[PATCH 07/22] exec/cpu: Introduce the CPU address space destruction function

[Philippe Mathieu-Daudé]

From: xianglai li <lixianglai@loongson.cn>

Introduce new function to destroy CPU address space resources
for cpu hot-(un)plug.

Co-authored-by: "Salil Mehta" <salil.mehta@opnsrc.net>
Cc: "Salil Mehta" <salil.mehta@opnsrc.net>
Cc: Xiaojuan Yang <yangxiaojuan@loongson.cn>
Cc: Song Gao <gaosong@loongson.cn>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Ani Sinha <anisinha@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Eduardo Habkost <eduardo@habkost.net>
Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Cc: "Philippe Mathieu-Daudé" <philmd@linaro.org>
Cc: Yanan Wang <wangyanan55@huawei.com>
Cc: "Daniel P. Berrangé" <berrange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: xianglai li <lixianglai@loongson.cn>
Message-ID: 
<3a4fc2a3df4b767c3c296a7da3bc15ca9c251316.1694433326.git.lixianglai@loongson.cn>
---
 include/exec/cpu-common.h |  8 ++++++++
 include/hw/core/cpu.h     |  1 +
 softmmu/physmem.c         | 24 ++++++++++++++++++++++++
 3 files changed, 33 insertions(+)

diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index 41788c0bdd..eb56a228a2 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -120,6 +120,14 @@ size_t qemu_ram_pagesize_largest(void);
  */
 void cpu_address_space_init(CPUState *cpu, int asidx,
                             const char *prefix, MemoryRegion *mr);
+/**
+ * cpu_address_space_destroy:
+ * @cpu: CPU for which address space needs to be destroyed
+ * @asidx: integer index of this address space
+ *
+ * Note that with KVM only one address space is supported.
+ */
+void cpu_address_space_destroy(CPUState *cpu, int asidx);
 
 void cpu_physical_memory_rw(hwaddr addr, void *buf,
                             hwaddr len, bool is_write);
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 92a4234439..c90cf3a162 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -366,6 +366,7 @@ struct CPUState {
     QSIMPLEQ_HEAD(, qemu_work_item) work_list;
 
     CPUAddressSpace *cpu_ases;
+    int cpu_ases_ref_count;
     int num_ases;
     AddressSpace *as;
     MemoryRegion *memory;
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 18277ddd67..c75e3e8042 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -761,6 +761,7 @@ void cpu_address_space_init(CPUState *cpu, int asidx,
 
     if (!cpu->cpu_ases) {
         cpu->cpu_ases = g_new0(CPUAddressSpace, cpu->num_ases);
+        cpu->cpu_ases_ref_count = cpu->num_ases;
     }
 
     newas = &cpu->cpu_ases[asidx];
@@ -774,6 +775,29 @@ void cpu_address_space_init(CPUState *cpu, int asidx,
     }
 }
 
+void cpu_address_space_destroy(CPUState *cpu, int asidx)
+{
+    CPUAddressSpace *cpuas;
+
+    assert(asidx < cpu->num_ases);
+    assert(asidx == 0 || !kvm_enabled());
+    assert(cpu->cpu_ases);
+
+    cpuas = &cpu->cpu_ases[asidx];
+    if (tcg_enabled()) {
+        memory_listener_unregister(&cpuas->tcg_as_listener);
+    }
+
+    address_space_destroy(cpuas->as);
+
+    cpu->cpu_ases_ref_count--;
+    if (cpu->cpu_ases_ref_count == 0) {
+        g_free(cpu->cpu_ases);
+        cpu->cpu_ases = NULL;
+    }
+
+}
+
 AddressSpace *cpu_get_address_space(CPUState *cpu, int asidx)
 {
     /* Return the AddressSpace corresponding to the specified index */
-- 
2.41.0