hw/ide: Fix crash when plugging a piix3-ide device into the x-remote machine

QEMU currently crashes when the user tries to do something like:

 qemu-system-x86_64 -M x-remote -device piix3-ide

This happens because the "isabus" variable is not initialized with
the x-remote machine yet. Add a proper check for this condition
and propagate the error to the caller, so we can fail there gracefully.

Message-Id: <20210416125256.2039734-1-thuth@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/hw/ide/ioport.c b/hw/ide/ioport.c
index b613ff3bba..e6caa537fa 100644
--- a/hw/ide/ioport.c
+++ b/hw/ide/ioport.c
@@ -50,15 +50,19 @@ static const MemoryRegionPortio ide_portio2_list[] = {
     PORTIO_END_OF_LIST(),
 };
 
-void ide_init_ioport(IDEBus *bus, ISADevice *dev, int iobase, int iobase2)
+int ide_init_ioport(IDEBus *bus, ISADevice *dev, int iobase, int iobase2)
 {
+    int ret;
+
     /* ??? Assume only ISA and PCI configurations, and that the PCI-ISA
        bridge has been setup properly to always register with ISA.  */
-    isa_register_portio_list(dev, &bus->portio_list,
-                             iobase, ide_portio_list, bus, "ide");
+    ret = isa_register_portio_list(dev, &bus->portio_list,
+                                   iobase, ide_portio_list, bus, "ide");
 
-    if (iobase2) {
-        isa_register_portio_list(dev, &bus->portio2_list,
-                                 iobase2, ide_portio2_list, bus, "ide");
+    if (ret == 0 && iobase2) {
+        ret = isa_register_portio_list(dev, &bus->portio2_list,
+                                       iobase2, ide_portio2_list, bus, "ide");
     }
+
+    return ret;
 }