hw/mips_int: hold BQL for all interrupt requests

Make sure BQL is held for all interrupt requests.

For MTTCG-enabled configurations, handling soft and hard interrupts
between vCPUs must be properly locked. By acquiring BQL, make sure
all paths triggering an IRQ are synchronized.

Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/hw/mips/mips_int.c b/hw/mips/mips_int.c
index 48192d22f3..5ddeb15848 100644
--- a/hw/mips/mips_int.c
+++ b/hw/mips/mips_int.c
@@ -21,6 +21,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/main-loop.h"
 #include "hw/hw.h"
 #include "hw/mips/cpudevs.h"
 #include "cpu.h"
@@ -32,10 +33,17 @@ static void cpu_mips_irq_request(void *opaque, int irq, int level)
     MIPSCPU *cpu = opaque;
     CPUMIPSState *env = &cpu->env;
     CPUState *cs = CPU(cpu);
+    bool locked = false;
 
     if (irq < 0 || irq > 7)
         return;
 
+    /* Make sure locking works even if BQL is already held by the caller */
+    if (!qemu_mutex_iothread_locked()) {
+        locked = true;
+        qemu_mutex_lock_iothread();
+    }
+
     if (level) {
         env->CP0_Cause |= 1 << (irq + CP0Ca_IP);
 
@@ -56,6 +64,10 @@ static void cpu_mips_irq_request(void *opaque, int irq, int level)
     } else {
         cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
     }
+
+    if (locked) {
+        qemu_mutex_unlock_iothread();
+    }
 }
 
 void cpu_mips_irq_init_cpu(MIPSCPU *cpu)