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>

1 files changed, 2 insertions, 2 deletions

diff --git a/target/arm/helper.c b/target/arm/helper.c
index a2a7f6c29f..7dfd0a1094 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -5851,7 +5851,7 @@ static void do_hcr_write(CPUARMState *env, uint64_t value, uint64_t valid_mask)
      * VFIQ are masked unless running at EL0 or EL1, and HCR
      * can only be written at EL2.
      */
-    g_assert(qemu_mutex_iothread_locked());
+    g_assert(bql_locked());
     arm_cpu_update_virq(cpu);
     arm_cpu_update_vfiq(cpu);
     arm_cpu_update_vserr(cpu);
@@ -11273,7 +11273,7 @@ void arm_cpu_do_interrupt(CPUState *cs)
      * BQL needs to be held for any modification of
      * cs->interrupt_request.
      */
-    g_assert(qemu_mutex_iothread_locked());
+    g_assert(bql_locked());
 
     arm_call_pre_el_change_hook(cpu);