Some SysBusDevices either use sysbus_init_mmio() without
sysbus_mmio_map() or the first MMIO memory region doesn't represent the
bus address, causing a firmware device path with an invalid address to
be generated.

SysBusDeviceClass does provide a virtual explicit_ofw_unit_address()
method that can be used to override this process, but it was originally intended
only as as a fallback option meaning that any existing MMIO memory regions still
take priority whilst determining the firmware device address.

There is currently only one user of explicit_ofw_unit_address() and that
is the PCI expander bridge (PXB) device which has no MMIO/PIO resources
defined. This enables us to allow explicit_ofw_unit_address() to take
priority without affecting backwards compatibility, allowing the address
to be customised as required.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
 hw/core/sysbus.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
index ecfb0cfc0e..1ee0c162f4 100644
--- a/hw/core/sysbus.c
+++ b/hw/core/sysbus.c
@@ -293,16 +293,8 @@ static char *sysbus_get_fw_dev_path(DeviceState *dev)
 {
     SysBusDevice *s = SYS_BUS_DEVICE(dev);
     SysBusDeviceClass *sbc = SYS_BUS_DEVICE_GET_CLASS(s);
-    /* for the explicit unit address fallback case: */
     char *addr, *fw_dev_path;
 
-    if (s->num_mmio) {
-        return g_strdup_printf("%s@" TARGET_FMT_plx, qdev_fw_name(dev),
-                               s->mmio[0].addr);
-    }
-    if (s->num_pio) {
-        return g_strdup_printf("%s@i%04x", qdev_fw_name(dev), s->pio[0]);
-    }
     if (sbc->explicit_ofw_unit_address) {
         addr = sbc->explicit_ofw_unit_address(s);
         if (addr) {
@@ -311,6 +303,13 @@ static char *sysbus_get_fw_dev_path(DeviceState *dev)
             return fw_dev_path;
         }
     }
+    if (s->num_mmio) {
+        return g_strdup_printf("%s@" TARGET_FMT_plx, qdev_fw_name(dev),
+                               s->mmio[0].addr);
+    }
+    if (s->num_pio) {
+        return g_strdup_printf("%s@i%04x", qdev_fw_name(dev), s->pio[0]);
+    }
     return g_strdup(qdev_fw_name(dev));
 }
 
-- 
2.11.0

On 06/29/18 15:56, Mark Cave-Ayland wrote:
> Some SysBusDevices either use sysbus_init_mmio() without
> sysbus_mmio_map() or the first MMIO memory region doesn't represent the
> bus address, causing a firmware device path with an invalid address to
> be generated.
> 
> SysBusDeviceClass does provide a virtual explicit_ofw_unit_address()
> method that can be used to override this process, but it was originally intended
> only as as a fallback option meaning that any existing MMIO memory regions still
> take priority whilst determining the firmware device address.
> 
> There is currently only one user of explicit_ofw_unit_address() and that
> is the PCI expander bridge (PXB) device which has no MMIO/PIO resources
> defined. This enables us to allow explicit_ofw_unit_address() to take
> priority without affecting backwards compatibility, allowing the address
> to be customised as required.
> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
>  hw/core/sysbus.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
> index ecfb0cfc0e..1ee0c162f4 100644
> --- a/hw/core/sysbus.c
> +++ b/hw/core/sysbus.c
> @@ -293,16 +293,8 @@ static char *sysbus_get_fw_dev_path(DeviceState *dev)
>  {
>      SysBusDevice *s = SYS_BUS_DEVICE(dev);
>      SysBusDeviceClass *sbc = SYS_BUS_DEVICE_GET_CLASS(s);
> -    /* for the explicit unit address fallback case: */
>      char *addr, *fw_dev_path;
>  
> -    if (s->num_mmio) {
> -        return g_strdup_printf("%s@" TARGET_FMT_plx, qdev_fw_name(dev),
> -                               s->mmio[0].addr);
> -    }
> -    if (s->num_pio) {
> -        return g_strdup_printf("%s@i%04x", qdev_fw_name(dev), s->pio[0]);
> -    }
>      if (sbc->explicit_ofw_unit_address) {
>          addr = sbc->explicit_ofw_unit_address(s);
>          if (addr) {
> @@ -311,6 +303,13 @@ static char *sysbus_get_fw_dev_path(DeviceState *dev)
>              return fw_dev_path;
>          }
>      }
> +    if (s->num_mmio) {
> +        return g_strdup_printf("%s@" TARGET_FMT_plx, qdev_fw_name(dev),
> +                               s->mmio[0].addr);
> +    }
> +    if (s->num_pio) {
> +        return g_strdup_printf("%s@i%04x", qdev_fw_name(dev), s->pio[0]);
> +    }
>      return g_strdup(qdev_fw_name(dev));
>  }
>  
> 


Reviewed-by: Laszlo Ersek <lersek@redhat.com>