system/cpus: rename qemu_mutex_lock_iothread() to bql_lock()

The Big QEMU Lock (BQL) has many names and they are confusing. The
actual QemuMutex variable is called qemu_global_mutex but it's commonly
referred to as the BQL in discussions and some code comments. The
locking APIs, however, are called qemu_mutex_lock_iothread() and
qemu_mutex_unlock_iothread().

The "iothread" name is historic and comes from when the main thread was
split into into KVM vcpu threads and the "iothread" (now called the main
loop thread). I have contributed to the confusion myself by introducing
a separate --object iothread, a separate concept unrelated to the BQL.

The "iothread" name is no longer appropriate for the BQL. Rename the
locking APIs to:
- void bql_lock(void)
- void bql_unlock(void)
- bool bql_locked(void)

There are more APIs with "iothread" in their names. Subsequent patches
will rename them. There are also comments and documentation that will be
updated in later patches.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Acked-by: Fabiano Rosas <farosas@suse.de>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Acked-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20240102153529.486531-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

3 files changed, 14 insertions, 14 deletions

diff --git a/target/sparc/int32_helper.c b/target/sparc/int32_helper.c
index 8f4e08ed09..058dd712b5 100644
--- a/target/sparc/int32_helper.c
+++ b/target/sparc/int32_helper.c
@@ -70,7 +70,7 @@ void cpu_check_irqs(CPUSPARCState *env)
     CPUState *cs;
 
     /* We should be holding the BQL before we mess with IRQs */
-    g_assert(qemu_mutex_iothread_locked());
+    g_assert(bql_locked());
 
     if (env->pil_in && (env->interrupt_index == 0 ||
                         (env->interrupt_index & ~15) == TT_EXTINT)) {
diff --git a/target/sparc/int64_helper.c b/target/sparc/int64_helper.c
index 1b4155f5f3..27df9dba89 100644
--- a/target/sparc/int64_helper.c
+++ b/target/sparc/int64_helper.c
@@ -69,7 +69,7 @@ void cpu_check_irqs(CPUSPARCState *env)
                   (env->softint & ~(SOFTINT_TIMER | SOFTINT_STIMER));
 
     /* We should be holding the BQL before we mess with IRQs */
-    g_assert(qemu_mutex_iothread_locked());
+    g_assert(bql_locked());
 
     /* TT_IVEC has a higher priority (16) than TT_EXTINT (31..17) */
     if (env->ivec_status & 0x20) {
@@ -267,9 +267,9 @@ static bool do_modify_softint(CPUSPARCState *env, uint32_t value)
         env->softint = value;
 #if !defined(CONFIG_USER_ONLY)
         if (cpu_interrupts_enabled(env)) {
-            qemu_mutex_lock_iothread();
+            bql_lock();
             cpu_check_irqs(env);
-            qemu_mutex_unlock_iothread();
+            bql_unlock();
         }
 #endif
         return true;
diff --git a/target/sparc/win_helper.c b/target/sparc/win_helper.c
index 16d1c70fe7..b53fc9ce94 100644
--- a/target/sparc/win_helper.c
+++ b/target/sparc/win_helper.c
@@ -179,9 +179,9 @@ void helper_wrpsr(CPUSPARCState *env, target_ulong new_psr)
         cpu_raise_exception_ra(env, TT_ILL_INSN, GETPC());
     } else {
         /* cpu_put_psr may trigger interrupts, hence BQL */
-        qemu_mutex_lock_iothread();
+        bql_lock();
         cpu_put_psr(env, new_psr);
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
 }
 
@@ -407,9 +407,9 @@ void helper_wrpstate(CPUSPARCState *env, target_ulong new_state)
 
 #if !defined(CONFIG_USER_ONLY)
     if (cpu_interrupts_enabled(env)) {
-        qemu_mutex_lock_iothread();
+        bql_lock();
         cpu_check_irqs(env);
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
 #endif
 }
@@ -422,9 +422,9 @@ void helper_wrpil(CPUSPARCState *env, target_ulong new_pil)
     env->psrpil = new_pil;
 
     if (cpu_interrupts_enabled(env)) {
-        qemu_mutex_lock_iothread();
+        bql_lock();
         cpu_check_irqs(env);
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
 #endif
 }
@@ -451,9 +451,9 @@ void helper_done(CPUSPARCState *env)
 
 #if !defined(CONFIG_USER_ONLY)
     if (cpu_interrupts_enabled(env)) {
-        qemu_mutex_lock_iothread();
+        bql_lock();
         cpu_check_irqs(env);
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
 #endif
 }
@@ -480,9 +480,9 @@ void helper_retry(CPUSPARCState *env)
 
 #if !defined(CONFIG_USER_ONLY)
     if (cpu_interrupts_enabled(env)) {
-        qemu_mutex_lock_iothread();
+        bql_lock();
         cpu_check_irqs(env);
-        qemu_mutex_unlock_iothread();
+        bql_unlock();
     }
 #endif
 }