[PATCH v2 1/1] hw/intc/loongson_ipi: Gate MMIO regions creation with property

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

From: Jiaxun Yang <jiaxun.yang@flygoat.com>

Commit 49eba52a52fe ("hw/intc/loongson_ipi: Provide per core MMIO address
spaces") implemented per core MMIO spaces for IPI registers.

However on LoongArch system emulation with high core count it may exhaust
QDEV_MAX_MMIO and trigger assertion.

Given that MMIO region is unused for LoongArch system emulation (we do have
it on hardware but kernel is in favor of IOCSR), gate MMIO regions creation
with "has-mmio" property and only set if for loongson3-virt machine to avoid
such limitation on LoongArch.

Reported-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 include/hw/intc/loongson_ipi.h |  1 +
 hw/intc/loongson_ipi.c         | 16 ++++++++++------
 hw/mips/loongson3_virt.c       |  1 +
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/include/hw/intc/loongson_ipi.h b/include/hw/intc/loongson_ipi.h
index 3f795edbf3..0e35674e7a 100644
--- a/include/hw/intc/loongson_ipi.h
+++ b/include/hw/intc/loongson_ipi.h
@@ -50,6 +50,7 @@ struct LoongsonIPI {
     MemoryRegion ipi_iocsr_mem;
     MemoryRegion ipi64_iocsr_mem;
     uint32_t num_cpu;
+    bool has_mmio;
     IPICore *cpu;
 };
 
diff --git a/hw/intc/loongson_ipi.c b/hw/intc/loongson_ipi.c
index e6a7142480..d1b7a80d7b 100644
--- a/hw/intc/loongson_ipi.c
+++ b/hw/intc/loongson_ipi.c
@@ -307,13 +307,16 @@ static void loongson_ipi_realize(DeviceState *dev, Error **errp)
 
     for (i = 0; i < s->num_cpu; i++) {
         s->cpu[i].ipi = s;
-        s->cpu[i].ipi_mmio_mem = g_new0(MemoryRegion, 1);
-        g_autofree char *name = g_strdup_printf("loongson_ipi_cpu%d_mmio", i);
-        memory_region_init_io(s->cpu[i].ipi_mmio_mem, OBJECT(dev),
-                              &loongson_ipi_core_ops, &s->cpu[i], name, 0x48);
-        sysbus_init_mmio(sbd, s->cpu[i].ipi_mmio_mem);
-
         qdev_init_gpio_out(dev, &s->cpu[i].irq, 1);
+
+        if (s->has_mmio) {
+            g_autofree char *name = g_strdup_printf("loongson_ipi_cpu%d_mmio", i);
+            s->cpu[i].ipi_mmio_mem = g_new0(MemoryRegion, 1);
+            memory_region_init_io(s->cpu[i].ipi_mmio_mem, OBJECT(dev),
+                                  &loongson_ipi_core_ops, &s->cpu[i],
+                                  name, 0x48);
+            sysbus_init_mmio(sbd, s->cpu[i].ipi_mmio_mem);
+        }
     }
 }
 
@@ -344,6 +347,7 @@ static const VMStateDescription vmstate_loongson_ipi = {
 
 static Property ipi_properties[] = {
     DEFINE_PROP_UINT32("num-cpu", LoongsonIPI, num_cpu, 1),
+    DEFINE_PROP_BOOL("has-mmio", LoongsonIPI, has_mmio, false),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/mips/loongson3_virt.c b/hw/mips/loongson3_virt.c
index 4ad36f0c5b..a27b30ab31 100644
--- a/hw/mips/loongson3_virt.c
+++ b/hw/mips/loongson3_virt.c
@@ -537,6 +537,7 @@ static void mips_loongson3_virt_init(MachineState *machine)
     if (!kvm_enabled()) {
         ipi = qdev_new(TYPE_LOONGSON_IPI);
         qdev_prop_set_uint32(ipi, "num-cpu", machine->smp.cpus);
+        qdev_prop_set_bit(ipi, "has-mmio", true);
         sysbus_realize_and_unref(SYS_BUS_DEVICE(ipi), &error_fatal);
         memory_region_add_subregion(iocsr, SMP_IPI_MAILBOX,
                                 sysbus_mmio_get_region(SYS_BUS_DEVICE(ipi), 0));
-- 
2.41.0