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[RFC,V5,25/30] tcg/mttcg: Introduce MTTCG thread unregistration leg

Message ID 20241015100012.254223-26-salil.mehta@huawei.com (mailing list archive)
State New, archived
Headers show
Series Support of Virtual CPU Hotplug for ARMv8 Arch | expand

Commit Message

Salil Mehta Oct. 15, 2024, 10 a.m. UTC 
From: Miguel Luis <miguel.luis@oracle.com>

Introduce the TCG thread unregistration leg which shall be called in context to
TCG/vCPU unrealize.

Reported-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: Miguel Luis <miguel.luis@oracle.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
---
 accel/tcg/tcg-accel-ops-mttcg.c |  1 +
 include/tcg/startup.h           |  7 +++++++
 tcg/tcg.c                       | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 41 insertions(+)
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Patch

diff --git a/accel/tcg/tcg-accel-ops-mttcg.c b/accel/tcg/tcg-accel-ops-mttcg.c
index ab2f79d2c7..4b26164ffd 100644
--- a/accel/tcg/tcg-accel-ops-mttcg.c
+++ b/accel/tcg/tcg-accel-ops-mttcg.c
@@ -122,6 +122,7 @@  static void *mttcg_cpu_thread_fn(void *arg)
     bql_unlock();
     rcu_remove_force_rcu_notifier(&force_rcu.notifier);
     rcu_unregister_thread();
+    tcg_unregister_thread();
     return NULL;
 }
 
diff --git a/include/tcg/startup.h b/include/tcg/startup.h
index a565071516..c035d03f7e 100644
--- a/include/tcg/startup.h
+++ b/include/tcg/startup.h
@@ -51,6 +51,13 @@  void tcg_register_thread(void);
 void tcg_register_thread(CPUState *cpu);
 #endif
 
+/**
+ * tcg_unregister_thread: Unregister this thread with the TCG runtime
+ *
+ * This leg shall be called whenever TCG vCPU is hot-unplugged
+ */
+void tcg_unregister_thread(void);
+
 /**
  * tcg_prologue_init(): Generate the code for the TCG prologue
  *
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 5e9c6b2b4b..3bdebdb332 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -811,6 +811,39 @@  void tcg_register_thread(CPUState *cpu)
 
     tcg_ctx = s;
 }
+
+static void tcg_free_plugin_context(TCGContext *s)
+{
+#ifdef CONFIG_PLUGIN
+    unsigned i;
+
+    if (s->plugin_tb) {
+        for (i = 0; i < s->plugin_tb->insns->len; i++) {
+            g_free(g_ptr_array_index(s->plugin_tb->insns, i));
+        }
+        g_ptr_array_free(s->plugin_tb->insns, TRUE);
+
+        if (!s->plugin_tb->insns) {
+            g_free(s->plugin_tb);
+        }
+    }
+#endif
+}
+
+void tcg_unregister_thread(void)
+{
+    TCGContext *s = tcg_ctx;
+    unsigned int n;
+
+    /* unclaim an entry in tcg_ctxs */
+    n = qatomic_fetch_dec(&tcg_cur_ctxs);
+    g_assert(n > 1);
+    qatomic_store_release(&tcg_ctxs[n - 1], 0);
+
+    tcg_free_plugin_context(s);
+
+    g_free(s);
+}
 #endif /* !CONFIG_USER_ONLY */
 
 /* pool based memory allocation */