[PATCH v2] arm: xlnx-versal: fix virtio-mmio base address assignment

[schspa]

At the moment the following QEMU command line triggers an assertion
failure On xlnx-versal SOC:
  qemu-system-aarch64 \
      -machine xlnx-versal-virt -nographic -smp 2 -m 128 \
      -fsdev local,id=shareid,path=${HOME}/work,security_model=none \
      -device virtio-9p-device,fsdev=shareid,mount_tag=share \
      -fsdev local,id=shareid1,path=${HOME}/Music,security_model=none \
      -device virtio-9p-device,fsdev=shareid1,mount_tag=share1

  qemu-system-aarch64: ../migration/savevm.c:860:
  vmstate_register_with_alias_id:
  Assertion `!se->compat || se->instance_id == 0' failed.

This problem was fixed on arm virt platform in commit f58b39d2d5b
("virtio-mmio: format transport base address in BusClass.get_dev_path")

It works perfectly on arm virt platform. but there is still there on
xlnx-versal SOC.

The main difference between arm virt and xlnx-versal is they use
different way to create virtio-mmio qdev. on arm virt, it calls
sysbus_create_simple("virtio-mmio", base, pic[irq]); which will call
sysbus_mmio_map internally and assign base address to subsys device
mmio correctly. but xlnx-versal's implements won't do this.

However, xlnx-versal can't switch to sysbus_create_simple() to create
virtio-mmio device. It's because xlnx-versal's cpu use
VersalVirt.soc.fpd.apu.mr as it's memory. which is subregion of
system_memory. sysbus_create_simple will add virtio to system_memory,
which can't be accessed by cpu.

Besides, xlnx-versal can't add sysbus_mmio_map api call too, because
this will add memory region to system_memory, and it can't be added
to VersalVirt.soc.fpd.apu.mr again.

We can solve this by simply assign mmio[0].addr directly. makes
virtio_mmio_bus_get_dev_path to produce correct unique device path.

Signed-off-by: schspa <schspa@gmail.com>
---
 hw/arm/xlnx-versal-virt.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/arm/xlnx-versal-virt.c b/hw/arm/xlnx-versal-virt.c
index 8482cd6196..87b92ec6c3 100644
--- a/hw/arm/xlnx-versal-virt.c
+++ b/hw/arm/xlnx-versal-virt.c
@@ -490,6 +490,7 @@ static void create_virtio_regions(VersalVirt *s)
         object_property_add_child(OBJECT(&s->soc), name, OBJECT(dev));
         sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
         sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, pic_irq);
+        SYS_BUS_DEVICE(dev)->mmio[0].addr = base;
         mr = sysbus_mmio_get_region(SYS_BUS_DEVICE(dev), 0);
         memory_region_add_subregion(&s->soc.mr_ps, base, mr);
         g_free(name);
-- 
2.30.0