hw/sparc/sun4m: Don't set up dummy cpu interrupts

In the sun4m machine init, we set up the cpu_irqs[] array
with the real inbound IRQs for each CPU, followed by some
dummy IRQs for the remaining slots from smp_cpus up to
MAX_CPUS. These dummy IRQs do nothing when set/cleared
because the dummy_cpu_set_irq() function does nothing.

Instead of creating these "do nothing" qemu_irqs, instead
pass the number of CPUs to slavio_intctl_init() so that it
can only wire up the interrupt controller's interrupts
for the CPUs that actually exist. Calling qemu_set_irq()
on an irq that isn't connected does nothing, so this is
a simpler way to achieve the same result.

This cleanup fixes an unimportant memory leak reported by
the address sanitizer that happens because we allocate these
dummy IRQs with qemu_allocate_irqs():

Direct leak of 1920 byte(s) in 15 object(s) allocated from:
    #0 0x5cb7b120cf63 in malloc (/home/pm215/qemu/build/san/qemu-system-sparc+0xe0bf63) (BuildId: d27f9230a7cc82ebfaf0cf9e439dc215ddd7ac68)
    #1 0x743cd6dc5ac9 in g_malloc (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x62ac9) (BuildId: 116e142b9b52c8a4dfd403e759e71ab8f95d8bb3)
    #2 0x5cb7b1a42fb4 in qemu_extend_irqs /home/pm215/qemu/build/san/../../hw/core/irq.c:77:51
    #3 0x5cb7b19e7e72 in sun4m_hw_init /home/pm215/qemu/build/san/../../hw/sparc/sun4m.c:845:23
    #4 0x5cb7b141d3dd in machine_run_board_init /home/pm215/qemu/build/san/../../hw/core/machine.c:1709:5
    #5 0x5cb7b1542895 in qemu_init_board /home/pm215/qemu/build/san/../../system/vl.c:2717:5
    #6 0x5cb7b1542895 in qmp_x_exit_preconfig /home/pm215/qemu/build/san/../../system/vl.c:2811:5
    #7 0x5cb7b15493ac in qemu_init /home/pm215/qemu/build/san/../../system/vl.c:3849:9
    #8 0x5cb7b1f3f201 in main /home/pm215/qemu/build/san/../../system/main.c:71:5
    #9 0x743cd4a2a1c9 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #10 0x743cd4a2a28a in __libc_start_main csu/../csu/libc-start.c:360:3
    #11 0x5cb7b1172114 in _start (/home/pm215/qemu/build/san/qemu-system-sparc+0xd71114) (BuildId: d27f9230a7cc82ebfaf0cf9e439dc215ddd7ac68)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-ID: <20260307112931.3322532-2-peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

hw/sparc/sun4m.c

@@ -196,10 +196,6 @@ static void cpu_set_irq(void *opaque, int irq, int level)
     }
 }
 
-static void dummy_cpu_set_irq(void *opaque, int irq, int level)
-{
-}
-
 static void sun4m_cpu_reset(void *opaque)
 {
     SPARCCPU *cpu = opaque;
@@ -344,6 +340,7 @@ static void *sparc32_dma_init(hwaddr dma_base,
 
 static DeviceState *slavio_intctl_init(hwaddr addr,
                                        hwaddr addrg,
+                                       unsigned int smp_cpus,
                                        qemu_irq **parent_irq)
 {
     DeviceState *dev;
@@ -355,7 +352,7 @@ static DeviceState *slavio_intctl_init(hwaddr addr,
     s = SYS_BUS_DEVICE(dev);
     sysbus_realize_and_unref(s, &error_fatal);
 
-    for (i = 0; i < MAX_CPUS; i++) {
+    for (i = 0; i < smp_cpus; i++) {
         for (j = 0; j < MAX_PILS; j++) {
             sysbus_connect_irq(s, i * MAX_PILS + j, parent_irq[i][j]);
         }
@@ -841,9 +838,6 @@ static void sun4m_hw_init(MachineState *machine)
         cpu_devinit(machine->cpu_type, i, hwdef->slavio_base, &cpu_irqs[i]);
     }
 
-    for (i = smp_cpus; i < MAX_CPUS; i++)
-        cpu_irqs[i] = qemu_allocate_irqs(dummy_cpu_set_irq, NULL, MAX_PILS);
-
     /* Create and map RAM frontend */
     dev = qdev_new("memory");
     object_property_set_link(OBJECT(dev), "memdev", OBJECT(ram_memdev), &error_fatal);
@@ -860,6 +854,7 @@ static void sun4m_hw_init(MachineState *machine)
 
     slavio_intctl = slavio_intctl_init(hwdef->intctl_base,
                                        hwdef->intctl_base + 0x10000ULL,
+                                       smp_cpus,
                                        cpu_irqs);
 
     for (i = 0; i < 32; i++) {