hw/mips_cpc: kick a VP when putting it into Run statewq

While testing mttcg VP0 could get stuck in a loop waiting for other
VPs to come up (which never actually happens). To fix this, kick VPs
while they are being powered up by Cluster Power Controller in an
async task which is triggered once the host thread is being spawned.

Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

hw/misc/mips_cpc.c

@@ -30,6 +30,14 @@ static inline uint64_t cpc_vp_run_mask(MIPSCPCState *cpc)
     return (1ULL << cpc->num_vp) - 1;
 }
 
+static void mips_cpu_reset_async_work(CPUState *cs, run_on_cpu_data data)
+{
+    MIPSCPCState *cpc = (MIPSCPCState *) data.host_ptr;
+
+    cpu_reset(cs);
+    cpc->vp_running |= 1ULL << cs->cpu_index;
+}
+
 static void cpc_run_vp(MIPSCPCState *cpc, uint64_t vp_run)
 {
     CPUState *cs = first_cpu;
@@ -37,8 +45,13 @@ static void cpc_run_vp(MIPSCPCState *cpc, uint64_t vp_run)
     CPU_FOREACH(cs) {
         uint64_t i = 1ULL << cs->cpu_index;
         if (i & vp_run & ~cpc->vp_running) {
-            cpu_reset(cs);
-            cpc->vp_running |= i;
+            /*
+             * To avoid racing with a CPU we are just kicking off.
+             * We do the final bit of preparation for the work in
+             * the target CPUs context.
+             */
+            async_safe_run_on_cpu(cs, mips_cpu_reset_async_work,
+                                  RUN_ON_CPU_HOST_PTR(cpc));
         }
     }
 }