From 7efd5d829730d0481659cda91f725df3b141f469 Mon Sep 17 00:00:00 2001
From: Salil Mehta <salil.mehta@huawei.com>
Date: Tue, 16 Jul 2024 12:15:01 +0100
Subject: [PATCH 66/78] physmem: Add helper function to destroy CPU
 AddressSpace

Virtual CPU Hot-unplug leads to unrealization of a CPU object. This also
involves destruction of the CPU AddressSpace. Add common function to help
destroy the CPU AddressSpace.

Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Tested-by: Xianglai Li <lixianglai@loongson.cn>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Tested-by: Zhao Liu <zhao1.liu@intel.com>
Acked-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20240716111502.202344-7-salil.mehta@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
---
 include/hw/core/cpu.h |  4 ++--
 system/physmem.c      | 18 +++++++++++-------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index ee04ee44c2..37f3a469c8 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -495,8 +495,8 @@ struct CPUState {
     QemuMutex work_mutex;
     QSIMPLEQ_HEAD(, qemu_work_item) work_list;
 
-    CPUAddressSpace *cpu_ases;
-    int cpu_ases_ref_count;
+    struct CPUAddressSpace *cpu_ases;
+    int cpu_ases_count;
     int num_ases;
     AddressSpace *as;
     MemoryRegion *memory;
diff --git a/system/physmem.c b/system/physmem.c
index 2c8b83f811..c50ac24786 100644
--- a/system/physmem.c
+++ b/system/physmem.c
@@ -761,7 +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;
+        cpu->cpu_ases_count = cpu->num_ases;
     }
 
     newas = &cpu->cpu_ases[asidx];
@@ -779,24 +779,28 @@ 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);
+    assert(asidx >= 0 && asidx < cpu->num_ases);
+    /* KVM cannot currently support multiple address spaces. */
+    assert(asidx == 0 || !kvm_enabled());
 
     cpuas = &cpu->cpu_ases[asidx];
     if (tcg_enabled()) {
         memory_listener_unregister(&cpuas->tcg_as_listener);
     }
 
-    cpuas->as->free_in_rcu = true;
     address_space_destroy(cpuas->as);
+    g_free_rcu(cpuas->as, rcu);
 
-    if (cpu->cpu_ases_ref_count == 1) {
+    if (asidx == 0) {
+        /* reset the convenience alias for address space 0 */
+        cpu->as = NULL;
+    }
+
+    if (--cpu->cpu_ases_count == 0) {
         g_free(cpu->cpu_ases);
         cpu->cpu_ases = NULL;
     }
-
-    cpu->cpu_ases_ref_count--;
 }
 
 AddressSpace *cpu_get_address_space(CPUState *cpu, int asidx)
-- 
2.39.1