn]);
 }
 #endif