hw/audio: Fix crashes when devices are used on ISA bus without DMA

The cs4231a, gus and sb16 sound cards crash QEMU when the user tries
to instantiate them on a machine with DMA-less ISA bus (for example
with "qemu-system-mips64el -M mips -device sb16"). Add proper checks
to the realize functions to avoid the crashes.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1521193892-15552-4-git-send-email-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 20 insertions, 4 deletions

diff --git a/hw/audio/cs4231a.c b/hw/audio/cs4231a.c
index 096e8e98d7..aaebec1839 100644
--- a/hw/audio/cs4231a.c
+++ b/hw/audio/cs4231a.c
@@ -28,6 +28,7 @@
 #include "hw/isa/isa.h"
 #include "hw/qdev.h"
 #include "qemu/timer.h"
+#include "qapi/error.h"
 
 /*
   Missing features:
@@ -663,8 +664,13 @@ static void cs4231a_realizefn (DeviceState *dev, Error **errp)
     CSState *s = CS4231A (dev);
     IsaDmaClass *k;
 
-    isa_init_irq (d, &s->pic, s->irq);
     s->isa_dma = isa_get_dma(isa_bus_from_device(d), s->dma);
+    if (!s->isa_dma) {
+        error_setg(errp, "ISA controller does not support DMA");
+        return;
+    }
+
+    isa_init_irq(d, &s->pic, s->irq);
     k = ISADMA_GET_CLASS(s->isa_dma);
     k->register_channel(s->isa_dma, s->dma, cs_dma_read, s);
 
diff --git a/hw/audio/gus.c b/hw/audio/gus.c
index 3e864cd36d..8e0b27e0f2 100644
--- a/hw/audio/gus.c
+++ b/hw/audio/gus.c
@@ -241,6 +241,12 @@ static void gus_realizefn (DeviceState *dev, Error **errp)
     IsaDmaClass *k;
     struct audsettings as;
 
+    s->isa_dma = isa_get_dma(isa_bus_from_device(d), s->emu.gusdma);
+    if (!s->isa_dma) {
+        error_setg(errp, "ISA controller does not support DMA");
+        return;
+    }
+
     AUD_register_card ("gus", &s->card);
 
     as.freq = s->freq;
@@ -272,7 +278,6 @@ static void gus_realizefn (DeviceState *dev, Error **errp)
     isa_register_portio_list(d, &s->portio_list2, (s->port + 0x100) & 0xf00,
                              gus_portio_list2, s, "gus");
 
-    s->isa_dma = isa_get_dma(isa_bus_from_device(d), s->emu.gusdma);
     k = ISADMA_GET_CLASS(s->isa_dma);
     k->register_channel(s->isa_dma, s->emu.gusdma, GUS_read_DMA, s);
     s->emu.himemaddr = s->himem;
diff --git a/hw/audio/sb16.c b/hw/audio/sb16.c
index 31de264ab7..5a4d32364e 100644
--- a/hw/audio/sb16.c
+++ b/hw/audio/sb16.c
@@ -1371,6 +1371,13 @@ static void sb16_realizefn (DeviceState *dev, Error **errp)
     SB16State *s = SB16 (dev);
     IsaDmaClass *k;
 
+    s->isa_hdma = isa_get_dma(isa_bus_from_device(isadev), s->hdma);
+    s->isa_dma = isa_get_dma(isa_bus_from_device(isadev), s->dma);
+    if (!s->isa_dma || !s->isa_hdma) {
+        error_setg(errp, "ISA controller does not support DMA");
+        return;
+    }
+
     isa_init_irq (isadev, &s->pic, s->irq);
 
     s->mixer_regs[0x80] = magic_of_irq (s->irq);
@@ -1389,11 +1396,9 @@ static void sb16_realizefn (DeviceState *dev, Error **errp)
     isa_register_portio_list(isadev, &s->portio_list, s->port,
                              sb16_ioport_list, s, "sb16");
 
-    s->isa_hdma = isa_get_dma(isa_bus_from_device(isadev), s->hdma);
     k = ISADMA_GET_CLASS(s->isa_hdma);
     k->register_channel(s->isa_hdma, s->hdma, SB_read_DMA, s);
 
-    s->isa_dma = isa_get_dma(isa_bus_from_device(isadev), s->dma);
     k = ISADMA_GET_CLASS(s->isa_dma);
     k->register_channel(s->isa_dma, s->dma, SB_read_DMA, s);