diff mbox series

[v5,62/73] cpu: introduce cpu_has_work_with_iothread_lock

Message ID 20181213050453.9677-63-cota@braap.org
State New
Headers show
Series per-CPU locks | expand

Commit Message

Emilio Cota Dec. 13, 2018, 5:04 a.m. UTC 
It will gain some users soon.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
---
 include/qom/cpu.h | 36 +++++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 8d4160689f..8c239c54d8 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -26,6 +26,7 @@ 
 #include "exec/memattrs.h"
 #include "qapi/qapi-types-run-state.h"
 #include "qemu/bitmap.h"
+#include "qemu/main-loop.h"
 #include "qemu/rcu_queue.h"
 #include "qemu/queue.h"
 #include "qemu/thread.h"
@@ -86,6 +87,8 @@  struct TranslationBlock;
  * @reset_dump_flags: #CPUDumpFlags to use for reset logging.
  * @has_work: Callback for checking if there is work to do. Called with the
  * CPU lock held.
+ * @has_work_with_iothread_lock: Callback for checking if there is work to do.
+ * Called with both the BQL and the CPU lock held.
  * @do_interrupt: Callback for interrupt handling.
  * @do_unassigned_access: Callback for unassigned access handling.
  * (this is deprecated: new targets should use do_transaction_failed instead)
@@ -157,6 +160,7 @@  typedef struct CPUClass {
     void (*reset)(CPUState *cpu);
     int reset_dump_flags;
     bool (*has_work)(CPUState *cpu);
+    bool (*has_work_with_iothread_lock)(CPUState *cpu);
     void (*do_interrupt)(CPUState *cpu);
     CPUUnassignedAccess do_unassigned_access;
     void (*do_unaligned_access)(CPUState *cpu, vaddr addr,
@@ -788,14 +792,40 @@  const char *parse_cpu_model(const char *cpu_model);
 static inline bool cpu_has_work(CPUState *cpu)
 {
     CPUClass *cc = CPU_GET_CLASS(cpu);
+    bool has_cpu_lock = cpu_mutex_locked(cpu);
+    bool (*func)(CPUState *cpu);
     bool ret;
 
+    if (cc->has_work_with_iothread_lock) {
+        if (qemu_mutex_iothread_locked()) {
+            func = cc->has_work_with_iothread_lock;
+            goto call_func;
+        }
+
+        if (has_cpu_lock) {
+            /* avoid deadlock by acquiring the locks in order */
+            cpu_mutex_unlock(cpu);
+        }
+        qemu_mutex_lock_iothread();
+        cpu_mutex_lock(cpu);
+
+        ret = cc->has_work_with_iothread_lock(cpu);
+
+        qemu_mutex_unlock_iothread();
+        if (!has_cpu_lock) {
+            cpu_mutex_unlock(cpu);
+        }
+        return ret;
+    }
+
     g_assert(cc->has_work);
-    if (cpu_mutex_locked(cpu)) {
-        return cc->has_work(cpu);
+    func = cc->has_work;
+ call_func:
+    if (has_cpu_lock) {
+        return func(cpu);
     }
     cpu_mutex_lock(cpu);
-    ret = cc->has_work(cpu);
+    ret = func(cpu);
     cpu_mutex_unlock(cpu);
     return ret;
 }