exec.c: Allow target CPUs to define multiple AddressSpaces

Allow multiple calls to cpu_address_space_init(); each
call adds an entry to the cpu->ases array at the specified
index. It is up to the target-specific CPU code to actually use
these extra address spaces.

Since this multiple AddressSpace support won't work with
KVM, add an assertion to avoid confusing failures.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>

cpus.c

@@ -1375,6 +1375,7 @@ void qemu_init_vcpu(CPUState *cpu)
         /* If the target cpu hasn't set up any address spaces itself,
          * give it the default one.
          */
+        cpu->num_ases = 1;
         cpu_address_space_init(cpu, &address_space_memory, 0);
     }
 

exec.c

@@ -538,25 +538,29 @@ CPUState *qemu_get_cpu(int index)
 #if !defined(CONFIG_USER_ONLY)
 void cpu_address_space_init(CPUState *cpu, AddressSpace *as, int asidx)
 {
+    CPUAddressSpace *newas;
+
+    /* Target code should have set num_ases before calling us */
+    assert(asidx < cpu->num_ases);
+
     if (asidx == 0) {
         /* address space 0 gets the convenience alias */
         cpu->as = as;
     }
 
-    /* We only support one address space per cpu at the moment.  */
-    assert(cpu->as == as);
+    /* KVM cannot currently support multiple address spaces. */
+    assert(asidx == 0 || !kvm_enabled());
 
-    if (cpu->cpu_ases) {
-        /* We've already registered the listener for our only AS */
-        return;
+    if (!cpu->cpu_ases) {
+        cpu->cpu_ases = g_new0(CPUAddressSpace, cpu->num_ases);
     }
 
-    cpu->cpu_ases = g_new0(CPUAddressSpace, 1);
-    cpu->cpu_ases[0].cpu = cpu;
-    cpu->cpu_ases[0].as = as;
+    newas = &cpu->cpu_ases[asidx];
+    newas->cpu = cpu;
+    newas->as = as;
     if (tcg_enabled()) {
-        cpu->cpu_ases[0].tcg_as_listener.commit = tcg_commit;
-        memory_listener_register(&cpu->cpu_ases[0].tcg_as_listener, as);
+        newas->tcg_as_listener.commit = tcg_commit;
+        memory_listener_register(&newas->tcg_as_listener, as);
     }
 }
 #endif
@@ -613,6 +617,7 @@ void cpu_exec_init(CPUState *cpu, Error **errp)
     Error *local_err = NULL;
 
     cpu->as = NULL;
+    cpu->num_ases = 0;
 
 #ifndef CONFIG_USER_ONLY
     cpu->thread_id = qemu_get_thread_id();

include/exec/exec-all.h

@@ -96,6 +96,10 @@ void cpu_reloading_memory_map(void);
  * The target-specific code which registers ASes is responsible
  * for defining what semantics address space 0, 1, 2, etc have.
  *
+ * Before the first call to this function, the caller must set
+ * cpu->num_ases to the total number of address spaces it needs
+ * to support.
+ *
  * Note that with KVM only one address space is supported.
  */
 void cpu_address_space_init(CPUState *cpu, AddressSpace *as, int asidx);

include/qom/cpu.h

@@ -236,6 +236,7 @@ struct kvm_run;
  * so that interrupts take effect immediately.
  * @cpu_ases: Pointer to array of CPUAddressSpaces (which define the
  *            AddressSpaces this CPU has)
+ * @num_ases: number of CPUAddressSpaces in @cpu_ases
  * @as: Pointer to the first AddressSpace, for the convenience of targets which
  *      only have a single AddressSpace
  * @env_ptr: Pointer to subclass-specific CPUArchState field.
@@ -285,6 +286,7 @@ struct CPUState {
     struct qemu_work_item *queued_work_first, *queued_work_last;
 
     CPUAddressSpace *cpu_ases;
+    int num_ases;
     AddressSpace *as;
 
     void *env_ptr; /* CPUArchState */

target-i386/cpu.c

@@ -2878,6 +2878,7 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
         memory_region_add_subregion_overlap(cpu->cpu_as_root, 0, cpu->cpu_as_mem, 0);
         memory_region_set_enabled(cpu->cpu_as_mem, true);
         address_space_init(newas, cpu->cpu_as_root, "CPU");
+        cs->num_ases = 1;
         cpu_address_space_init(cs, newas, 0);
 
         /* ... SMRAM with higher priority, linked from /machine/smram.  */